SYNTHESJS AND THERMAL DECOMPOSJTEON OF SOME BIS ( 2-THENOY‘L) PBROXBDES Thain: for N10 Dogma of Ph. D. MYCHIGAIN STATE UNIVERSITY Daniel Myron Teller 1959 “Hump“. This is to certify that the thesis entitled Synthesis and Thermal Lecomposition of Some Eis(2-Ehenoyl) Ieroxides presented by Daniel Myron Teller has been accepted towards fulfillment of the requirements for _£hL_D._dqpm:nL£hemi£Lry ”:va .ZZVVKMMZ: / {XV Major professor LIBRAR Y Michigan Sta tr: Univcr..j;y SYNTHESIS AND THERMAL DECOMPOSITION OF SOME BIS(2-THENOYL)PEROXIOES BY Daniel Myron Teller A THESIS Submitted to the School for Advanced Graduate Studies of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Chemistry 1959 ACKNOWLEDGMENT The author wishes to express his sincere gratitude to Dr. Robert D. Schuetz for his faithful guidance throughout the course of this study. Appreciation is extended to the Renaud Foundation for their financial support. Heartfelt thanks are extended to Harold Bryan and Joseph W. Horton who programmed the kinetic data for the Mistic Electronic Digital Computer at Michigan State University. **-3i-'3'r**%* 11 To my wife, Madelyn 111 VITA Daniel Myron Teller Candidate for the Degree of Doctor of Philosophy Major Subject: Organic Chemistry Minor Subjects: Inorganic and Biological Chemistry Biographical Data: Date of Birth: February 10, 1930 in Nashville, Tennessee Education: B. S. in Chemistry, Northwestern University, 1952 M. S. in Organic Chemistry, Loyola University, 1955 Additional Graduate Study, Michigan State University, 1953-1959 Experience: Graduate Assistant, Loyola University, September 1952 to June 1953 Research Assistant, Loyola University, Summer, 19Sh Graduate Assistant, Michigan State University, September 1953 to June 1958 Professional Affiliations: American Chemical Society The Society of Sigma Xi iv ABSTRACT The effect of substituents on the rate of Spontaneous thermal decomposition of substituted bis(2-thenoy1)peroxides in carbon tetrachloride has been investigated. A new series of symmetrical S,S'-disubstituted bis(2-thenoyl)peroxides was prepared, in which the substituents were chloro, bromo, methyl, t-butyl and nitro groups. Two new h,h'-disubstituted bis(2-thenoy1)peroxides, the h,h'-dimethyl and h,h'-dibromo compounds were also studied, as well as the unsymmetrical Semethyl bis(2—thenoy1)peroxide. Although it is not struc- turally a bis(2-thenoyl)peroxide, bis(3-thenoyl)peroxide was prepared and studied for comparative purposes. The rates of the Spontaneous decomposition of these peroxides were determined by carrying out their decompositions in the presence of an efficient free-radical scavenger. The scavenger trapped the radicals formed in the spontaneous de- composition, thus preventing any induced decomposition of unreacted peroxide by attack of the initially-formed radicals. All of the decompositions were carried out in dilute ' solutions of carbon tetrachloride. The scavenger used was 3,h-dichlorostyrene. In all cases studied with the exception of bis(S-nitro-2-thenoy1) peroxide, the rates of thermal de- composition followed strict first order kinetics. The first order rate constants for the decomposition of the peroxides in carbon tetrachloride in the geesence of 3,h-dichlorostyrene, determined at 75° are: Peroxide k x 103 (min.‘1) _Bis(5-methy1-2-thenoyl) 2.5M Bis ( S-E-butyl-Z- thenoyl) 2A3 S-Methyl bis(2-thenoy1) 1.79 Bis(LL—methyl-2-thenoyl) 1.76 Bis(2—thenoyl) 1.33 Bis(3-thenoy1) 1.29 Bis(5-chloro-2-thenoyl) 0.95 Bis(5-bromo-2-thenoyl) 0.92 Bis(h-bromo-2-thenoy1) 0.69 Examination of the rate constants Shows that the presence of electron donating substituents on the thiophene ring accelerates the rate of decomposition, while electron drawing substituents have the opposite effect. A close parallel in rate constants is observed, both in the absolute values and the relative order for the corresponding thenoyl and benzoyl peroxides, if the reasonable assumption is made that the 5-substituted 2-thenoy1 peroxides are analogous teetheepara-substituted benzoyl peroxides, and the h—substituted 2-thenoy1 peroxides are analogous to the meta-substituted benzoyl peroxides. vi' When the values of log k/kO were plotted against the sum of the 6' values for the substituents, a reasonably good straight line resulted, which had a e value of -O.uh. Thus it was demonstrated that the Hammett equation is applicable to the spontaneous decomposition of the substituted bis(2-thenoyl) peroxides. The activation energies were obtained from the rate constants determined at three different temperatures, andttere found to be 29.5 - 1.0 kilocalories per mole for all of the peroxides -studied. The fact that the rate constants show a definite dependence on the electronic character of the particular substituent, while the activation energies are relatively constant over the entire range of substituents, indicates that the frequency factor must vary with a change in substituent, and thus the Hammett relationship can only be approximate when applied to an interpretation of the rates of decomposition of the substituted bis(2-thenoyl) peroxides. viii TABLE OF CONTENTS I:\TTRODTJCTIONO O O O O O O O O O O O O O O O O O O O O 0 O O O O O C O O O O O O O O O C O O O O O O . HISTORICAL. C O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O EXPERIPfiENTAL . C O O O O O O O O O O O O O O 0 O O O O O O O O O O 0 O 0 O O O O O O O O O O O O O O . Chemical Reagents and Apparatus.................... Syntheses.......................................... Preparation of the Thenoyl Chlorides.......... Preparation of the Bis(2-Thenoyl) Peroxides... Preparation of 3,h—Dichlorostyrene............ Product Analyses................................... Products of the Decomposition of Bis(2-thenoyl) peroxide in Carbon Tetrachloride in the Absence of 3,u-Dichlorostyrene............. Carbon Dioxide Analyses....................... Kinetics........................................... Effects of Variables on the Kinetics.......... Oxygen..................................... Surface area of the Ampoules............... LightOOOOOOOOOO00.00.000.0000000000000000000 initial Peroxide Concentration............. Nature of the Free-Radical Inhibitor....... DISCUSSIONeeooeeooeoeee eeeeeeeee eeeeoeoee eeeeeeeeeeeee coo ST‘DIQ‘ARYOOOOOO oooooooo ooeeoee ooooooooooooooo eoeoe eeeeeee co APPEI‘IDIXoeee ooooo e ooooooo e ooooo eeeeoooeooeeooo oooooooooo e Page 1 71 72 LITERATLTRE CITEDooeoe ccccc co eeeeee 00000000000000.00000000119 TABLE 1. 2. 3. ’4. 10. 11. 12. LIST OF TABLES Preparation of the Thenoyl ChlorideS............. Preparation of the Bis(2-thenoyl) Peroxides...... Carbon Dioxide Analyses.......................... Decomposition of Bis(2-thenoy1) Peroxide in the Presence of 0.20 M 3,4-Dichlorostyrene in Carbon TetraChloride at 7000....COCOOOOOOOCOOOOOOCCOO... Decomposition of Bis(2-thenoyl) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in Carbon TetraChloride at 750.000.000.00000000000000...... Decomposition of Bis(2-thenoy1) Peroxide in the Presence of 0.20 M §,h-Dichlorostyrene in Carbon Tetra-chloride at 800.0...OOOOOOOOOOOOOOOOOOCCOOOQ Decomposition of Bis(5-bromo-2-thenoy1) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in Carbon Tetrachloride at 75°...................... Decomposition of Bis(5-bromo-2-thenoyl) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in carbon Tetra-Chloride at 8000......000000000...... Decomposition of Bis(5-bromo-2-thenoyl) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in Carbon Tetrachloride at 85°...................... Decomposition of Eis(5-chloro-2-thenoy1) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in Carbon Tetrachloride at 75°...................... Decomposition of Bis(5-chloro-2—thenoyl) Peroxide in the Presence of 0.20 M g,h-Dichlorostyrene in Carbon Tetrachloride at 80 ...................... Decomposition of Bis(5-chloro-2-thenoyl) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in Carbon Tetrachloride at 85°...................... ix Page 3h #7 53 58 59 60 72 73 7h 76 77 78 LIST OF‘TABLES - Continued 13. 1h. 15. 16. 17. 18. 19. 20. 21. 22. 23. Decomposition of Bis(5-methyl-2-thenoyl) Peroxide in the Presence of 0.20 M 3, -Dichloro- styrene in Carbon Tetrachloride at 65 .......... Decomposition of Bis(5-methyl-2-thenoyl) Peroxide in the Presence of 0.20 M 3,h-Dichloro- styrene in Carbon Tetrachloride at 70°.......... Decomposition of Bis(5-methy1-2-thenoyl) Peroxide in the Presence of 0.20 M 3, -Dichloro- styrene in Carbon Tetrachloride at 75 .......... Decomposition of Bis(5-t-butyl- 2- thenoyl) Peroxide in the Presence of 0. 20 M 3, h- Dichloro- styrene in Carbon Tetrachloride at 65°.......... Decomposition of Bis(5- t- butyl- 2-thenoyl) Peroxide in the Presence of 0. 20 M 3, -Dichloro- styrene in Carbon Tetrachloride at 70 .......... Decomposition of Bis(S-t-butyl- 2-thenoy1) Peroxide in the Presence of 0. 20 M 3, h-Dichloro- styrene in Carbon Tetrachloride at 75° .......... Decomposition of Bis(h-methy1-2-thenoyl) Peroxide in the Presence of 0.20 M 3,%-Dichloro- styrene in Carbon Tetrachloride at 70 .......... Decomposition of Bis(h-methyl-2-thenoy1) Peroxide in the Presence of 0.20 M 3,h-Dichloro- styrene in Carbon Tetrachloride at 75°.......... Decomposition of Bis(h-methyl-2-thenoy1) Peroxide in the Presence of 0.20 M 3,h-Dichloro- styrene in Carbon Tetrachloride at 80°.......... Decomposition of Bis(h- bromo- 2-thenoy1) Peroxide in the Presence of 0. 20 M 3, h-Dichloro- styrene in Carbon Tetrachloride at 75° .......... Decomposition of Bis(h- bromo-2-thenoyl) Peroxide in the Presence of 0. 20 M 3, -Dichloro- styrene in Carbon Tetrachloride at 80 .......... Page 80 81 82 8b. 85 86 88 89 90 92 93 LIST OF TAPLES - Continued 2h. 25. 26. 27. 28. 29. 300 31. 32. Page Decomposition of bis(h-bromo-2-thenoy1) Peroxide in the Presence of 0.20 M 3, -Dichloro- styrene in Carbon Tetrachloride at 85 ........... 9h Decomposition of Bis(3-thenoyl) Peroxide in the Presence of 0.20 M g,h-Dichlorostyrene in Carbon TetraChloride at 70 0.0.000...00.0.0.0...00000... 96 Decomposition of Bis(3-thenoy1) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in Carbon Tetrachloride at 75°............................. 97 Decomposition of Bis(3-thenoy1) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in Carbon TetraChloride at 800.0000coco-00000000000000.0000 98 Decomposition of 5-Methyl bis(2-thenoyl) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in carbon TetraChloride at 6500......0...0.000000... 1'00 Decomposition of 5-Methyl bis(2-thenoyl) Peroxide in the Presence of 0.20 M 3,4-Dichlorostyrene in Carbon TetraCh-loride at 7000.00.00.00000000...... lOl Decomposition of S-Methyl bis(2-thenoy1) Peroxide in the Presence of 0.20 M 3,h-Dichlorostyrene in Carbon TetraChlorj-de at 750....COCOCOOOOOOOCCOOO. 102 Decomposition of Bis(2-thenoy1) Peroxide in the Presence of 0.20 M Styrene in Carbon Tetra-Chloride at 750.000.000.000...OOOOOOOOOOOOO. 103 Decomposition of Bis(5-t-butyl-2-thenoy1) Peroxide in the Presence of 0.20-M Styrene in Carbon Tetrachloride at 750............................. 10k xi FIGURE I. II. III. IV. V. VI. VII. LIST OF FIGURES Plot of log Peroxide Concentration versus Time for the Decomposition of Bis(2-thenoy1) Peroxide in Carbon Tetrachloride in the P esence of 0.20 M 3,h-Dichlorostyrene at 70, 75°, and 800.. Plot of log Peroxide Concentration versus Time for the Decomposition of Bis(5-bromo-2-thenoyl) Peroxide in Carbon Tetrachloride inO the Presence of 0. 20M 3, h- -Dichlorostyrene at 750 , 800 and 850 0.0000000000000000.000000000000000coco... Plot of log Peroxide Concentration versus Time for the Decomposition of Bis(5-ch10ro-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0. 20 M L u- Dichlorostyrene at 75°, 80° and 850 eeeeeeeeeeoeeoeeeeoeeeeeeeeeoeeeeoeoooooo Plot of log Peroxide Concentration versus Time for the Decomposition of Bis(5-methyl-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene at 65°, 70° and 7500.00.00...OOOOOOOOOOOOOOOOOOO.0.00.0.0... Plot of log Peroxide Concentration versus Time for the Decomposition of Bis(5-t-buty1- 2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0. 20 M 3, h-Dichlorostyrene at 65°, 700 and 75° ......................................... Plot of log Peroxide Concentration versus Time for the Decomposition of Bis(h-methy1-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0. 20 M 3, h- Dichlorostyrene at 70°, 75° and 800 .00....0000......OOOOOOOOOOOOOOOOOIOOOOO. Plot of log Peroxide Concentration versus Time for the Decomposition of Bis(h-bromo-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0. 20 M 3, h-Dichlorostyrene at 75°, 800 and 85° ooeeoeeeeeeeeeeeeeoeeo.eoeeeeeeeoeeeeeeeo xii Page 57 71 75 79 87 91 LIST OF FIGURE‘ VIII. IX. XI. XII. XIII. XIV. FIGURES - Continued Page Plot of log Peroxide Concentration versus Thne for the Decomposition of Bis(3-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene at 70°, 75° and O goeoeeeeeeeoeeeeeeoeeeoeoeeoeoeeoeeooeeo. 95 Plot of log Peroxide Concentration versus Time for the Decomposition of 5-Methy1 bis(2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene at 65°, 70° and 750.000.000.000000000.000.000.00...0.00.0... 99 Plot of log Peroxide Concentration versus Time for the Decomposition of0.025 M Bis(2-thenoy1) Peroxide in Carbon Tetrachloride in the Absence of an Inhibitor at 75°.......................... 105 Plot of log Peroxide Concentration versus Time for different Initial Concentrations of Bis (2-thenoy1) Peroxide and Bis(5-methy1-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene at 75°............ 107 Plot of log Peroxide Concentration versus Time for different Initial Concentrations of Bis (u-methy1-2-thenoy1) Peroxide and Bis(5-chloro- 2-thenoy1) Peroxide in Carbon Tetrachloride in :the Pgesence of 0.20 M 3,h-Dichlorostyrene at 80 0.0.0....OOOOOOOOOOOOOOOOOOOOOOO0.0.000...108 Plot of log Peroxide Concentration versus Time for the Decomposition of 0.01 M Bis(S-nitro- 2-thenoy1) Peroxide in Carbon Tetrachloride at 75° in the Presence of 0. 20 M Styrene, and in the Presence of 0. 20 M 3, h-Dichlorostyrene.......... 109 Plot of log Rate Constant versus Reciprocal of Absolute Temperature for the Decomposition of Bis(2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene... 110 xiii LIST OF FIGURES - Continued FIGURE XV. XVI. XVII. XVIII. XIX. XXI. XXII. Page Plot of log hate Constant versus Reciprocal of Absolute Temperature for the Decomposition of Bis(5-bromo-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene............................. 111 Plot of log Rate Constant versus Reciprocal of Absolute Temperature for the Decomposition of Bis(5-chloro-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene............................. 112 Plot of log Rate Constant versus Reciprocal of Absolute Temperature for the Decomposition of Bis(5-methy1-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene............................. 113 Plot of log Rate Constant versus Reciprocal of Absolute Temperature for the Decomposition of Bis(5-t-buty1-2-thenoyl) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene............................. 11h Plot of log Rate Constant versus Reciprocal of Absolute Temperature for the Decomposition of Bis(n-methy1-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,u-D10h10r05tyr6n6............................. 115 Plot of log Rate Constant versus Reciprocal of Absolute Temperature for the Decomposition of Bis(h-bromo-2-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene............................. 116 Plot of log Rate Constant versus Reciprocal of Absolute Temperature for the Decomposition of Bis(3-thenoy1) Peroxide in Carbon Tetrachloride in the Presence of 0.20 M 3,h-Dichlorostyrene... 117 Plot of log Rate Constant versus Reciprocal of Absolute Temperature for the Decomposition of S-Methyl bis(2-thenoy1) Peroxide in Carbon Tetra- chloride in the Presence of 0.20 M 3,h-Dichloro- styrene......................................... 118 xiv LIST OF FIGURES - Continued FIGURE Page XXIII. Plot of log k/kg versus Sigma Values for the Decomposition o the Bis(2—thenoy1) Peroxides in Carton Tetrachloride at 75°.................. 119 XV INTRODUCTION The effect of structural changes in organic molecules on their rate of non-radical reactions has been rather thoroughly investigated (1,2). In the reactions of meta and para-substituted benzene derivatives, such investigations have shown that for a wide variety of substituents the effect on the reactivity of a given benzene derivative is determined by the polar effect of a particular substituent. The quantitative relationship between the effect of the substituent and the rate of reaction is embodied in the Hammett equation for meta and para-substituted benzene derivatives (3), log k/ko : 6f The term log k/ko represents the logarithm of the ratio of the rate constant of the substituted compound, k, to the rate constant of the unsubstituted compOund, k0. The reaction constant,(9, is a measure of the susceptability of a given reaction to polar effects produced by the substituents. The substituent constant, 6, is a measure of the ability of a given substituent to change the electron density at the reaction center. The first successful application of the Hammett equation to a unimolecular free-radical reaction was reported (h) in I study of the effect of substituents on the rate of the spontaneous thermal decomposition of a series of meta and para- substituted benzoyl peroxides. In view of this work it seemed of interest to study a series of substituted bis(2-thenoy1) peroxides, to determine whether the Hammett equation would be applicable to the spontaneous thermal decomposition of such a series of compounds. If this were the case, then it should be possible to draw a correlation between the corresponding benzoyl and thenoyl peroxides. HISTORICAL Diacyl peroxides are relatively unstable compounds, which can be decomposed either thermally or photochemically. There is good experimental evidence that such decompo- sitions proceed by a free-radical mechanism. The decomposition of acetyl peroxide is catalyzed by ultra-violet light (5). The rate of decomposition of benzoyl peroxide is accelerated by the presence of free-radicals.(6). When benzoyl peroxide is decomposed in substituted benzene solvents, substitution of peroxide fragments occurs in the ortho and para position of the solvent molecules, regardless of the directive influence of the substituent (7). Perhaps of greater significance is the fact that certain substances, which are known to inhibit free-radical chain reactions, will lower the overall rate of decomposition of benzoyl peroxide (6). The initial cleavage in the decomposition of diacyl per- oxides is, at present, thought to occur at the oxygen-oxygen bond, 9 O 9 R-C-O-O-C-R _, 2 R-d-O- Convincing evidence for this mode of cleavage, in the case of benzoyl peroxide, was obtained by Hammond and Soffer (8). They decomposed benzoyl peroxide in anhydrous carbon tetra- chloride, in the presence of a very efficient free-radical inhibitor, iodine, and isolated iodobenzene in 90% yield, However, when the decomposition was carried out in moist carbon tetrachloride in the presence of iodine, an almost quantitative yield of benzoic acid was obtained. They pro- posed the following sequence of reactions to account for these products, 0 II II I c -c- - -c-c H Ii 2 -c- - 6HS O 0 6 5 ii céHé O O O I! u CéHS-C-O° + IZ______¢ CéHs-C-O-I___fl,CgH§-C-I 1H20 9 CéHS-C-O’H Benzoyl hypdiodite as Sought to decompose under anhydrous con- ditions to form iodobenzene, and in the presence of waterhwould hydrolyze; rapidly to yield benzoic acid. Thus the initial cleavage of benzoyl peroxide must produce intact benzoate radicals quantitatively. This evidence more or less precludes the mechanism postulated by Nozaki and Bartlett (6) in which the initial cleavage of benzoyl peroxide yielded a molecule of carbon dioxide, a benzoate radical and a phenyl radical. 0 CHC-O-O-a-CH—_—.CH0 CH3: C e s e S 6 S * 6 5' '0 +. 02 However, the decomposition of benzoyl peroxide does not Obey a first-order kinetic rate expression which it would be expected to do if the Spontaneous cleavage proposed by Hammond and Soffer were the only decomposition process taking place. The overall rate of decomposition of the peroxide is greater than first-order to an extent which varies widely with the solvent. Thus, another mode of decomposition must be superimposed upon the Spontaneous decomposition. This induced decomposition is thought to involve a chain reaction in fliich the initially formed radicals attack benzoyl peroxide molecules to produce further decomposition, or alternatively, the initially formed radicals may attack solvent molecules to form solvent radicals which are in turn capable of attacking benzoyl peroxide molecules. These views on the overall de- composition path were put forth independently by Bartlett and Nozaki (6,9) and by Cass (10), who derived mathematical expressions for obtaining the rate constant for the Spontaneous decomposition from the experimental data on the overall de- composition rate. More recently, Swain, Stockmayer and Clarke (A) have employed free-radical inhibitors to completely repress the induced decomposition of benzoyl peroxides, thereby making the observed rate of decomposition equivalent to the rate of their spontaneous decomposition. Several vinyl monomers were found to be efficient inhibitors of the induced decomposition. However, from such studies, for a series of para and meta- substituted benzoyl peroxides in various Solvents, it was concluded that 3,h-dichlorostyrene was the most generally effective inhibitor. Employing the inhibitor method with sub- stituted benzoyl peroxides, these investigators found that the rate of spontaneous decomposition was increased by electron- repelling substituents and decreased by electron-attracting substituents. The rate constants for the spontaneous decomposition of Sixteen para and meta-substituted benzoyl peroxides were found to fit the Hammett equation (page 1) reasonably well. This was the first case of a successful application of the Hammett relationship to a unhmolecular free-radical process. Blomquist and Buselli (11) made a similar and independent study of the Spontaneous decomposition of substituted benzoyl peroxide. They found that the induced decomposition could be eliminated by using acetophenone as a solvent. Their results are in good agreement with those of Swain, Stockmayer and Clarke (n). However, they found that both the activation energy and the frequency factor were affected in a systematic manner by the substituents. Since the Hammett relationship is exact only for those reactions in which the frequency factor is unaffected by a change of substituents, the Hammett equation is only approximate for substituted benzoyl peroxide. Diaroyl peroxide are, in general, prepared by the1~eaction of an acid chloride with sodium peroxide at 0° (12). Sub- stituted benzoyl peroxides (13) are readily prepared by the addition of the acid chloride, dissolved in toluene or cyclohexane, to a chilled aqueous solution of sodium peroxide. The peroxide precipitates from the reaction mixture in a high state of purity. Breitenbach and Karlinger (1A) prepared bis(2-thenoy1) peroxide, the only thenoyl peroxide reported, prior to the present investigation, by the action of hydrogen peroxide on 2-thenoy1 chloride in the presence of pyridine. These investigators used this peroxide as a free-radical initiator in the polymerization of styrene. By analyzing the resulting polymer for sulfur, they were able to determine the fate of the peroxide initiator. Recently, Ford and Mackay (15) made a detailed study of the products of the decomposition of bis(2-thenoy1) peroxide in a variety of aromatic solvents. They found that very little carbon dioxide was evolved and that the products formed could be attributed largely to reactions of the thenoate free-radical, apparently due to the high degree of resonance stabilization of this radical. This is in distinct contrast to the de- composition of benzoyl peroxide, in which carbon dioxide is evolved in high yields (16). When benzene, nitrobenzene, chlorobenzene, bromobenzene and iodobenzene were used as reaction media, the products of the decomposition of bis(2- thenoyl) peroxide consisted of large amounts of unidentified, amorphous sulfur-containing material, moderate amounts of 2-thenoic acid and small amounts of simple neutral products. The simple neutral products included aryl 2-thenoates formed by nuclear attack of thenoate radicals on the solvent, and in the case of the halo benzenes, phenyl 2-thenoates formed by the displacement of the halogen atom, as well as the para- substituted esters. Presumably, the 2-thenoic acid arises through a hydrogen abstraction by the 2-thenoate radicals, involving the accumulating amorphous, sulfur containing material. When toluene and especially cumene were used as reaction solvents, the availability of active hydrogen atoms in the side-chains lead to hydrogen abstraction from the solvent, with the formation of large amounts of dibenzyl and dicumyl, respectively, and no amorphous material. In cumene the yield of 2-thenoic acid was quantitative, and dicumyl was the only neutral product isolated, indicating exclusive side-chain hydrogen abstraction. In toluene, dibenzyl was the major neutral product, but small quantities of tolyl—2-thenoates and 2-benzy1 thiophene were also isolated. The formation of small amounts of 2-benzy1 thiophene in the decomposition of bis(2-thencyl) peroxide in toluene, together with the observation that its decomposition in thio- phene as a selvent produced some 2,2'-dithieny1 was offered as evidence for the generation of 2-thienyl free-radicals. However, the low yields of these products together with.the scanty evolution of carbon dioxide seem to substantiate the hypothesis that 2-thenoate free-radicals are rather stable and undergo decarboxylation to only a limited extent. EXPERIMENTAL Chemical Reagents and Apparatus The carbon tetrachloride used as the solvent in the kinetic studies and product analyses was purified by heating two liters of C.P. grade carbon tetrachloride at 60°, for one-half hour, with a caustic solution prepared from 20 g. of potassium hydroxide, 150 ml. of ethyl alcohol and 150 ml. of water. This treatment was repeated and the carbon tetra- chloride layer was separated and washed thoroughly with water to remove the ethyl alcohol. It was then Shaken with small portions of concentrated sulfuric acid until the acid layer no longer Showed any color. It was finally washed with water to remove the sulfuric acid, dried over anhydrous calcium chloride, and distilled from phOSphorous pentoxide through a 12" glass helix packed column. The styrene, used as a radical trap in the kinetic studies, was Eastman Kodak Co., White Label material, stabilized with E-butylcatechol. It was distilled in a nitrogen atmOSphere under reduced pressure, just prior to use. Its properties were, b.p. 50° (25 mm.), n50 1.5h62. Literature values (17), b.p. A60 (20 mm.), n30 1.5h62. The styrene was stored in the refrigerator without the addition of an inhibitor. The 3,h-dichlorostyrene used as a radical trap, in the kinetic studies and carbon dioxide determinations was syn- 10 thesized as described in a later section of this thesis (see page A6). It was stored in the refrigerator without the addition of an inhibitor. Under these conditions polymeri- zation did not occur, as evidenced by the fact that the re- fractive index was unchanged after a storage period of two months. By comparison, the refractive index of the dichloro- styrene decreased from n50 1.58hh to n60 1.5838 after allowing it to stand at 250 for ten hours. The N-bromosuccinimide used in the preparation of 3- thenyl bromide was obtained from.Mathieson and Co., and was recrystallized from glacial acetic acid just prior to use. The aua'-azodiisobuternitrile, a free-radical source used in the same preparation, was obtained from Eastman Kodak Co., as their White Label product. The toluene, cyclohexane and benzene used in the preparation of the bis(2-thenoy1) peroxides were of C.P. grade, and were dried over metallic sodium. The 3-methy1thiophene was obtained from the Socony-Mobil Oil Company as a research sample and was distilled just prior to use. The 2-bromothiophene was obtained from the Michigan Chemical Corporation as a research sample and was distilled just prior to use. The 2-chlorothiophene was obtained from the same source and was used without further purification. Thiophene was purchased from the Pennsalt Chemicals Corporation. ll Thionyl chloride, practical grade, was purchased from the Eastman Kodak Company and was used as received, unless otherwise specified in the section of this thesis entitled, ”Syntheses". Dimethyl formamide was purchased from the Eastman Kodak Company, as their White Label product. PhOSphorous oxychloride was purchased from the Baker Company, as their Analyzed Reagent product. Sodium peroxide was purchased from the Mallinkrodt Company, as their Analytical Reagent product. All melting points were determined using capillary tubes, in an electrically heated, mechanically stirred silicone oil bath, and are uncorrected. The microelementary analyses were performed by the Micro- Tech Laboratories, Skokie, Illinois. Syntheses 0 ll 2-Acetylthiophene CuHBSCCH3 The method of Hartough and Kosak (18) was used in this preparation. A solution of 252 g. (3.0 moles) of thiophene and 117 g. (1.1 moles) of 95% acetic anhydride was heated to 70° in a one-liter three-necked flask fitted with a reflux condenser, dropping funnel, stirrer, and thermometer. With vigorous stirring, 10 g. of 85% orthophosphoric acid was added over a period of ten minutes. A slight rise in temperature 12 occurred after the addition of the orthophosphoric acid was begun and cooling with an ice-bath became necessary towards the end of the addition of the catalyst to maintain the re- action temperature below 90°. The reaction solution was then refluxed at 96° for two hours and allowed to cool to 50°. A volume of 200 m1. of water was added and the solution was stirred for another 15 minutes. The organic layer was separated and washed with 200 ml. of 10% sodium carbonate solution, followed by washing with 200 ml. of water. The thiophene-water azeotrope was removed by distillation at 68°, followed by excess thio- phene distilling at 8h°. Vacuum distillation of the residue through an 8" Vigreux column gave 120 g. (0.95 mole, 95%) of colorless 2-acetylthiophene boiling at 75° (2 mm.). Literature value, (18) b.p. 770 (H mm.). ' 9 5-Bromo-2-acetylthiophene BrCuHZSCCH 3 Using the apparatus and general procedure described above, 81 g. (0.5 mole) of 2-bromothiophene and 59.2 g. (0.58 mole) of analytical grade acetic anhydride were heated to 80°. Heating was discontinued and 5 g. of 85% orthophOSphoric acid were added dropwise, during which time the reaction temperature rose to 82°. The solution was heated at loo-110° for three hours, during which time it darkened to a red-black color. Upon cooling to room.temperature the material solidified. The solid was melted by heating with a microburner, 100 ml. of water were added and the mixture was stirred for another 15 A c on. I «I ._¢ 13 minutes. The resulting brown solid was filtered, washed with 100 m1. of 10% sodium carbonate solution, and then with water. The yield of crude product after drying was 77 g. (0.375 mole, 75%)'melting at 90-920. Literature value (19), m.p. 9h-95o. Recrystallization of the crude product from ethyl alcohol yielded 59 g. of light yellow colored crystals melting at 90-920. An additional 9 g. of product was obtained by adding water to the mother liquor. O I 5-Chloro-2-acetylthiophene ClcuHZSCCH3 Using the apparatus and general procedure described above, 108 g. (0.91 mole) of 2-chlorothiophene, and 118 g. (1.15 moles) of analytical grade acetic anhydride were heated to 75°. Upon careful addition of 10 g. of 85% orthophosphoric acid, there was no rise in the reaction temperature. The reaction solution was heated at 100-1100 for two hours, during which time it darkened and finally turned black in color. The reaction solution was allowed to cool to room.temperature and 100 ml. of water were added. The organic layer was sep- arated, washed twice with water, then with 10% sodium carbonate solution until neutral to pHydrion paper, and finally twice with water. The black colored solution was distilled $9 13332, to give 102 g. (0.638 mole, 70%) of light yellow colored liquid boiling at 88° (u mm.). Literature value (18), b.p. 88° (h.mm.). Recrystallization from cyclohexane gave 87 g. of colorless needles melting at 45.5-h6.5°. Literature value (18), 1’4 mop. uéos-u7oo 9 2-Thena1 CgHBSCH The method of Campaign and Archer (20) was employed in this preparation. A solution of 126 g. (1.5 moles) of thio- phene and 138 g. (1.92 moles) of dimethyl formamide contained in a one-liter three-necked flask fitted with an Allihn condenser (protected by a calcium chloride tube), stirrer and dropping funnel was cooled to 0°. With stirring, 288 g. (1.86 moles) of phosphorous oxychloride were added at 0° over a period of one hour. The reaction.mixture was heated on the steam bath for two hours, during which time it darkened and finally became black in color. After being set aside at room temperature overnight, the reaction solution was poured with stirring, into a beaker containing 1500 g. of ice. A volume of 300 m1. of a saturated solution of sodium acetate was added. The heavy oily layer was separated, and the aqueous layer was extracted with 300 m1. of ethyl ether. The combined oily layer and ether extracts were washed free of acid with 10% sodium bicarbonate solution, then washed with water, and dried over anhydrous calcium chloride. The ether was removed by distillation on a steam bath and the red oily residue was distilled lgngg 2 through an 8" Vigreux column to yield 133 g. (1.19 moles, 79%) of a colorless liquid boiling at 5&0 (3 mm.). Literature value (20), b.p. hh-hSo (1.1 mm.). 15 2-Methy1 thiophene C H SCH The experimental procedufieBOf :ing and Nord (21) was followed to obtain this compound. A solution containing 112 g. (1.0 mole) of 2-thenal, 200 m1. (h.0 moles) of 85% hydrazine hydrate and 800 ml. of ethylene glycol was stirred in a two-liter three-necked flask fitted with a stirrer, ther- mometer and Vigreux column equipped with a distillation head. The solution was heated at 130-1600 to distill excess hydrazine and water. The residue was cooled to 50°, the Vigreux column was replaced by an Allihn condenser, 200 g. of potassium hydroxide pellets were added, and heating was resumed. At about 90° the evolution of nitrogen commenced. The reaction mixture was stirred with heating for another 12 hours. The condenser was replaced by a Vigreux column.and distilling head, and the distillate boiling up to 1500 at atmospheric pressure was collected. The distillate was extracted with several portions of ethyl ether, which were combined, washed with 6 N hydrochloric acid and finally washed with water. After drying over anhydrous calcium chloride, the ether was removed by distillation on a steam bath. Distillation of the residue through an 8" Vigreux column gave a total of 63 g. (0.6h mole, 6h%) of colorless 2-methyl thiophene boiling at 110-110.5° (1 atm.). Literature value (21), b.p. 112-113° (1 atm.). l6 2-ErButyl thiophene CHH3SC(CH3)3 The general experimental procedure of Caesar (22) was followed in the preparation of the alkylthiophene. A solution prepared from 168 g. (2.0 moles) of thiophene and 15 g. of 75% sulfuric acid, contained in a one-liter three-necked flask fitted with a stirrer, reflux condenser, thermometer and a sintered glass gas inlet tube, was heated to 70°. Gaseous isobutylene (116 g., 12.1 moles) was introduced into the well-stirred reaction solution through the gas inlet tube at a rate sufficient to maintain the reaction temperature at 60-700. The addition of the alkene required four hours. After allowing the reaction.mixture to come to room temperature, the organic layer was separated, washed with 10% sodium hydroxide solution until the washings were basic to pHydrion paper, then washed with water, after which it was dried over anhydrous calcium chloride. Distillation at atmOSpheric pressure through a 12" glass helix packed column yielded 153 g. (1.09 moles, 5h.6%) of product. Its physical properties are,b.p. 160-166°, n50 l.h983. Literature values (23), b.p. 163.9, n50 1.h979. 9 5-Methy1-2-acety1thiophene CH3CuH2SCCH3 The apparatus and general procedure described in the preparation of 2-acetylthiophene were used to obtain this material. A total of 5 g. of orthophOSphoric acid were added. dropwise, at room temperature, to a stirred solution of A9 2. (0.5 mole) of 2amethy1 thiophene and 55 g. (0.5h mole) of 17 reagent grade acetic anhydride. The reaction temperature rose to h0° during the addition of the acid catalyst, after which the solution was heated at loo-110° for three hours. After cooling the reaction mixture, adding water and stirring for 15 minutes, the organic layer was separated and washed with 10% sodium carbonate solution. The dark brown colored crude product was dried over anhydrous magnesium.sulfate and distilled through an 8" Vigreux column 13 Egggg. The yield was ho g. (0.285 mole, 57%) of clear liquid boiling at 8&0 (3 mm.). Literature value (18), b.p. 8h.5o (3 mm.). 8 5-23Buty1-2-acety1thiophene (CH3)3CC H SCCH 2 The apparatus and general procedure desciibed i: the preparation of 2-acetylthiophene were used to obtain this product. A total of 5 g. of orthophosphoric acid were added dropwise, at room temperature, to a stirred solution of 70 g. (0.50 mole) of 2-tfbutyl thiophene and 58 g. (0.527 mole)of practical grade acetic anhydride. The reaction temperature rose to 35° during the addition of the acid catalyst. The stirred reaction solution was heated at 80-900 for one and three-quarter hours, cooled to 50°, and water was added. The resulting solution was set aside at room.temperature overnight. A 50 m1. volume of ethyl ether was added to dissolve the milky suspension which had formed. The organic layer was separated, washed with 10% sodium carbonate solution, then washed with water, and dried over anhydrous magnesium sulfate. Vacuum l8 distillation through an 8" Vigreux column yielded a fore-run of 12 g. of unreacted 2-Efbutyl thiophene, b.p. 35-h00 (2 mm.), and 2 g. of a liquid, b.p. 80-100° (2 mm.), followed by 66 g. (0.362 mole, 72%) of a clear liquid product boiling at 100- 101.50 (2 mm.), n50 1.53u7. Literature values (23), b.p. 11ho (u mm.). n50 1.53h3. 2-Methoxythiophene CAH3SOCH3 aft The experimental procedure of Sicé (2A) was followed in the preparation of this compound. A solution prepared by dissolving 19.8 g. (0.86 g.atJ of sodium in 225 g. of absolute methanol was contained in a one-liter three-necked flask fitted with a stirrer and reflux condenser. The quantities, h5.6 g. (0.28 mole) of 2-bromothiophene, ll.h g. of pulverized cupric oxide and 0.2 g. of sodium iodide were added to the solution at room temperature. The stirred mixture was refluxed for 87 hours. After it had cooled to room temperature, the reaction mixture was filtered and the filtrate was poured into 600 ml. of cold water. The resulting solution was set aside overnight and extracted with ethyl ether. The combined ether extracts were washed with water, dried over anhydrous magnesium sulfate and the ether removed by distillation on a steam bath. The residue was distilled ;§;zgggg from sodium through an 8" Vigreux column to give 20.5 g. (0.18 mole, 6h%) of clear liquid product boiling at 3h-35° (h mm.). Literature value (2h), b.p. 714-750 (50 mm.). l9 ‘0 5-Methoxy-2-thenoic acid CH3OChHZSEOH The experimental procedure of Sicé (2h) was used to obtain this acid. A 2.8 g. (0.2h8 g.at.) quantity of lithium, cut into pieces of approximately 2 cm.3, was added to 20 m1. of anhydrous ethyl ether contained in a 300-ml. three-necked flask fitted with an Allihn condenser, stirrer, dropping funnel and nitrogen inletvtube. The reaction was carried out in an atmosphere Of dry nitrogen. A solution containing 21.7 g. (0.138 mole) of dry bromobenzene dissolved in 80 ml. of anhydrous ethyl ether was added dropwise to the stirred suspension of lithium in ether, over a period of approximately 30 minutes. The rate of addition was sufficient to cause the reaction solution to reflux gently. Stirring was continued for 30 minutes after the addition of bromobenzene was completed, at which time refluxing had ceased. A solution of 2h g. (0.211 mole) of 2-methoxythiophene dissolved in 80 ml. of anhydrous ethyl ether was added dropwise to the stirred reaction.mixture, over a period of AS minutes. The resulting mixture was heated on a steam bath for one hour, cooled to room temperature, and poured into a three-liter beaker containing a slurry of 300 g. of crushed dry ice in anhydrous ethyl ether. After standing at room temperature fOr two and one-half hours, 200 m1. of water were added dropwise to the stirred reaction mixture, while maintaining the temperature at 0°, by means of an ice bath. The hydrolyzed reaction mixture was stirred 20 for two hours following the addition of the water, to remove any unreacted lithium. The water layer was separated. The ether layer was extracted with three 100 m1. portions of 10% sodium hydroxide solution and the basic extracts were added to the water layer. The combined aqueous layer and basic extracts were washed with two 100 m1. portions of ethyl ether, cooled to room temperature, filtered, and acidified with concentrated hydrochloric acid. The resulting precipitate was recovered by filtration, washed with water and air-dried to yield 18 g. of light tan material melting at 130°. Re- crystallization from toluene yielded 15 g. (0.095 mole, h5%) of colorless flakes melting at 159-1600. Literature value (2h), m.p. 162-1630. $2 5-Nitro-2-thenal NOZChHZSCH The method of Buu H01 (25) was used to obtain this material. To a solution of 26 g. (0.232 mole) of 2-thenal dissolved in 50 g. of acetic anhydride contained in a 300-ml. three- necked flask, immersed in an ice bath and fitted with a stirrer, reflux condenser and dropping funnel, was added drop- wise a solution containing 19.8 g. of fuming nitric acid (d ' 1.h9) dissolved in 50 g. of glacial acetic acid, over a period of 15 minutes. The reaction solution was stirred for 90 minutes at 0°. A volume of 200 m1. of water was added, causing the immediate precipitation of a yellow solid. The precipitate was recovered by filtration, washed thoroughly with 21 water, air dried, and recrystallized from 95% ethyl alcohol to yield 32 g. (0.20h mole, 88%) of slightly yellow crystals melting at 71°. Literature value (25), m.p. 77°. 9 5-Nitro-2-thenoic acid NogCuHZSCOH The experimental procedure was adapted from the general method described by Migridichian (26). An 18.8 g. (0.12 mole) quantity of 5-nitro-2-thenal was suspended in a solution prepared from h0.8 g. (0.2M mole) of silver nitrate dissolved in a mixture of too ml. of water and too ml. of 95% ethyl alcohol contained in a two-liter three-necked flask fitted with a°stirrer, reflux condensor, thermometer and dropping funnel. The vigorously stirred reaction mixture was heated to h5° and an alkaline solution containing 19.2 g. (0.h8 mole) of sodium hydroxide dissolved in MOO ml. of water was added dropwise at a rate sufficient to maintain the reaction temper- ature at u5-50°. The addition required 30 minutes, after which the reaction solution was stirred at 500 for another 15 minutes, cooled in an ice bath to room temperature and filtered to remove the metallic silver. After washing the silver with hot water, the combined filtrate and washings were evaporated under an air-jet at room temperature for h8 hours to remove theethy1~a1cohol, and reduce the volume of the filtrate to approximately 500 ml. A volume of 500 m1. of ethyl ether was added and the stirred mixture was carefully acidified. with concentrated hydrochloric acid. The other layer was 22 separated. The aqueous layer was extracted with ethyl ether and the combined other layer and extracts were dried over anhydrous magnesium sulfate. Evaporation of the ether gave 12 g. of a yellow solid melting at lh7-l50°. Recrystallization from hot water yielded 10 g. (0.058 mole, h8%) of product in the form of light yellow needles melting at 155-157°. Literature value (27). m.p. 158°. ' S? 2-Thenoic acid CMHBSCOH The method of Harilough and Conley (19) was used to obtain this acid. A solution of sodium hypochlorite was prepared by passing 322 g. (h.50 moles) of chlorine into a tared four-liter beaker containing th g. (11.0 moles) of sodium hydroxide dissolved in 600 ml. of water, to which 2500 g. of ice had been added. The chlorine addition was completed in 15 minutes, after which the hypochlorite solution was heated to 60° on a steameath. It was transferred quickly to a two-liter three-necked flask fitted with a stirrer, dropping funnel, thermometer and reflux condenser. A 126 g. (1.0 mole) quantity of 2-acety1 thiophene was added dropwise at a rate sufficient to maintain the reaction temperature between 60° and 70°. After the addition of acetyl thiophene was completed, the reaction solution wassstirred at 65° for four hours, cooled to room temperature and a solution containing lOO'g. of sodium bisulfite dissolved in.200 ml. of water was added. The resulting solution was transferred to two two-liter 23 beakers and acidified with concentrated hydrochloric acid. The white solid product was recovered by filtration, washed with cold water, and recrystallized from water to yield 88 g. (0.69 mole, 69%) of colorless needles melting at 128°. Literature value (19), m.p. 129-130°. ' 9 5-Bromo-2-thenoic acid BrC H SCOH 2 Using the procedure described tbove, 20.5 g. (0.10 mole) of 5-bromo-2-acety1 thiophene were added in small portions to a solution of sodium hypochlorite prepared from MA g. (1.10 moles) of sodium hydroxoide, 32.2 g. (0.h5 mole) of chlorine and 250 g. of ice. The initial reaction temperature was 60° and was maintained at 60-65° during the addition of the bromoacetyl thiophene by means of an ice-bath. The reaction solution was allowed to come to room temperature, 10 g. of sodium bisulfite dissolved in 20 ml. of water were added and the resulting solution was transferred to a one-liter beaker. After acidification with concentrated hydrochloric acid the colorless precipitate was recovered by filtration and washed with cold water. The dried product was recrystallized from cyclohexane to yield 13 g. (0.062 mole, 62%) of product in the form of white needles melting at lhO—lhl°. Literature value (19), m.p. lhl-lhl.5°. I S-Chloro-2-thenoic acid ClCuHZSCOH Using the procedure described for the preparation of 2h 2-thenoic acid, 32.0 g. (0.20 mole) of 5-chloro-2-acetyl thiophene were added in small portions to a solution of sodium hypochlorite prepared from 88 g. (2.20 moles) of sodium hydroxide, 6h.h g. (0.90 mole) of chlorine and 500 g. of ice. The initial reaction temperature was 60°, and was maintained at 65-70° during the addition of the chloroacetyl thiophene by means of an ice bath. The reaction solution was heated at 65° for an additional one and one-half hours, cooled to room temperature and a solution containing 20 g. of sodium bisulfite dissolved in no ml. of water was added. The resulting solution was transferred to a two-liter beaker and acidified with concentrated hydrochloric acid. The colorless precipitate was recovered by filtration, and washed with cold water. The dried product was recrystallized from ligroin (b.p. 90-120°) to yield 23 g. (0.1M mole, 71%) of colorless needles melting at lh9-150°. Literature value (19) m.p. 152-153.5°. $3 5-Methy1-2-thenoic acid. CH C H SCOH Using the procedure described To? fhe preparation of 2-thenoic acid, AC g. (0.30 mole) of 5-methy1-2-acetyl thiophene were added dropwise to a solution of sodium hypo- chlorite prepared from 132 g. (3.30 moles) of sodium hydroxide, 9A.5 g. (1.35 moles) of chlorine and 800 g. of ice. The initial reaction temperature was 55°, and was maintained at 75° during the addition of the methylacetyl thiophene by means of an ice bath. After allowing the reaction solution to come to room 25 temperature, 35 a. of sodium bisulfite dissolved in 100 ml. of water were added and the resulting solution was transferred to a four-liter beaker. Acidification with concentrated hydrochloric acid gave a white precipitate which was recovered by filtration and washed with cold water. The dried product was recrystallized from ligroin (b.p. 90-120°) to yield 30 g. (0.20 mole, 70%) of colorless needles, melting at 138°. Literature value (19Llngp. 137-138°. 0 ll S-EfButy1-2-thenoic acid (CH3) CC H SCOH Using the procedure described for gheupieparation of 2-thenoic acid, 5h.6 g. (0.30 mole) of 5-tfbutyl-2-acety1 thiophene were added dropwise to a solution of sodium hypochlorite prepared from 132 g. (3.30 moles) of sodium hy- droxide, 96 g. (1.35 moles) of chlorine and 800 g. of ice. The initial reaction temperature was 55°, and rose near the end of the addition of the Eybutylacetyl thiophene. ITherefore, it was necessary to cool the reaction mixture in an ice bath, to maintain its temperature at 70-75°. The reaction solution was heated at 75° for two hours, cooled to room temperature and a solution containing 30 g. of sodium bisulfite dissolved in 100 m1. of water was added. The basic reaction mixture was extracted with ethyl ether to remove neutral material. The aqueous layer was transferred to a two-liter flask fitted with a stirrer and 500 m1. of ethyl ether were added. The stirred reaction mixture was carefully acidified with concentrated 26 hydrochloric acid. The ether layer was separated, the aqueous layer was extracted with ethyl ether and the combined other layer and extracts were dried over anhydrous magnesium sulfate. Evaporation of the other on a steam bath yielded 52 g. of a colorless solid. Recrystallization of the crude product from petroleum ether (b.p. 60-90°) gave no g. (0.217 mole, 72%) of colorless rosettes melting at 12ll-l25°. Literature 9 ll-Me thy1-2-thenoic acid OHBCLLHZSCOH The method of Schick and Hartough (28) was used to pre- par-e this acid. The reaction was carried out in an atmOSphere Of dry nitrogen. A 23 g. (1.0 g.at.) quantity of sodium, 15 8. (0.073 g.at.) of mercury and 750 m1. of dry toluene were Placed in a two-liter three-necked flask fitted with a stirrer, ‘ I’elf‘lhlx condenser and thermometer. The mixture was rapidly heated to 95°, then slowly until the sodium amalgamated at 100°. The amalgam mixture was stirred vigorously until the temperature dropped to 35°. The toluene was removed by filtration through a glass wool plug placed in a neck of the flask and the sodium amalgam was immediately covered with 600 m1. of dry ethyl ether. A 98 g. (1.0 mole) quantity of 3-methy1 thiophene was added, followed by the dropwise addition of 68.5 g. (0.50 mole) °f E-butyl bromide. Cooling of the reaction mixture in an 1“ bath was necessary to permit a reasonable rate of addition 01’ the _r_l_-buty1 bromide. Following the addition of the alkyl 27 bromide, the reaction solution was refluxed for two hours, and then poured onto a slurry of 300 g. of freshly crushed dry ice and 300 ml. of dry ethyl ether. A volume of 100 ml. of absolute alcohol was added to the stirred carbonated mixture, followed by the addition of 350 ml. of water, and the resulting solution was set aside overnight. An additional 200 ml. of water was added to dissolve the gray suSpended solid. The aqueous layer was separated and acidified with concentrated hydrochloric acid. The resulting yellow colored precipitate was recovered by filtration, washed with cold water and air- dried to yield 9 g. (0.063 mole, 6%) of a crude product melting at 110-1160. Literature value (28), m.p. 119-1210. Dis- tillation of the other layer yielded 79 g. (0.81 mole) of un- reacted 3-methyl thiophene boiling at ill-113° (1 atm.). Literature value (29), b.p. 115.h° (1 atm.). 0 II u,S-Dibromo-2-thenoic acid BrZCuHSCOH The method of Steinkopf, Jacob and Penz (30) was used to cibtain this material. A hSO g. (2.8 moles) quantity of bromine was placed in a one-liter three-necked flask, immersed in an 1<3e bath, and fitted with a stirrer and1*eflux condenser. CFC) the rapidly stirred bromine, 57 g. (0.uh5 mole) of 2-thenoic a42>.1d were added, in small portions, from a 125 ml. Erlenmeyer flask attached to a neck of the reaction flask by means of a I‘ltfloer tube. After the addition of the acid was completed, 28 the ice bath was removed and the reaction.mixture was stirred at room temperature for one hour. Excess bromine was removed by evaporation at reduced pressure with a water aspirator. The white residue was stirred with 100 ml. of 10% ammonium carbonate solution to remove the last traces of bromine, and was acidified with concentrated hydrochloric acid. The white solid was recovered by filtration and washed with cold water. The dried product was recrystallized from absolute ethyl alcohol to yield 95 g. (0.332 mole, 75%) of colorless solid melting at 22h-2260. Literature value (30), m.p. 225-227°. 0 . I u-Bromo-Z-thenoic acid BrC H SCOH 2 The method of S. Gronowitz (31% was used to synthesize tfluis acid. A solution of butyl lithium in ethyl ether was Prepared as follows (32). A 120 ml. volume of dry ethyl ether was placed in a SOC-ml. three-necked flask fitted with a stirrer, alcohol thermometer, dropping funnel and nitrogen inlet tube. Under a stream of nitrogen, 33 g. (0.1435 g.at.) of lithium, curt into chunks of approximately 1 cm.3 were added to the ether. A11 iJnitial quantity of 5.0 g. (0.036 mole) of freshly distilled E-butyl bromide was added to the lithium suSpension and the Pesnilting reaction.mixture was cooled to ~100 in a solid ' carbondioxide-isopropyl alcohol bath. An additional 23 g. (O-lfifi3 mole) of nrbutyl bromide was added to the above described m1X1ntre, with vigorous stirring, while maintaining the reaction temperature at 2:10-20. The cooling bath was removed. The _.,—__t__ V ”IV—W‘ f 4 29 reaction mixture was allowed to warm to 100 and was quickly filtered through a glass wool plug directly into a separatory funnel. The latter was fitted to a one-liter three-necked flask, which had been previously charged with a solution containing 800 ml. of dry ethyl ether and 23 g. (0.080 mole) of 3,u-dibromo-2-thenoic acid and cooled to -600 in a solid carbon dioxide-isopropyl alcohol bath. The butyl lithium solution was added to the ether solution of 3,h-dibromo-2- thenoic acid over a period of 15 minutes, while maintaining the temperature of the reaction mixture below -60°. The resulting solution was stirred at -600 for ten minutes after the addition of the butyl lithium solution was completed, and was poured into a beaker containing 600 ml. of water. After being set aside at room temperature overnight, the aqueous layer was separated and the other layer was extracted with 100 ml. of water. The combined aqueous layer and extracts were acidified with concentrated hydrochloric acid, resulting in the separation from solution of a brown colored oil, which solidified on cooling in an ice bath. The crude product was recovered by filtration, washed with cold water and air-dried at 250 for 2h hours. The yield of crude tan colored h-bromo- 2-thenoic acid was 10.1 g. (0.0h9 mole, 61%) melting at lOO-tho. Literature value (31), m.p. 122-1230.. 3-Thenyl bromide ChHBCH2Br The method of E. Campaigns and B. F. Tullar (33) was 30 followed in the synthesis of this compound, with the exception that fl,&J-azodiisobutyronitrile was used as the free-radical source in place of benzoyl peroxide. A solution prepared from lhO ml. of benzene, uh g. (O.uh8 mole) of 3-methy1thiophene and 1.0 g. (0.00612 mole) of “yiJ-azodiisobutyronitrile was re- fluxed for 15 minutes in a 500 ml., three-necked flask, fitted with a stirrer, Allihn reflux condenser, and a wide-bore re- flux condenser having an 18 mm. I.D. inner tube. An intimately mixed powder, consisting of 71 g. (0.h0 mole) of N-bromosuc- cinimide and 1.0 g. (0.00612 mole) of at»?-azodiisobutyronitrile was added in portions through the top of the wide-bore con- denser, over a period of 10 minutes. The reaction flask was cooled to 25° in an ice bath, and the succinimide which had precipitated during the reaction was removed by filtration. The succinimide was washed with 50 m1. of benzene and the combined filtrate and washing was transferred to a 500 ml. flask, equipped with an 8" Vigreux column fitted with a distillation head. A few chips of calcium carbonate were added and the benzene was removed by distillation under re- duced pressure (103 mm.). Vacuum distillation of the residue yielded 52 g. of clear liquid boiling at 16-520 (1 mm.), n55 1.597. A second fraction of slightly yellow colored liquid boiling at 58-8-2o (1 mm.), n35 1.603 raised the total or product yield to 62 g. (0.350 mole, 78%). Literature Values (33),b.p. 76° (1 mm.), n55 1.6030. In order to avoid 31 its decomposition, the 3-theny1 bromide was used immediately after it was prepared, for the synthesis of 3-thena1. R -Thena1 C H CH 3 A3 The method of E. Campaigns, R. C. Bourgeois and w. C. McCarthy (3h) was used to synthesize this aldehyde. A total of 62 g. (0.350 mole) of 3-theny1 bromide was added to a solution prepared from 56 g. (0.u00 mole) of hexamethylene tetramine and 250 m1. of chloroform contained in a 500 ml., three-necked flask, fitted with a stirrer, reflux condenser and dropping funnel. The addition was carried out at a rate sufficiently rapid to keep the reaction mixture at its reflux temperature. The reaction solution was then heated on a steam bath for 30 minutes and allowed to cool to room temp- erature, whereupon a white material precipitated from solution. The reaction mixture and precipitate were poured into 200 m1. of water and stirred until the precipitate dissolved. The chloroform layer was separated andwwashed withvaater. The combined water layer and extracts were steam distilled until the distillate was no longer cloudy in appearance. The dis- tillate was acidified with concentrated hydrochloric acid and extracted several times with ethyl ether. The ether extracts were dried over anhydrous magnesium sulfate and the ether was removed by distillation on a steam bath. Vacuum distillation Of the residue yielded 25 g. (0.223 mole, 6h%) of colorless liquid boiling at 75° (12 mm.). Literature value (3h)!b.p. 72‘780 (12 m. ) o 32 0 ll 3-Thenoic acid ChHBSCOH The method of E. Campaigne and w. M. LeSuer (35) was used to synthesize this acid. A suSpension of silver oxide was prepared by the addition, with vigorous stirring, of a solution containing 75 g. (0.hh2 mole) of silver nitrate dissolved in 150 ml. of water to a solution prepared from 35 g. (0.875 mole) of sodium hydroxide and 150 m1. of water and contained in a 500 ml., three-necked flask, fitted with a stirrer and dropping funnel. The reaction mixture was cooled to 0° in an ice bath, and 2h g. (0.207 mole) of 3-thena1 were added over a period of ten minutes. Stirring of the reaction mixture at 00 was continued for ten minutes after the addition of the aldehyde was completed. The metallic silver was removed by filtration and was washed with hot water. Acidi- fication of the combined filtrate and washings with concentrated hydrochloric acid precipitated a colorless solid product which was recovered by filtration and was washed with cold water. The crude product was recrystallized from water to yield 21 g. (0.16M mole, 79%) of colorless 3-thenoic acid in the form of needles melting at 137-1380. Literature value (35),m.p. 137-138°. Preparation of the Thenoyl Chlorides All of the thenoyl chlorides used in this study were Prepared from the corresponding acids by reaction with thionyl chloride. A typical procedure is described below.. ‘11.. h..n|.v..../vl. 33 0 II 5-Methy1-2-thenoy1 chloride CH c H 8001 3 2 In a 100 ml. round-bottomed flask fiited with a reflux condenser were placed 10 g. (0.0705 mole) of 5-methy1-2-thenoic ‘ acid and 33 g. (0.277 mole) of thionyl chloride. The reaction solution was refluxed on the steam bath for ten hours. Excess thionyl chloride was removed by distillation and the residue was distilled in a micro-distillation apparatus through a h" Vigreux column to yield 10.1 g. (0.0632 mole, 90%) of a colorless liquid boiling at 99-1000 (8 mm.). Literature value, (36) b.p. 102° (16 mm.). The thenoyl chlorides prepared in this investigation, together with their boiling points, literature references and yields are summarized in Table 1. Three of these thenoyl chlorides have not been previously reported. The amide of 5-methoxy-2-thenoy1 chloride was prepared by passing gaseous ammonia into an ethereal solution of the acid chloride. An elementary analysis was run on the amide, since the ex- pected bis(5-methoxy-2-thenoy1) peroxide could not be prepared from the acid chloride. I Preparation of the Bis(2-Thenoy1) Peroxides The bis(2-thenoy1) peroxides used in this study, with the exception of 5-methy1-bis(2-thenoy1) peroxide, were prepared -by reaction of the corresponding acid chloride with aqueous sodium peroxide. The acid chloride was dissolved in an inert organic solvent, which coated the crystalline peroxide as it 3h mm.om .m “me.m .2 “mm.: .m ame.m: .o “oases o:.oa .n mee.m .z aes.s .m mem.me .o “mNOZNmoo woe e.oaeo opfimeonnmo onenaoanpnmumxonpofium Mo mammawcw mmmpcosoams em x.ea one ooa mm ooaaoaho Heosona-m connects no: A.EE av mmumw :m opfinoamo HmOConpnmnosonmn: eopaodoa so: less NV m.mo-mo so oowaoano Hmoaohpum-aahaoa-: em x.ea NV oaanmoa oe ooasoaso Haoaehp-m-oapaz-m seesaoaos nos “.22 my own He onwaoaeo Haoaohs-m-ewoheozum :3 “.22 :1 OHH mm ooasoano Haocohs-m-aapsm-Mrm hm x.ea mi ooa-ee aw ooaaoaho Haoaoaaum-aanpoz-m em x.es may moa om oowaoaso Haoaoeoum-oaoaeo-m om A.ss my om mo sewaoaeo Haoaose-m-oaowm-m ma g.as may me me oeaaoaho awesose-m ooaosowom oasneaepaq .oo.m.m a ease» ooasoaso Haosoee mMQHmOQEO qwozmmfi mmH mo ZOHEaow mmmeOmmm AqwozmeINvam Ewe ho ZOHB¢m¢mmmm m. mqmg #8 (1.13 moles) of ammonium chloride and 300 ml. of water was added to the hydrolyzed reaction mixture to dissolve the znagnesium salts, and this was followed by the addition of 50 ml. of concentrated hydrochloric acid. The ether layer vuas separated and extracted with two 200 ml. portions of C).1 N sodium thiosulfate solution. After washing with water, tile other layer was separated and dried over anhydrous mag- Inesium sulfate. The ether was removed by distillation on a Esteem bath and the residue was vacuum distilled through an 8"‘Vigreux column to yield 92 g. (0.#85 mole, 81%) of colorless ILiquid boiling at 125-1290 (3 mm.). Literature value (#0), bop. 125-130 (34+ mm.). l(3,#-Dichloropheny1) ethyl acetate The method described by Elderfield, Gensler, Brody, Head, JDickerman, Wiederhold, Kremer, Hageman, Kreysa, Griffing, iKupchan, Newman and Maynard (#1), was modified for the prepar- ation of this ester. A solution prepared from 92 g. (0.#85 tmole) of l(3,#-dichloropheny1) ethanol and 70 g. (0.686 mole) of acetic anhydride was contained in a 500-ml. two-necked flask fitted with a stirrer and reflux condenser. The stirred reaction solution was gently refluxed for two hours and was allowed to cool to 25°. A 200 m1. volume of water was added to the reaction solution and it was stirred for an additional #5 minutes. The organic layer was separated andvvashed with 10% sodium carbonate solution until the washingsvvere neutral 1+9 to pHydrion paper. After washing with water, the organic layer was dried over anhydrous magnesium sulfate. Vacuum distil- lation yielded 80 g. (0.3#5 mole, 71%) of a clear liquid 'bodling at l20-123° (2 mm). Literature value (#0),b.p. 100- 102° (11 mm.). 3,#-Dichlorostyrene The method of Swain, Stockmayer and Clarke (#), was lised to prepare this compound. A 12" electrically-heated IQyTex column having an I.D. of 18 mm., was filled to a height (bf 8" with 1 cm. lengths of pyrex rod. Under a steam of Iaurified nitrogen, 80 g. (0.3#5 mole) of l(3,#-dichloropheny1) ethyl acetate was dropped on the vertically supported column, at a.rate of one drop per second, while maintaining the temp- erature of the column.at 550° by means of a chromel-alumel thermocouple in conjunction with a Leeds-Northrup galvanometer. The dark brown colored pyrolysis product was washed with three 50 ml. portions of 10% sodium carbonate solution. After washing with water, the crude product was dried over anhydrous magnesium sulfate. Vacuum diStillation yielded #0 g. (0.232 mole, 67%) of a clear liquid boiling at 7#-75° (2 mm.), n50 1.58#3. Literature values (#0), b.p. 88-89° (5 mm.), n30 1.58##. Product Analyses Products of the Decomposition of Bis(2-thenoy1) peroxide in Carbon Tetrachloride in the Absence of 3,#-Dichlorostyrene 50 The apparatus consisted of a standard-taper two-liter three-necked flask, fitted with a Graham condenser to the top of which was attached a train for collecting exit gases. Thm reaction flask was also equipped with a water cooled jplug, and a nitrogen inlet tube extending to the bottom of 'bhe flask. The exit gases were led, in turn, through a cold ‘trap immersed in a dry ice-is0propy1 alcohol bath, a tared ziscarite U-tube containing ascarite and anhydrone in a volume :Patio of two to one, a protective ascarite U-tube and a pro- ‘tective anhydrone U-tube. A special carbon tetrachloride insoluble stop-cock grease (#2) was used on the standard- ‘taper joints to prevent contamination of the peroxide solution. An 800 m1. volume of purified carbon tetrachloride ( page 9) was placed in the flask and flushed with purified nitrogen, 'at 25°, for one half hour. A 10.23? g. (0.0#03 mole) quantity of bis(2-thenoy1 peroxide was added to the carbon tetrachloride and the reaction solution was heated under a steady stream of purified nitrogen, at 75 $0.29 for ## hours. At this point, the solution had taken on a brownish coloration and a dark brown colored material had precipitated from solution. The product isolation procedure was similar to that described by Ford and Mackay (15). The gain in weight of the ascarite U-tube after the decomposition showed that 0.713 g. of carbon dioxide had been evolved. The carbon tetrachloride was re- moved from the reaction mixture by low pressure distillation 51 through a 12" glass helix packed column. The dark colored residue was extracted with five 100 m1. portions of hot ethyl ether, which left #.7 g. of a brown powdery residue. This residue was dissolved in hot chloroform and treated with norite. The addition of methanol to the chilled chloroform filtrate gave a brown colored amorphous powder which melted with decomposition, at l55-167°. Analysis of this material for carbon, hydrogen and sulfur gave the following results: Found: C, #7.#2; H, 2.65; S, 27.6# The combined ether extracts were washed with five 50 m1. portions of 2 N potassium carbonate solution to separate any 2-thenoic acid, and then with water, followed by drying over anhydrous magnesium sulfate. The ether was removed by distillation, through a 12" Vigreux column, on a steam bath. The viscous dark brown colored residue was distilled in a molecular still at a pressure less than 2 x 10’3 mm. The small amount of yellow distillate collected could not be identified. The potassium carbonate extracts and water washings were combined and acidified with concentrated hydrochloric acid. The acidified solution was extracted with five 50 ml. portions of ethyl ether. Evaporation of the other with an air-stream yielded 2.1 g. of 2-thenoic acid melting at lat-126°. 52 Carbon Dioxide Analyses The carbon dioxide determinations were carried out in a standard-taper, single-necked 250-ml. flask modified with a sealed-on nitrogen inlet tube extending almost to the bottom of the flask and a sealed-on Graham condenser. A standard- taper cold finger fitted into the neck. The exit gases passed through a sealed-on stopcock at the top of the condenser, and then successively, through a cold trap maintained at dry ice- isopropyl alcohol temperature, a tared ascarite U-tube con- taining ascarite and anhydrone in a volume ratio of two to one, a protective ascarite U-tube and a protective anhydrone U-tube. The following experimental procedure was used in a typical carbon dioxide determination. A 50 ml. volume of purified carbon tetrachloride (page 9) was placed in the flask. The latter was immersed in an oil bath thermostated at 7530.20 and a slow stream of purified nitrogen was passed through the system for a period of 2# hours. The ascarite U-tube was removed and weighed. A 0.328 g. (0.00129 mole) quantity of bis(2-thenoy1) peroxide and 1.# m1. (0.010 mole) of 3,#- dichlorostyrene were dissolved in the nitrogen flushed carbon tetrachloride. The ascarite U-tube was placed in the system and the nitrogen flow was resumed. After 72 hours the ascarite U-tube was removed and found to have gained .005 g. in weight, corresponding to 0.00011# mole of carbon dioxide. S3 The results of the carbon dioxide determinations are summarized in Table 3. TABLE 3 CARBON DIOXIDE ANALYSES Peroxide (ETTXide §é§;§i§h(§§°3 T2?) ngle %) Bis(2-thenoy1) 0.198 0 0.016 23.# Bis(2-thenoy1) 0.328 1.# 0.005 #.# Bis(3-thenoy1) 0.190 0 0.036 5#.7 Bis(3-thenoy1) 0.252 l.# 0.003 3.# *Calculated on the basis of two moles of carbon dioxide theoretically possible per mole of peroxide decomposed. Kinetics The rates of thermal decomposition of the bis(2-thenoy1) peroxides were followed by iodometric titration of samples of the peroxide solutions, which had been heated for definite intervals of time. The decompositions were carried out in an electrically-heated mineral oil bath, the temperature of which could be controlled to 30.2° by means of a Fisher-Serfass Electronic Relay. The peroxide solutions were contained in 10 ml. Kimble Neutraglass ampoules. The ampoules were cleaned (#) by immersing them in warm cleaning solution for 15 minutes. They were then 51+ rinsed with water, immersed in dilute ammonium hydroxide solution for one hour, thoroughly rinsed with water, given a final rinse with acetone and dried at 100° for 12 hours. The nitrogen used to remove oxygen from the peroxide solutions was purified (#3) by bubbling it successively through, two towers containing 200 m1. of Fieser's solution, a tower containing 200 ml. of saturated lead acetate solution, a tower containing 300 m1. of concentrated sulfuric acid and finally through a tower containing anhydrous calcium chloride. The approximately 0.01N standard thiosulfate solution was prepared by dissolving #.# g. of Analytical Reagent grade sodium thiosulfate in two liters of freshly boiled, distilled water. A quantity of 0.2 g. of sodium carbonate wasaidded as a preservative. The solution was standardized with Analytical Reagent grade potassium iodate, using the titration technique described below for the titration of the peroxide solutions. The fOllowing experimental procedure was used in a typical kinetic determination. 'A quantity of 0.315 g. (0.0012# mole) of bis(2-thenoy1) peroxide and 1.# m1. (0.010 mole) of 3,#-dichlorostyrene was made up to volume with purified carbon tetrachloride (page 9) in a 50 ml. volumetric flask. The solution was cooled to 00 in an ice bath and purged of oxygen by bubbling purified nitrogen into the flask for 15 minutes. The solution was warmed to room temperature and six 5-m1. samples were pipetted into ampoules. The ampoules 55 were sealed at room temperature, under a nitrogen atomsphere, with an air-gas torch. They were placed in a metal rack and the rack was immersed in an oil bath, maintained at the desired temperature. A period of three minutes was allowed for the samples to reach the temperature of the bath, thus zero time was assumed to be three minutes after the ampoules were immersed in the bath. At various time intervals an ampoule was removed from the bath and immediately quenched by immersion in cold water. The tip of the ampoule was broken off and the contents were emptied into a 125 m1. Erlenmeyer flask. The ampoule was rinsed thoroughly with carbon tetrachloride and the rinsings were placed in the flask. Several small lumps of dry ice were placed in the flask and 10 m1. of Analytical Reagent grade acetic anhydride and 1 g. of Analytical Reagent grade sodium iodide were added. The solution was stoppered . with a cork and was stirred for ten minutes by means of a magnetic stirrer. A volume of 50 m1. of distilled water was added and the rapidly-stirred solution was immediately titrated with standard sodium thiosulfate solution. The dead- stop method (#5) was used to determine the end-point in the titration, employing a Fisher Electropode in conjunction with a pair of platinum electrodes immersed in the vigorously- Stirred solution. rhe end-point corresponded to the increment of’thiosulfate added, after which current failed to register on the galvanometer of the Electropode. It was found that no 'blank was necéssary as long as dry ice was added. In the absence of dry ice a positive correction of 0.10 ml. was necessary. Duplicate samples were titrated during several kinetic determinations (see Tables 1#, 22, 23, 27, 28 and 30) and the average deviation varied from 1 to 15 parts per thousand. As would be expected, thezaverage deviation us- ually increased in proportion to the percent peroxide de- composed. Plots of the logarithm of the peroxide con- centration versus time for bis(2-thenoy1) peroxide determined at three different temperatures are shown in Figure 1. Similar plots for the other thenoyl peroxides studied are shown in the Appendix. Several of the kinetic determinations carried out in the preliminary phases of this investigation, in which styrene was used as a free-radical inhibitor, are also shown in the Appendix. Effects of Variables on the Kinetics Oxygen The effect of oxygen on the rate of decomposition of the thenoyl peroxides was demonstrated by allowing one ampoule to remain open to the atmOSphere during a given kinetic determination. The volume of standard thiosulfate solution required to titrate the exposed sample was slightly larger than that required for a sealed sample heated for the same period of time (see Tables 25 and 31). These results indicate that the presence of oxygen increases the concentration of material oxidized by iodide ion during the titration. 57 1.#0 1.30 T “ 1.?0 h 700 (D 1.; x - (J 1.10 - A. a, 0 75 11; o u 1.00 F \).O]O - . 130° v.30 " J l 1. 1 L 0 103 ”00 300 L00 500 600 Time in minutes Figure 1. Log per xide pnncentrstion versus time for the deromposition of t 58 TABLE # DECOMPOSITION OF BIS(2-THENOYL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,#-DICHLOROSTYRENE IN CARBON TETRACHLORIDE AT 70° m1. : milliliters of 0.01109 N sodium thiosulfate C : molarity of peroxide solution t 3 time in minutes Sample ml. 0 x 103 log (0 x 103) t 1 21.27 23.59 1.37273 90 2 20.00 22.18 1.3s59e 165 3 18.62 20.65 l.31#92 290 h 15.68 17.39 1.2h030 500 5 1h.32 15.89 1.20112 610 k a 705u - x 10-° 59 TABLE 5 DECOMPOSITION OF BIS(2-THENOYL) PEROXIDE IN THE PRESENCE OF 0.6K3M 3,#-DICHLOROSTYRENE IN CARBON TETRACHLORIDE AT 75° m1. : milliliters of 0.01109 N sodium thiosulfate C : molarity of peroxide solution t : time in minutes Sample m1. C x 103 log (C x 103) t 1 21.68 2#.00 1.38021 0 2 17.99 19.95 1.2999h 135 3 1#.#8 16.06 1.20575 295 # 11.89 13.19 1.1202# #50 5 11.30 12.53 1.09795 A90 6 10.h8 11.62 1.06521 5h0 k : 1.33 t .02 x 10'3 TABLE 6 DECOMPOSITION 0F BIS(2-THENOYL) PEROXIDE IN THE PIESENCE 0F 0.20 M 3,#-DICHLOROSTYRENE IN CARBON TETRACHLORIDE AT 800 m1. : milliliters of 0.01109 N sodium thiosulfate C = molarity of peroxide solution t : time in minutes 9 Sample m1. 0 x 103 log (C x 103) t 1 22.09 2#.#9 1.38899 0 2 17.55 19.#6 1.2891# 90 3 13.#3 l#.89 1.17289 185 # 10.22 11.33 l.05#23 290 5 8.9# 9.9lh 0.99625 370 6 6.29 6.976 '0.8h361 has k : 2.55 2 .09 x 10'3 61" Surface area of the ampoules The surface area of one ampoule in a given kinetic deter- mination was greatly increased by the addition of glass wool. The volume of standard tkiosulfate solution required to titrate this sample was slightly smaller than that required for a sample not containing glass wool, which had been heated for the same period of_time (see Table 31). Since the ampoules were uniform in shape and size, it was felt that a slight variation in the surface area of the ampoules would offer no serious interference with the kinetic determinations. Li t The ampoules were protected from direct light by covering the constant-temperature bath with aluminum foil during the kinetic determinations. Initial peroxide concentration In order to determine the affect of a change in the initial peroxide concentration on the rate of the decomposition of the thenoyl peroxides,several kinetic runs were made in which the initial peroxide concentration was varied by a factor of two (see Figures XI and XII), and all other variables were held constant. With bis(2-thenoy1) peroxide the ratevuas not affected. With bis(S-methyl-Z-thenoyl) peroxide, bis(h-methyl-2-thenoyl) peroxide and bis(S-chloro-2-thenoyl) peroxide, there was a slight decrease in rate on halving the initial concentration. It wauld be expected that if induced decomposition were occuring, a de- 62 crease in the initial peroxide concentration would decrease the overall rate of decomposition. Thus, it appears that very little induced decomposition occurs under the experimental conditions employed in this study. Nature of the free-radical inhibitor Styrene was used as the free-radical inhibitor in the preliminary phases of this inventigation, and was found totae effective in eliminating the induced decomposition. Later in these studies, 3,u-dichlorostyrene was tested and found to be equally effective. In the presence of 0.20 M quantities of either monomer (cf. Tables 5 and 31, and 18 and 32), the rates of decomposition of bis(2-thenoyl) peroxide are the same, as is the case of bis(S-tfbuty1-2-thenoy1) peroxide. However, the overall rate of decomposition of bis(S-nitro-2-thenoy1) peroxide, in which a large amount of induced decomposition would be expected to occur (A) appears to be somewhat slower in 3,u-dichlorostyrene than in styrene (see Figure XIII). With neither inhibitor was the induced decomposition of the nitro- peroxide completely eliminated, as evidenced by the non-linearity of the rate curves shown in Figure XIII. Breitenbach and Karlinger (1h) carried out the decomposition of 0.001 M bis(2-thenoy1) peroxide in carbon tetrachloride in the presence of 0.10 M styrene, and found that the resulting polymer contained 0.39% sulfur. In this investigation it was found that in the decomposition of 0.20 M bis(Z-thenoyl) peroxide 63 in carbon tetrachloride in the presence of 0.20 M 3,h-dichloro- styrene (approximate concentrations used in the kinetic deter- minations), the polymer that resulted after heating at 75° for 60 hours also gave a positive test for sulfur (us). The colorless polymer was precipitated by the addition of methanol to the chilled decomposition mixture. 6h DISCUSSION This investigation can be divided into two parts, the preparation of the substituted bis(2-thenoyl) peroxides, and a study of the kinetics of their thermal decomposition. The peroxides investigated, with the exception of S-methyl bis(2-thenoy1) peroxide, were readily prepared by the inter- action of the appropriate thenoyl chloride with aqueous sodium peroxide. In many of the syntheses, toluene was found to be a poor solvent to employ for the purpose of adding the acid chloride to the aqueous sodium peroxide, inasmuch as the reaction product, the bis(thenoyl) peroxide, failed to pre- cipitate from the two phase reaction mixture (13). However, in the cases where this occured, substitution of cyclohexane or benzene for toluene produced the desired solubility effect. The peroxides were obtained in purities ranging from 98-100%, after one recrystallization, as determined by iodometric titration. TheS-methyl bis(2-thenoy1) peroxide was prepared by the reaction of S-methyl-Z-thenoyl chloride with sodium perthenoate (h, 38). The peroxide partially decomposed and took on a slight yellow coloration after storage in a vacuum dessicator, at 0°, for several months. The other peroxides remained color- less and showed no decomposition when stored at 00 for shmilar periods of time. 65 beveral attempts at the preparation of bis(S-methoxy- 2-thenoyl) peroxide were unsuccessful. This peroxide is unstable and decomposed spontaneously on exposure to the atmos- phere. While this investigation was in progress, Ford and Mackay (15) reported their studies on the decomposition of bis (2-thenoyl) peroxide in a variety of aromatic solvents. Their results indicated that the thenoate free-radical initially formed in the spontaneous decomposition of the bis(P-thenoyl) peroxide is considerably more stable towards decarboxylation than is the benzoate free-radical (see page 8). In the present study, it was found that very little carbon dioxide was evolved during the decomposition of bis(2-thenoy1) peroxide in carbon tetrachloride as a solvent. of interest is the fact that under similar experimental conditions (see page 53) bis(3- thenoyl) peroxide evolved more than double the amount of carbon dioxide than did bis(2-thenoy1) peroxide. This indicates that the resonance stabilization of the 3-thenoate free-radical is much less than that of the 2-thenoate free-radical. o 30 n n 0.09 66 The product analysis determined with bis(2-thenoy1) peroxide in the absence of any free-radical inhibitor indicates that in the presence of a solvent lacking easily extractable hydrogen atoms, such as carbon tetrachloride, the thenoate radical preferentially attacks undecomposed peroxide molecules by abstracting a hydrogen atom to yield 2-thenoic acid (16% of theory). This would account for the rapid initial rate of its decomposition, which gradually decreases as the concentration of unreacted peroxide diminishes (see Figure X). The dark colored amorphous material, which was isolated in yields of net by weight, is probably formed from the peroxide molecules attacked by the initially formed thenoate free-radicals. Elementary analysis (see page 51) of the amorphous material corresponded to neither polythienyl thenoate nor polythienyl. The material was not further investigated. The presence of either 0.20 M styrene, or 0.20 M 3,u- dichlorostyrene markedly lowered the rate of decomposition of bis(2-thenoyl) peroxide (of. Figures I and X). Phrther- more, at the end of the kinetic runs the sample solutions were colorless as contrasted to the brown coloration in the absence of an inhibitor. Styrene was found to be an effective inhibitor, while 3,h—dichlorostyrene is probably an even more efficient inhibitor (see Figure XIII on the kinetics of the decomposition of bis(S-nitro-2-thenoy1) peroxide). The in- creased polarity of the chlorinated styrene probably makes it 67 more succeptible to electrophilic attack by thenoate radicals and thus more efficient in eliminating the induced decomposition. All kinetic determinations were carried out in carbon tetrachloride containing 0.20 M 3,h-dichlorostyrene. bome preliminary studies were made using 0.20 M styrene as the inhibitor. The peroxide concentrations varied from 0.0090 M to 0.025 M. The rates of thermal decomposition of the bis (thenoyl) peroxides were found to obey the first order rate equation, dt which on integration gives, k.2-_%92 log%Q (2) where C is the concentration of peroxide at time t, 00 is the initial concentration of peroxide and k is the first order rate constant. The rate constants were calculated from the slope (h?) of the plots of log C versus t (see Figure I for a typical plot), the slope in each case having been determined by the method of least squares. The activation energies, Ea, were calculated using the Arrhenius equation, 10. k u. E l g 2.§0§R T l mole'l, the gas law constant. where R is 1.987 calories degree“ The E8 values were estimated from the slope of the plots of log k versus l/T (see Figures XIV-XXII). 68 The rate constants calculated at each point (equation 2) were used to determine the standard deviations (h8). The rate constants for the thermal decomposition of the thenoyl peroxides, 0 determined at 75 , in carbon tetrachloride are, Peroxide , k x 103 (min.'l) Bis(5-methy1-2-thenoy1) 2.5h Bis(S-Eebutyl-a-thenoyl) 2.u3 5&Methy1 bis(2-thenoy1) 1.79 Bis(h-methy1-2-thenoy1) 1.76 Bis(Z-thenoyl) 1.33 Bis(3-thenoy1) 1.29 Bis(5-chloro-2-thenoy1) 0.95 Bis(5-bromo-2-thenoy1) 0.92 Bis(h-bromo-Z-thenoyl) 0.69 Examination of the rate constants show that the presence of electron donating substituents on the heterocyclic ring accel- erate the rate of decomposition of the peroxide, while electron withdrawing substituents have the opposite effect. These re- sults are similar to those reported (A, 11) for the benzene analogs of these peroxides. The first order rate constants for the thermal decomposition of several substituted benzoyl peroxides, determined at 80°, in a dioxane medium containing 0.20 M 3,h-dichlorostyrene as the inhibitor as reported by Swain, Stockmayer and Clarke (4) are shown on page 69. The (6.4’5») values listed are the sums of the substituent constants for the groups on the benzene ring of the peroxide (see page 1). 69 Peroxide k x 103 (min.-l) €¢+éz Bis(p-methyl) benzoyl 3.68 -0.3h0 Bis(pgt-buty1) benzoyl 3.65 —0.39h bis(m-methyl) benzoyl 2.6h -O.138 Bis(benzoyl) 2.52 0.000 Bis(p-chloro) benzoyl 2.17 -0.h5h Bis(p-bromo) benzoyl 1.98 -0.h6h Bis(m-bromo) benzoyl 1.5h —0.782 When the values of log k/ko were plotted against (€,i6‘,), a fairly good straight line resulted. Thus, it has been demon- strated that the Hammett equation is applicable to the spontaneous decomposition of substituted bis(benzoyl) peroxides. However, the linear relationship is only approximate, since the frequency factor as well as the activation energy was found to be affected by a change of substituent. There is a close parallel in rate constants, both in the absolute values and the relative order for the corresponding thenoyl and benzoyl peroxides, if the reasonable assumption is made that the 5-substituted thenoyl peroxides are analogous to the para-substituted benzoyl peroxides. As the rate constants for the benzoyl peroxides were determined at 800 while those for the thenoyl peroxides were determined at 75°, a better comparison between the two series of peroxides can be made by doubling the recorded rate constants for the thenoyl peroxides, since in the latter case the rate constant doubles,roughly, for each five degree rise in the decomposition temperature. 70 When the values of log k/ko for the bis(2-thenoy1) peroxides were plotted against (¢£+<fi), a fairly good straight line resulted for the“ha and 5-substituted thenoyl peroxides studied. Ihe assumption was made that theis'values derived from the ionization constants of the substituted benzoic acids are reasonably applicable to the corresponding thiophene analogs. The value of the reaction constant, e', is equal to -0.38 for the benzoyl peroxides. The small magnitude of this value shows that the electronic effect of the substituents has only a very small influence on the rate of decomposition of the benzoyl peroxides. The reaction constant, 6’, for the bis(2-thenoy1) peroxides is -0.hh (see Figure XXIII), and is approximately equal to the Q value for the substituted benzoyl peroxides. The activation energies for the decomposition of the bis (2-thenoyl) peroxides are all of the same magnitude, 29.5 f 1.0 kilocalories per mole (slopes of Figures XIV-XXII). The relative constancy of the activation energy throughout the entire range of substituents would seem to indicate an insensitivity of the rate of decomposition to the electron withdrawing or electron releasing power of the substituents. However, the rate constants themselves do show a definite dependence on the electronic character of the particular substituent. Thus, it appears reasonable to conclude that the frequency factor must vary with a change in substituents, and the Hammett relationship can only be approximate When applied to an interpretation of the ratasof decomposition of the substituted bis(2-thenoy1) peroxides. 71 SUMMARY 1. Ten previously unreported bis(2-thenoy1) peroxides were prepared. Three new intermediate thenoyl chlorides were also synthesized. 2. The rates of decomposition of the bis(2-thenoy1) peroxides were determined. All of the kinetic studies were carried out in dilute carbon tetrachloride solution in the presence of 3,h-dichlorostyrene as a free-radical scavenger. The decompositions all followed strict first order kinetics, with the exception of bis(5-nitro-2-thenoy1) peroxide.. The rate constants as determined at 75° are: Peroxide k x 103 (min.'l) Bis(5-methyl-2-thenoyl) 2.5M Bis(S-Egbutyl-2-thenoyl) 2.u3 5-Methy1 bis(2-thenoy1) 1.79 Bis(h-methyl—Z-thenoyl) 1.76 Bis(2-thenoy1) ‘ 1.33 Bis(3-thenoy1) 1.29 Bis(5-chloro-2-thenoy1) 0.95 Bis(5-bromo—2-thenoy1) 0.92 Bis(h-bromo-2-thenoy1) 0.69 3. Activation energies were determined and found to be 29.5 *‘l.0 kilocalories per mole for all the peroxides studied. 71a The Hammett equation was found to be applicable to the de- composition of the peroxides. However, the fact that the rate constants show a definite dependence on the electronic character of the particular substituent, while the activation energies are relatively constant over the entire range of substituents, indicates that the frequency factor must vary with a change in substituent and therefore the Hammett re- lationship can only be approximate for the decomposition of the bis(2-thenoy1) peroxides. APPENDIX (C x 10)) ~ LOP 1.05 0.95 0.75 72 i . . ... J 0 200 goo 600 800 Time in minutes Figure II. Log peroxide concentration versus time for the decomposition of bis(S-bromO-2-thenoy1) peroxide in carbon tetrachloride in the presence of 0.89 M 3,h-dichloro~ styrene at 759, 800 and 850. 73 TABLE 7 DECOMPOSITION 0F BIS(5-BROM0-2-TFENOYL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,h-DICHLOROSTYRENE IN CARBON TETRACRLORIDE AT 75° ml. : milliliters of 0.01109 N sodium thiosulfate ' C : molarity of peroxide solution t = time in minutes Sample ml. 0 x 103 alog (C x 103) t 1 8.12 9.005 0.95uh8 0 2 8.09 8.972 0.95289 70 3 7.14 7.918 0.89862 220 u 5.96 6.610 0.82020 370 5 5.21 5.778 0.76178 525 6 -N.2s n.713 0.67330 735‘ k : 9.23 *1.A7 x io-h 7h TmmEB DECOMPOSITION 0F BIS(5-PROM0-2-THEN0YL) PEROXIDE IN THE PRE§ENCE 0F 0.20 M 3,u-DICHL0R0STYRENE IN CARRON TETRACRLORIDE AT 80 ml. milliliters of 001109 N Sodium thiosulfate C molarity of peroxide solution t = time in minutes Sample ml. C x 103 log (C x 103) t 1 8.42 9.338 0.97025 95 2 5.76 6.388 0.80536 2h5 3 4.21 8.669 0.66922 380 u 3.81 u.225 0.62583 uu5 5 3.16 3.50h 0.5hh56 5&5 k = 2.18 t x 10"3 75 TABLE 9 DECOMPOSITION OF BIS(5-BROV0-2-THENOYL) PEROXIDE IN TFE PREéENCE OF 0.20 M 3,8-DICHLOROSTYBENE IN CARBON TETRACBLORIDE AT 85 m1. : milliliters of 0.01109 N sodium thiosulfate C = molarity of peroxide solution t 3 time in minutes Sample ml. C x 103 log (0 x 103) t 1 8.88 9.h08 0.97331 0 2 6.90 7.6521 0.88377 70 3 5.51 6.111 0.78611 180 u 8.50 8.991 0.69819 200 5 3.90 8.325 0.63599 260 6 3.18 3.5?7 0.5h7h1 320 76 1.10 0 1.00 - A O 0.90 ‘ . ‘ "E; I. C) 8 0.80 " 33 U; n O A O 0.70 " n 8 CO L 0.60 f 853 0.50 * h1_ L l, L, L 0 200 u00 * 600 800 Figure III. Time in minutes Log peroxide concentration versus time for the decomposition of bis(5-ch10ro-2-thenoy1) peroxide in carbon tetrachloride in the presen dichlorostyrene at 75°, 80° and 85 86 or 0.20 I" 3,11- 77 TABLE 10 DECOMPOSITIoN 0F RIS(5-CRLORO-2-TREN0YL) PEROXIDE IN TEE PR§SENCE 0F 0.20 M 3,8-DICHL0ROSTYRENE IN CARPON TETRACRLORIDE AT 75 m1. 2 milliliters of 0.009535 N sodium thiosulfate C : molarity of peroxide solution t = time in minutes Sample m1. 0 x 103 log (0 x 103) t 1 11.71 11.17 1.08805 0 2 11.31 10.78 ' 1.03262 90 3 9.80 9.388 0.97053 2N0 u 8.33 7.983 0.89998 390 S 7.03 6.703 0.82627 600 6 5.h9 5.235 0.71892 810 k : 9.86 31.96:: 10"LL 78 TABLE 11 DECOMPOSITION OF BIS(5-CRLOR0-2-TREN0YL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,h-DICRL0R0STYRENE IN CARBON TETRACHLORIDE AT 80° m1. : milliliters of 0.009535 N sodium thiosulfate C ; molarity of peroxide solution t = time in minutes Sample ml. C x 103 log (0 x 103) t 1 11.73 11.18 1.08888 0 2 9.95 ' 9.887 0.97713 110 3 8.19 7.809 0.89260 220 u 7.08 6.751 0.8293? 310 5 5.85 5.578 0.7u6u8 810 6 h.69 h.h72 0.65050 530 k :1.7Li 1’ .09x 10"3 79 TABLE 12 DECOMPOSITION OF BIS(5-CHLORO-2-THENOYL) PEROXIDE IN THE PRESENCE OF 0.2I)M 3au-DICHLOROSTYRENE IN CARFON TETRACHLORIDE AT 85° ml. : milliliters of 0.009535 N sodium thiosulfate C : molarity of peroxide solution t = time in minutes Sample m1. 0 x 103 log (C x 103) t 1 11.78 11.23 1.05038 0 2 9.97 9.506 0.97800 60 3 8.33 7.983 0.89998 110 8 8.61 8.396 0.68296 280 5 3.69 3.518 0.58630 360 k =3.30 : .86x 10'3 (C x 1C3) ~7- 0 Log H O b) \i\ 1.15 1.05 80 J - o A O n O b o h o 65 r 730 h l 1 1 _ | .7 '3 200 800 600 :00 Time in minutes Figure IV. Log peroxide concentration versus time for the desomposition of bis(5~methy1-2-thenoy1) peroxide in carbon tetrachloride in thg presence of 0.80 V 3,8- dichlorostyrene at 65‘, 7O , and 75°. 81 TABLE 13 DECOMPOSITION OF BIS(5-NETNYL—2-THENOYL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,8-DICHLOROSTYRENE IN CARBON TETRACHLORIDE AT 65° ml. . milliliters of 0.01109 N sodium thiosulfate C = molarity of peroxide solution t = time in.minutes Sample ml. C x 103 log (0 x 103) t l 28.89 23.35 [1.36829 0 2 23.80 22.69 1.35583 75 3 21.95 20.93 1.30982 195 8 19.18 18.25 1.26126 375 5 16.88 16.06 1.20575 590 6 18.95 18.25 1.15381 785 k : 6.63 11.05.x 10’“ TABLE 18 DECONPOSITION 0F BIS(5-METHYL-2-THENOYL) PEROXIDE IN THE PRESENCE OF 0.20 M 3.8-DICRL0R0STYRENE IN CARPON TETRACNLORIDE AT 700 milliliters of 0.01109 N sodium thiosulfate m1. C : molarity of peroxide solution t : time in minutes Sample ml. 0 x 103 log (C x 103) t 1 21.00 23.29 1.36717 0 2 19.18 21.28 1.32797 70 3 16.32 18.10 1.25768 190 8 13.82 15.33 1.18558 310 58 11.28 12.87 1.09587 865 68 11.39 12.63 1.10180 865 k :- 1.33 2 .02 x 10'”3 aDuplicate samples 83 TABLE 15 DECOMPOSITION 0F BIS(5-METHYL-2-THENOYL) PEROXIDE IN THE PRgSENCE 0F 0.20 M 3,8-DICRL0R0STYRENE IN CARBON TETRACBLORIDE AT 75 m1. milliliters of 0.01109 N sodium thiosulfate O I _ molarity of peroxide solution t s time in minutes Sample ml. 0 x 103 log (C x 103) t 1 20.68 22.89 1.35965 0 2 17.89 19.88 1.29758 60 3 18.15 15.69 1.19562 155 8 10.91 12.10 1.08279 265 5 7.76 8.606 0.93880 390 6 7.13 7.907 0.89801 815 k -_. 2.58“ t .06 x 10"3 Log (C x 103) 1.35 H O C) \J'l .. \ U 1 0.75 88 65° 75° 1 1 l 0 200 800 600 800 ‘ Time in minutes Figure V. Log peroxide concentration versus time for the decomposition of tis(5-t-hutyl—“-thencyll peroxide in Carbon tetrachloride in the presence of 3.20 N 3,8- dichlorostyrene at b5 , 7 0 an o— '40 85 TABLE 16 DECOMPOSITION 0F BIS(5-geBUTIL-2-THEN0YL) PEROXIDE IN THE PREgggCE 0F 0.20 M 3,8-DICHLOROSTYRENE IN CARBON TETRACRLORIDE AT ml. = milliliters of 0.009535 N sodium thiosulfate C = molarity of peroxide solution t : time in minutes Sample ml. C x 103' log (0 x 103) t 1 20.97 19.99 1.30081 0 2 19.80 18.50 1.26717 90 3 17.22 16.82 1.21537 280 8 15.80 15.07 1.17811 390 5 13.20 12.59 1.10003 610 6 11.62 11.08 1.08858 815 k : 7.36 t .53.x 10'“ 86 TABLE 17 DECOMPOSITION OF BIS(5eg-BUTYL-2-TPENOYL) PEROXIDE IN THE . PRESENCE 0F'0.2K>M 3,8-DICHLOROSTYRENE IN CARBON TETRACHLORIDE AT 70 ml. - milliliters of 0.01109 N sodium thiosulfate C a molarity of peroxide solution t = time in minutes Sample m1. C x 103 log (C x 103) t 1 18.80 20.81 1.30988 0 2 16.92 18.76 1.27323 60 3 15.25 16.91 1.22818 150 8 12.79 18.18 1.15168 270 5 10.60 11.76 1.07081 820 6 8.36 9.271 0.96713 585 k = 1.33 3 .19 x 10'3 87 TABLE 18 DECOMPOSITION 0F BIS(5-3eBUTYL-2-THEN0YL) PEROXIDE IN‘TEE PRESEgCE 0F 0.20 M 3,8-DICHLOROSTYRENE IN CARBON TETRACRLORIDE AT 75 m1. milliliters of 0.01109 N sodium thiosulfate C a molarity of peroxide solution t = time in minutes Sample ml. C x 103 log (0 x 103) t l 18.26 20.25 1.30683 0 2 15.52 17.21 1.23578 60 3 12.81 13.76 1.13862 160 8 10.87 11.61 1.06883 285 5 7.88 8.695 0.93927 335 6 5.90 6.583 0.81578 865 k : 2.83 t .11x 10"3 88 F" I \N U". ,. ) ”75"0 0.75 P 309 " J" C) :71; \4'5 T \J ' I X.) ‘J 85-; \ H. I) 15 C~"i :3 r‘ H d p U) A) Time‘ Tisure VI. Lo: rernxido O'ncentrrtion versus tire for b s “ ' 4“, Fl 3 I ‘ I ‘.‘ ‘ "~ ~ I ‘ ‘\~y .-' ‘ £29 deemvputlfiun of bis(n—fieLPyI-v-Luenoyl; pUJCAIdB 1: carbon Letr cll rile in tie 'resenre of‘0.20’” 3,8- ! 1‘ . .. "" LN ’ ‘JU -‘ ""0 11C :irostyrene n, 79 , 75 9n* 80 . 89 TARLE l9 DECOMPOSITION OF BIS(8-METHYL-2-TEENOYL) PEROXIDE IN THE PRESENCE OP‘O.20 N 3,8-DICHLOROSTYRENE IN CARBON TETRACPLORIDE AT 700 m1. milliliters of 0.01109 N sodium thiosulfate C molarity of peroxide solution t 2 time in minutes Sample m1. 0 x 103 log(C x 103) t 1 20.50 22.73 1.35660 ' . 0 2 18.78 20.83 1.31869 ' 95 3 16.33 18.11 1.25792 280 8 13.68 15.13 1.17988 835 5 11.76 13.08 1.11528 585 6 10.27 11.39 1.05652 700 k : 9.77 t 622 X 10- 90 TABLE 20 DECOMPOSITION OF BIS(8-NETHYL-2-THENOYL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,8-DICHLOROSTYRENE IN CARBON TETRACHLORIDE AT 75° ml. milliliters of 0.01109 N sodium thiosulfate C 3 molarity of peroxide solution t : time in minutes Sample m1. 0 x 103 log (0 x 103) t 1 20.87 22.70 1.35603 0 2 18.00 19.96 1.30016 70 3 18.87 16.89 1.21722 160 8 12.11 13.83 1.12808 275 5 9.79 10.86 1.03583 815 6 7.95 8.817 0.98532 535 k z 1.76 t .092: 10‘3 TABLE 21 DECOMPOSITION OF BIS(8-METHYL-2-THENOYL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,8-DICHLOROSTYRENE IN CARBON TETRACHLORIDE AT 800 m1. : milliliters of 0.01109 N sodium thiosulfate C : molarity of peroxide solution t : time in minutes Sample m1. C x 103 log (C x 103) t 1 20.83 23.10 1.36361 0 2 19.28 21.38 1.32919 25 3 15.32 16.99 1.23019 90 8 10.63 11.79 1.07151 210 5 6.81 7.552 0.87806 335 6 5.11 5.667 0.75335 815 k z 3.37 2.09 x 10-3 91 Log (C x 103) 0.95‘ C) \O O "3.75 0.70 92 ‘11 I o (:0 l 8 ’1 1 l 200 800 600 800 Time in minutes _ Log peroxide co:.centration versus He decomposition of bis.8- bromo-2-thenoy1) peroxide in tetrac.. oride (in the presence of 0.20’ if diihiorostvrene at 75 , 330 ani 3S time for 93 TABLE 22 DECOMPOSITION OF 818(u-BRON0-2-TEEN0YL) PEROXIDE IN THE PRESENCE OF 0.201M 3,u-DICHLOROSTYEENE IN CARBON TETRACHLORIDE AT 75° ml. - milliliters of 0.009535 N sodium thiosulfate C) II molarity of peroxide solution t : time in minutes Sample m1. C x 103 log (C x 103) t 1a 9.53 9.087 0.95882 0 2a 9.58 9.098 0.95885 0 3 9.08 8.858 0.93782 ' 120 u 8.19 7.809 0.89280 2&0 5 7.19 8.858 0.83807 820 8b 6.33 6.035 0.78088 800 7b 6.38 6.085 0.78180 800 8 - 5.58 5.321 0.72599 800 k = 8.92 z .951: 10"LL a’bDuplicate samples 98 TABLE 23 DECOMPOSITION OF BIS(u-BROVO-2-T?EN0YL) PEROXIDE IN THE PRESENCE OF 0.2C>M 3,8-DICHLOROSTYRENE IN CARBON TETRACPLORIDE AT 800 m1. = milliliters of 0.009535 N sodium thiosulfate C : molarity of peroxide solution t = time in minutes Sample ml. C x 103 log (C x 103) t 1a 9.58 9.135 0.98071 0 2a 9.56 9.115 0.95976 0 3 8.79 8.381 0.92330 70 u 7.67 7.313 0.88810 170 5 8.88 8.350 0.80277 285 '8b 5.83 5.388 0.72981 820 7b 5.77 5.502 0.78052 820 8 5.32 5.073 0.70526 880 k g 1.23 t .03 x 10"3 a,b Duplicate samples 95 TABLE 28 DECOMPOSITION OE BIS(u-BR0M0-2-TBEN0YL) PEROXIDE IN THE PRESENCE 0P‘0.20 M 3gh-DICHLOROSTYRENE IN CARBON TETRACHLORIDE AT 0 ml. : milliliters of 0.009535 N sodium thiosulfate C 3 molarity of peroxide solution t = time in minutes Sample ml. C x 103 log (C x 103) t 1 9.53 9.087. 0.95882 0 2 8.12 7.782 0.88885 50 3 7.38 7.037 0.88739 125 u 5.00 8.788 0.6783h 235 5 h-hS n.283 0.62767 335 k a 2.35 1.73 i 10-3 96 1.80 1.30 b . 750, l L l l l 0 100 200 300 800 500 800 00 Time in minutes Figure VIII. Log peroxide cencentration versus time for the decomposition of bis(B-thenoyl) peroxide in carbon tetrachleride in the oresence of 0.90 M 3,8-dich10rostyrene at 700, 750 and 800 TABLE'25 DECOMPOSITION OF BIS(3-TREN0YL) PEROXIDE IN THE PRESENCE OF 0.20 N 3,8-DICHLOROSTYRENE IN CARBON TETRACRLORIDE AT 70° ml. _ milliliters of 0.009905 N sodium thiosulfate C a molarity of peroxide solution t g time in minutes Sample m1. C x 103 log(C x 103) t 3 1 23.20 22.98 1.38135 0 2 21.83 21.82 1.33888 90 3 20.08 19.89 1.28285 210 8 18.57 18.39 1.28858 330 5 16.80 16.68 1.22115 880 8EL 18.92 18.78 1.22827 880 7 15.08 18.90 1.17319 830 k g 8.85 1.06 x 10"“ 8Exposed to the air 98 TABLE 26 DECOMPOSITION 0F BIS(3-THENOYL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,8-DICRLOR0STYRENE IN CARBON TETRACPLORIDE AT 75° ml. milliliters of 0.009535 N sodium thiosulfate C a molarity of peroxide solution t = time in minutes Sample ml. 0 x 103 log (C x 103) t 1 25.15 23.98 1.37912 0 2 23.78 22.67 1.35585 60 3 20.52 19.57 1.29159 180 8 18.77 15.99 1.20385 330 5 13.05 12.88 1.09882 510 8 10.19 9.718 0.98789 710 k 3 1.29 t .22x 10'3 TABLE 27 DECOMPOSITION-0F BIS(3-TREN0YL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,8-DICHLOROSTYRENE IN CARPON TETRACRLORIDE AT 800 ml. . milliliters of 0.009535 N sodium thiosulfate C . molarity of peroxide solution t 3 time in minutes Sample ml. 0 x 103 log (C x 103) t 1 25.50 28.31 1.38578 0 2 21.78 20.75 1.31702 70 3 18.28 17.81 1.28080 180 8 13.03 12.82 1.09377 275 5a 10.05 9.583 0.98150 390 6a 9.98 9.878 0.97672 390 7 8.53 8.228 0.79821 585 k a 2.36 3.06 x 10-3 aDuplicate samples 100 1.10 1.009 7 20.80 . ' ° 85° , , I 700 0.60 . 750 C) .50 0 200 '800 800 800 1000 Time in minutes Figure IX. Log peroxide concentration versus time for the decomposition of S-methyl bis(7-thenoyl) peroxide in.carbon tetrachloride in the presence of 0.29!w 3,8—dichlorostyreno at 65°, 700 and 75° 101 TABLE 28' DECOMPOSITION 0F S-NETHYL BIS(2-THENOYL) PEROXIDE IN THE PRTSENCE 0F 0.20 3,8-DICELOROSTYRENE IN CARBON TETRACHLORIDE AT 650 m1. - milliliters of 0.009905 N sodium thiosulfate C = molarity of peroxide solution t = time in minutes Sample ml. C x 103 log (C x 103) t 1a 9.87 9.380 0.97220 0 2a 9.85 9.360 0.97123 0 3 9.85 9.380 0.97128 180 8.18 8.102 0.90859 310 5 7.88 7.809 0.88976 890 8b 8.70 i 8.838 0.82191 705 7b 8.88 6.596 0.81928 70; 8 _ 6427 6.210 0.79309 820 k = 5019 ’ .80 X 10-” 102 TABLE 29 DECOMPOSITION 0F 5-NETRYL BIS(2-TEENOYL) PEROXIDE IN THE PRESENCE OF 0.iN>M 3,8-DICHLOROSTIRENE IN CARFON TETRACELORIDE AT 700 ml. : milliliters of 0.01109 N sodium thiosulfate C = molarity of peroxide solution t : time in minutes Sample ‘ ml. 0 x 103 log (C x 103) t l 8.91 9.881 0.99880 0 2 8.69' 9.637 2 0.98398 65 3 7.85 8.706 0.93928 185 8 7.00 . 7.783 0.89003 295 5 5.88 8.521 -0.81831 880 6 8.88 5.368 0.73062 700 k-: 8.98 t 1.8 x 10'” 103 TABLE 30 DECOMPOSITION 0F 5-8ETEYL BIS(2-TREN0YL) PEROXIDE IN THE PRESENCE OF 0.20 M 3,8-DICPLOROSTIRENE IN CARBON TETRACBLORIDE AT 75° F“ - milliliters of 0.009535 N sodium thiosulfate O I - molarity of peroxide solution t = time in minutes Sample m1. 0 x 103 18g (0 x 103) t 1EL 10.58 10.05 1.00217 0 23 10.86 9.978 0.99887 0 3 9.07 8.688 0.93692 80 7.97 7.599 0.88078 170 5 6.78 6.827 0.80801 280 8b . 5.20 8.958 0.89531 380 7b 5.17 8.929 0.89278 380 8 8.10 3.909 0.59207 580 k z 1.79 t .09 x 10'3 a’bDuplicate samples TABLE 31 DECOMPOSITION OR BIS(2-THENOYL) PEROXIDE IN THE PRES 0.20 M STIRENE IN CARBON TETRACELORIDE AT 75° NOE 0F 108 ml. C s molarity of peroxide solution t - time in.minutes milliliters of 0.00978 N sodium thiosulfate Sample ml. 0 x 103 18g (0 x 103) t l 22.57 22.07 1.38330 70 2 18.33 17.93 1.25358 235 38 18.13 13.82 1.18051 805 8 18.17 13.88 1.18176 805 5 12.93 12.85 1.10209 890 8b 13.00 12.71 1.10815 890 k . 1.38 - x 10-3 aGlass wool added to ampoule bExposed to the air 105 TABLE 32 DECOMPOSITION 0F BIS(5-t-BjTyL-2-TRENOIL) PEROXIDE IN THE PRESENCE OR 0.20 M STYRENE IN CARBON TETRACBLORIDE AT 75° ml. = milliliters of 0.00978 N sodium thiosulfate C = molarity of peroxide solution t = time in minutes Sample 3 ml. 0 x 103 log (C x 103) t 1 21.15 20.88 1.31555 0 2 18.58 18.15 1.25888 ' 55 3 18.00 15.85 1.19851 115 8 11.38 11.13 1.08650 285 5 7.72 7.550 0.87795 885 8 8.17 8.030 0.78032 520 k = 2.32 - .08 x 10-3 Log (C x 103) 1.80 1.30 1,20 106 0 200 800 600 Time in minutes Figure X. Log peroxide concentration versus time for the decomposition of 0.095 V bis(2-thenoy1) peroxide in carbon tetrechlcride in the absence of an inhibitor at 75 Log (0 x 103) 1.60 1.80 1.?0 1.00 0.80 0.60 107. o I . . B r P O ) O . F’ A L . C l 1 F ‘ 4 g 100 200 300 . 800 500 Time in minutes Figure XI.. Log peroxide concentration versus time for different initial peroxide concentrations in carbon tetra- chloride in the presence of 0.80’M 3,8-dichlorostyrene at « 75 . A-0.01 M bis(P-thenoyl) peroxide 8-0.09 M bis (P-thenoyl) peroxide, C-0.01 M bis(S-methyl-?-thenoyl) ' peroxide, D—D.0? bis(5-oethyl-2-thenoyl) peroxide 1.60 1.80 1.?0 Log (C x 103) 1.00 0.60 108 0 ' 100 200 300 800 500 Time in minutes Figure XII. Log peroxide concentration versus time for different initial peroxide concentrations in carbon tetra- chloride in the presence of 1&9" 3,8-dichlorostyrene, at 80°. A-0.01 M bis(u-methyl-2-thenoyl) peroxide, B- 0.0? N bis(h-methyl-2-thenoyl) peroxide, C-0.01 M bis (5-chloro-2-thenoy1) peroxide, D-0.0? M bis(5-Chloro-9- thenoyl) peroxide 109 1.203. 1.10 - 1.00 p Log (C x 103) .0 ~o O 0.80 r- ' A 0.70 - J L l L J I- 200 300 7 800 500 (00 700 Time in minutes Figure XIII. Log peroxide manoentration versus time for the decomposition of bis(5-nitro-2-thenoyl) peroxide in carbon tetrachloride at 75°. A-0.01 M peroxide in the presence of 0.30’" styrene. B-0.01 M peroxide in the presence of OJEP M 3,8-dichlorostyrene 110 1.80 1.30 — a.“ O r—4 1.20 - K .51 Lu 3 ’ 1.10 - 1.00 r- 0.90 - If i . i . 2.38 9.86 9.38 9.90 9.99 l/T x 103 Figure XIV» Log rate constcnt versus reciprocal of atsolute temperature for the decomposition of bis (9-thenoyl) peroxide in carbon tetrachloride in the presence of 0.QO N 3,8-dichlorostyrene 1.50 1.80, 1.30 .55. O .4 1.20 K x GU O F-J 1.10 1.00 0.90 P l I 1 1 1 l 2.80 2.82 2.88 2.88 2. 1/T x 103 Figure '21. Log rate constant versus reciprocal of absolute temperature for the decomposition of bis (S-bromo-2-thenoyl) peroxide in carbon tetrachloride in the presence of 0.80’V 3,8-dichlorostyrene lll 8 Log (8 x 10 ) 1.50 1.80 1030 1.00 11? . . .____._i P.3O 9.32 2.88 2.86 2.88 l/T x 103 Figure :71. Log- rate constant versus reciprocal of absolute temperature for the decomposition of bis(5-ch10ro-2ethenoyl) peroxide in carbon tetrachloride in the presence of 0.90 M 3,8-dichlorostyrene 113 1.807 1.30P Log (‘8 x 10“) 1.00_ 5 83 .J l/T x 103 Figure m1, Log rate constant versus reciprocal of“ absolute termneratdre f0" tne decomposition of his (5-methyl-9-thenoyl) n9POX139 in carton tetrachloride in the presence of 3.30 V 3,8-dichlorostyrene Log (k x 10L) (‘1 .33 23 .s. 118 Dewy: 57.5.0 909? 9091‘» 9096 l/T x 103 Figure mu. Log rate constant versus reciprocal of absolute temperature for the decomposition of his (5-t-butyl—9-thenoyl) peroxide in carbon tetrachloride in the presence of 0.20 V 3,8-dichlorostyrene 1.50 1.140 I'“ e W O Log (k x 10”) H 0 \) O 1.10 1.00 115 P p t l 4_J ti 1 ?.33 ?.90 ?.99 ?.9h 9.96 '1 l/T x 104 Figure 111. - Log rate constant versus recinrocal of absolute temperatwre for the decoroosition of his (h-rethyl-9nthenoyl) peroxide in carton tetrachloride ~1n tFe presence of‘O.30 M 3,u-dichlorostyrene 1.uo l l l l 9.90 9.3? ”.Qu ?.86 P.38 l/T x 103 Figure $2.. Log rate constant versus reciprocal of arsolute temoerature for the decornosition of bis (g-bromo-Q-thenoyl) peroxide in cerbon tetrachloride in the presence of 0.20 W 3,u-dichlorostjrene 116 117 1.40 1.30 F" 1.?0 b 1.10 F Log (k x 10“) O 0 00 L- O.8O “ 7.8? 9.8g 9.36 9.38 9.90 l/T x 103 Figure REL Lop rate constant versus reciprocal of nosolute tenperatare for the decomoosition of bis (j-thenoyl) peroxide in carbon tetrachloride in the presence of O.@0’V 1,3-dichlorostyrene o’ 118 1.30 1.90 P 1.10 _ Log (k x 10L) 0.90 0.80 1.00 P 0.70 l i l 1 _* po‘qn" 9090 73.9") 00914 9.96 l/T x 103 Log rate constant verSws reciprocal of Figure XXII. qrsolute temperature for the decomposition of )~methyl bis(fi-thenoyl) peroxide in carbon tetrachloride in the presence of 0.30 V 3,h-iichloroct§rene log k/ko 0°33? Bis(S-methyl) ‘0 “15(5-E-butyl) 3.?Or :is(h-methyl) oS-Vechyl H J. Loi- 0.01, O Thenoyl -O.lOF Bis(S—chloro) Fis(§-bromo) -O.90P ‘0 Bis(u-brom l I l l l L -O;h0 -O.20 0.00 0.20 O.h0 0.60 O.» 5.1-+52 & igure XXIII. Plot of log' lt/ko versus‘ +4? for the de- composition of the bis(fi-thenoyl) oeroxi es in carbon tetrachloride at 73° 7. 9. 10. 11. 120 LITERATURE CITED L. P. Hammett, Chem. Rev., 11, 125 (1935). G. N. Burkhardt, W. G. K. Ford and E. Singleton, J. Chem. Soc., 17 (1936). L. P. Hammett, "Physical Organic Chemistry " McGraw- Hill Book Co., Inc., New York, 19u0, pp. léu-l90. C. G. Swain, w. T. Stockmayer and J. T. Clarke, J. Am. Chem. 800., 1g, 5&26 (1950). 0. J. Walker and G. L. E. Wild, J. Chem. Soc., 1132 (1937). K. Nozaki and P. D. Bartlett, J. Am. Chem Soc., §§, 1686 (l9u6). D. H. Hay and w. A. Waters, Chem. Rev., 21, 202 £1937). G. 5. Hammond and L. N. Soffer, J. Am. Chem. Soc., 1g, M711 (1950). P. D. Bartlett and K. Nozaki, J. Am. Chem. Soc.,‘ég, 2299 <19u7). W. E. Cass, J. Am. Chem. 800., é§, 1976 (l9u6). A. T. B. Blomquist and A. J. Buselli, J. Am. Chem. Soc., 12. 3883 (1951). s. Gambarjan, Ber., g2, u003 (1909). C. C. Price and E. Krebs, Org. Syn., 2;, 6S (19u3). J. W. Breitenbach and H. Karlinger, Nonatsh., QQ, 739 (19h9); 30h (1951). M. C. Ford and D. Nackay, J. Chem. 800., A620 (1957). D. H. Hey, J.Chem. Soc., 1966 (193k). F. R. Mayo and F. M. Lewis, J. Am. Chem. Soc., 66, 159h (19hh)- H. D. Hartough and A. I. Kosak, J. Am. Chem. Soc., 92, 3093 (19u7). 19. 2h. 25. 26. 29. 30- 31. 32- 33. 3h. 35. 360 37. 121 H. D. Hartough and L. G. Conley, J. Am. Chem. Soc., 92, 30% (19M). E. Campaigns andil L. Archer, J. Am. Chem. Soc., 25, 989 (1953). W. J. King and F. F. Nord, J. Org. Chem., 13, 635 (19MB). P. D. Caesar, J. Am. Chem. Soc., 70, 3623 (19u8). H. D. Hartough, "The Chemistry of Heterocyclic Compounds," Volume III, "Thiophene and Its Derivatives," Interscience Publishers, Inc., New York, 1952, p. 3&1. J. Sice, J. Am. Chem. Soc., 15, 3697 (1953). Ng. Ph. Buu Hoi, J. Chem. Soc., 1721_(l958). V. Migrdichian, "Organic Syntheses," Volume II, Reinhold Publishing Corp., New York, 1957, p. 258. O. Dann, Ber., 16, #19 (19h3). J. W. Schick and H. D. Hartough, J. Am. Chem. Soc.,‘19, 16AS (1948). F. S. Fawcett, J. Am. Chem. boc.,é§, 1u2O (19u6). W. Steinkopf, H. Jacob and H. Penz, Ann., 512, 136 (193A). S. Gronowitz, Arkiv. Kemi, g, 87 (1955); C. A., 5Q, 11312 (1956). H. Gilman and J. W. Morton, Jr., "Organic Reactions," Volume 8, John Wiley and Dons, Inc., New York, 195h, p. 258. E. Campaigne and B. F. Tullar, Org. Syn., 33, 96 (1953). E. Campaigne, 3. C. Bourgeois and W. C. McCarthy, Org. Syn., 33, 93 (1953). E. Campaigne and W. M. LeSuer, Org. Syn., 33, 9A (1953). Ne. Ph. Buu H01 and Nguyen Hoan, Rec. Trav. Chim., QQ, 5 (19h9). E. Campaigne and W. M. LeSuer, J. Am. Chem. 300., 19, 1555 (l9h8). . 380 39. A0. A1. A2. #3. AA. #5. A6. A7. A8. 122 G. Braun, "Organic Syntheses," Col. Vol. I, John Wiley and Sons, Inc., New York, 1956, p. A31. G. Lock and E. Book, Per., 19, 916 (1937). C. S. Narvel, C. G. Overberger, R. E. Allen, H. W. Johnston, J. H. Saunders and J. D. Young, J. Am. Chem. Soc., 68, 861 (19A6). H. C. Elderfield, W. J. Gensler, F. Brody, J. D. Head, S. C. Dickerman L. Wiederhold III, C. B. Kramer, H. A. Hageman, 8. J. Kreysa, J. F. Griffing, S. M. Kupchan, B. Newman and J. T. Maynard, J. Am. Chem. Soc., 68, 1579 (19A6). C. Neloche and W. D. Fredrick, J. Am. Chem. 800., ii. 326A (1932) L. F. Fieser, "Experiments in Organic Chemistry," Part II, D. C. Heath and Co., New York, 19A1, p. 395. M. Sy, Ng. Ph. Buu H01 and Ng. D. Xuong, J. Chem. Soc., 1975 (195A). C. W. Foulk and A. T. Hawden, J. Am. Chem. Soc., Afl, 2OA5 (1926); E. W. Abrahamson and H. Linschitz, Anal. Chem., 2A. 1355 (1952). R. L. Shriner and R. C. Fuson, "The Systematic Identification of Organic Compounds," John Wiley and Sons, Inc., New York, 19A8, p. 52. A. G. Worthing and J. Geffner, "Treatment of Experimental Data," John Wiley and Sons, Inc., New York, 19A3. H. Diehl and G. F. Smith, "Quantitative Analysis," John Wiley and Sons, Inc., New York, 1952, p. A75 and p. A30.