MICH {GI-‘9! STATE L' N EVERSITY EAST LA£‘453NG, LEECHIGAN ABSTRACT SYNTHESIS AND STUDY OF DECOMPOSITION RATES OF SOME BIS(THENOYL)-PEROXIDES by Fred Martin Gruen This study concerns the effects of various substituents on the rates of decomposition of substituted bis(thenoyl)peroxides. Interest in the rates and mechanisms of decomposition of the thenoyl peroxides is based on the possible feasibility of using these compounds commercially as initiators of free radical type polymerizations, or as catalysts in other polymerization processes. The investigation involved a) the first syntheses and characteriza- tion of thenoyl chlorides, and bis thenoyl peroxides, and b) comparisons of the rates of decomposition of the peroxides as affected by (or governed by) the substituted groups. The prepared thenoyl peroxides, all of which are derivatives of 2— and 3-thenoic acids, are listed in Table I. As intermediates in preparing the peroxides, the following acid chlorides were prepared for the first time: S-bromo-B-thenoyl chloride S-chloro-3-thenoyl chloride 3-methyl—2-thenoyl chloride S-nitro-B-thenoyl chloride 2,5-dichloro-3-thenqyl chloride b,5—dibromo-2-thenqyl chloride S—ethyl-b-bromo-2-thenoyl chloride S-phenyl-2-thenoyl chloride 2,5-dimethyl—3-thenoyl chloride. The general method of preparing the thenoyl peroxides was to add the appropriate thenoyl chloride, dissolved in a suitable solvent to an ice cold aqueous solution of sodium peroxide, and to let the mixture Fred Martin Gruen stand until the reaction was completed. The formed, solid material was filtered off, washed with ice water and the product purified by recrystallization from an organic solvent. The thenoyl peroxide decomposition rate determinations were carried out in a carbon tetrachloride solution, with the exception of the de- composition of bis(S—nitro-B-thenoyl)peroxide, which was insoluble in this solvent; the solvent used for this latter compound was chloroform. Styrene was employed with all peroxide decomposition rate determinations as a free radical scavenger, to eliminate induced decomposition and make certain that only the spontaneous thermal decomposition would be occur- ring. Infrared spectroscopy was employed as an analytical tool, the ”peroxide peak" at a wavelength of 5.7 microns being observed. The absorption peak intensity was used as a measure of the concentration of peroxide remaining after various reaction periods, at a specific temperature, for each kinetic run. The absorption coefficient A equal to log Io/I was computed, where I was the distance of the peak from some arbitrary zero line, and ID the distance of the base line from the same arbitrary line. The logarithm of A was then plotted against the time, in order to obtain first order rate constants. The rate constvms and corresponding half lives obtained, at 79.60, for the various peroxides investigated are given in Table I. These data indicate that, in general, electron releasing substituents tend to increase the decomposition rate, whereas electron attracting groups de— crease the rate with one exception; that one being the peroxy compound bearing the nitro-group as a substituent. Fred Martin Gruen Table I. Rate constants and corresponding half lives obtained for the various peroxides investigated. Peroxide k x 103 (min.-1) Tl/2 (min.) Bis(5-bromo-3-thenoyl) 2.031 381.2 Bis(5-chloro-3-thenoyl) 1.862 372.b Bis(3-methyl—2-thenoyl) 2.699 256.7 Bis(5-nitro-3-thenoyl) 5.889 118.5 Bis(5-ethyl-h-bromo-2-thenoyl) 3.120 222.1 Bis(2,5-dichloro—3-thenoyl) 1.681 h12.3 Bis(5'phenyl-2—thenoyl) 8.580 80.8 Bis(2,5-dimethyl-3-thenoyl) 3.789 182.9 Bis(2-thenoyl)* 2.550 271.8 Bis(3-thenoyl)* 2.360 293.6 *For comparison (10). Activation energies were obtained by plotting the logarithms of the rate constants against the reciprocal of the absolute temperature. It was found that they varied over a rather wide range, from 20.135 kilocalories per mole for bis(5-chloro-3—thenoyl)peroxide to 38.180 kilo- calories per mole for bis(5—phenyl-2-thenoyl)peroxide. The entropies of activation were calculated and it was found that they varied from -22.22 entropy units for the first of the above mentioned compounds to plus 29.72 entropy units for the latter compound mentioned. It is significant that a plot of the entropies of activation against energies of activation gives a straight line, indicating the possibility of an "isokinetic" reaction series for the sulfur heterocyclic peroxides studied in the present investigation. SYNTHESIS AND STUDY OF DECOMPOSITION RATES OF SOME BIS-(THENOYL)~PEROXIDES By Fred Martin Gruen A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF‘PHILOSOPHY Department of Chemistry 196A VITA Fred Martin Gruen Candidate for the Degree of Doctor of Ph11050phy Major Subject: Organic Chemistry Minor Subjects: Inorganic and Biological Chemistry Biographical Data: Date of Birth: February b, 1915 in Nuernberg, Germany Education: Study at University of Pavia, Italy B.S. in Chemistry, The City College, New York, N.Y., 19h8 M.S. in Organic Chemistry, Illinois Institute of Technology, Chicago, Ill. 1950 Additional Graduate Study: Michigan State University, 1952-1968 EXperience: Graduate Assistant: Illinois Institute of Technology 1988-1950 Instructor of Chemistry, Buena Vista College, Storm Lake, Iowa, Summe r l 950 Research Chemistry, Schering Corporation, Bloomfield,New Jersey, 1950-1951 Chairman of Department of Chemistry, Olivet College, Olivet, Mich., 1951 to date. Professional Affiliations: 'American Chemical Society The Society of Sigma Xi Phi Kappa Phi ACKNOWLEDGMENT The author wishes to express his gratitude to Dr. Robert D. Schuetz for his faithful guidance throughout the course of this investi- gation. Thanks are also expressed to the National Science Foundation, to Research Corporation, and the Administration of Olivet College for their financial support. Special recognition goes to the author's own students, particularly to Mr. Delos R. Byrne and Mr. Richard L. Brennan for their devoted ef- forts and invaluable interest in the pursuit of this study. ii To My Wife Marian TABLE OF CONTENTS INTRODUCTION AND HISTORICAL . EXPERIMENTAL . . . . . . . . . . . . . . . . . . Chemical Reagents and Apparatus . . . Syntheses . . . . . . . . . . . . . . 3-Bromothiophene 3- -Thenoic Acid . 5- Bromo- -3- thenoic Acid 5- Chloro- -3- -thenoic Acid . 5-Nitro-3-thenoic Acid ‘2-Acety1thiophene . 2- Thenoic Acid . h, 5- Dibromo- 2- thenoic Acid 3-Bromothiophene from h, 5- Dibromo- 2- thenoic Acid 3-Acety1- -2 ,5 -dichlorothiophene . . . . . . . . 2 ,5- Dichloro-3-thenoic Acid . . . . 2-Thena1 . . . . . . . 2- -Methylthiophene . . 3, 5- Dibromo- 2- -methy1thi0phene . 3- -Bromo- 2-methy1thiophene . 2-Methy1- -3- -thenoic Acid . 2- -Ethy1thiophene . 3, 5- Dibromo- 2- -ethy1thiophene 3-Bromo-2-ethy1thiophene Attempted Preparation of 2- -Ethy1- -3- thenoic Acid . 3- -Methyl- -2- thenoic Acid . Preparation of the Thenoyl Chlorides . 5- Bromo- 3- -thenoy1 Chloride Bis(5-bromo-3-thenoyl)peroxide Bis(5-chloro-3-thenoyl)peroxide . Bis(3-methy1-2-thenoyl)peroxide . Isopropyl- -2- -thieny1 Ketone . . . 2- -Isobuty1thiophene . . 5- -Isobutyl- -2- -acety1thiophene . . . . 5- -Isobuty1- -9 thenoic Acid . . . . . . Bis(2, 5- dichloro- -3- -thenoyl)peroxide . Bis(h, 5- dibromo- -3- -then0y1)peroxide Bis(5-pheny1- 2-thenoy1)per0xide . . Bis(9 -ethy1- -b- bromo- 2- thenoyl)peroxide 2 ,5- -Dimethy1- 3-acetylthiophene . 2 ,5 -Dimethyl- -3- thenoic Acid . . . Bis(2, 5- -dimethyl- 3- -thenqyl)peroxide . Analytical Procedures for the Determination of the Purity of the Peroxides Kinetic Determinations . . . . . . . . . . . . . . iv TABLE OF CONTENTS (Cont.) PAGE DummsRMTWDREmrB . ... ... ... ... ... ... L6 SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . 58 APPENDIX 61 TABLE II. III. IV. LIST OF TABLES Rate constants and half lives for the decomposition of substituted thenoyl peroxides at 79.60 Bis(thenoyl)peroxides . Preparation of thenoyl chlorides List of peroxides prepared V.-XXVIII. Spectr0500pic information leading to kinetic data XXIX. XXX. Summary of kinetic data for the thenoyl peroxides . Calculation of entropies of activation vi PAGE 29 A 30 37 AS . 62-86 87 89 FIGURE 10. 11. 13. 18. 15. LIST OF FIGURES Infrared spectrum of bis(3-methyl-2-thenoy1)peroxide . Infrared spectrum of bis(2,5-dichloro-3-thenoyl)peroxide Infrared spectrum of bis(5-pheny1-2-thenoy1)peroxide . Infrared spectrum of bis(2,5-dimethy1-3-thenoyl)peroxide Quantitative infrared spectra on the decomposition of bis(5-bromo-3-thenoy1)per0xide Quantitative infrared spectra of the decomposition of bis(3-methyl-2-thenoy1)peroxide . Quantitative infrared spectra of the decomposition of bis(3-methyl-2-thenoy1)peroxide . Quantitative infrared spectra of the decomposition of bis(h-bromo-S-ethy1-3-thenoy1)peroxide Quantitative infrared spectra of the decomposition of bis(h-bromo-S-ethy1-2-thenoy1)peroxide Quantitative infrared spectra on the decomposition of bis(5-ethyl-b-bromo-2-thenoy1)peroxide Quantitative infrared spectra on the decomposition of bis(2,5-dich10ro-3-thenoyl)peroxide . Quantitative infrared spectra on the decomposition of bis(2,5-dichloro-3-thenoy1)peroxide . Energy of activation of bis(5-pheny1-2-thenoyl)peroxide. Energy of activation of bis(2,5-dimethy1-3-thenoy1) peroxide. . . . . . . . . . . . . . . . . . . . . Plot of energy of activation versus entropy of activation vii PAGE 91 92 93 9b 95 96 97 98 99 100 101 102 103 10h INTRODUCTION AND HISTORICAL Organic peroxides have been of both theoretical and practical interest to the chemist for quite some time. The oxygen-oxygen bond being relatively weak (36.0 kcal. mole—1), is capable of fission by thermal and photochemical methods with relative ease. Evidence of the interest in peroxides of this type is the 196A symposium "Development, Stabilization and Uses of Organic Peroxides"(1). One of the papers by Guillett was of particular interest and value because of its relation to the present work. This paper dealt with the determination of decompo- sition rates of diacyl peroxides and presented clear evidence that the relative stabilities of aliphatic and aromatic peroxides are, Alkyl-Peroxides > Aromatic Acyl Peroxides > Aliphatic Acyl Peroxides. The aromatic and hetero aromatic acyl peroxides, such as benzoyl, furoyl, and thionyl peroxides apparently occupy a middle position in this stabil- ity series. This behavior may eventually add to their importance as initiators of free radical type polymerizations, which occupy an import- and place in present industrial chemistry. It was brought out repeatedly during the symposium, that a careful study of the decomposition rates and mechanisms of as many of these compounds as is feasible should pro- vide a sound basis for the choice of catalysts and optimum reaction temperatures for use in polymerization processes. 2 The only compound in the aromatic acyl peroxide group which had been studied originally in any detail was benzoyl peroxide. It ap- peared that, whereas the decomposition of di-t-butyl peroxide followed a strictly first order rate law, the kinetics of the thermal decomposi- tion of benzoyl peroxide was much more complex. Brown (2) demonstrated that at least two simultaneous reactions were occurring in the decomposi- tion of the aromatic acyl peroxide, one exhibiting first order kinetics, the other following a rate law of an order higher than first. Product analysis, as reported by Erlenmeyer and Schwenauer (3) substantiated Brown's hypothesis. An initial fission of the peroxide linkage result- ing in benzoyl free radicals was postulated by Hey and Waters (h), with secondary reactions initiated by the acyl radicals initially formed lead- ing to complications in the kinetic results. Bartlett and Nozaki (5) soon after interpreted the results of kinetic experiments by considering the overall reaction to consist of the sum of a spontaneous cleavage of the peroxide into acyl radicals followed by a radical induced chain re- action, the rate of which was different from first order and varied greatly with the reaction solvent. Kinetic orders varying from 0.5 to 2.0 were observed. The spontaneous cleavage, on the other hand, appeared to vary very slightly with the solvent employed. Attempts were made to kinetically isolate the spontaneous cleavage from the radical induced chain reaction by the addition of suitable inhibitors, such as oxygen, hydroquinone, p—t-butyl catechol or methyl methacrylate. Swain, Stock- mayer, and Clarke (6) found that 3,h-dich10rostyrene and methyl methacry- late would suppress the induced reaction to such an extent as to make the overall reaction rate practically identical with the rate of spontaneous cleavage of the oxygen-oxygen bond. The effectiveness of these inhibitors, was demonstrated by the observation that the half life of a 0.05 M benzoyl peroxide was 23 minutes at 800 in the absence of inhibitors, but 275 min- utes, or approximately twelve times as long, in the presence of 0.2 M, styrene, 2,h-dichlorostyrene, 1,h-diphenyl butadiene, or acrylonitrile. variations in the rate with different solvents in the presence of the above inhibitors was found to be negligible, e.g. the specific rate constant for the decomposition was found to be b.3 x 10.3 min.-1 in benzene (6), and b.32 x 10_3 min.—1 in acetophenone (7), both determined at 80°. If one considers the wide difference in polarity of the two solvents, these results show clearly both the relative independence of the reaction from the solvent, and the absence of polar steps in the reaction mechanism. An interesting study has been reported on the relative effect of substituents on the rate of the decomposition reaction of symmetrically substituted bis(benzoy1)peroxides. Swain and his coworkers (6) as well as Blomquist and Buselli (7) found that the Hammett equation (8) is rather well obeyed for meta and para substituted benzoyl peroxides. A reaction constant S’ of -0.38 indicates that the spontaneous cleavage reaction is favored by high electron density at the reaction site and thus, electron releasing substituents such as alkyl groups should ac— celerate the process, whereas electron attractors, such as the halogens and nitro substituents should retard the decomposition. The small value of the rho would indicate a relatively low susceptibility of this reac— tion to electronic effects (9). In these laboratories Schuetz and hiscxfllaborators have extended these studies to the hetero aromatic systems, specifically to the u derivatives of thiophene. In such systems two series of peroxides could be prepared and investigated; those derived from 2-thenoic acid and those prepared from 3-then0ic acid. The only peroxide reported prior to the work of Schuetz and his coworkers (10) was bis(2-thenoyl-) peroxide which had been prepared by the Austrian chemists Breitenbach and Karlinger (11) for use as an initiator in the free radical polymer- ization of styrene. These investigators synthesized the peroxide by the interaction of hydrogen peroxide and 2-thenoy1 chloride in pyridine as a solvent. Schuetz and Teller (12) prepared a total of ten deriva- tives of bis(2-thenoy1) peroxide, as well as the unsubstituted bis(3- thenoyl)peroxide, using aqueous sodium peroxide which was allowed to react with the corresponding acid chloride dissolved in a dry inert organic solvent such as toluene or cyclohexane. This procedure had been originally used by Price and Krebs (13) in the preparation of bis- (p-nitrobenzoyl)peroxide. It is this experimental procedure which was employed, at times with some variation, in the present work for the synthesis of the peroxides described in the present study. The peroxides studied by Schuetz and Teller were in the main derivatives of bis(2- thenoyl)peroxide with substituents in the 5-position. Their work also included two sulfur heterocyclic peroxides having substituents (bromo and methyl respectively) in the h-position. The decomposition reaction rates for these compounds were determined kinetically at three different temperatures in carbon tetrachloride as a reaction media. Reaction rates were followed by analyzing for unreacted peroxide employing the iodometric determination of the peroxide linkage. Activation energies were estimated by plotting the logarithm of the rate constants against the reciprocal of the absolute temperature. The inhibitor, 3,h—dichlor0styrene 5 was used as a free radltal scavenger, and under these experimental con- ditions it was found that the first order rate law.was obeyed for all the peroxides studied except for the case of bis(5-nitro-2-thenoyl)per- oxide. It was also determined that for these compounds the Hammett equation was followed reasonably well; a plot of‘Qf’l +-Q§’2 against log k gave rho values close to -0.hh. It was noted by Tellen however, that the activation energy was remarkably constant for all the peroxides of the parent and substituted 2-thenoic acids studied, at a value of 29.3 kcal. mole-1. This points to a variation in the frequency factor, which in turn indicated that the Hammett equation can only be obeyed approximately for these heterocyclic peroxides (lb). The reaction con- stant rho of -0.hh, as obtained by Schuetz and Teller compares well with that obtained by Blomquist and Buselli (7) for the m- and p-substituted benzoyl peroxides; it is interesting to note that Jaffe (15) in his re- view article reports -0.20 as a value of rho for the decomposition of substituted benzoyl peroxides. The present study was undertaken to extend the investigation of heterocyclic peroxides to include, a. derivatives of substituted 3-thenoic acids, b. peroxides‘comparable to ortho substituted benzoyl deriva- tives, and c. a phenylated thenoyl peroxide. The preparation of these compounds, especially of those derived from 3-thenoic acid, presented some difficult synthetic problems. The parent acids of this series are not as readily accessible as are the 2-thenoic acids. This is due to the fact that the alpha positions in thi0phene are considerably more active toward aromatic electrophilic 6 substitution than are the beta positions. All beta derivatives have therefore to be prepared by indirect methods, usually involving several steps, and consequently lower over-all yields. Several improvements in these synthetic methods have been developed during the preparation of these compounds. To indicate only a few: Dodson (16) had prepared 3- bromothiophene, an important intermediate in the synthesis of 3-thenoic acid and its derivatives, from 2,5-dibromothiophene through a bromina- tion-debromination reaction sequence with an overall yield of 35%. In the present work by careful control of experimental conditions in each it was possible to increase the yield, following essentially the analo— gous procedure, to an overall yield of 71%. The nitrile synthesis of 3-thenoic acid from 3-bromothiophene reported by Nishimura, Motoyama and Imoto (17) with an overall yield of 68%, has been increased in this study to 85% by eliminating the purification of the intermediate 3- thenonitrile. Attempts to prepare 2-ethy1-3-thenoic acid failed, when 2-ethyl-3-bromothiophene was allowed to react with a lithium Grignard (n-butyl-lithium) at -70°. The only acid that could be isolated, in relatively small yield, was 5-ethyl-8-bromo-2-thenoic acid. A peroxide was prepared and studied from this latter acid instead of from the one originally desired. 0n the suggestion of Schuetz and Shea of these laboratories the analytical procedure used by Schuetz and Teller in their initial studies of thi0phene peroxide was not employed in the present work. The analytical kinetic results were determined from infrared spectra. Shea (18) used infrared techniques successfully in his study of the decomposition rates of t—butyl perthenoates. His help in acquainting the author with the experimental techniques needed for 7 this study is herewith gratefully acknowledged. The iodate titration analytical technique was only used for assaying the purity of the per- oxides; all kinetic data were obtained by infrared techniques, and are described in the experimental portion of the thesis. EXPERIMENTAL Chemical Reagents and Apparatus The solvent carbon tetrachloride used in the kinetic determinations was purified by a method slightly modified from that described by Teller (12). A two liter quantity of C.P. grade carbon tetrachloride was heated at 60° for 30 min., with an alkaline solution prepared by dissolving 20 g. (0.357 mole) of potassium hydroxide in a mixture of 150 m1. of ethyl alcohol (95%) and 150 ml. of water. This alkaline treatment was repeated; the carbon tetrachloride layer was separated and washed thoroughly with water to remove the ethyl alcohol. It was then shaken with 50 ml. por-v tions of concentrated sulfuric acid until only a very faint ivory colored tinge remained in the acid layer. The sulfuric acid was then removed by washing with water; the carbon tetrachloride was dried in contact with potassium hydroxide pellets and finally distilled from the solid base using a 12 in. Vigreux column. The chloroform employed in the rate determinations of the decomposi— tion of bis(5—nitro-3-thenoyl)peroxide only, was purified by washing 2 liters of C.P. chloroform with small portions of concentrated sulfuric acid, until no yellow color was observable in the acid layer; the chloro- 'form layer was subsequently washed with water to remove the sulfuric acid, and dried with anhydrous calcium chloride. The chloroform was then distilled from phosphorus pentoxide using a 12 in. Vigreux column. The styrene, employed as a radical trap, in the kinetic determination, 'was Eastman Kodak, white label brand, containing t—butylcatechol as a stabilizer. It was vacuum distilled, and then stored in the refrigerator, 9 in a brown bottle, without an inhibitor. The toluene, cyclohexane, and benzene used in the preparation of the various peroxides were C.P. grade; they were dried in contact with anhydrous calcium chloride. The 2,5-dibromothiophene was "practical" grade and purchased from the Eastman Kodak Corporation; 2,5-dimethylthiophene was a product of the Aldrich corporation; thi0phene and 3-methy1-2-acetylthi0phene were purchased from the Pennsalt Corporation. All these materials were used directly in the eXperimental work without any further purification. The 2,5-dichlorothiophene and 5-phenyl-2-thenoic acid were furnished to us by Dr. Schuetz of the Department of Chemistry, Michigan State Uni- versity; these materials were also used without purification. Thionyl chloride, practical grade, was purchased from Matheson, Coleman and Bell, and distilled at atmospheric pressure immediately prior to use. Dimethylformamide was purchased from Eastman Kodak Company, as their white label product. Phosphorus oxychloride was a Baker Product, Analytical Reagent. Sodium peroxide was purchased from Mallinckrodt Company, their best Analytical Reagent Product. All melting points were determined on a Fisher-Jones melting point apparatus and are reported uncorrected. 3-Bromothiophene The method used here differed slightly in detail from that re- ported by Gronowitz (19); it was originally used at Michigan State University by Dodson (16), but the yields obtained in the present work were somewhat improved. 10 To a 885 g. (2 moles) quantity of 2,5-dibromothiophene contained in a 1 l. three-necked flask fitted with condenser, dropping funnel, and mechanical stirrer, were added, with vigorous stirring, 332 g. (2.2 moles) of bromine during an hour while the reaction flask was cooled by immer- sion in an ice-bath. The reaction solution was stirred for an additional 3 hrs. without external cooling. During, and following the addition of the bromine copious quantities of hydrogen bromide were evolved. The reaction solution was set aside at room temperature overnight (16 hrs.) without stirring. To the cooled solution was added methanolic potassium hydroxide (120 g. of potassium hydroxide pellets dissolved in 250 m1. of methanol). The alkaline mixture was heated to and held at its reflux temperature for 3 hrs., and then exhaustively steam distilled to isolate the crude product. The yellow oil was separated from the water (approximately 615 g.) and transferred to a 3 1. three-necked flask fitted with a mechanical stirrer and reflux condenser. To the oil were added, 320 ml. of glacial acetic acid, 1,200 m1. of water, and 235 g. of metallic zinc dust. The latter was added carefully in small quantities through a powder funnel. An initial spontaneous exothermic reaction occurred, which raised the reaction mixture's temperature to its reflux point. This subsided in about 80 min. and the mixture was then held at this temperature for an additional 18 hrs. by the application of external heat. The mixture was then steam distilled using a 6 in. Vigreux column until the vapor temperature in the distillation head reached 103°. The light colored oily product was separated, dried in contact with anhydrous calcium chloride, and redistilled at atmospheric pressure to obtain a pure product boiling at 156-1600, n50 1.5915, yield: 237.8 g. (1.82 moles, 71%). ll 3-Thenoic Acid Two different experimental procedures were used in converting 3- bromothiophene to 3-thenoic acid. The first of these suggested by Zabik at Michigan State University (20) and also employed by Gronowitz (21) with slight modifications was used in the preparation of about half the 3-thenoic acid used in the present work. A 500 m1. three-necked flask was equipped with a mechanical stir— rer, an adapter carrying a -100° thermometer and a dropping funnel. A 100 ml. volume of anhydrous ether was introduced into the flask, and 6.8 g. (0.98 mole) of finely cut lithium metal added to the ether. A calcium chloride tube was placed on top of the dropping funnel and a solution containing 61.6 g. (0.85 mole) of n-butyl bromide dissolved in'60 ml. of anhydrous ether was placed in the dropping funnel. About 10 ml. of this solution was admitted to the reaction flask. The stirrer was then started and after a few minutes the reaction mixture became cloudy with spots appearing on the lithium metal indicating that reaction had been initiated. The reaction temperature was lowered to -10 - -20° by means of a dry-ice-isopropyl alcohol bath, and the remainder of the g-butyl-bromide solution was added at a constant rate during an hour, after which the solution was stirred for an additional two hours, while the temperature was allowed to rise to 10°. The B-butyl lithium solu- tion, colored an intense violet, was then filtered through glass wool into a l l. three-necked flask equipped with a stirrer and dropping funnel, which had been precooled to -700 by means of a dry-ice-acetone bath. The remaining neck in the reaction flask was fitted with a -100 - 0° thermometer. An additional 300 ml. of anhydrous ethyl ether was 12 added to the E-butyl lithium solution, and it was cooled to -70°. In the dropping funnel was placed a solution containing 52.2 g. (0.32 mole) of 3-bromothiophene dissolved in 320 ml. of anhydrous ether. This solu- tion was run into the stirred reaction mixture in a steady stream, while the reaction temperature was carefully maintained at -70° (30 min.). Following the addition of the bromothiophene the reaction mixture was stirred for an additional 3 hrs. at -70°, and then it was poured over powdered dry ice. At this point the solution changed color from purple to white. The carbonated mixture was then allowed to warm to 0° and then a mixture of 200 ml. of 6 N hydrochloric acid and 100 g. of ice was added to it. A white precipitate formed in the water layer, which redissolved in the ether layer on stirring. The ether layer was then separated and the water layer extracted twice with 200 ml. portions of ether. The combined ether layers were extracted with 250 ml. of 2 N sodium hydroxide solution. The aqueous alkaline layer was separated and acidified with 6 N hydrochloric acid at 0°. A white precipitate formed, which was recovered by filtration and washed with 50 ml. of ice—cold water. The crude solid was recrystallized from hot water, to obtain 38 g. (0.27 mole) of 3-thenoic acid, m.p. 135-36°. From the filtrate there was isolated an additional 3 g. of acid, total yield 37 g. (0.29 mole, 90%). The second method used is that reported by Nishimura, Motoyama and Imoto (17), based on 3-cyanothiophene. In a 500 m1. single necked reaction flask fitted with two efficient reflux condensers fitted on top of one-another there were added 28.8 g. (0.18 mole) of 3-bromothiophene, 20 g. of cupruous cyanide and 120 ml. of quinoline. The mixture was first heated slowly and cautiously. It was observed that the initially 13 yellowish green heterogenous mixture slowly changed its color to a canary yellow, in about a half hour. Violent bumping of the reaction mixture was evident during this period, but the reaction remained under control throughout this period. The reaction mixture was held at its reflux temperature an additional 3 hrs., and it was then vacuum distilled without prior cooling, to avoid solidification. Approximately 100 ml. of distillate was collected. Acidification of the distillate with 1:1 hydrochloric acid, caused a yellowish orange oil to separate from the reaction mixture. This was extracted with ether and the ex- tract washed once with 1:1 hydrochloric acid and three times with water. The ethereal solution was dried in contact with anhydrous sodium sul- fate. After removal of the ether on a water bath, there remained 18 g. of crude 3-cyanothiophene as an oil. This material was not further purified, yield, 18g. (0.165 mole, 93%). A mixture of 18 g. of crude 3-cyanothiophene and 360 ml. of concen- trated hydrochloric acid (ap. gr. 1.19) was placed in a single necked 1 l. flask, fitted with two efficient reflux condensers above one another, and heated at its reflux temperature for 3.5 hrs. The top of the reflux condensers was fitted with a sodium hydroxide trap to neutralize the evolving hydrogen chloride gas. After the 3.5 hrs. of heating at its reflux temperature the mixture was cooled very slowly. Within minutes long white needle like crystals began to form. The crystals were separated from the mother liquor by filtration. The mother liquor was extracted with ether, dried and the ether removed to obtain additional quantities of product. Total yield, 18.7 g. (0.187 mole) of 3-thenoic acid (83.85%), m.p. 136-370, literature value, m.p. 137-380 (22). 18 5-Bromo-3-Thenoic Acid The method of Campaigne and Bourgeous (23) was employed in the preparation of this acid. A solution containing 9.2 g. (0.058 mole) of bromine dissolved in 85 m1. of glacial acetic acid was carefully added at room temperature, from a dropping funnel, to a stirred solution of 7.6 g. (0.060 mole) of 3-thenoic acid dissolved in 70 ml. of glacial acetic acid. The mixture was stirred for 15 min. at room temperature, and then poured into 800 m1. of ice-cold water. The white precipitate was recovered by filtration, washed with cold water and recrystallized from hot water, yielding 9.0 g. (0.835 mole, 72%) of a white crystalline product, m.p. 138-80°. Literature value (23) 180-1820. 5-Chloro-3-Thenoic Acid The method of Campaigne and Bourgeois (23) was again used, with slight modifications, to obtain this acid. The quantity 30 g. (0.230 mole) of 3-thenoic acid was dissolved in a liter of glacial acetic acid, and chlorine gas was bubbled through the previously tared solu- tion, until the weight increase amounted to 16 g. (0.23 mole of chlorine). After being set aside a few minutes the mixture was poured into three liters of ice water and stirred for a few minutes. A snowy white, fluffy precipitate was obtained immediately. The mixture was allowed to remain in the refrigerator overnight. The crystals formed were separated by filtration and the mother liquors were extracted with ether. Recrystallization of the original crystalline material, as well as of the solid material obtained from the ether extract, yielded 18.0 g. (0.086 mole, 37.3%) of a white, crystalline product, m.p. 158-56°. Literature value (23) l56-57°. 15 5-Nitro-3-Thenoic Acid This acid was also prepared according to the procedure suggested by Campaigne and Bourgeois (23). A mixture of 80 m1. of conc. nitric acid (sp. gr. 1.82) and 11.5 ml. of conc. sulfuric acid was mechanically stirred in a tall beaker and cooled to -10° by means of a dry-ice iso- propanol bath. The temperature of the acid mixture was maintained at -5°, while 20 g. (0.156 mole) of 3-thenoic acid were added in small portions. The reaction mixture was then poured into ice-water and steam distilled to remove any unreacted 3—thenoic acid. The residual liquid crude acid was separated from the steam distillation flask. It solidified on cooling, weight 20.0 9. (0.0115 mole, 78.0%). A 3 g. quantity was recrystallized from benzene, m.p. 188-86°. Literature value (23) 185-60. 2-Acety1thiophene The method of Hartough and Kosak(23a) was employed in the prepara- tion of this material. A stirred solution containing 508 g. (6.0 moles) of thiophene and 238 g. (2.2 moles) of acetic anhydride was heated to 70° in a two-liter three-necked flask equipped with a dropping funnel, stirrer and thermometer, and 20 g. of 85% ortho-phosphoric acid were added to this mixture during a period of 15 min. There was a slight rise in reaction temperature during the initial addition of the acid, and external cooling, with an ice-bath, was essential, to hold the temper- ature at 88 - 90°. The reaction mixture was then heated to its reflux temperature (96°) for 2 hrs. A 800 m1. volume of water was then added. The mixture was stirred for an additional 25 min. The organic layer was separated, washed with 800 m1. of a 10% sodium carbonate solution, 16 and then three times with 800 ml. portions of water. Drying was not necessary, as the thi0phene water azeotrope would distill at 68°, followed by practically pure thiophene; the fraction boiling at 88° was collected. The residue was distilled using a 6 in. Vigreux column to obtain 238 g. (1.88 moles, 98%) of 2-acety1thiophene b.p. 79.5° (6 mm.). Literature value (29a)77° (8mm.). 2-Thenoic Acid The method of Hartough and Conley (28) was employed to convert 2-acetylthiophene to 2-thenoic acid. A solution was prepared contain- ing 880 g. (11.0 moles) of sodium hydroxide dissolved in 600 ml. of water. A 2,500 9. quantity of chipped ice was weighed directly into the alkaline solution, contained in a 8 1. beaker. This was tared and 332 g. (8.68 mole) of chlorine gas was allowed to flow into the solu- tion from a cylinder, employing two gas addition tubes, linked through a T-type joint. The sodium hypochlorite solution was then warmed on a water bath to 60-62° and rapidly transferred to a 5 1. flask (three- necked) equipped with dropping funnel, stirrer and two reflux condensers placed vertically on top of one another. The flask was then immersed in a cooling bath and 126 g. (1.0 mole) of acetylthiophene were added from the dr0pping funnel at a rate as to maintain the reaction tempera- ture between 65-72°. Emission of chloroform in rather copious quanti- ties could be observed. Following the addition of the acetylthiOphene - stirring was continued for an additional 3 hrs., until the reaction temperature had dropped to 25-300, without the aid of external cooling. The excess hypochlorite was destroyed by the addition of a solution of sodium bisulfite (100 g. of salt to 200 m1. of water). The solution was 17 transferred to a 8 l. beaker and carefully acidified with conc. hydro- chloric acid (sp. gr. 1.19). The crude product was collected on a Buchner funnel and recrystallized from 1200 ml. of hot water. The mother liquor was made alkaline with sodium hydroxide (to pH about 8) and concentrated to one quarter of its volume, and extracted with ether. The total yield of product obtained was 112 g. (0.87 mole, 87%). It melted at 125-127°. Literature value (28) 128-29°. 8,5-Dibromo-2-Thenoic Acid This halogenated acid was prepared from 2-thenoic acid utilizing the method of Jacob, Steinkopf, and Penz (25) with some modifications. A 228 g. (1.8 moles) quantity of bromine was placed in a 1 1. three- necked flask; the latter was fitted with a stirrer, reflux condenser and a flexible rubber tube, to which was attached a 125 m1. Erlenmeyer flask containing 28.5 g. (0.225 mole) of 2-thenoic acid. The acid was added slowly from the Erlenmeyer flask to the vigorously stirred bromine. During the addition of the acid the reaction flask was cooled by immer- sion in an ice bath. Following the addition of the halogen, the cooling bath was removed, and the reaction mixture was stirred at room temper— ature for an additional hour. The excess bromine was removed by evapora- tion with a water aspirator vacuum. To remove the final traces of bromine the white residual acid was stirred with 100 m1. of 10% ammonium carbonate solution, followed by acidification with cone. hydrochloric acid. The white solid product was recovered by filtration on a Buchner funnel, washed with cold water did recrystallized from absolute ethanol. Yield, 85.2 g. (0.158 mole, 70.2%); m.p. 223-225°. Literature value (25) 225-2270. 18 3-Bromothiophene from 8,5-Dibromo-2-thenoic Acid The method suggested by Nishimura, Motayama and Imoto (17) was used in the preparation of this material. In a l 1. three-necked flask fitted with a thermometer and distilling head there were placed 180 g. (1.09 moles) of previously distilled (b.p. 238-280°) quinoline and a mixture of 60 g. (0.21 mole) of 8,5-dibromo—2-thenoic acid and 10 g. of copper_powder; the two latter substances had been previously ground together in a mortar, to assure intimate mixture. The reaction mixture was carefully heated, and at 75-80° it was observed that a fairly vigorous bubbling was occurring. The color of the reaction mixture turned at this point from a yellow to a brownish-black. The reaction temperature rose to 185°, the reflux temperature of the reaction mixture. The mixture was held at its reflux temperature for an hour, and then it was heated until distillation occurred. About 70-75 m1. of distillate was collected. This was acidified with 1:1 hydrochloric acid, to separate the 3-bromothiophene from the quinoline. The acidi- fied distillate was extracted with ether, the ether layer was separated and washed twice with 1:1 hydrochloric acid and once with water. After having been dried in contact with anhydrous calcium chloride the ether layer was decanted from the drying agent and the ether evaporated. Vacuum distillation of the product gave 26.7 g. (0.16 mole, 78%) of 3-bromothiophene, b.p. 53-55°/15 mm. Literature value (17) 66- 68.50/31 mm. 3-Acetyl-2,5-dichlorothiophene This ketone was prepared by the procedure originally described by Steinkopf and Kohler (26) and modified by Hartough and Conley (28,27). 19 A mixture of 153 g. (1.0 mole) of 2,5-dichlorothiophene, 150 g. (1.9 moles) of acetyl chloride, and 750 ml. of petroleum ether was placed in a 3 1. three-necked flask fitted with a stirrer, thermometer and powder addition funnel. A 150 g. (1.13 moles) quantity of anhydrous aluminum chloride was added to the reaction mixture, which had been precooled to -15°. The metal halide catalyst was added in portions from the powder funnel slowly and carefully during a 15 min. period, at which point the evolution of hydrogen chloride gas became rather vigorous. The powder funnel was replaced by a condenser fitted with a sodium hydroxide trap and the temperature of the stirred reaction mixture was maintained at 15° for 2 hrs. At this point the reaction temperature was permitted to slowly rise to room temperature and main- tained there for 3.5 hrs. Finally the reaction mixture was heated at 80° for 30 min. It was then cooled to about 10° and carefully poured over 1 l. of crushed ice. The petroleum ether layer was separated and washed three times with water and dried over anhydrous calcium chloride. The solvent was removed by distillation at atmospheric pressure and the residue was distilled in vacuum from a Claissen flask directly connected to a receiver; the latter was cooled by a stream of water. The product solidified in the receiver flask to a yellowish white crystalline mater- ial: mlp. 35-37°. Literature value (27) 38-38.5°. No recrystalliza— tion was attempted. Yield: 181 g. (0.72 mole, 72%). 2,5-Dichloro-3-thenoic Acid The experimental procedure described here is analogous to that dis- cussed previously for the preparation of 2—thenoic acid. A mixture of sodium hypochlorite was prepared by using 180 g. (8.5 moles) of sodium 20 hydroxide, 1,023 g. of ice and bubbling into the alkaline solution, chlorine gas until 131 g. (1.85 moles) of the halogen had been absorbed. The hypochlorite solution was heated to 65°, transferred to a three- necked 5 1. flask and 88 g. (0.81 mole) of 2,5-dich10ro-3-acety1thiophene was added slowly through a powder funnel fitted on top of a short Allhijn condenser. The color of the reaction mixture changed from pale yellow to orange rose and chloroform evolved in rather copious quantities. The reaction temperature remained at 70-730 during the chloroform evolu- tion and then decreased. The mixture was set aside at room temperature. over night. A solution of sodium bisulfite (81 g. CL398 mole) of bi- sulfite in 82 ml. of water) was then added, and the mixture was acidified with conc. hydrochloric acid (sp. gr. 1.19). The solid product was recovered by filtration and recrystallized from ethanol. Recrystalliza- tion presented some difficulties and had to be repeated several times in order to obtain a pure crystalline product. Yield, 36.8 g. (0.19 mole, 86.3%), m.p. 185-86°. Literature value (28) m.p. 187-88°. 2-Thena1 The method suggested by Campaignzand.Archer (28) was employed in the preparation of the heterocyclic aldehyde. A solution of 252 g. (3.0 moles) of thiophene and 276 g. (3.88 moles) of N,N-dimethylform- amide was cooled to 0° in a 3 l. three-necked flask fitted with a stirrer, reflux condenser and a 500 m1. dropping funnel. A total of 576 g. (3.72 moles) of phosphorus oxychloride was added to the cooled, stirred solution during a 2 hr. period. The color of the originally colorless mixture changed to straw yellow during this addition of the chloride. The reaction mixture was then heated at its reflux temperature 21 on a water bath for an additional 2 hrs., and then set aside overnight at room temperature. During the time the reaction mixture was heated at its reflux temperature it turned first red, then brown, and finally almost black in color. The reaction solution was next carefully poured onto 3,000 g. of ice. The heat of reaction between the excess phosphorus oxychloride and the water was sufficient to melt all the ice and heat the water almost to its boiling point. After being set aside for a short period, the mixture was steam distilled, as recommended in the literature (28), since direct separation of the organic layer from the water was impossible. The oily liquid was readily separated from the water in the distillate. The impure product was stored over calcium chloride in a brown bottle. Further purification of the crude product was not attempted. Yield, 255 g. (2.58 moles, 78%) of unpurified product, a light yellow oil, which darkened slightly on storage. 2-Methylthiophene The experimental procedure of King and Nord (29) was employed in the reduction of 2-thenal to obtain this alkyl thiophene. A solution was prepared containing 228 g. (2.0 moles) of 2-thenal, 800 m1. of 85% hydrazine hydrate and 1,600 m1. of ethylene glycol. This reduction solution was placed in a 5 1. three-necked flask fitted with a stirrer, thermometer and Vigreux column carrying a distilling head. The re— action solution was then heated to 160-1700, to remove water and excess hydrazine by direct distillation. The mixture was then set aside over- night to cool. The distillation head was replaced by two condensers one placed on top of the other and 800 g. (0.718 mole) of potassium hydroxide pellets were added to the reaction mixture while cooling the latter, care 22 being taken to hold the temperature below 80°. After adding the base, the stirred mixture was carefully heated to 90°, at which temperature nitrogen gas evolution commenced. The nitrogen evolution was rather vigorous for about 2 hrs. When the most vigorous evolution of gas had subsided, the mixture was heated at its reflux temperature for 2 hrs. at 105-110°. The mixture was then set aside at room temperature to cool. The condensers were replaced by a Vigreux column, fitted with a distil- lation head, and the mixture was distilled. The distillate boiling up to 180° was collected. This was extracted three times with 100 ml. portions of ether. The extracts were combined and washed with 6 N hydrochloric acid and finally with water. The ether solution was dried over anhydrous calcium chloride, filtered, and the ether was re— moved on the water bath. The product was distilled at atmospheric pressure using an 8 in. Vigreux column. The yield of product was 110 g. (1.12 moles, 56.8%) of a colorless liquid, boiling at 110-110.5°. 3,5-Dibromo-2-methylthiophene The method originally described by Steinkopf (30) after consider- able modification was used in this preparation. To a solution of 50 g. (0.51 mole) of 2-methylthiophene and 250 ml. of carbon disulfide con- tained in a 1 1. three-necked flask fitted with a stirrer, condenser and dropping funnel were added 180 g. (1.1 moles) of bromine during an hour; the reaction flask was kept cool by immersion in an ice—bath. Following the addition of the halogen, the ice-bath was removed and the reaction mixture was stirred for 3 hrs. at room temperature; hydrogen bromide was emitted copiously, throughout the reaction period. The reaction was set aside over night at room temperature, then washed three 23 times with water, next three times with 10% aqueous potassium hydroxide solution, and finally three times with water. With efficient stirring the washed reaction mixture was then cooled by immersion in an ice-bath and to it were added 100 m1. of methanolic potassium hydroxide (60 g. of potassium hydroxide pellets dissolved in 126 m1. of methanol) , slowly and carefully to avoid any rise in the reaction temperature. The mixture was then heated at its reflux temperature for an hour. Suffic— ient water was then added to double the volume of the mixture, and the carbon disulfide was removed by steam distillation on a water bath. The oily residue was exhaustively steam distilled (for about 9 hrs.). The oil product was separated from the water layer, dried over anhydrous calcium chloride, and distilled under reduced pressure, to obtain 63 g. of a heavy oil, with a density of 2.1 g. ml?1 A small sample of this material distilled at atmospheric pressure boiled at 220-226°. Literature value (30) 227.5—2300. 3-Bromo-2-methy1thigphene The procedure used by Gronowitz was followed to obtain this material (31). A 60 g. (0.238 mole) quantity of 3,5-dibromo-2-methylthiophene was added to a refluxing mixture of 77 ml. of water, 25.5 g. (0.390 9. atoms) of zinc powder and 32 ml. of glacial acetic acid. The reaction mixture was heated at its reflux temperature for 28 hrs. and the product was isolated by steam distillation. The organic layer, was separated, washed with 10% sodium carbonate solution and water, dried over anhydrous calcium chloride and fractionated to yield 36.8 g. (0.207 moles, 88.6%) of pure product boiling at 169-173°. Literature value (31) b.p. 173-178°. 28 2-Methyl-3-thenoic Acid A procedure essentially analogous to the one described previously for the preparation of 3-thenoic acid was followed. A 500 ml. three- necked flask was equipped with a mechanical stirrer, reflux condenser, dropping funnel, and a -20 to —35° thermometer. A 100 ml. volume of anhydrous ether, previously dried over sodium wire, was introduced into the flask and 6.8 g. (0.98 9. atoms) of lithium metal were cut into. small pieces and added to the ether. A solution containing 61.6 g. (0.85 moles) of n-butyl bromide dissolved in 60 m1. of absolute ether was placed in the dropping funnel, and about 10 ml. of this solution were admitted to the flask. Stirring was initiated and after a few minutes it was observed that the liquid turned dark and cloudy in ap- pearance with discolored spots appearing on the lithium metal surface. The reaction temperature was lowered to -10- -20° by means of a dry ice- iSOpropanol bath, and the remainder of the g-butyl bromide solution was added at a constant rate during an hour. The reaction solution was stirred for an additional 2 hrs. during which its temperature was allowed to rise to 10°. As the temperature increased the color of the originally dark gray reaction mixture turned to a deep violet-purple. The n-butyl lithium solution was then filtered through glass wool into a 1 1. three- necked flask equipped with stirrer, dropping funnel, and a -100 to 10° thermometer. This reaction flask had been cooled previously to -70° in a dry ice-isopropanol bath, contained in an unbreakable polystyrene cookie jar, which had good insulating properties. An additional 300 m1. of absolute ether was then added to the solution of g-butyl lithium and it was then cooled to -70°. In the dropping funnel there were placed 30 g. (0.17 mole) of 2-methyl-3-bromothi0phene dissolved in 320 m1. of 25 ether. This solution was run into the well stirred B—butyl lithium solution in the flask in a steady stream, while the reaction temperature was held below -70° (30 min.). Following the addition of the alkylhalo- thiophene solution the reaction mixture was stirred for an additional 3 hrs. at -70°. It was then poured over powdered dry ice and allowed to warm up to 0°. The violet color of the mixture changed to almost pure white on the addition to the dry ice. After the solution had warmed to 0° a mixture of 200 m1. of 6 N hydrochloric acid and 100 g. of ice was slowly poured into it. A white precipitate was formed initially, but this dissolved in the ether. The ether layer was separated, and the water layer was extracted twice with 200 ml. portions of ether. The combined ether extracts were then extracted with 250 ml. of 2 N sodium hydroxide. The aqueous layer was separated and acidified with 6 N hydrochloric acid at 0°. The precipitate, which formed immediately on acidification was recovered by filtration and washed with ice-cold water. The solid product was recrystallized from hot water, to yield 18.5 g. (0.13 mole, 68%) of pure 2-methyl-3-thenoic acid, melting at 103-110°. Literature value (32) ll5-ll7°. Calculated for C6H602S: C, 50.7; H, 8.2; S, 22.5 Found: C, 89.7; H, 8.3; S, 22.3. 2-Ethy1thiophene The procedure of King and Nord (29) previously described was em- ployed to prepare this alkylthiophene. Acetylthiophene instead of 2- thenal was used as a starting material for the Wolff-Kishner reaction. A mixture of 200 g. of 2-acety1thiophene (1.58 moles), 310.18 ml. of hydrazine hydrate and 1,238.2 ml. of ethylene glycol was heated to 170° 26 to remove the excess hydrazine and water, and then it was cooled to 80°. Potassium hydroxide pellets (110.8 g., 1.98 moles) were then added and the stirred reaction mixture was cautiously heated to 120°. Nitrogen gas evolution was initiated at 120° and external heating was removed and the mixture was set aside overnight. The reaction solution was then heated at its reflux temperature for three hours followed by distillation to collect the product. Distillation was continued until the vapor temperature in the distillation head reached 135°. The distillate was extracted with ether; the ether extract was washed twice with 6 N hydrochloric acid and once with water, and dried over anhydrous calcium chloride. The ether was removed on a steam bath, and the product was distilled at atmospheric pressure to obtain 188 g. (1.36 moles, 86%) of the desired product boiling at 130-133°. Literature value (32) b.p. 132—1380. 3,5-Dibromo-2-ethylthiophene Direct bromination of 2-ethylthiophene in a manner analogous to that described above for the preparation of 3,5-dibromo-2-methylthio- phene was used to obtain 3,5-dibromo-2-ethylthiOphene. A solution containing 57 g. (0.5 mole) of 2-ethy1th10phene dis- solved in 250 m1. of carbon disulfide was placed in a l 1. three-necked flask fitted with a mechanical stirrer and dropping funnel. The drop- ping funnel was charged with 180 g. (1.1 moles) of bromine dissolved in- 125 ml. of carbon disulfide. The experimental procedure followed in conducting the bromination reaction was exactly analogous to that pre- viously described for the preparation of 2-methy1-3,5-dibromothiophene. Steam distillation of the bromination reaction mixture yielded 222 g. 27 of yellow oil, which was separated from the distillate, dried, and used immediately, without further purification, in the next reaction of the synthesis. 3—Bromo-2-ethylthiophene The crude oil, essentially 3,5-dibromo-2-ethylthiophene, isolated as described above was introduced into a l 1. three-necked flask and a solution containing 88 ml. of glacial acetic acid and 180 m1. of water was added to the oil. To the stirred solution, from a powder funnel, there was slowly added 35.25 g. (0.538 g. atoms) of zinc powder. The reaction mixture was then heated carefully to its reflux temperature and kept at that temperature 3 hrs. The desired monobromo product was isolated from the reaction mixture by steam distillation, decanted from the water layer, dried and twice vacuum distilled, using a 6 in. Vigreux column in both distillations. The yield obtained was, 79 g. (0.81 mole, 82%), b.p. 56-60° 20mm. The material boiled, with some decomposi- tion, at 178-175° at atmospheric pressure by a boiling point determina- tion employing a small sample. Literature value (38) l80-l90°. Calculated for C6H7SBr: Br, 82.07; Found: Br, 82.67. Attempts to Prepare 2-Ethyl-3-thenoic acid A procedure analogous to that previously described for the prepara- tion of 2-methyl-3-thenoic acid by the "lithium-butyl-process" was fol- lowed in attempting to synthesize 2-ethyl—3-thenoic acid. However, the product obtained in small yield was not the expected 2-ethyl-3-thenoic acid but 5—ethy1-8-bromo-2-thenoic acid. Yield, 2.5 g. (0.011m01e, 2,6%) of 5-ethyl-8-bromo-2-thenoic acid, m.p. l98-202°, dec. 28 Calculated for C7H702BrS: C, 35.75; H, 3.0; s, 18.31 Found: C, 36.53; H, 3.25; s, 18.25. Further, the preparation of the desired acid by the nitrile syn- thesis could not be effected either. 3-Methyl-2-thenoic Acid A completely analogous experimental procedure was followed in con- verting 3-methy1-2-acetyl thiophene to the corresponding carboxylic acid as has been described in the oxidation of 2-acety1thiophene and 2,5-diChloro-3~acetylthiophene to 2-thenoic and 2,5-dichloro-3-thenoic acids. A 180 g. (1.0 mole) qunatity of 3-methyl-2-acety1thiophene (sample generously furnished from Pennsalt Chemical Company) was em- ployed in the oxidation and the yield obtained after a single recrystal- lization from hot water was 127 g. (0.89 mole, 89%) of 3-methy1-2- thenoic acid, m.p. 185-187°. Literature value (32) m.p. 188°. Preparation of the Thenoyl Chlorides All of the thenoylchlorides employed in the present work were prepared from the corresponding carboxylic acids by interaction with thionyl chloride. A typical procedure is described as an example of these preparations. 5-Bromo-3-thenqyl Chloride In a 100 m1. one-necked flask fitted with a reflux condenser having a sodium hydroxide trap attached to it, there were placed 10 g. (0.0883 mole) of 5-bromo-3-thenoic acid and 25 g. (0.209 mole) of thionyl chloride. A rather vigorous initial reaction occurred with the immed- iate evolution of hydrogen chloride gas. When this had subsided the 29 Table I. Rate constants and half lives for the decomposition of substituted thenoyl peroxides at 79.6°. Peroxide . k x 103(min.-1) T1/,(minutes) Bis-(5—bromo-3-thenoyl) 2.031 381.2 Bis-(5-chloro-3-thenoyl) 1.862 372.8 Bis-(5-nitro-3-thenoy1) 5.889 118.5 Bis-(3-methy1-2-thenoy1) 2.699 256.7 Bis-(5-ethy1-8-bromo-2-thenoyl) 3.120 222.1 Bis-(2,5-dichloro-3-thenoyl) 1.681 812.3 Bis-(5-phenyl-2-thenoyl) 8.580 80.8 Bis-(2,5—dimethy1—3-thenoyl) 3.789 182.9 Bis-(2-thenoyl)* 2.55 271.8 Bis-(3-thenoyl)* 2.36 293.6 *For comparison (12). 30 «opwpofino Umow map pom pco>fiom on .Acoc-om .a.ov tuned .euac .ooNHHHmamxpoop on p0: UHSOo Coma: oomxopoQAonconuumnoEoopmo umaqvmwm mo cowpaooXo opp rpm: compmmmaambmzooop oco popmm 5pmhamo .oopoouoooco mom mpcmoa mcmpaoe Had p .oomoaaso mm: opHuoHComopop coppmo gown: pow soHxOooQAHzoconpumnflxfipoemoumamvmwm ocp mo comuaooXo 058 cows moowxoooa mCHCHMEou map mo ommo map cw cohquso mm: ocosflop mmouozz mm pom: mm: 0cmXocoHozo moowxouma oopmcomofimcmo ocmnocos map oomm >1 I Ra.6m mc.om mm.a mm.a aa.mm ma.am a.cm mm aucac .aua -ascamwammmmemHm . . . . . . uW.-. . - . . Aaacauca-m-oecac aw Ma cc ma we m cm m cm mm mm mm a ma NOA ca Na uccac acu -a-aacac-mvaam . . . . . . . A.aaouucv Aasccuca-m ma ma cm ma as m ca m 6 ac 6 me m as am ca accucucacu -asccca-mvmam . . . . . . . A.Qeoooov Aahocoapum 56 6a mm Ha am 0 mm 0 cm Om mo am m am mma-mma mm uccz -cacucac-m.avmam kn I mm.ca mm.ca Ha.o am.o am.0m _Hc.om 5.4m ma-mm ca aucau .aua -cacHMw8mmmmwvmam mm.mm Na.mm mc.m ma.m ma.am mo.am m.am ,mm-mm mm accwmuwwwm -mwmwwmmmwmam . h u am.aa ac.aa aa.a ea.a ac.mm aa.am a.aa ama-mma ca mwmwwcowmm mwammmmwvmam . . . . . . . . . -. . fiasccuca-m aw ma am ma cc H mm a ma am ca an m as ma ma mm cuccau sud -cucacc-mvmam a -I a . cm.ma cm.ma ca.a mam.o mm.mm aa.mm o.wm moa-m6a aa cucflwcwcwwmcm mwammmmmVMam . l, soap bosom .ofimo ,ocsom ..oamo. bosom .ono & R umuaaumwm>Uoom HSMHUW, .Tcomouoxr monumu humusm p m z ofiow> pow pco>Hom U 17 4 11 I8 . mmfimXOqu ATAOCNC/ p m . 31 dark mixture was heated at its reflux temperature for 8 hrs. The excess thionyl chloride was removed by distillation at atmospheric pressure and the residue was distilled using a 8 in. Vigreux column to obtain 12 g. of crude product containing some thionyl chloride. This material distil- led at 120 - 130° 10-15 mm. The exact yields obtained were difficult to determine as the heterocyclic acid Chlorides were not further puri- ~ fied to remove the thiohyl chloride completely, since its presence of- fered no experimental difficulties in using these impure acid chlorides to prepare their corresponding heterocyclic peroxides. Bis-(5-bromo-3-thengyl Peroxide) A vigorously stirred 25 m1. volume of water contained in a 300 m1. three-necked reaction flask fitted with a stirrer, thermometer and drop- ping funnel was cooled to 0° in an ice-sodium chloride bath and 1.95 g. (0.025 mole) of sodium peroxide were dissolved in it in small portions, care being taken that each portion was completely dissolved in the water, before additional sodium peroxide was added. To the cold peroxide solu- tion, a second solution containing 10.0 g. (0.088 mole) of 5-bromo-3- thenoyl Chloride dissolved in 35 m1. of dry cyclohexane was added in one portion. A colorless solid precipitated immediately. The mixture was then stirred at 0° for an additional 1.5 hrs. The colorless, crystal- line product was removed by filtration, washed with ice water, and dried at 0°, for 88 hrs. in a vacuum desiccator. The product was recrystal- lized from the minimum amount opr-butyl ether, preheated to 50°, and then reprecipitated by the addition of chloroform. The yield of color- less peroxide obtained was 8.0 9. (0.0097 mole, 88%), melting at 102- 103°. 0n melting, the material turned red in color and detonated, after 32 having been maintained at its melting temperature for about 2 min. Calculated for C10H4Br204SZ: C, 29.18; H, 0.978; S, 15.56; Br, 38.65 Found: C, 28.98; H, 1.10; S, 15.56; 'Br, 38.65. Bis-(5-chloro-3-thenoylperoxide) Using apparatus and experimental conditions analogous to those described for the synthesis of bis-(5-bromo-3-thenoyl peroxide) 2.50 g. (0.032 mole) of sodium peroxideiere dissolved, at 0°, in small portions in 35 m1. of water. A solution of 10.0 g. (0.056 mole) of 5-Chloro-2- thenoyl Chloride dissolved in 35 m1. of dry cyclohexane was added, all at once, to the vigorously stirred aqueous peroxide solution. A color- less solid immediately precipitated. The reaction mixture was stirred at 0° for 1.5 hrs. to complete the reaction. The colorless crystalline solid was collected by filtration on a sintered glass funnel and washed with ice water, then four times with 25 m1. portions of ice-cold petroleum ether, to remove ahy unreacted 5-chloro-3-thenoyl Chloride. After drying for 88 hrs. in a vacuum desiccator, the crude product was recrystallized from petroleum ether (b.p. 30-60°). The yield obtained was 5.2 9. (0.0163 mole, 58%), m.p. 72-73°. It melted into a clear liquid without detonation. Calculated for C10H4C1204SZ: C, 37.16; H, 1.25; s, 19.88; C1, 21.98 Found: C, 37.88; H, 1.66; s, 19.88; Cl, 21.86. 33 Bis-(3-methyl-2-thenqyl,peroxide) Following the general procedure in the two previous preparations just described, 3.1 g. (0.080 mole) of sodium peroxide were added at 0° in small portions to 30 m1. of water. A solution containing 10 g. (0.062 mole) of 3-methyl-2-thenoyl chloride dissolved in 30 m1. of dry toluene was added dropwise, at 0°, during 15 min., to the vigorously stirred aqueous sodium peroxide solution. The reaction mixture was then stirred, at 0°, for an additional 2.5 hrs. to complete the re- action. About 15 min. after the addition of acid chloride, a color- less solid material began to separate from solution. The crystalline product was recovered by filtration and thoroughly washed with ice-water. After drying for 88 hrs. at 0°, in a vacuum desiccator, the crude product was recrystallized from a minimum quantity of benzene by the addition of petroleum ether (b.p. 30-60°). The yield of colorless peroxide obtained was 3.1 g.(0.0110 mole, 35%), melting at 108°. This heterocyclic peroxide on melting turned red in color and detonated. Calculated for C12H1004S: C, 51.05; H, 3.75; S, 22.72. Found: C, 51.12; H, 3.62; S, 22.58. Isopropyl-2-thiehy1 Ketone The general acylation procedure as described by Hartough and Kosak (23a) was used in the synthesis of this ketone. A 182 g. (1.0 mole) quantity of phosphorus pentoxide was weighed directly into a solution prepared from 600 m1. of benzene and 600 ml. of thiophene. Isobutyric acid (88 g., 1.0 mole)(Eastman Organic Chemical Division Product) was added very carefully to the acylation mixture. The reac- tion temperature was held under control by immersing the reaction flask 38 in an ice bath, and no appreciable heat of reaction could be observed. A short time after initiating the reaction, the reaction mixture turned a turbid purple in color, and separated into two phases. One phase was straw color, the other a deep purple solid. After heating the reaction mixture at its reflux temperature for 8 hrs. the liquid was decanted from the solid mass, and extracted with 10% sodium hydroxide. Experi- mental difficulties were encountered in this as the alkali extraction resulted in the formation of a thick emulsion, which necessitated it being set aside for several hours to effect a phase separation. The organic phase was finally separated; the thiophene was removed by dis- tillation, and the Crude product was purified by distillation in vacuo, b.p. 137-390/35mm. Yield: 87.5 g. (0.59 mole, 59%). 2-Isobuty1 thiophene The Wolff-Kishner reduction desCribed previously in the preparation of 2-methy1-thiophene and originally reported by King and Nord (29), was used for the reduction of 2-isopropy1thiehyl ketone to 2-isobuty1 thio- phene. A solution containing 87.5 g. (0.57 mole) of 2-isopropylthieny1 ketone, 583.8 m1. of ethylene glycol and 135.97 ml. of 85% hydrazine hydrate was stirred in a 2 1. three-necked reaction flask, fitted with a stirrer, thermometer, and a 12 in. Vigreux column fitted with a dis— - tillation head. The reaction solution was heated to 130-160° to remove water and excess hydrazine, by distillation and then it was allowed to cool to 50°. The Vigreux column was replaced by two reflux condensers mounted on top of one-another. While vigorously stirring 50 g. of potassium hydroxide pellets were added slowly to the reaction mixture, then it was heated carefully at about 100° until the slow evolution of 35 nitrogen gas commenced. The reaction proceeded smoothly with no vigor- ous gas evolution occurring at any time. After being heated at its reflux temperature for 28 hrs. the solution was allowed to cool to room temperature. The condensers were replaced by the Vigreux column and the product was isolated by distillation. The major portion of the pure product distilled at 165-173°. Yield: 62 g. (0.88 mole, 77%) of color- less clear liquid. 5-Isobutyl-2-acetylthiophene The procedure described above for the synthesis of 2-acetylthiophene was employed for the preparation of this ketone. A 6 g. quantity of 85% phosphoric acid was added slowly at 80° to a mixture of 62 g. (0.88 mole) of 2-isobutylthiophene, and 73.5 g. (0.72 mole) of acetic anhydride under vigorous stirring. An immediate color Change in the reaction mixture from colorless to light red to deep red-black, was observed. The temperature of the mixture initially rose rapidly to 135°, its temper- ature of reflux. After the refluxing had subsided, the temperature was allowed to drop to 110°, and was maintained there for 3 hrs. after which it was again heated at its reflux temperature for 30 min. The mixture was allowed to cool to room temperature, 100 ml. of water were added to the mixture and it was stirred for an additional 15 min. A clear, green oil separated from solution at this point. The mixture was washed with water and separation of the phases required the emulsion to be set aside for several hours. The crude product was purified by distillation. A water-product azeotrope initially distilled as a small forerun from the organic phase. The pure product was collected boiling in the range 168- 1720/25 mm. Yield: 61 g. (0.33 mole, 75%). 36 5-Isobupyl-2-thenoic acid This acid was prepared by the hypochlorite oxidation of 5-isobutyl- 2-acetylthiophene in a manner described above for synthesis of 2-thenoic acid. The yield of acid obtained from 60 g. (0.380 mole) of starting material was 82 g. (0.238 mole, 71%), m.p. 67-69°. Bis(2,5-dichloro-3-thenoyl)peroxide Apparatus and methods analogous to those described for the prepara- tion of bis(5-bromo-3-thenoy1)peroxide above were used to obtain the peroxide. A 25 ml. volume of water was cooled to 0° and 1.66 g. (0.021 mole) of sodium peroxideiude dissolved in the water, the solid being added in small portions and under vigorous stirring. A second solution con- taining 8.9 g. (0.022 mole) of 2,5-dichloro-3—thenqylchloride dissolved in 22 m1. of dry cyclohexane was added, in one portion, to the aqueous solution of sodium peroxide. A white solid separated from solution immediately. The reaction mixture was then stirred for an additional 1.5 hrs. at 0°. The white, crystalline product was recovered by filtra- tion, washed thoroughly with ice water, dried 88 hrs. at 0° in a vacuum desiccator, and recrystallized from petroleum ether to obtain 3.0 9. (0.00766 mole, 70%) of a pure, crystalline product, m.p. 92-950. Calculated for C10H201404S2: C, 30.61; H, 0.51; S, 16.33; C1, 36.92. Found: C, 30.51; H, 0.71; S, 16.28; Cl, 36.12. Bis-(8,5—dibromo-3-thenoyl)peroxide Apparatus and experimental procedures entirely analogous to the above preparation were employed to prepare this peroxide. A solution containing 37 Table III. Preparation of thenoyl chlorides A Thenoyl Chloride Yield % Boiling Point °C. 5-Brom03-thenqy1 chloride 68 99-100/ 8 mm. 5-Chloro-3-thenoyl chloride 98 128-125/ 15 mm. 3-Methyl-2-thenoy1 chloride 88 125-130/ 15 mm. 5-Nitro-3-thenoy1 chloride 67 120-130/10 - 15 mm. 2,5-Dichloro-3-thenqyl chloride 66 135-180/ 15 mm. 8,5-Dibromo-2-thenqyl chloride 58 167-168/ 0.1 mm. 5-Ethy1-8-bromo-2-thenqy1 chloride 85 102-108/ 15 mm. 5-Phehyl-2-thenqyl chloride 69 l2-22/’10 mm. 2,5-Dimethyl-3-thenoyl chloride 80 110—111/ 5 mm. 38 2.1 g. (0.027 mole) of sodium peroxide dissolved in 30 ml. of ice-cooled water was prepared. A second solution prepared from 19 g. (0.0062 mole) of 8,5-dibromo-3-thenoyl chloride and 35 m1. of dry cyclohexane was added to the aqueous peroxide in one portion. A white solid precipitated immediately. After the reaction mixture had been stirred for 2 hrs. at 0° the white solid product was removed by filtration and washed with ice water. The yield of peroxide was 10.2 9. (0.00183 mole, 59%), melt- ing at 158-159° while turning red in color. Caculated for ClonBr4SZO4: c, 21.05; H, 0.35; Br, 56.18; s, 11.23. Found: C, 20.96; H, 0.31; Br, 53.7; 5, 10.67. Bis-(Siphegyl-Z-thenoyl)peroxide A 6 g. (0.027 mole) quantity of 5-pheny1-2-thenoyl chloride was dissolved in 20 ml. of dry toluene. This solution was then added to a second s01ution containing 1.0 g. (0.013 mole) of sodium peroxide dis- solved in 35 m1. of ice cold water. A yellowish solid precipitated about a minute after mixing the two solutions. The reaction mixture was allowed to stir at 0° for 2 hr. to insure completeness of reaction. The solid material was removed by filtration, washed with ice water, set aside in a vacuum desiccator at 0° for 88 hrs; and recrystallized from chloroform. The yield of pure product was 5 g. (0.012 mole, 80%), melting at 81° with decomposition. Calculated for C22H1404s2: C, 65.0; H, 3.80; 5, 15.80. Found: C, 61.0; H, 3.82; s, 15.98. 39 Bis-(5-ethyl-8-bromo-2-thenoyl)peroxide The general method for the synthesis of peroxide described above was again followed. The aqueous solution of sodium peroxide was pre- pared by dissolving 1.2 g. (0.016 mole) of the solid in 35 ml. of ice- Cold water. A second solution containing 7.5 g. (0.030 mole) of 5- ethyl-8-bromo-2-thenoyl Chloride dissolved in 35 ml. of dry toluene was added dropwise to the rapidly stirred aqueous peroxide solution. In this case about 15 min. of reaction time elapsed before a white precipi- tate separated from solution. The reaction mixture was stirred at 0° for an additional 2 hrs. to complete the reaction. The solid was then recovered by filtration. The product after recrystallization from petroleum ether melted at 102-5°, with decomposition. The yield obtained was 3.6 9. (0.0077 mole, 51%). 8 Calculated for C14H12Br2S204: C, 35.89; H, 2.56; S, 13.68; Br, 38.19. Found: C, 35.36; H, 2.62; S, 13.29; Br, 33.56. 2,5-Dimethyl-3-acety1thiophene The procedure employed by Goldfarb, Litvinoff, and Shedov (35) was used in this preparation. A 80 g. (0.357 mole) quantity of 2,5-dimethy1- thiophene was placed in a 1 1. four-necked flask fitted with mechanical stirrer, calcium chloride drying tube, thermometer and dropping funnel. With the aid of a special graduated pipet 880 ml. of chlorobenzene, and 0.88 mole of acetyl chloride were added to the flask. The mixture was cooled to 0° under Stirring (the cooling was achieved by means of a dry ice isopropanol bath), and during the course of 1.5 hrs. 0.28 mole of stannic chloride dissolved in 120 m1. of chlorobenzene was added, 80 the temperature being maintained at 0-3°. The mixture was allowed to warm to room temperature and the stirring was continued for an additional hour. A hydrochloric acid solution (20 m1. of conC. (sp. gr. 1.19) acid in 180 ml. of water) was then added at 10-l5° in order to decompose the Complex salt. The acid layer was then separated and extracted with 280 m1. of chlorobenzene. The chlorobenzene layer was washed with water, then with 10% sodium hydroxide, and twice more with water. The wash liquors were again extracted with 280 m1. of chlorobenzene. The chlorobenzene layers were combined and dried over anhydrous calcium chloride. The chlorobenzene was removed in vacuo and the ketone distilled in a micro distillation apparatus, yielding 86 g. (0.299 mole, 83.7%) of product boiling at 120-1220/25 mm. Literature value (35) 128-1300/30 mm. 2,5-Dimethyl-3-thenoic acid A variation of the method of Hartough and Conley (28) was used in the preparation of the acid. A solution of sodium hypochlorite was prepared by passing 160 g. (0.225 mole) of chlorine gas into a solution of 220 g. (5.5 moles) of sodium hydroxide in 300 m1. of water to which 1,000 g. of ice had been added. The Chlorine addition was completed in 25 min., after which the hypochlorite solution was heated to 60° on a steam bath. The solution was then transferred to a 3 l. four-necked flask, fitted with a mechan- ical stirrer, dropping funnel, thermometer and reflux condenser. The mixture was then slowly heated under stirring to 85°. A quantity of 86 9. (0.2923 mole) of 2,5-dimethy1-3-acetylthiophene was then added dropwise from the addition funnel at a rate sufficient to maintain the 81 reaction temperature between 85-95°. After the addition was completed the mixture was stirred at 95° for 10 hrs., and then cooled to room temperature. The cooled solution was washed with ether to remove any residual starting material, and the ether layer was discarded. A solution containing 50 g. of sodium bisulfite dissolved in 100 m1. of water was then added to the washed reaction mixture and the re- sulting solution was transferred into a 8 1. beaker. It was acidified with conc. hydrochloric acid and the white solid product, which pre- cipitated at this point, was recovered by filtration, washed, and re- crystallized from hot water. This yielded 3.9 9. (0.0025 mole, 8.55%) of product melting at 107-108°. Literature value (28) ll9-l20°. Bis-(2,5-dimethyl-3-thenoyl)peroxide A volume of 80 m1. of water, contained in a 300 m1. three-necked flask fitted with stirrer, thermometer and dropping funnel was cooled to 0° by means of an ice bath. Under vigorous stirring 7 g. (0.089 mole) of sodium peroxide were added in small portions. A solution prepared from 3.5 9. (0.2008 mole) of 2,5-dimethyl-3-thenoyl chloride in 10 m1. of dry carbon tetrachloride was added dropwise, at 0° to the aqueous peroxide solution with stirring over a period of 15 min. A white in- soluble material began to form about 30 min. after the addition of the , acid chloride solution had been completed. The reaction mixture was stirred at 0° for an additional 8 hrs. and the white, crystalline pro- duct was recovered by filtration, washed with ice water yielding 3.2 9. (0.0103 mole, 82.8%) of product. Calculated for C14H1404SZ: H, 8.52; S, 20.65. Found: H, 8.82; S, 20.17. 82 ,Analytical Titration Procedures Employed for Determination of the Purity of the Thenoyl Peroxides The peroxide analyses were performed by Mr. James Stoia and Mr. Anton Westveld at the laboratories of Olivet College. The analytical results obtained for the substituted thenoyl per- oxides prepared are summarized in Table IV. The experimental procedure used was taken from the Ph.D. Thesis of Joseph Shae (18). A sample of peroxide (170.9 mg. (0.526 millimole) in the case of bis-(5-chloro-3-thenoyl)peroxide) was accurately weighed and transfer- red to a 25 m1. volumetric flask. It was dissolved in specially puri— fied carbon tetrachloride and made up to volume. Four aliquots of 8 ml. each were then removed with a pipet and transferred to clean, dry 125 ml. Erlenmeyer flasks. A 10 m1. volume of glacial acetic acid containing 0.005% ferric chloride and a small piece of dry ice were then added to each aliquot. The dry ice was added to displace the atmOSpheriC oxygen with carbon dioxide. The flasks were then shaken to make certain that all the dry ice had sublimed (to avoid the displacement of iodine vapor later), and finally 1.0 m1. of satur- ated sodium iodide solution was added to each sample. A blank solution was also prepared containing all the reactants except the peroxide sample. The samples were set aside in the dark for a period of 85 min., with occasional shaking, and were then titrated with standard sodium thiosulfate. Just prior to titration 25 ml. of water was added to each sample. Starch solution was added just before the end point had been reached (light straw yellow color). The sodium thiosulfate had been standardized against potassium iodate as a primary standard. 83 Kinetic Determinations The thermal decomposition rates of the various substituted thenoyl peroxides were followed by a study of their infrared spectra at 5.5 to 6.1 microns of carbon tetrachloride solutions containing 0.2 mole of purified styrene to inhibit induced decompositions. The typical "perox- ide peak" occurred at approximately 5.7 microns with a slight shifting from compound to compound. The samples were exposed to the required re- action temperatures for definite times, extending from "zero time" to the estimated half life of the compound. The decompositions were con- ducted in an electrically heated mineral oil bath, the temperature of which was controlled to i 0.20 by a relay supplied by Central Scientific Company. The peroxide solutions were prepared, using specially purified carbon tetrachloride for all the peroxides except bis-(5-nitro-3-thenoy1)peroxide, which was only slightly soluble in carbon tetrachloride. For this peroxide purified chloroform was used as a solvent. The concentration of the peroxide solutions were prepared as closely to 0.01 N as was feasable for all compounds. They were transferred into ampoules of ap- proximately 1 ml. capacity employing a hypodermic syringe, frozen in dry ice, and immediately sealed with the gas flame torch. The samples were then introduced into the Constant temperature bath which had been preheated to the desired reaction temperature. A 3 min. period was a1- 1owed for the peroxide solutions to come to thermal equilibrium. Dup- licate samples were removed from the thermostatted bath for all determina- tions at this "zero time". The results of the kinetic runs are shown in Tables V through XXVIII. They were determined from the respective 88 infrared spectra obtained on a Perkin-Elmer 21 spectrograph in the region of 5.5 to 6.1 microns. Base-lines were determined using solvent for both the sample and the reference beams. The values I and lo rep- resent the distances of the peak and corresponding base-line values from some arbitrary zero line (see photographs of spectra in Appendix). These distances on the graphs were determined with a ruler, designated as Io and I respectively and the absorption coefficients were calculated as log Io/I. (A). The logarithms of the absorption coefficients were then computed and plotted against the time in minutes, to determine the rate constants initially. (See appendix.) All final values of the rate constants were calculated using the method of least squares. Only for one compound, namely bis-(5-chloro-3-thenoyl)peroxide, were the rate values Calculated manually, all others were programmed and calculated in a Burroughs B-500 type computer. These calculations were carried out by the offices of Mr. Thomas Aird of Detroit to whom we are most grateful. Activation energies were determined from a plot of the logarithm of the rate constants determined, at three different reaction tempera- tures, against the reciprocal of the absolute temperature. These are shown in Table XXIX. Using the formula, AS#/8.576 ; log k - 10.753 - log T + E/8.576T (36) the entropies of activation were then calculated for each Case. These, as well as the frequency factors, are summarized in Table XXX. 85 Table IV. List of peroxides prepared. Peroxide Yield Melting Solvent(s) used % Point for Recrystalliza- °C. ' tion Bis-(5-bromo-3-thenqyl) 88 102-103 Chloroform peroxide p-butyl ether Bis-(5-Chloro-3-thenqyl) 58 72-73 Petroleum ether peroxide , Bis-(5-nitro-3-thenqy1) 153-158 Chloroform peroxide ' det. at 157 Petroleum ether Bis-(3-methyl-2-thenoyl) 35 108- Benzene peroxide (Decomp.) Petroleum ether Bis-(2,5-dichloro-3-thenoy1) 70 92_93 Petroleum ether perOX1de Bis-(8,5—dibromo-2-thenqy1) 158-159 . peroxide 59 (Decomp.) Not recrystalllzed Bis-(S‘Phehy1-2-thenoyl) 81- peroxide 80 (Decomp.) Chloroform B‘s'(5‘ethy1‘h'br°m°'2' 51 102-105 Petroleum ether thenoyl)peroxide DISCUSSION AND RESULTS Essentially the work described in this thesis involved two main tasks. Initially to develop suitable synthetic procedures for the preparation of the thenoyl peroxides studied, and secondly an investi- gation of their decomposition rates. Originally the object of the pre- sent investigation was to extend the studies of sulfur heterocyclic peroxides initated by Schuetz and Teller (12). It was planned to pre- pare a complete series of subsfituted 3—thenoy1 peroxides, containing both electron repelling and electron attracting substituents attached to suitable positions in the heterocyclic ring. Once the parent acids to these peroxides are prepared, the synthesis of the corresponding peroxides themselves is a relatively easy task, provided the right solvent media is Chosen fopireaction involving the intermediate acyl Chlorides. The best solvents for the reactions of the acyl chlorides with aqueous inorganic peroxide are those in which the acyl chlorides are highly soluble, but in which the final peroxide product is suffic- iently insoluble to allow it to precipitate from the medium immediately after it has been produced. Toluene, cyclohexane, benzene, and carbon tetrachloride were found suitable for different compounds, after con- siderable "trial and error". The parent acids having the carboxyl group in the three position are relatively difficult to obtain, compared to their corresponding isomeric 2-thenoic acids. The reason for this is that the canonical forms (37) of the type I 'copiribute considerably less to the final resonance hybrid of thiophene than do the structures typified by II. As thiophene has only a single uncharged Canonical 86 87 C3:- 8 + S + I ' II form contributing to the resonance hybrid, those charged forms which have their chafiges Closer together are known to contribute more to the hybrid than those having the centers of charge further removed from one another (38). As long as the alpha positions are free of substitu- ents, practically all electrophylic substitutions will occur in these positions; this is true of halogenation,_acylation, and sulfonation, etc. The parent, 3-thenoic, acid was originally prepared by the side- chain oxidation of 3-methylthiophene, itself a substance rather difficult to obtain. Permanganate oxidation, known to be so successful in the preparation of benzoic acid and its derivatives, by oxidation of‘alkyl side chains had given only a very poor yield (8%) of the theoretical amount of 3-thenoic acid by oxidation of 3-methy1thiophene (39). Campaigne and Le Suer (22) prepared 3-thenoic acid by a side chain bromination of 3-methylthiophene, followed by the Sommelett reaction and subsequent oxidation of the resulting 3-thena1. In the present work 3-bromothiophene was used as a starting material, from which 3-thenoic acid was prepared in good yields by two different methods. A Grignard ‘ type reaction using p-butyl lithium (20), and a nitrile synthesis (17), employing cuprous cyanide in quinoline, followed by hydrolysis of the nitrile with concentrated acid. Primarily through the efforts of Byrne, working in the laboratories of Olivet College (80), the yields in the 88 latter process have been improved considerably above those indicated in in the literature (19). Fortunately, the 5—substituted bromo-, ch10ro-, and nitro—3-thenoic acids can be prepared by simple (23) procedures from the parent acid directly, as the meta directing influence of the carboxy group augments alpha orienting character of the heterocyclic sulfur, directing the substituents into the five position exclusively. 0n the other hand, the synthesis of simple derivatives of 3-thenoic acid, hav- ing electron releasing substituents,is a rather lengthy, difficult pro- cess, requiring numerous steps resulting in relatively low overall yields. An attempt to prepare 2-ethy1-3-thenoic acid from the corres- ponding brominated precursor, 2-ethy1-3-bromothiophene, by the "lithium- butyl" procedure was unsuccessful. In a second attempt to obtain the alkyl substituted 3-thenoic acid by this procedure, the resulting product proved to be 5-ethyl-8-bromo-2-thenoiC acid, obtained in low yield. Apparently the ortho-directing influence of the halogen collaborates with the alpha orienting power of the hetero atom to yield the acid obtained. It should be emphasized here that according to the findings of Gronowitz (81), 3-bromothiophene, when treated with butyl lithium at 0°, yield, after carbonation, 3-bromo-2-thenoic acid, whereas at -70° 3-thenoic acid is the product; mixtures of the acids are presumably ob- tained at intermediate temperatures. These results suggest that under the activating influence of the ethyl subséituent, an even lower tempera- ture of reaction may be indicated in order to obtain the desired 2-ethy1- 3-thenoic acid. Since 5-ethyl-8-bromo-2-thenoic acid was obtained,it was decided to use this acid as a starting material for the preparation of its corresponding peroxide, and for this reason bis-(8-bromo-5-ethy1- 2—thenoyl)peroxide was included in the kinetic studies. 89 Further it was decided that it was better to use the alpha-alpha substituted thiophenasas starting materials for further 3-substituted acids, as 2,5-dichloro- (28), as well as 2,5-dimethylthiophenes (35), both commercially available can easily be acylated in the 3-position, yielding methylketones which could be readily oxidized by hypo-iodite oxidation to the corresponding carboxylic acids. Peroxides were pre- pared from these acids, yielding the desired substituted thenoyl peroxide examples for comparison between electron attracting (chlorine) substituents and electron releasing (methyl) groups. A thenoyl per- oxide was also prepared from 8,5-dibromo-2-thenoic acid, readily avail- able through direct bromination of 2-thenoic acid. However, this peroxide, evidently due to its high molecular weight,could not be dis- solved in any solvent compatible with infrared techniques. It was there- fore not included in the kinetic investigations. All other peroxides, with the exception of bis-(5—nitro-3-thenqy1)peroxide,were easily soluble in carbon tetrachloride. The latter peroxide had to be dissolved in chloroform. Considering the results obtained from the kinetic determinations, the following generalizations can be suggested. In contrast to the compounds investigated by Schuetz and Teller (10), the majority of the compounds studied in the present investigation would not be expected to decompose at rates following the Hammett equation. Only the derivatives of 5- substituted 3-thenoic acids could be expected to follow this law, as they are comparable to the "meta"-substituted analogues in the benzenoid series. The results of the present study show that bis-(5-nitro-3-thenoy1)peroxide decomposes at a faster rate than the peroxide obtained from unsubstituted 3-thenoic acid; Tl/2 for 50 the nitro derivative equals 118.5 minutes, for the "parent" peroxide 293.5 minutes. This result is contrary to that normally expected, since the nitro group is typically electron withdrawing (-I, -T). A reason- able explanation for this has been given by Hine (82). If the spontane- ous decomposition can be assumed to be due to the repulsion of two di- poles joined at their negative ends, 0 0 ' R-C-o—o-C-R then the rate of decomposition should be proportional to the magnitude of these dipoles. Electron releasing groups would therefore increase the rate, whereas electron attracting substituents would retard the re- action. “Blomquist and Buselli (7) found however that for p,p'-, as well as m,m'-dinitrobenzoyl peroxides the rates were considerably higher than predicted by the Hammett equation. Similar results were found to be true for the bis-(5-nitro-3-thenqyl)peroxide in the studies described here. The above authors point out that they believe the nitro group may be such a strong electron withdrawing group that the direction of the dipole is actually reversed. There is also the possibility that, in Spite of the presence of styrene as a free radical scavenger, the in- duced part of the reaction may not have been completely suppressed in the case of the nitro-derivatives under consideration. According to Swain and Stockmeyer (6), electron withdrawing substituents aid, rather than hinder, the induced decomposition. It should also be mentioned here that Schuetz and Teller (10) found that bis-(5-nitro-2-thenqyl)per- oxide does not decompose according to a strict first order law in the presence of 3,8-dichlorostyrene as a scavenger, whereas all other compounds they investigated did follow a first order pattern. The only two remaining 51 peroxides in the series which might decompose according to the Hammett equation are bis-(5-chloro) and bis-(5-bromo)thenoyl peroxides. The values which should be used for these compounds are 0.373 for C1 and 0.391 for Br. Thus, for these two halo substituted heterocyclic perox- ides, the results are, Substituent (3‘1 41- G 2 109 k/ko Calc'd. Cl 0.786 -0.065 -0.087 Br 0.782 -0.093 0123 As can be readily seen from these data, the Hammett equation is obeyed only to a very rough approximation. This is not too surprising, as Imoto (83) and his coworkers found that a linear plot is not obtained when the rates of hydrolysis of 5-substituted-3-thenoic esters are plot- ted against the acidity constants of the corresponding acids in a Ham- mett type plot. Blomquist and Buselli (7) make the statement that for those aromatic and hetero-aromatic compounds whose reactions obey the Hammett equation. the frequency factor of the Eyring equation (88), and therefore the en- tropy of activation, should be constant, or at least nearly so. For the peroxides studied in the present investigation both energies and entropies of activation vary over a rather wide range (Tableloqx). A number of the peroxides, such as bis-(3-methyl-2-thenoy1)—, bis-(2,5-dichlor0-3- thenoy1)-, and bis-(25,-dimethyl-3-thenoyl)-, bear substituents on car- bons next to the atoms bearing the peroxyl group. A considerable "ortho effect" (8) is therefore to be anticipated. However, it was of interest to determine that if the energies of activation are plotted against the entropies of activation in the entire series studied a rather good straight line results (see Figure 30). This points toward an 52 "isokinetic" relationship as discussed by Bunnett (85) in his article of the "Interpretation of Rate Data". The above author talks about "Reaction Series" and classifies them into four categories: 1) Changes of reaction rate are due mainly to changes in the en- thalpy of activation, with the entropy of activation remaining essentially constant. It is for these reactions that the Hammett Law is essentially obeyed. 2) Changes in reaction rate are due mainly to changes in the entropy of activation, with the energy factor being practically constant. Such reactions are relatively rare, but they do occur. 3) Reactions for which both the entropy and the enthalpy of activa- tion change in a rather random fashion. 8). Reactions for which the changes in reaction rate are due to a change in both factors, but for which a linear relationship can be found to exist between the entr0py and the enthalpy factor. The proba- bility that the reaction series investigated in the present study falls; into the last mentioned type is apparently given. Leffler (86), as well as Wilmarth and Schwartz (87) have investi- gated this type of reaction series. In Leffler's paper a total of eighty-one reaction series were investigated; the authors employed either the simple Arrhenious equation (88) k ___ A e-E/RT or the modified collision approach (89) k = P Z e-E/RT where P is the "probability factor", and Z the "collision frequency". 53 Leffler used for his plots of reaction data either log A, log P2 or directly the entropy of activation as abscissa, and the energy of activa- tion as ordinate for the reaction series under study and obtained good straight line plots in the majority of cases. The various methods of treating rate data used by Leffler are equivalent as A is quite apparently equal to P2 and P2 is related to the entropy of activation by the rela- tionship: , P2 = (km/h) e‘AS/R (89) where k is the Boltzmann constant, R is the molar gas constant, andléfl is the "transmission" coefficient (89). Included in the studies made by Leffler (86) was the series investigated by Blomquist and Buselli (7), on the decomposition rates of substituted benzoyl peroxides. In this series it was found that two separate straight lines were obtained, when the entropies of activation were plotted against the energies of activation, one for the meta- and para- substituted benzoyl peroxides, and a second one for those peroxides bearing the substituents ortho relative to the peroxy linkage. It is particularly noteworthy that for the reactions investigated . in this study only one straight line is obtained, and that the experimental points show an almost perfect fit to this line, although there were included in this study compounds which would be expected to show marked "ortho" effects (8); these compounds are bis(2,5—dichloro-3-thendyl), bis(2,5- dimethy1-3-thenqyl), bis(8-bromo-5-ethyl-2-thenoy1), and bis(3-methy1- 2-thenoy1) peroxides. If the pattern shown for the substituted benzoyl peroxides (7) were followed, one would expect two separate straight lines to result, one for the above mentioned heterocyclic peroxides, and one S8 for the remaining compounds investigated in this work as the latter group would be comparable to the meta- and para- derivatives in the benzenoid series. This is apparently not the case for the substituted thendyl peroxides investigated. Leffler (86) states that "moderate changes in the degree of steric hindrance do not remove a reaction from the isokinetic line, but merely move it to a different position on the same line. One would expect with a considerable increase in steric hindrance in the transition state an increase in the enthalpy of acti- vation and decrease in the entropy of activation." From the data ob- tained in this investigation this seems to apply mainly for the case of bis(5—phehy1-2-thenoy1)peroxide, where a steric hindrance factor ap- pears to play only a minor role. Further investigation is quite ob- viously indicated, and is planned for the future study. The slope of the "isokinetic line" has the dimensions of temperature and is called the "isokinetic temperature". It is denoted by the symbol 8 (86). For the straight line plot: AH# = BAS# + constant for two points on the line: AH2# - 8H1# = B(ASZ# - ASI#) but AH# = AF# + TAS# and AHZ# - AH1# = T (usz# - ASI#) + T(AFZ# - AF1#) therefore, $(ASZ# - ASl#) = T (usz# - Asl#) + (AF2# - AF1#) Thus, it is apparent that 55 if AFZ# = AF1#, then B = T and at the temperature 8 all the reactions in the series should occur at the same rate, as their free energies of activation would then be equal. For the reaction series under investigation in the present study the slope of the line, (Fig. 15 ) is 369.8°K. or 96.2°C. If the series follows a true isokinetic behavior all the heterocyclic peroxides under investigation should decompose at equal rates at 96.20. There should also be, above the isokinetic temperature, an inversion of relative rates; the compounds showing the fastest rate below 96.2o should de- compose at the slowest rate above that temperature and vice versa (85). Again it is rather apparent that the present study has opened a wide field for further investigation. 3. SUMMARY Nine previously unreported bis thenoyl peroxides were prepared; four of these were derivatives of 2-thenoic acid and five were derived from 3-thenoic acid. All the intermediate acid chlorides used to synthesize the peroxides were also new compounds, char- acterized for the first time. The rates of thermal decomposition, in carbon tetrachloride, of eight of the nine above mentioned peroxides were studied, the only peroxide not so investigated being bis(8,5-dibromo-2-thenoy1)per- oxide for which a solvent Compatible with infra-red technique could not be found. The first order law was found to be obeyed for all compounds studied. Rate constants determined at 79.6° are, Peroxide k x 103 (min.‘1) Bis(5-bromo-3-thenoyl) 2.031 Bis(5-chloro-3-thenoy1) 1.862 Bis(3-methyl-2-thenoyl) 2.699 Bis(5-nitro-3-thendyl) 5.889 Bis(5-ethy1-8-bromo-2-thenoy1) 3.120 Bis(2,5-diChlor0-3-thendyl) 1.681 Bis(5-phenyl-2-thenoy1) 8.580 Bis(2,5-dimethy1-3-thenoy1) 3.789 Activation energies were determined and found to vary over a wide range, from 20.1 to 38.1 kilocalories per mole. This fairly well pre- . Cluded the applicability of the Hammett equation. A Hammett type rela- tionship was not expected, as several of the peroxides studied could be related to ortho-substituted benzenoid compounds. Entropies of activa- tion were also computed which varied from -22 to plus 30 entropy units. When the entropies of activation were plotted against the energies of 56 57 activation a straight line plot was obtained, which pointed toward an "isokinetic" reaction series, with the "isokinetic" temperature being equal to the slope of the straight line obtained -369.8°K. (or 96.2°C.). This opened possibilities for further investigation. (l) (2) (3) (8) (S) (6) (7) (8) (9) (10) (ll) (12) (13) (18) (15) (16) (17) (18) (19) (20) LITERATURE CITED Program for 188th American Chemical Society Meeting, Chem. Eng. New, N2, 100 (1968) - July 27 issue. Brown, D. J., J. Am. Chem. Soc., pg, 2657 (1980). Erlenmeyer, E. and W. Schwenauer, Helv. Chim. Acta, $2, 338 (1936). Hey, D. H. and W. A. Waters, Chem. Rev., 21, 202 (1937). W. A. Waters, The Chemistry of Free Radicals, Oxford Univ. Press, 1986. Bartlett, P. D. and K. Nozaki, J. Am. Chem. Soc., 68, 1686 (1986); ibid., 69, 2299 (1987). Swain, C. G., W. T. Stockmeyer and J. T. Clarke, ibid., 72, 5826 (1950). _ Blomquist, A. T. and A. J. Buselli, ibid., 13, 3883 (1951). Hammett, L. P., Physical Opganic Chemistry, McGraw Hill Book Co., New York, 1980. Bunnett, J. F., "The Interpretation of Rate Data," in A. Weissberger, Editor, Techniques of Organic Chemistry, Vol. VIII, Interscience Publishers, N. Y., 1961, page 218. Schuetz, R. D. and D. M. Teller, J. Org. Chem., 21, 810 (1962). Breitenbach, J. W. and H. Karlinger, Monatsh., 80, 739 (1989). Teller, D. M, Ph.D. Thesis, Michigan State University, 1959. Price, c. C. and E. Krebs, Org. Syn.,gg, 65 (1983). Bunnett, J. F., op. cit., page 217. Jaffe, H. H., Chem. Reviews, 53, 191 (1953). Dodson, H. A., Ph.D. Thesis, Michigan State University, 1961. Nishimura, J., R. Motoyama, and E. Imoto, Bull. Univ. Osaka Prefect: Ser. A, 6, 127 (1958). Shea, J. L., Ph.D. Thesis, Michigan State University, 1963. Gronowitz, s., Arkiv for Kemi, 1, 271 (1958). Zabik, Matthew, M. S. Thesis, Michigan State University, 1962. 58 (21) (22) (23) (28) (25) (26) (27) (28) (29) (30) (31) (32) (33) (38) (35) (36) (37) (38) (39) (80) (81) (82) 59 Gronowitz, S., Arkiv. Kemi, Z, 361 (1958). Campaigne, E. and W. Le Suer, J. Am. Chem. Soc., IQ: 3898 (1988). Campaigne, E. and R. C. Bourgeois, J. Am. Chem. Soc., 76, 2885 (1958). (a) Hartough, H. D. and A. I. Kosak, ibid., lg, 3898 71988). Hartough, H. D. and L. G. Conley, ibid., 52, 3096 (1987). Steinkopf, W. and Penz, Ann., 552, 836 (1938). Steinkopf, W. and W. Kohler, Ann., 552, 265 (1937). Hartough, H. D., "Thiophene and its Derivatives," in The Chemistry of Heterppyclic Compounds, Interscience Publishers, N.Y., 1952, page 505. Campaigne, E. and W. C. Archer, J. Am. Chem. Soc., 15, 989 (1953). King, J. W. and F. F. Nord, J. Org. Chem., 55, 635 (1988). Steinkopf, W., Ann., 212: 281 (1938). Gronowitz, S, EE_il°: Arkiv. Kemi, $1, 775 (1961). Steinkopf, W. and H. Jacob, Ann., 515, 273 (1935). Fawcett, R. J. and P. G. Rasmussen, J. Am. Chem. Soc., 67, 1705 (1985). " Rinkes, I. J., Rec. Trav. Chem., 55(8), 683 (1938). Goldfarb, Y. L., V. P. Litvinov, and V. I. Shedov, Zhurn. Obsh. Khimii, 39(2), 538 (1960). Rossini, F. D., F. T. Gucker,, H. L. Johnston, L. Pauling, and G. W. Vinal, J. Am. Chem. Soc., ZN, 2699 (1952). Daudel, P., R. Buii-Hoi and L. Martin, Bull. Soc. Chim., 15(5), 1202 (1988). Wheland, G. W., Resonance in Organic Chemistry, John Wiley and Sons, Inc., New York, 1955. Muhlert, L., Ber., 18, 3003 (1885). Byrne, D. R. and F. M. Gruen, Unpublished Results. Gronowitz, S., Arkiv. Kemi, Z, 361 (1958). Hine, J., Physical Organic Chemistry, McGraw-Hill Book Co., New York, 1962, p.7888. (83) (88) (85) ( 86) (87) (88) (89) 60 Imoto, E., T. Kimura, Y. Serugimoto, Y. Omori, and T. Okawara, Nippon Kagaku Zasshi, 89, 1021 (1959); C. A., 5g, 21276 (1959). Laidler, K. J., Chemical Kinetics, McGraw-Hill Book Co., New York, 1950, p’ 1311- Bunnett, J. P., op. cit., p. 208-210. Leffler, J. E., J. Org. Chem., g9, 1202 (1955). Wilmarth, W. K. and N. Schwartz, J. Am. Chem. Soc., 11, 8583 (1955). Arrhenius, 8., Z. physik. Chem., N, 226 (1889). Glasstone, S., K. Laidler, and H. Eyring, The Theory of Rate Processes, McGraw-Hill Book Co., New York, 198T, pp. 186-150. APPENDIX 61 62 Table V. SpeCtroscopic information leading to kinetic data. Bis-(5-br0mO-3-thenoyl)peroxide. . ' Code No. A - l - a Temperature: 78.3°C i 0.1. Solvent: .CC14-plus 0.2 M;styrene. saggfe gig? I0 I log Io log I A ' log A Run No. l. 1 0 13.2 1.1 1.12057 0.08139 1.07928 0.02310 2 60 12.8 0.9 1.10721 —0.08576 1.15297 discard 3 180 13.2 1.3 1.12057 0.11398 1.01663 1- 0.00715 ('8 300 13.1 1.8 1.11757 ' 0.25527 ~ 0.86230 "-0.06838 5 820 '13.8 2.6 1.12710 _ 0 81897_ 0.71313 -0.l8683 6 580 13.2 (3.0 1.12057 0.87712 0.68385 -0 19188 slope: 3.5590 x 10" k = 8.195 x 10‘4 min.‘1 Tl/z = 886 minutes. Run No. 2.4 Code No. A - 1 - b 1 0 13.6 1.8 1.13358 0.18613 0.98781 -0.00550 2 60 13.1 ‘ 1.2 1.11727 0.07918 0.93809 -0.02275 3 180 13.35 1.8 1.12588 0.25527 0.87021 -0.06037 8 300 13.35 2.5 1.12588 0.39798 0.72758 -O.13815 5 820 13.5 2.8 1.13033 0.88716 0.68317 -0.16185 6 580 13.35 3.8 . 1.12588 0.53188 0.59800 -0.22621 Slop€:f-8.0707 x 10'4 k - 9.375 x 10’4~min.’i Tl/Z = 780 minutes. Sum of square error (to indicate accuracy of data) = 5.786 x 10-4. "Far-rap, .._"' . o. 63 Table VI. Spectroscopic information leading to kinetic data. Bis-(5-bromo-3-thenoy1-) peroxide. Code No. A - 2 - a Temperature: 79.6°C i 0.1 Solvent: CC14 plus 0.2 N styrene. saggfe gig? I0 I log Io log I A log A Run No. . 1 0 13.9 1.3 1.18301 0.11398 1.02907 0.01285 2 60 13.8 2.3 1.13988 0.36173 0.77815 -0.10899 3 180 18.2 3.3 1.15229 0.51851 0.63378 -0.19807 8 300 18.0 8.5 1.18613 0.65321 0.89292 -0.30722 5 820 18.8 5.6 1.15836 0.78819 0.81017 -0 38703 6 580 18.2 6.6 1.15229 0.81958 0.33275 -0.87788 Slope: -8.5972 x 10’4 k 1.980 x 10'3 min."1 Tl/Z = 350.0 minutes. Run No. . Code No. A - 2 — b l 0 18.1 1.0 1.18922 0.00000 1.18922 0.06080 2 60 18.0 2.3 1.18613 0 36173 0.78880 -o.10586 3 180 18.3 3.5 1.15538 0.58807 0.61127 -0.2l377 8 300 18.2 8.5 1.15229 0.65321 0.89908 -0.30183 5 820 18.5 5.7 1.16137 0.75587 0.80550 -0 39201 6 580 18.8 6.6 1.15836 0.81958. 0.33882 —0.87003 Slope: —9.0875 x 10’4 k = 2.090 x 10'3 min.”1 Tl/2 = 331.1 minutes. Tablelflfl; Spectroscopic information leading to kinetic data. 68 Bis-(5-bromo-3-thenoyl-) peroxide. Code No. A - 3 - a Temperature: 85.0°C i 0.1 Solvent: CC14.p1us 0.2 N styrene. safifife' iii? I0 I log Io log I A log A Run No. 1. 1 0 13.1 1.0 1.1271 0.00000 1.12710 0.10815 2 60 13.3 2.8 1.2385 0.38021 0.78368 -0.12868 3 180 13.6 8.8 1.3358 0.68385 0.89009 -0 30972 8 300 13.3 6.1 1.12385 0.78533 0.33852 -0 87082 5 820 13.9 7.6 1.18301 0.88081 0.26220 -0.58l37 6 580 13.1 8.7 1.11727 0.93952 0.17775 -0.75260 Slope: 1.8635 x 10‘3 k = 3.370 x 10‘3 min.’1 Tl/2 = 205.6 minutes. Run.No. 2. Code No. A - 3 - b 1 0 13.8 1.5 1.13988 0.17609 0.96379 -0 01601 2 60 13.5 2.7 1.13033 0.83136 0.69897 -O.15558 3 180 13.9 5.1 1.18301 0.70757 0.83588 -0 36107 8 300 13.9 6.6 1.18301 0.81958 0.32387 -0 89017 5 820 18.2 8.0 ' 1.15229 0.90309 0.28920 —0.60385 6 580 18.0 9.1 1.18613 0.95908 0.18709 -0.72795 Slope: -1.2756 x 10'3 k = 2.937 x 10'3 min.’1 Tl/2 = 281.8 minutes. 65 Table VIII. Spectroscopic information leading to kinetic data. Bis—(5-chloro-3-thenoy1)peroxide Code No. B - 1 - a Temperature: 73.6°C. i 0.1 Solvent: CC14 plus 0.2N styrene. saggie iii? I0 I log Io log I A log A Run No. 1. 1 0 15.8 1.0 1.18752 0.00000 1.18752 0.07852 2 60 15.15 2.20 1.18081 0.38282 0.83799 -0.07676 3 180 15.8 2.95 1.19866 0.86982 0.72888 -0.13737 8 300 15.75 8.80 1.19728 0.68385 0.55383 -0.25663 5 820 15.9 8.85 1.20180 0.68836 0.55308 -0.25728 6 580 16.0 8.95 1.20812 0.69861 0.50951 -0.29285 Slope: '-8.032 x 10'4 k = 9.288 x 10‘4 min.‘1 Tl/Z = 786.1 minutes. Run No. 2. Code No. B - 1 - b 1 0 15.2 1.9 1.18188 0.27875 0.90309 -0.08836 2 60 15.3 2.0 1.18869 0.20103 0.88366 -0.05372 3 180 15.25 2.65 1.18327 0.82325 0.76002 -O.ll918 8 300 15.8 3.05 1.18752 0.88830 0.70322 —0.15297 5 820 15.5 3.85 1.19033 0.58586 0.60887 -0.21838 6 580 15.55 8.25 1.19173 0.62839 0.56338 -0.28923 Slope: -3.889 x 10'4 k = 8.956 x 10-4 sec.-1 Tl/z = 829.1 minutes. 66 Table IX. Spectroscopic information leading to kinetic data. Bis-(S—chloro—B—thenoyl)peroxide Code No. B - 2 - a Temperature: 79.6°C. i 0.1 Solvent: CC14 plus 0.2% styrene. Sa$g1e :12? IO I log Io log I A log A Run.No. l. 1 0 13.5 1.8 1.13033 0 18613 1 00820 0.00182 2 60 13.8 1.0 1 12710 0.00000 1.12710 0.05195 3 180 13.7 2.3 1.13672 0.36173 0.77899 -0.11070 8 300 13.6 3.8 1.13358 0 53188 0.60206 -0.22036 5 820 13.5 8.6 1.13033 0.66276 0.86757 -0.33015 6 580 13.8 5.8 1.13988 0.76383 0.37685 -0.82829 Slope: -9.167 x 10'4 k = 2.111 x 10'3 sec.‘1 Tl/é = 328.3 minutes. Run No. 2. Code No. B - 2 - b 1 0 13.95 1.8 1.1885? 0 18613 0.99888 -0.00062 2 60 18.0 2.0 1 18613 0.30103 0.88510 -0.07308 3 180 18.2 2.8 1.15229 0 88716 0.70513 -0.15173 8 300 18.0 3.8 1.18613 0.57978 0.56635 —0.28616 5 820 18.3 5.2 1.15538 0.71600 0.83938 -0.37720 6 580 18.25 6.1 1.15381 0.78533 0.36888 —0 83358 Slope: —7.50 x 10'4 k = 1.727 x 10‘3 sec.‘1 T1/2 = 801.3.minutes. Table X. Spectroscopic information leading to kinetic data. 67 Bis-(S-chloro-B-thenoy1)peroxide Code No. Temperature 85°C. i 0.1 B — 3 - a Solvent CCl4 plus 0.2M styrene. Safigle iii? 8 Io 1 log I0 log I A log A Run.No:1. 1 0 18.0 1.0 1.18613 0.00000 1 18613 0.16878 2 60 13.8 1.9 1.13988 0.27875 0.86113. -0.06893 3 180 18.1 3.9 1.18922 0.59106 0.55816 -0.25328 8 300 18.0 5.2 1.18613 0.71600 0.83013 -0.36680 5 820 18.8 7.7 1.15836 0.88689 0.27187 -0.56568 6 580 18.3 9.2 1.15538 0.96379 0.19155 -0.71771 Slope: -1.3889 x 10'3 k = 3.1986 x 10‘3 sec.”1 T1/2 = 216.7 minutes. Run No. 2. Code No. B - 3 - b 1 0 18.6 1.6 1.16835 0.20812 0.96023 -0 01758 2 60 18.8 2.6 1.15836 0.81897 0.66339 -0.17823 3 180 18.8 8.8 1.17026 0.68128 0.88902 -0.31067 8 300 18.7 6.6 1.16732 0.81958 0.38778 -0.85867 5 820 18.8 8.7 1.17026 0.93952 0.23078 -0.63688 6 580 18.8 9.8 1.17026 0.99123 0.17903 -0 78708 Slope: -1.2222 x 10'3 k = 2.8188 x 10‘3 sec.'1 Tl/Z = 286.2 minutes. 68 Table XI. Spectroscopic information leading to kinetic data. Bis-(5-nitro—3-thenoyl)peroxide Code No. C — l — a Temperature: 73.80C i 0.1 Solvent: CHC13 plus 0.2M styrene. s 1 T' afig e migf I0 I log Io log I A log A Run No.8 1. 1 0 12.0 0.7 1.07918 9.88510 1.23808 0.08132 -10 2 60 12.1 1.1 1.08279 0.08139 1.08180 0.01785 3 180 12.2 1.85 1.08636 0.16137 0.92899 -0.03386 8 '300 12.1 2.3 1.08279 0.36173 0.72106 —0.18200 5 820 12.3 3.95 1.08991 0.59660 0.89331 -0.30689 6 580 12.0 8.8 1.07918 0.68128 0.39798 -0.80017 Slope: -8.9769 x 10.4 k = 2.067 x 10.3 mini1 T1/ = 335.2 minutes. 2 Run No. 2. Code No. C - l - b 1 0 12.1 0.3 1.08279 9.87712 1.66567 0.20575 -10 2 60 11.9 0.85 1.07555 9.65321 1.82238 0.15290 -10 3 180 12.1 1.3 1.08279 0.11398 0.96885 -0.01572 8 300 11.95 2.8 1.07237 0.38021 0.69716 -0.15668 5 820 12.1 3.1 1.08279 0.89136 0.59183 -0 22812 6 580 11.9 8.65 1.07555 0.66785 0.80810 —0.38923‘ Slope: -1.123 x 10’3 k = 2.586 x 10‘3 min. -1 Tl/é = 268 minutes. 69 Table XII. Spectroscopic information leading to kinetic data. Bis-(5-nitro-3—thenoyl)peroxide Code No. C - 2 - a Temperature: 79.6°C i 0.1 Solvent: CHC13 plus 0.2fl styrene. saggfe ;::f 10 I log 10 log I A log A Run No. 1. 1 0 7.5 0.1 0.87506 -1.00000 1.87506 0.27300 2 60 7.5 0.7 0.87506 -0.15890 0.97996 -0.02877 3 120 7.5 0.9 0.87506 -0.0510 0.88383 -0.05318 8 180 7.8 1.2 0.86923 0 07918 0.79005 -0.10237 5 280 7.8 2.5 0.86923 0.39798 0.87129 -0.32670 6 300 7.2 3.0 0.85733 0.87712 0 38021 -0.82998 Slope: -2.1526 x 10'3 k = 8.957 x 10'3 min.'1 Tl/Z = 139.8 minutes. Run No. Code No. C - 2 - b 1 0 7.8 0.2 0 86923 -0.69897 1.56820 0.19580 2 60 7.8 1.3 0.89209 0.11398 0.77815 -0.01893 3 120 7.9 2.0 0.89763 0 30103 0.59660 -0.22832 8 180 7.5 2.65 0.87506 0.82325 0.85181 -0.38508 5 . 280 7.6 3.6 0 88081 0.55030 0.33051 -0.88082 6 ' 300 7.5 8.9 0.87506 0.69020 0.18886 -0.73316 Slope: -2.9281 x 10’3 k = 6.771 x 10‘3 min.’1 Tl/Z = 102.8 minutes. 70 Table XIII. Spectroscopic information leading to kinetic data. Bis-(5—nitro-3—thenoyl)peroxide Code No. C - 3 Temperature: 85.0°C. i 0.1 Solvent: CHC13 plus 0.2% styrene. Sa§§1e‘ gig? I0 I log Io log I A log A Run No. l. l 0 7.9 0.1 0.89763 -1.00000 1.89763 0.27821 2 60 7.7 1.6 0.89863 0.20812 0.69351 -0.15898 3 120 7.7 3.0 0.88689 0.87712 0.80937 -0.38788 8 180 7.9 8.0 0.89763 0.60206 0.29557 -0.52938 5 280 7.85 5.25 0.89887 0.72016 0.17871 -0.75768 6 300 7.5 666 0.87506 Slope: -8.0703 x 10‘3 k = 9.378 x 10‘3 min. "1 Ty/Z = 78.50 minutes. Table XIV. 71 Bis-(3-methyl—2-thenqyl)peroxide Spectroscopic information leading to kinetic data. Code No. D - l - a Temperature: 78.3°C. : 0.1 Solvent: CC14 plus styrene. Sa£§1e $888 10 1 log 10 log I A log A IMnNm L 1 0 15.0 0.8 1.17609 -0.09691 1.17300 0.06930 2 60 15.0 1.05 1.17609 0.02119 1.15890 0.06629 3 180 15.0 1.95 1 17609 0.29063 0.88586 -0.05283 8 300 18.6 2.25 1.16835 0.35218 0.81217 -0.09035 5 820 18.6 3.0 1.16835 0.87712 0.68723 -0.16270 6 580 18.6 3.7 1.16836 0.56820 0.59615 -0.22868 Slope: -5.31777 x 10'4 k = 1.225 x 10‘3 min.-1 Tl/Z = 565.9 minutes. Run No. 2. Code No. 0 - 1 - b 1 0 15.1 0.9 1.17869 -0.08576 1.22885 0.08798 2 60 15.0 1.6 1.17758 0 20812 0.97382 -0.01170 3 180 18.8 1.8 1.17026 0.25527 0.91899 -0.03858 8 300 18.8 2.5 1.17026 0.39798 0.77798 -0 10905 5 820 18.8 2.95 1.17026 0 86982 0.70088 —0.15888 6 580 18.8 3.8 1.17026 0.57978 0.59088 -0.22879 Slope: -5.25998 x 10" k = 1.211 x 10‘3 min.’1 Tl/Z = 603.5 minutes. Table XV. Spectroscopic information leading to kinetic data. 72 Bis-(3—metnyl-2-thenoyl)peroxide Code No. D — 2 - a Temperature: 79.6°C. t 0.1 Solvent: C014 plus 0 02! styrene. Saggle iigf I0 I ' log Io log I A log A Run No. l. 1 0 12.85 0.95 1.09517 -0.02228 1.11785 0.08823 2 60 12.3 1.75 1 08991 0.28308 0.86687 -0 06208 3 180 12.8 3.15 1.09382 _0.89831 0.59511 -0.22530 8 300 12.25 8.50 1.08889 0 65321 _0.83528 -0.36123 5 820 12.3 5.10 1.08991 ' 0.70757 0.38238 _0.81755 6 580 12.35 6.5 1.09167 0.81291 0.27876 -0.55877 s1ope: -1.0708 x 10‘? k = 2.865 x 10'3 min.'1 Tl/Z = 281.1 minutes. Run No. 2. Code No.7 D - 2 - b t 1 0 12.1 0.9 1.08279 -0.08576 1.12855 0.05252 2 60 11.8 1.3 1.07188 0.11398 0.95798 -0.01866 3 180 11.8. 2.7 1.07188 0.83136 0.68052 -0.19387 8 .300 11.85 8.1 1.07372 0.61278 0.86098 —0 33635 5 820 11.95 5.8 1.0773? 0.732398 0.38898 -0.86281 6 580 11.95 .7.0 1 07737 0.88510 0.22627 -0.68538 Slope: -l.2725 x 10-3 ,1: = 2.930 x 10‘3 min.‘1 Tl/z = 287.6 minutes. 73 Table XVI. Spectroscopic information leading to kinetic data. Temperature: Bis-(3-metnyl-2éthenoyl)peroxide Code No. 85.0°C. i 0.1 Solvent: D - 3 - a CC14 plus 0.02! styrene. Sa$§1e iii? Io .1 log 10 log 1 A log A Run No. 1. 1 0 11.9 0.2 1.07555 -0.69897 1.77852 0.28908 2 30 12.1 0.8 1.08279 -0.09691 1.17970 0.07177 3 60 - 11.5 0.9 1.06070 -0.08576 1.10686 0.08398 8 90 11.3 1.8 1.05308 0 25527 0.79781 -0.09806 5 120 11.5 2.0 1 06070 0.30103 0.75852. -0.12233 6 150 11.5 2.9 1 06070 0.86280 0.59030 —0.22308 Slope: -2.9381 x 10-3 k = 6.767 x 10.: min.‘1 Tl/Z = 102.8 minutes. Run No. 2. Code No. D - 3 - b 1 0 12.7 0.6 1.0380 -0.22185 1.22565 -0 08837 2 30 12.5 1.15 1.09691 0.06070 1.03621 0.01585 3 60 12.5 2.1 1.09691 0.32222 0.77869 -0.11082 8 90 7 12.0 2.3 1.07918 0 36173 0.71785 -0 18821 5 120 12.8 3.65 1.10721 0.56229 0.58892 -0.26366 6 150 11.8 8.0 1.07188 0 60206 0 86982 -0.32807 Slope: -2.8123 x 10-3 k = 6.877 X 10-3 min.-1 minutes. 78 Table XVII. Spectroscopic information leading to kinetic data. Bis-(S-éthyl-8-bromo—2—thenoyl)peroxide Code No. F — 1 - a Temperature: 73.80C. i 0.1 Solvent: CC14 plus styrene. Saggle gig? Io I log 10 log I A log A Run No. l. 1 0 13.3 0.8 1.12385 -0.39798 1.52179 0.18235 2 120 12.8 0.75 1 10721 -0.12898 1.23215 0.08066 3 280 13.1 0.85 1.11727 -0.07058 1.08663 0.01979 8 360 12.8 1.85 1.09382 0.16137 0.93205 -0.03056 5 880 12.8 1.5 0.17609 0.93112. 0.93112 -0.03099 6 600 12.5 2.2 1 09691 0.32282 0.75889 -0.12235 -1 Slope: -8.8873 x 10'4 k - 1.0338 x 10J min. T1/ = 670.6 minutes. 2 Run No. 2. Code No. F - l - b 1 0 18.1 1.8 1.11727 0.18613 1.00309 0.00008 2 120 12.9 1.0 1.11059 0.00000 1.11059 0.08558 3 280 13.8 1.5 1.12710 0.17609 0.95101 —0.02181 8 360 12.8 1.6 1.10721 0.20812 0.90309 -0.08826 5 880 13.2 2.25 1.12057 0 35218 0.76839 -0.11888 6 600 12.85 2.6 1.10890 0.81897 0.69393 —0.15868 Slope: -8.17592 x 10'4 k = 9.615 x 10'4 min.‘1 Tl/z - 720.7 minutes. Table XVIII. 7S Spectroscopic information leading to kinetic data. Bis-(5-ethyl-8—bromo-2-thenoyl)peroxide Code No. F - 2 - a Temperature 79.6°C. i 0.1 Solvent: CCl4 plus styrene. sagfiTe iii? 10 1 log 10 log I A log A Run No. 1. 1 0 11.35 0.85 1.05500 -0.38679 1.80179 0.18669 2 60 11.35 0.75 1.05500 -0.12898 1.17998 0.07187 3 120 11 35 1.6 1 05500 0.20812 0.85088 _0.07013 8 180 11.85 2.1 1.05881 0.32222 0.73659 -0.13278 5 280 11.2 2.35 1.08922 0.37107 0.67885 -0 16888 6 300 11.65 3.0 1.06633 0.87712 0.58921 -0.22973 Slope: -1.2698 x 10’3 k = 2.923 x 10'3 min.”1 Tl/Z = 237.1 minutes. Run No. 2. Code No. F - 2 - b 1 0 11.35 0.85 1.05500 -0.38679 1.18079 0 18669 2 60 10.95 0.9 1.03981 -0.08576 1.08517 0.03390 3 120 11.15 1.6 1.08727 0.20812 0.88315 -0.07809 8 180 11.0 1.85 1.08139 0.26717 0.77822 -0.11118 5 280 10.5 2.15 1.02119 0.33288 0.68875 —0 16198 6 300 10.35 2.6 1.01898 0.81897 0.59997 —0.22187 Slope: -1.1789 x 10'3 k = 2.706 x 10’3 min.“1 Tl/Z = 262.1 minutes. 76 Table XIX. Spectroscopic information leading to kinetic data. Bis-(5—ethy1-8-brompe2-thenoyl)peroxide Code No. F - 3 - a Temperature: 85.0°C. i 0.1 Solvent: C014 plus Styrene. Sa$§1e iii? 10 1 log 10 log 1 A log A Run No. 1. 1 0 12.5 1.35 1.09691 0.13033 0.96558 -0.01522 2 60 12 35 2.2 1.09167 0 38282 0.78925 -o.12531 3 120 12 35 3.7 1 09167 0.56820 0.52387 -0.28028 8 180 12.65 8.6 1.10209 0 66276 0.83933 -0.35728 5 280 12.5 5.2 1 09691 0 71600 0.38091 -0.81918 6 300 12.6 5.75 1.10037 0.75967 0.38070 -0.86763 Slope: -1.53363 x 10'3 k = 3.578 x 10‘3 min.“1 Tl/Z = 193.1 minutes. Run No. 2. Code No. F — 3 - b 1 0 11.8 0.5 1.05690 -0.30103 1.35793 0.13288 2 60 11.05 1.5 1.08336 0 17609 0.86667 -0 06218 3 120 11.5 2.8 1.06070 0.88716 0.61358 -0.21273 8 180 11 35 3.5 1.05500 0.58807 0.51093 -0.29168 5 280 11.8 8.8 1.05690 0 68385 0.81385 -0.38357 6 300 11.25 8.9 1.05115 0.69020 0.35895 -0.88897 s1ope: -1.8726 x 10'3 k = 8.293 x 10'3 min.71~ Tl/z = 161.8 minutes. 77 Table XX. Spectroscopic information leading to kinetic data. Bis-(2,5-diChloro-3—thenoyl)peroxide Code No. 0 - l - a Temperature: 73.80C. i 0.1 Solvent: CC14 plus sytrene. safiife 38:? Io 1 log 10 log I A log A Run No. 1. 1 0 9.0 0.8 0.95828 -0.09691 1.05115 0.02166 2 60 9.1 0.85 0.95908 -0.07058 1.02962 0.01268 3 180 9.10 1.2 0.95908 0 07918 0.87986 -0.05559 8 300 9.05 1.8 0.95665 0.18613 0.81052 -0 09128 5 820 8.75 1.8 0.98201 0.25527 0.68678 -0.16388 6 580 9.25 2.25 0.96618 0.35218 0.61396 -0.21186 “Lg ll Slope: -8.828 x 10" k 1 111 x 10'3 min. 1 Tl/Z = 628.3 minutes. Run No. 2. Code No. 0 - 1 - b 1 0 9.0 0.8 0.95828 -0.09691 1.05115 0.02116 2 60 9.2 1.05 0.96379 0.02119 0.98260 -0.02567 3 180 9.15 1.3 0.96182 0.11398 0.88788 -0.07187 8 300 9.1 1.65 0.95908 0.21788 0.78356 -0.12868 5 820 9.1 2.2 0.95908 0 38282 0.61662 —0.20999 6 580 8.9 2.35 0.98939 0.37107 0.57832 -O.2379O s1ope: -8.581 x 10'4 k = 1.055 x 10'3 min.-1 Tl/z = 657.8 minutes. 78 Table XXI. Spectroscopic information leading to kinetic data. Bis-(2,5-dichloro-3-thenoyl)peroxide Code No. 0 - 2 - a Temperature: 79.80C. i 0.1 Solvent: CC14 plus styrene. sa§§%€ gig? I0 I log Io log I A log A Run No. . 1 0 9.3 1.15 0.96888 0 06070 0.90778 —0.08202 2 60 9.3 1.65 0 96888 0.21788 0.75100 -0.12836 3 180 9.35 2.25 0.97081 0.35218 0.61863 -0.20857 8 300 9.35 3.1 0.97081 0.89136 0.87985 _0.31925 5 580 9.1 3.9 0.95908 0.59106 0.36798 _0.83817 6 660 9.1 8.85 0.95908 0.68836 0.31068 -0.50769 s1ope:-7.095 x 10‘4 k = 1.638 x 10'3 min."1 Tl/é = 828.1 minutes. Run No. . Code No. G - 2 - b 1 0 9.1 0.9 0.95908 -0.08576 1.00880 0.00208 2 60 9.15 1.3 0.96182 0.11398 0.88788 -0.07187 3 180 9.05 2.0 0 95665 0 30103 0.65562 -0 18335 8 300 9.0 2.7 0.95828 0.83136 0.52529 —0 27960 5 580 9.1 3.9 0.95908 0.59106 0.36798 -0.83817 6 660 8.8 8.8 0.98888 0.68385 0.30103 _0.52139 Slope:-7.899 X 10—4 k = 1 727 x 10‘3 min."1 Tl/z = 801.3 minutes. 79 Table XXII. Spectroscopic information leading to kipetic data. Bis-(2,5-dichloro-B-thenoyl)peroxide Code No. C - 3 — a Temperature: 85.0°C. i 0.1 Solvent: CC14 plus styrene saggie gig? I0 I log Io log I A log A Run No. l. 1 0 9.15 0.95 0.96182 -0.02228 0.98370 -0.02787 2 60 9.05 1.65 0.95665 0 21788 0.73917 -0.13126 3 180 9.1 3.1 0.95908 0.89136 0.86768 -0.33005 8 300 9.05 8.3 0.95665 0.63387 0.32318 —0.89056 5 820 9.0 8.85 0 95828 0.68578 0.26850 -0.57106 6 580 9.0 5.5 0.95828 0.78036 0.21388 —0.67893 k = 2.891 x 10’3 min.‘1 Slope: ~-l.255 x 10-3 T1/ = 239.7 minutes. 2 Run No. 2. Code No. 0 — 3 - b 1 0 9.15 1.0 0.96182 0.00000 0.96182 -0 03709 2 60 8.9 1.5 0.98939 0.17609 0.77330 -0.11165 3 180 8.8 3.0 0.98888 0.87712 0.86736 ~0.33035 8 300 8.8 3.9 0.98888 0.59106 0.35382 -0.85170 5 820 9.15 8.9 0.96182 0.69020 0.27122 -0.56668 6 580 9.0 5.5 0.95828 0 78036 0.21388 -0.66983 Slope: -1.330 x 10‘3 k . 3.063 x 10‘3 min."1 Tl/Z =237.0 minutes. 80 Table XXIII. Spectroscopic information leading to kinetic data. Bis-(S-phenyl-2-thenoyl)peroxide Code No. H - l — a Temperature: 73.8°C. i 0.1 Solvent: CC14 plus 0.2 M styrene. sa§§fe gig? I0 I log Io log I A log A Run No. 1. 1 0 12.8 3.25 1.09382 0.51188 0.58158 -0.23582 2 30 12.5 3.55 1 09691 0.55023 0.58668 -0.26227 3 60 12.5 8.10 1 09691 0 61278 0.88813 -0.31508 8 90 12.8 8.60 1.10721 0.66276 0.88885 -0 35218 5 120 12.8 8.80 1.09382 0.68128 0.81218 -0.38891 Slope: -1.33 x 10‘ k = 3.056 x 10‘3 min.‘1 Tl/Z = 226. minutes. Run No. 2. Code No. H - 1 - b 1 0 6.9 1.7 0.83885 0.23086 0.60880 -0.21581 2 30 7.0 1.9 0.88510 0.27875 0.56685 -0.28688 3 60 6.85 2.25 0.83569 0.35218 0.88351 -0.31559 8 90 7.0 2.3 0.88510 0.36173 0.88337 -0.31571 5 120 7.05 2.75 0.88819 0.83933 0.80886 -0.38882 6 150 Reduced to shoulder. s1ope: ~1.80 x‘10‘3' k = 3.228 x 10'3 min.‘1 Tl/2 = 218.9 minutes. 81 Table XXIV. Spectroscopic information leading to kinetic data. Bis-(5-pehny1-2-tnenoy1)peroxide Code No. H - 2 - a Temperature: 79.8°C. : 0.1 Solvent: CC14 plus 0.2 M styrene. Sa$21e iii? I0 I log Io log I A log A Run No. 1. 1 0 7.2 0.7 0.85733 -0 15890 1.01223 0.00528 2 10 6.7 1.2 0.82607 0.07918 0.78689 -0.12675 3 20 6.35 1.0 0.80277 0.00000 0 80277 -0 09581 8 30 6.50 1.6 0.81291 0 20812 0.60870 -0.21558 5 80 6.35 1.3 0.80277 0 11398 0.68883 -0.16189 6 50 6.50 1.8 0.81291 0.25527 0.55768 —0 25365 Slope: -8.099 x 10'3 k = 9.88 x 10'3 min.‘1 Tl/Z = 78.66 minutes. Run No. 2. Code No. H - 2 - b 1 0 7.25 1.80 0.86038 0 18613 0.71821 I—0.18617 2 10 7.00 1.80 0 88510 0.25527 0.58983 -0.22928 3 20 7.30 1.95 0.86332 0.29003 0.57329 -0.28163 8 30 7.35 2.30 0.86629 0.36173 0.50856 -0.29708 5 80 7.35 2.30 0.86629 0.36173 0.50856 -0.29708 6 50 7.35 2.80 0.86629 0 88716 0.81913 -0.37765 Slope: -3.203 x 10-3 k = 7.377 x 10-3 min.-1 T1/2 - 93.98 minutes. Table XXV. 83 Bis-(5-pheny1-2-thenqyl)peroxide Spectroscopic information leading to kinetic data. Code No. H — 3 — a Temperature: 85.0°C. i 0.1 Solvent: CCl4 p1us styrene. saggfe 8:27 I0 I log Io log I A log A Run No. 1. 1 0 6.35 0.75 0 80277 -0.12898 0.92771 -0.03258 2 5 6.30 .0.90 0.79938 -0 08576 0 88510 —0.07309 3 10 6.20 0.70 0.79239 -0.15390 0.98729 -0.02351 8 15 6.15 1.05 0.78888 0 02119 0.76770 -0.11881 5 20 6.20 1.30 0.79239 0.11398 0.67885 ~0.16888 6 25 6.80 1.85 0.80618 0.25717 0.58901 -0.25972 Slope: -8.098 x 10'3 k = 1.865 x 10‘2 min."2 Tl/2 = 37.2 minutes. Run No. 2. 1 0 6.35 0.70 0 80277 -0.15890 0.95767 -0.01879 2 5 6.30 0.90 0.79938 -0.08576 0.88510 -0.07309 3 10 6.25 0.75 0.79588 -0.12898 0.92082 -0.03518 8 15 6.20 1.10 0.79239 0.08139 0 75100 -0.12836 5 20 6.20 1.25 0 79239 0.09691 0.69588 -0.15771 6 25 6.20 1.75 0.79239 0.28308 0.58935 -O.26015 Slope: -9,206 x 1073 k = 2.12 x 10:2 min.-1 Tl/2 = 38.2 minutes. 88 Table XXVI. Spectroscopic information leading to kinetic data. Bis-(2,5-dimethy123-thenoyl)peroxide Code No. I — 1 - a Temperature: 83.80C. i 0.1 Solvent: CC14 plus 0.2M styrene. sa§§%€ iii? I0 I log Io log I A log A Run No. 1. 1 0 9.55 0.85 0.98000 -0.07058 1.05058 0.02182 2 60 10.15 1.25 1.00687 0 09691 0.90956 -0.08117 3 180 9.55 2.0 0.98000 0 30103 0.67897 -0.16815 8 300 10.1 2.6 1.00832 0.81897 0.58935 -0.22962 5 820 9.85 3.25 0.99388 0 51188 0.88156 -0 35501 6 580 10.2 3.9 1.00860 0 59106 0.81758 -0.38930 #4; —3 Slope: —l.0 x 10 k = 2.303 x 10'3 min. '1 Tl/Z = 300.9 minutes. Run No. 2. Code No. I - l - b 1 0 9.15 0.15 0.96182 _0.82391 1.78533 0.25172 2 60 9.1 0.3 0.95908 —0.52288 1.88192 0.17083 3 180 9.65 1.8 0.98853 0.18613 0.83880 —0.07655 8 300 9.60 2.0 0.98227 0.30103 0.68128 -0.16670 5 820 9.85 2.7 0.99388 0.83136 0.56098 -0.25105 6 580 9.15 3.15 0 96182 0.89831 0.86311 -0 33832 Slope: -1.25 x 10’3 k = 2.896 x 10‘3 min.-1 Tl/2 = 239.3 minutes. 85 Table XXVII. Spectroscopic information leading to kinetic data. Bis-(2,5-dimetnyl—3-thenoyl)peroxide Code No. I - 2 - a Temperature: 79.6°C. i 0.1 Solvent: CC14 p1us 0.2M styrene. saggfe 8:3? I0 I log Io log I A log A Run No. 1. 1 0 9.8 0.2 0.97313 —0.69897 1.67210 0.22327 2 60 8.85 0.9 0.98698 -0.08576 1.09270 0.03850 3 180 9.15 2.8 0.96182 0.38021 0.62121 -0.20676 8 300 8.85 3.35 0.98698 0.52508 0.82190 -O.37879 5 820 9.85 8.8 0.97583 0.68385 0.33198 -0.87889 6 580 8.75 5.25 0 98201 0.72016 0.22185 -0.65398 Slope: -1.63 x 10‘3 k = 3.758 x 10‘3 min.“1 Tl/Z = 188.6 minutes. Run No. 2. Code No. I - 2 — b 1 0 9.35 0.25 0.97081 -0.60806 1.57887 0.19723 2 60 9.2 1.6 0.96379 0.20812 0.75967 -0.11938 3 180 8.85 1.8 0.98698 0.18613 0.80081 -0.09687 8 300 9.2 3.3 0.96379 0 51851 0.88528 -0.35137 5 820 9.25 8.6 0.96618 0.66216 0.30398 -0.51716 6 580 9.0 5.0 0.95828 0 69897 0.25527 -0.59300 s1ope: -1.66 x 10‘3 k = 3.823 x 10'3 min.‘1 Tl/Z = 181.3 minutes. 86 Table XXVIII. Spectroscopic information leading to kinetic data. Bis-(2,5—dimethyl-3—thenoyl)peroxide Code No. I - 3 - a Temperature: 85.0°C. i 0.1 Sample Time No. min. lo I log Io log I A log A Run No. l. 1 0 9.25 0.1 0.96618 -1.00000 1.96198 0.29268 2 60 9.0 1.7 0.95821 0.23085 0.72376 -0.18081 3 180 9.25 3.95 0 96618 0 59660 0.36958 -0.83238 8 300 8.65 5.5 0.93702 0.78036 0.19666 -0.70629 5 820 9.25 6.5 0.96618 0.81291 0.15323 -0.81866 ‘1 Slope: -2.82 x 10’ k = 5.57 x 10'3 min. T1/ = 128.8 minutes. 2 Run No. 2. Code No. I - 3 - b l 0 9.8 0.2 0.97313 -0.69897 1.67110 0.22301 2 60 8.65 1.8 0.93702 0.18613 0.79089 —0.10188 3 180 9.05 8.25 0.95665 0 62839 0.32826 -0.88578 8 300 8.85 8.5 0.98698 0 65321 0.29373 -0 53205 5 820 8.85 6.0 0.98698 0.77815 0.16879 —0.77265 s1ope: -2.5 x 10'3 k = 5.75 x 10':5 min.-1 T1/: = 120.5 minutes. 2 87 Table XXIX. Summary of kinetic data for the thenoyl peroxides. Compound . -1 T l/T (peroxide) k (mln' ) 109 K (°K.) x 103 Bis-(5-bromo- 8.79 X 10:4 -3.05601 387.5 2.878 3-thenoyl) 2 031 x 10_: -2.69229 352.8 2.835 3.589 x 10 -2.55897 358.2 2.792 Energy of activation: 28,818 Cal. mole—l Entropy of activation (average): -8.823 e.u. Bis-(5-chloro- 1.355 x 10‘3 -2 86806 386.8 2.883 3-thenoyl) 1.862 x 10‘3 -2 73002 352.8 2.835 3.268 x 10‘3 -2.88572 358.2 2 792 Energy of activation: 20,135 cal. mole-l Entropy of activation (average): -22.22 e.u. Bis-(5-nitro- 2.329 x 10-3 -2.63282 387.0 2.883 3-thenoyl) 5.889 x 10'3 -2.23292 352 8 2 835 9.373 x 10’3 -2.02812 358.2 2 792 Energy of activation: 30,202 cal. mole"l Entropy of activation (average): 7.589 e.u. Bis-(3-metny1- 1.535 x10:3 -2.81389 387.5 2.878 2—thenoyl) 2.699 x 10_3 -2.56880 352 8 2.835 6.333 x 10 3 -2.19839 358.2 2.792 Energy of activation: 29,836 cal. mole-1 Entropy of activation (average): 5.739 e.u. Bis-(8-bromo- 1.070 x 10:3 -2.97062 387.0 2.882 5-ethyl-2-thenoyl) 3 120 x 10_: —2 50585 352 8 2.835 8.369 X 10 -2.35962 358.2 2.792 Energy of activation: 28,710 cal. mole.1 Entropy of activation (average): 2.833 e.u. 'Bis-(2,5—dichloro- 1.080 x 10'3 -2.96658 387.0 2 882 3-thenqyl) 1.681 x 10-3 -2.77883 353.0 2.833 2.976 x 10‘3 -2 52637 358 2 2 792 Energy of activation: 23,063 cal. mole-1 Entropy of activation (average): -l8.71 e.u. 88 Table XXIX. (Cont.) Compound . -1 T 1/T (peroxide) k (min. ) log K (°K.) X 103 Bis—(5-phenyl- 3.180 x 10‘3 -2.50307 387.0 2.883 H 1 2-thenoyl) 8.580 x 10:3 -2.06651 353.0 2.835 H 2 2.000 x 10 2 -1 69897 358.2 2.792 H 3 Energy of activation: 38,180 cl. mole-l Entropy of activation (average): 29.72 e.u. Bis—(2,5-dimetny1- 2.599 x 10‘3 —2.58519 387.0 2.883 I 1 3-thenoy1) 3 789 x 10‘3 -2 82188 352.8 2 833 1-2 I 3 5.666 x 10‘3 —2.28672 358.2 2.792 Energy of activation: 21,050 cal. mole"1 Entropy of activation (average): -20.87 e.u. 89 Table XXX. Calculation of entropies of activation. AA... ) Compound E Temp. log k ~1 Entropy of (peroxide) iCt’l - 0K. (sec.) 5 (S€C° ) Activation ca “m0 e cal. deg.’ mole"l Bis—(S-bromo— 28,818 387 5 -8.838 5.889 x 1010 -9.555 3-thenoyl) 352.8 -8.870 7.983 x 1010 -9.001 358.2 -3.976 1.889 x 1011 —7.925 Bis-(5-chloro- 20,135 386.8 -8.686 1.099 x 108 -22.05 3-thenoy1) 352.8 -8.288 1.582 x 108 -22.81 358.2 -8.268 1.685.x 108 -22.21 Bis—(5-nitro- 30,202 387.0 -8.811 1.567 x 1014 6.127 3—thenoy1) 352.8 -8.977 8.977 X 1014 8.578 358.2 -3.806 8.159 x 1014 8.068 Bis—(3-metny1- 29,836 387.5 -8-592 1.863 x 1014 5.721 2-tnenoy1) 352 8 -8 387 1.386 x 1014 6.237 358.2 -3.976 2.090 x 1014 5 260 Bis-(8-bromo— 28,710 387 0 -8.789 2.183 x 1013 2.173 5-etny1- 352.8 -8.288 3.083 x 1013 2.850 2—thenqyl 358.2 -8.l38 2.383 x 1013 2.306 Bis-(2,5-di 23,063 387.0 -8 785 6.012 x 109 -18.81 chloro-3-thenqyl) 353.0 -8.552 5.333 x 109 —15.50 358.2 -8.305 5.821 x 109 -18.22 Bis-(S-pheny1- 38,180 287.0 -8.281 5.870 x 1019 29.87 2—thenqyl 353.0 -3.888 5.835 x 1019 29.56 358.2 -3.877 7.889 x 1019 30.13 Bis-(2,5—di- 21,050 387.0 -8.136 7.835 x 108 -20.18 methyl-3-thenoyl) 352.8 —8.l99 6.919 x 108 -20.83 358.2 -8.025 6.587 x 108 —20.88 m .1H 90 NH Ha .opflxOnmaAaxoconumufixfiboeumvman mo asupooam ConmnMCH mcouUMS cm camcofio>m3 m u o m a q _ _ H - _ .H oQSmHm .— 91 Ha a- .oCHxOuoaflfihoconu:MIOpoHcUwpumamvmHQ mo evapooam popmpMCH .m madmwm mcouowz.cw camcoao>m3 2 a m a. o m a m A H _ a a Jl 1 92 Ha .opwaquAHzococbumuaxdocanmvman mo Ednpoomm Conmuwcw .m opnmflm mcopome cm Cpmcmflo>m3 OH m w m o m a m m a q u d 1 fl OH .ocmequAHzococoumlflxnpoemoum.mvmab mo ESppoon UopmnwcH mCOpomz cm Cpmcoflo>m3 a a a. o..m a .4 whamam 93 ..4 d -1 _ _ .14 98 13 - 12 — \] l (see Table VII) 0\ .55- g 55"? \J‘L l Tiansmisoion be [—7 r O I 1 I I I J I _J I I 5.7 5.7 5.7 5.7 5.7 Wavelengths in Microns Figure 5. Quantitative infrared spectra on the decomposition of bis(5-bromo—3-thenoy1)peroxide H r—a 00 \o O 1-4 l? f —r 2 \ ##‘j 5.7 18 12 ll 10 «1 O\ 1:“ Transmission (See Table XV) L3,) W I\_) 0% 95 q- I l L l I l I I I 1— I . 577 9:7 . 5.7 07 a Wavelength in Microns Figure 6. Quantitative infrared Spectra of the decomposition of bis(3-methyl-2-thenoy1)peroxide. Transmission (see Table XVI) Lo 1? \n O\ \l 00 I 1 T I! I\) I CL_ 96 m 78 “7, fl . l . l . i . I .‘ i . . 51.7 5.7 5.7 5.7 5.7 5.7 Wavelength in Microns Figure 7. Quantitative infrared spectra of the decomposition of bis(3—methyl-2—thenqyl)peroxide. 97 Transmission (see Table XVII) ,3 m m 1:— 01 0\ ~51 (13 \o O 5.7 5.7 5.7 5.7 5.7 Wavelength in Microns Figure 8. Quantitative infrared spectra of the decomposition of bis(8—bromo—5-ethy1-3-thenoyl)peroxide. 5.7 12' 11 NWW Transmission (see Table XVIII) R) p... (g . 1L‘_ 0‘3 11“ U1 kn) 98 (I) \| ” :‘ _ g . i . 5 . E . 1 5.7 7 5.7 5.7 5.7 5.7 Figure 9. Quantitative infrared spectra of the decomposition of ~ bis(8—bromo—5-ethyl-2—thenoyl)peroxide. W \1 99 13 121- W ...... 1 JS \1 O\ \JI 8' TransmiSSiOn (see Table XIX) 3 U 2 I 1 - O J 1 I 1" I l I l I L I 41 5.7 5.7 5.7 5.7 5.7 5.7 Wavelength in Microns :‘ Figure 10. Quantitative infrared spectra on the decomposition of bis(5-ethyl-8-bromo-2-thenoy1)peroxide. 100 10. '1 i \1 If O\ t 1?‘ w I Transmission (589 Table XX) “J \n I 1 8 1 I 1 I 1 I I I 141 1 1 7 ' 5.7 5.7 5.7 5.7 ‘ 5.7 Wavelength in Microns Figure 11. Quantitative infrared spectra on the decomposition of bis(2,5-diChloro-3-thenoyl)peroxide. 101 (33 I O\\] U‘L b) 1?‘ Transmission (see Table XXI) O- l I 1 l I I I 1 In 1 I I1 I 5.7 5.7 5.7 5. 5.7 Wavelength in Microns [\3 Figure 12. Quantitative infrared spectra on the decomposition of bis(2,5-diChloro-3-thenqyl)peroxide. m~.m ”OH x A\H rm am.m mm.m am.m om.m mw.m am.m mm.m mw.m Hw.m cm.w V . . _ a q u d a q — A m .. . a n” . .m .a-oHoa .Hno 04H mm a we 0mm.m- . uaoam .maohawa .onHxOpoQAfixoconumnflxdonaumean mo compm>wuum mo monocm 1...: ..a.m-_ k 501 H.m IOoNI m.Hu om.m mm.m ‘1 moa x b\a Fm.m - ow.m mmwm am.m mw.m mm.m H.oaoa .Hno omo.am u nma 08.4.. 33m . 0638qu Aaaoeoeo-m-aacooaao-m.mvuao mo ooaoo>apon mo Smnocm Hmfi .aa onomaa O®.m QTN _ma.m .40.? H 501 a.m- m.m: .16.m- 108 .cowpm>wuom Ho xaoppcm mdmuo> cowum>wpom mo xmuoco mo uon .mH madman mums: SQOppco m< om. mm. on. -ma+ 68. m. o m.8 o8- ma- on- A! _ m u 4 H j - u a law 3 G a ‘ Q a -8 ‘ ‘37 An‘ 5 ‘ 10m 1.mm Q\ I_anm/I_aa.152p {eoy#3v "1111711771711117117s