OXIDATION OP SODIUM AZIDE AND HYDRAZINE WITH CERIUM(IV) IN GLACIAL ACETIC ACID By William Charles Harris A THESIS Submitted to the School of Advanced Graduate Studies of Michigan State University of Agriculture and Applied Science in p a r t i a l fu lfillm e n t of the requirements fo r the degree of DOCTOR OP PHILOSOPHY Department of Chemistry 19 58 ProQuest Number: 10008595 All rights reserved INFO RM ATION TO A LL USERS The quality o f this reproduction is dependent upon the quality of the copy subm itted. In the unlikely event that the author did not send a com plete m anuscript and there are missing pages, these will be noted. Also, if m aterial had to be removed, a note will indicate the deletion. uest ProQuest 10008595 Published by ProQ uest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code M icroform Edition © ProQ uest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 - 1346 ACKNOW LEDGEMENT The author wishes to express h is sincere appreciation to Dr, K. G-. Stone for his encour­ agement and stimulating guidance throughout the course of t h i s in v e stig a tio n . Appreciation i s also due to various other members of the Department of Chemistry who have given help ful advice from time to time, and esp ecially to Dr. J. C. Sternberg for his very kind help with the gas id e n t if ic a tio n . The author also wishes to express his thanks to his wife, Joan, f o r her help in the preparation of th is manuscript. ii VITA Name: William Charles Harris Borns August 3, Academic Career: 19 30 in Clinton, Iowa Clinton High School Clinton, Iowa, (1944-19 48) Clinton Junior College Clinton, Iowa, (19 48-19 50) State University of Iowa Iowa City, Iowa, (1950-1954) Michigan State University East Lansing, Michigan, (1954-19 58) Degrees Held: A. A. Clinton Junior College (19 50) B. S. State University of Iowa (1952) M. S. State University of Iowa (1954) Thesis t i t l e : The Adaption of a Breaker-Type D. C. Amplifier to a Photoelectric Microdensitometer. iii OXIDATION OP SODIUM AZIDE AND HYDRAZINE WITH CERIUM(IV) IN GLACIAL ACETIC ACID By William Charles Harris AN ABSTRACT Submitted to the School of* Advanced Graduate Studies of Michigan State University of Agriculture and Applied Science in p a r t i a l f u lfillm e n t of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Chemistry Year Approved 19 58 . ABSTRACT The oxidation of sodium azide, hydrazine ace ta te , acethydrazide, and symmetrical diacethydrazide can be affected by cerium(lV) in g la c ia l acetic acid. Of these m aterials only the sodium azide i s q u a n tita tiv e ly oxidized. This oxidation to nitrogen was achieved by dissolving the sample in g la c ia l acetic acid, excess of the cerium(IV) reagent, adding an allowing the mixture to stand fo r one-half hour and then determining the excess cerium(IV) with sodium oxalate. This determination may also be done as a d i r e c t t i t r a t i o n with the cerium(IV) reagent, provided the g la c ia l acetic acid used as a solvent is made one normal in perchloric acid. The oxidation of both hydrazine acetate and sym­ metrical diacethydrazide resu lte d in odd values for the stoichiometry. Xn both cases the stoichiometry values were quite reproducible. The stoichiometry values obtained in the oxidation of the symmetrical diacethy­ drazide were more consistent than those obtained in the oxidation of hydrazine acetate. This would be expected because of the i n s t a b i l i t y of a solution of hydrazine acetate in g la c ia l acetic acid. In each case i t appeared that the oxidation resulted in the formation of nitrogen as the only product. v In the oxidation of hydrazine acetate and symmetrical d ia c e t­ hydrazide the amount of nitrogen produced i s not q u a n tita tiv e a t f i r s t glance. However, i f the amount of nitrogen collected is compared to the r a t i o of the number of mi111equivalents of cerium(IV) a c tu a lly used to th a t required f o r oxidation to nitrogen, the evolution is quantitative* Under standardized conditions, the stoichiometry achieved in the oxidation of hydrazine acetate was 2.21 i .09 equivalents of cerium(IV) per mole of hydrazine a c e ta te . Similarly, the oxidation of sym­ metrical diacethydrazide required 3.37 t .03 equivalents of cerium(IV) per mole of diacethydrazide. For the l a t t e r oxidation the following route is proposed: CH3CNHNHCCH3 f II 0 2 Ce(IV) ---------►CH3CN=NCCH3 * 2 C e(III) * 2 H + U 0 11 u n 0 0 00 CH3CCCH3 f na 2 OH” f II 0 4* K g C H 3 C H =N C C H 3 ---------- » C H 5C C C H 5 it U 0 2 Ce(XV) » 2 CH3C00H 4- 2 C e(IIl) 00 Hydrazine acetate and acethydrazide were found to be t i t r a t a b l e with perchloric acid in g la c ia l acetic acid using the blue-green color of c ry s ta l v io le t as an in d ication of the end point. Both m aterials behave as monobasic substances and require one equivalent of acid per mole. vi A colorim etric determination of hydrazine based on reaction with salicylaldehyde was also developed. The reaction produces a yellow colored solution which was measured a t 4 1 8 ^ . The apparent lim it of concen­ t r a t i o n of hydrazine is determined by the s o lu b ility of the reaction product, disalicylalhy drazin e. v ii TABLE OF CONTENTS Page I. INTRODUCTION............................................................................................ 1 II. EXPERIMENTAL............................................................................................ 3 A. Chemicals....................................................................................... B. Apparatus....................................................................................... C. Oxidation Procedures......................................................... 1. Excess Methods........................................................... 2. Direct T itr a tio n ...................................................... D. Colorimetric Determination ofHydrazine.. E. Gas Collection and I d e n t i f ic a t i o n .................... 3 5 6 7 9 10 15 RESULTS OF OXIDATIONS.................................................................. 20 A. Sodium Azide...................... B. Hydrazine....................................................................................... 1. Hydrazine Acetate Oxidation....................... 2. Symmetrical Diacethydrazide Oxidation.......................................... . ........................... 20 25 29 IV. HYDRAZINE-ACETIC ACID REACTION......................................... 38 V. SUMMARY.......................................................................................................... 46 LITERATURE CITED................................................................................................ 49 APPENDIXES................................................................................................................ 51 III. v iii 34 TABLES TABLE 1 Pag© Absorbance vs. Concentration of Hydrazine A cetate................................................................................................................. 13 E ffect of Other Constitutents on Absorbancy Values f o r Hydrazine Acetate...................................................... 15 3 Retention Times fo r Gas Samples............................................ 18 4 Sodium Azide by Excess Cerium.................................................. 22 5 Sodium Azide Stoichiom etry....................... 22 6 Gas Measurements for Sodium Azide....................................... 23 7 D irect T itr a tio n of Sodium Azide......................................... 24 8 Preliminary Hydrazine - Cerium S to ich io m etry .... 27 9 Preliminary Gas Measurement....................................................... 28 10 Hydrazine Acetate - Cerium Stoichiometry 30 11 Hydrazine Acetate Gas Measurements.................................... 31 12 Diacethydrazide - Cerium Stoichiom etry..................... 35 13 Gas Data for Diacethydrazide..................................................... 36 2 ix FIGURES FIGURE Pag© 1 Visible Spectrum fo r D isalicylalhydrazin e................ 12 2 Hydrazine-Acetic Acid R eaction,........................................ 43 3 Disproportionation of Acethydrazide,......................... 44 x INTRODUCTION 1 I. INTRODUCTION The study of organic oxidations in non-aqueous solutions from an a n a ly tic a l point of view has been very lim ited. There has been some work using lead t e t r a ­ a c e ta te , bromine, chromic acid, sodium permanganate, t i t a n i u m ( I I I ) chlo rid e, iodine monochloride, and iodine monobromide in g la c ia l acetic acid, as reviewed by Kolthoff and Belcher (13). Hinsvark (12) found that cerium(IV) in g la c ia l acetic acid could be used fo r the q u an titativ e oxidation of c e r ta in organic oxygenated compounds, notably some dibasic acids. I t was deemed desirable to extend h is work to nitrogen compounds to see i f a fe a sib le method fo r th e ir determination might be developed. Sodium azide and hydrazine were the nitrogen compounds to be inv estigated. The l i t e r a t u r e yields various oxidative measurements f o r azides. Among the reagents which have been used are iodine (18), potassium permanganate, potassium persulphate, potassium chlorate (19), n i t r i c acid (6), and cerium(IV) (14,21). Audrieth and Ogg (1) have reviewed the d if fe r e n t oxidative measurements fo r hydrazine in aqueous media, Including an in d ir e c t cerium method. Higginson and Sutton (10) have stated th a t the products of the oxidation 2 of hydrazine and the stoichiometry depend on the nature of the oxidizing agent i . e . , whether i t can be c l a s s i f i e d as a one-electron or a two-electron tra n sfe r reagent. In a subsequent report (11) they have stated that the reaction between cerium(IV) and hydrazine was not s t o i ­ chiometric, although consistant r e s u l ts could be obtained i f a standard procedure was used. They report a s t o i ­ chiometry of 1.05 - 1.5 equivalents of cerium(IV) per mole of hydrazine, and th a t under c a re fu lly controlled conditions 1.06 Ce(lV) = Cahn and Powell (5) have also investigated the mechanism of the oxidation using various oxidizing agents. Since cerium(iv) is known to be an effectiv e reagent for the oxidation of azides in aqueous media and because of i t s questionable application to hydrazine in th is media, these oxidations were to be investigated in g la c ia l acetic acid . The ultimate objective was the development of an an aly tical method fo r these compounds. I t was also hoped th a t some fu rth e r elucidation of the mechanism of the oxidation of hydrazine by cerium(IV) would r e s u l t . EXPERIMENTAL 3 I I . EXPERIMENTAL A. Chemicals Baker1s ”Analyzed” and duPont ”Reagent Grad©” g la c ia l acetic acid were both used as solvents without f u r th e r p u r if ic a tio n . A typical Karl Fisher water analysis of the acid showed a water content of 0.16 per cent* Eastman Kodak Company ”White Label” acetic anhydride was used in the preparation of diacethydrazide. The 70 per cent perchloric acid used was Mallinckrodt ”AR” grade. The ammonium hexanitratoeerate was obtained from the G. Fredrick Smith Chemical Company. Merk ”Reagent” primary standard sodium oxalate was used. Anhydrous ethyl acetate from Matheson, Coleman and Bell was used in the preparation of acethydrazide. The hydrazine hydrate used was Eastman Kodak ”Yellow Label” 64 per cent p r a c t i c a l. This was analyzed by the in d ir e c t iodate method of Bray and Cuy (4) before use. Technical grade sodium azide was obtained from the Explosives Division, E. I . duPont de Nemours and Company. All solutions of sodium azide were analyzed by the in d ire c t cerium method of Martin (14) to serve as a reference analysis fo r the cerium(IV) oxidations in acetic acid. 4 The hydrazine acetate used was prepared by adding acetic acid to a quantity of hydrazine hydrate u n t i l there was no evolution of heat upon fu rth er addition. Upon cooling to room temperature the mixture became very viscous, and with spot cooling on dry ice the hydrazine acetate c r y s ta l li z e d . The crude m aterial was collected on a f i l t e r and washed with eth er. The m aterial was then r e c r y s ta lliz e d from a 1:1 chloroform-ethanol mixture, f i l t e r e d , and again washed with eth e r. The resu ltin g m aterial had a melting point of 96-97°C. and an acid-base equivalent weight of 92 i 0.4. The th e o re tic a l equiv­ ale n t weight i s 92.11. The acethydrazide was prepared by a modification of the procedure used by Curtius and Hofmann (8). To seventy-five grams of hydrazine hydrate in a 250 ml. iodine f la s k was added slowly one hundred and ten grams of anhydrous ethyl acetate. The fla sk was then f i t t e d with a re flu x condenser and placed in a water bath at approximately 97°C. for two days. At th i s time the mixture was cooled and the volume reduced about one third by vacuum d i s t i l l a t i o n of p a rt of the water-ethanol solution l e f t a f t e r reaction . Cooling of the remaining solution on dry ice for a short time induced p re cip itatio n of the acethydrazide. The crude material was then dissolved in hot chloroform and rep re cip itated with ethyl eth e r. The p re c ip ita te was collected on a f i l t e r , washed 5 with ethyl ether and allowed to a i r dry* This procedure re su lte d In a m aterial having a melting point of 66-67°C. and an equivalent weight, by t i t r a t i o n with perchloric acid in g la c ia l acetic acid, of 74*2 f 0.5. This compared to a melting point of 67°, as reported by Curtius and Hofmann, and a formula weight of 74.11. Symmetrical diacethydrazide was prepared according to the procedure of S to lle (22). Hydrazine hydrate and acetic anhydride were mixed in a mole r a t i o of one to three. Care must be taken to keep the r a tio a t th is level since higher r a ti o s lead to the production of the tri- and tetraacethydrazides. The heat of mixing was s u f f ic ie n t to cause the reaction to proceed. Upon cooling, the material was p re cip itated by d ilu tin g with ethanol. The crude m aterial was collected on a f i l t e r and then r e c r y s ta lliz e d from a 1:1 chloroform-ethanol mixture, f i l t e r e d , a i r dry. washed with ethyl ether and allowed to The fin a l product had a melting point of 138-40°C. as compared to reported values of 138° (22) and 140°C. (17). A Kjeldahl nitrogen determination produced 24.05 per cent nitrogen compared to 24.15 per cent th e o r e tic a l. The symmetrical diacethydrazide exhibited n e ith e r acidic nor basic p ro p e rties. B. Apparatus A Sargent Model I I I Manual Polarograph equipped with a Beckman Number 19031 twin inlay platinum electrode was 6 used fo r the detection of equivalence points in the amperonetrie t itr a tio n s * The li g h t s e n s i t i v i t y of the cerium(lV) reagent, as reported by Hinsvark (12), made necessary the use of amber burets fo r t i t r a t i o n s with th is reagent* Gas measurements were made using a Lunge nitrometer tube of 50 ml* capacity. The gas id e n t if ic a tio n was carried out on a Perkin Elmer Model 154 Vapor Practometer. The instrument was equipped with a Cenco coiled aluminum tubing assembly containing Linde Molecular Sieves Type 13X. The aluminum c o il was approximately 3.5 inches in diameter with ten and one-half turns of one-quarter inch 0* D. tubing. Helium was used to sweep the gas samples through the packed tubing. A Fisher Recordall was used to record the instrument response and determine reten tio n times. A Perkin-Elmer Model 21 Recording Infra-Red Spectro­ photometer equipped with a one meter gas c e l l was used to determine whether or not the gas had an infrared spec trum. C. Oxidation Procedures All the oxidations using cerium(IV) in g la c ia l acetic acid were carried out by an excess method. In addition to th is method i t was found that the analysis of sodium 7 azide could be accomplished by means of a d i r e c t t i t r a t i o n with the cerium(IV) reagent. 1. Excess Methods All the nitrogen compounds were oxidized by a method using an excess of the cerium(IV) reagent. This excess was subsequently determined by t i t r a t i n g with a standard sodium oxalate solution. In each case the sample to be oxidized was dissolved in g la c ia l acetic acid and thoroughly mixed. Aliquots of the solution were added to 50 ml. of g la c ia l acetic acid in a 250 ml. iodine f la s k . To th is was added a volume of cerium(IV) reagent calculated to be in excess of the amount needed f o r oxidation of the sample. iodine fla s k was then stoppered, The sealed with acetic acid, and placed in the dark in a desk drawer. At the end of the specified period of time the fla sk was removed from the drawer and the contents transferred to a 180 ml. tall-fo rm beaker for t i t r a t i o n of the excess cerium(IV). The sodium oxalate solution used fo r t i t r a t i o n of the excess cerium(IV) was prepared by weighing out a portion of dried, reagent grade sodium oxalate and dissolving i t in g la c ia l acetic acid. S u fficien t perchloric acid was added so th a t a f t e r d ilu tio n to a d e fin ite volume with g la c ia l acetic acid the resu ltin g solution would be one normal with respect to perchloric acid. 8 Hinsvark (12), in h is work with eerium(IV) in g l a c i a l acetic acid, found that the end point in the oxidation-reduc t i on t i t r a t i o n s could be detected by an amperometric method with two active electrodes. This method was applied to the present in v estig atio n using a twin inlay platinum electrode. A Sargent Model I I I Manual Polarograph was used as the source of p o te n tia l applied across the two platinum leads of the electrode. The p o ten tial applied was s e t a t 275 mv. As the sodium oxalate solution i s added to the solution containing the excess cerium(lV), increases s li g h t ly and then f a l l s i s approached. curre nt f a l l s the current off as the end point The end point i s indicated when the to a steady value. The approach of the end point can also be detected v isu a lly . The solution containing the excess cerium(lV) i s orange in color, and as the t i t r a t i o n proceeds th is color fades to lig h te r and l i g h t e r shades of yellow. After considerable expe­ rience and in the presence of the proper lig h tin g , it is possible to d e te c t the end point v isu ally by watching for the l a s t change from pale yellow to white or c le a r. amperometric end p oin t, however, The is much more r e lia b le and the author believes th at the t i t r a t i o n should not be attempted as a visual method in accurate work. I t i s not necessary to p lo t the data in order to locate the end 9 point, provided additions of t i t r a n t are s u f f ic ie n t l y small in the v ic i n i t y of the end p oint. Standardization of the cerium(IV) reagent was accomplished in a lik e manner. An aliquot of the reagent, usually 25 ml., was added to 50 ml. of g la c ia l acetic acid in a 150 ml. "beaker. This solution was then t i t r a t e d with the sodium oxalate in the manner ju st described. 2. D irect T itr a tio n Sodium azide samples, dissolved in g la c ia l acetic acid which was one normal with respect to perchloric acid content, could be analyzed by a d ir e c t t i t r a t i o n with the cerium(IV) reagent. The sodium azide was dried at 110°C. fo r a minimum of two hours, weighed, and dissolved in g la c ia l acetic acid. Aliquots were then added to 50 ml. of g la c ia l acetic acid which was a t l e a s t one normal in perchloric acid. To the re su ltin g solution, in a 150 ml. beaker, was added the cerium(IV) reagent. There was no flow of current when the twin inlay platinum electrode was immersed in the solution. remained unchanged u n t i l The current the end point was reached, at which p oint the galvanometer deflected rapidly in the p o sitiv e d ire c tio n . There was considerable M foaminglf in the beaker due to the evolution of nitrogen. In t h i s t i t r a t i o n also I t was possible to detect the end point v is u a lly . The color change in t h i s case was 10 j u s t til© opposite of th at previously described, from co lo rless to l i g h t yellow. i.e ., The v is u a l end point was much easier to see than before, but the instrumental detection was always used* An in v estig a tio n was made to determine i f the t i t r a t i o n could be done using n i t r o - f e r r o i n as the i n d i­ c a to r . This was found to be unacceptable in th a t the in d ic a to r changed color before the end point was reached. The potentiometric end point, as detected by a saturated calomel-platinum electrode system, coincides with the amperometric end p oint. I>. Colorimetric Determination of Hydrazine While studying the reaction of hydrazine with g la c ia l acetic acid, as described in a l a t e r section, it becjame necessary to devise a method f o r determining hydrazine in the presence of acethydrazide. Several methods were attempted before i t was found th a t a colorimetric method might be f e a s ib le . The reactio n of hydrazine acetate with salicyaldehyde (9) to yield the corresponding S c h iff 's base r e s u l t s in a yellow p r e c ip i ta t e or a yellow colored solution, depending on the concentration of the hydrazine a c e ta te . The same reaction with acethydrazide yields a colo rless so lu tion or a white p r e c ip i ta t e . The p o s s i b i l it y of a colorimetric method thus presented i t s e l f . IX In the development of the colorim etric method a concentration range of 0.2-1.2 mg* of hydrazine acetate per ml. was used. The hydrazine acetate was prepared as sta te d previously in the chemicals section. The p ra c tic a l grade salicyaldehyde was d i s t i l l e d and the f r a c tio n boiling a t 194.5°C. and above was collected fo r use. This single d i s t i l l a t i o n resulted in a material having a very s l i g h t tinge of yellow. Because of th is s l i g h t color in the salicyaldehyde i t was necessary to add some to the g la c ia l acetic acid of the reference blank. A solution of hydrazine acetate in g la c ia l acetic acid was prepared to contain four mg. per ml. Various aliquots of th is solution were then placed in 10 ml. glass stoppered volumetric flask s such that the re su ltin g concentrations upon d ilu tio n to volume would be 0.2, 0.6, 0.8, and 1.2 mg. hydrazine acetate per ml. 0.4, To these fla sk s was added 5 ml. of the salicyaldehyde and the flask s brought to volume with acetic acid. A reference solution was prepared by mixing salicyaldehyde and g la c ia l a c e tic acid in a 1:1 r a t i o . All preliminary semi-quantitative work was done on the Beckman Model DK-2 Recording Spectrophotometer. The v is ib le spectrum of the disalicylalhydrazine is shown in Figure 1. be seen, it As can i s extremely simple with the absorbance ABSORBANCE 12> 450 wavelength in m illim ic ro n s FIG. I VISIBLE S P E C T R U M FOR DISALICYLALHYDRAZINE 13 Increasing rapidly from about 4 5 0 ^ to 4 1 0 ^ , but showing no maximum. I t was found th a t by using a blank of 50 per cent salicylaldehyde in acetic acid, a Beer's Law p lo t of concentration versus absorbance yielded a s t r a i g h t lin e fo r a v a rie ty of wavelengths. Table 1 shows the consistancy of the absorbance versus concentration r a t i o at 413^«# • TABLE 1 ABSORBANCE VS. CONCENTRATION OP HYDRAZINE ACETATE N2H4*H0Ac Cone . mg./ml. As. (418^) As ./mg./ml. c\i • o 0.157 0.78 0.4 0.318 0.79 0.6 0.469 0.78 • o GO 0.611 0.76 1.2 0.930 0.77 Since the blank gave an i n f i n i t e absorption at wave1engths below 410«^k, i t was necessary to choose a wavelength above th i s which would give good accuracy and s e n s i t i v i t y . As the wavelength i s increased from 416 to 4 2 8 and beyond, the s e n s i t i v i t y , i.e ., change in absorbance per change in concentration, decreased. At 416~*/* th is change was so great that the precision and corresponding accuracy suffered. As a consequence 418 14 which offered the next best s e n s i ti v i ty and good accuracy and precision , was selected as the wavelength fo r a l l colorim etric measurements* These measurements were made on a Beckman Model DU Spectrophotometer using one cm* Corex cells* The e f f e c t of acethydrazide, hydrazide, symmetrical d iac et- and water on the accuracy of the colorimetric measurements was then determined* This was done by adding varying amounts of each of the three m aterials to th e hydrazine acetate solutions* The r e l a ti v e amounts of each were changed so th a t measurements were made in which each of these materials was present in amounts both larger and smaller than the amount of hydrazine acetate• Table 2 shows the absorbancy values obtained with these m aterials present and absent* The g re a te st interference occurs in the presence of acethydrazide alone* This, it is f e l t , is a r e s u l t of the dispropor- tion ation of the acethydrazide to hydrazine and symmetrical diacethydrazide and i s not d ir e c tly a t t r i b u t ­ able to the acethydrazide i t s e l f . 15 TABLE 2 EFFECT OF OTHER CONSTITUTENTS ON ABSORBANCY VALUES FOR HYDRAZINE ACETATE Absorbance Values NgH4*H0Ac(l) Alone I with 5.4 Mm. AcNHNHg I with 5.4 Mm. AcNHNH2 and 5.2 Mm. AcNHNHAc I with 1% h2o *318# .305 .314 .316 .612## .618 .610 .611 #■ cone, NgH^*HOAc ##conc. NgH4 *HOAc 0.4 mg./m l. 0.8 mg ./ml. (4.35 Mm.) (8.7 Mm.) E. G-as Collection and Id e n tific a tio n The oxidations of sodium azide, hydrazine acetate, and symmetrical diacethydrazide produced a gas as one of the products. This gas, shown to be nitrogen, was co l­ lected over 50 per cent potassium hydroxide in a Lunge nitrometer tube. The sample to be oxidized was placed in a 150 ml. e le c t r o ly ti c beaker, which had been covered with black tape to exclude l i g h t during oxidation by the cerium(IV) reagent. These samples were aliquots of solutions of the various m aterials In g la c ia l acetic acid. The reaction vessel was f i t t e d with a three-hole rubber stopper. Through one hole was passed a glass tube which was connected, by means of rubber tubing, to the o u tle t of a Dewar f la s k containing dry ice as a source of carbon dioxide. This tube extended nearly to the bottom 16 of the reaction vessel so th a t the flow of carbon dioxide would bubble through and mix the reaction medium. The sample of m aterial to be oxidized was introduced through a second hole. Through the third hole was passed a glass tube which was in turn connected to a washing tower containing water. The washing tower was connected to a U shaped tube which was inserted in an ice bath in order to remove any low boiling gases and low melting liq u id s . This tube was then connected to the lower end of the nitrometer tube, which was f i l l e d with 50 per cent potassium hydroxide. Once the apparatus was assembled the en tire system was swept with carbon dioxide to remove a l l a i r . The nitrometer tube was then f i l l e d with the potassium hydroxide, and 50 ml. of solvent and 50 ml. of reagent were added to the reaction vessel. This solution was swept with carbon dioxide fo r a period of one hour, and the r e s u ltin g volume of gas co llec te d was recorded as the blank. When determined in th is manner, the blank was quite reproducible fo r a given amount of solvent and reagent on a given day. After measurement of the blank the reaction vessel was disconnected from the apparatus, emptied, and reconnected. The en tire system was again swept free of a i r with carbon dioxide. Then solvent, sample, and reagent were placed in the reaction v e sse l. The system was swept for one hour, as before, 17 and the re su ltin g gas collected* of gas was corrected fo r The r e s u ltin g volume the blank and then reduced to standard temperature and pressure by use of the nitrogen reduction tables as given on pages 301-310 in Organic Quantitative Microanalysis by Niederl and Niederl. After co llec tio n of the gas produced during the oxidations i t was deemed necessary to make a q u a lita tiv e id e n ti f ic a tio n of the material obtained. To do th is a Perkin Elmer Model 154 Vapor Practometer was equipped with a Cenco coiled aluminum tubing assembly containing Linde Molecular Sieves Type 13X. The aluminum c o il was approximately 3.5 inches in diameter with ten and oneh a lf turns of one-quarter inch 0. B. tubing. Using th is packing for the tube, a sample of a i r was separated to give two response peaks, presumably due to oxygen and nitrogen. A 0.5 ml. sample of the gas col­ lected as a blank gave these same two peaks. Samples of the gases collected from oxidation of each of the materials under study were injected into the instrument. samples were 0.5 ml. in s iz e . All Helium was used to sweep them through the tube containing the molecular sieves. A pressure of approximately 15 p . s . i . the separation. was used to e ffe c t These samples produced the same two peaks as the blank and a i r . The second peak in each case was g re a tly increased in height over th a t of the blank, in d i­ cating an increase in the amount of nitrogen present. 18 A sample of pure nitrogen was then passed through the instrument to produce a single peak. Table 3 shows the reten tio n time of the two peaks for the various samples te s te d . TABLE 3 RETENTION TIMES FOR GAS SAMPLES Peal< 2 Peak 1 Trial 1# Trial 2*h* Trial 1# Trial ( seconds) ( seconds) Sample Air 61 Oxidation Blank 67.5 75 56 A.zide Gas 67.5 75 61 56 NgH4* HOAc Gas Diacethydrazide Gas Pure Nitrogen 56 75 61 none 67.5 none 75 Pure Oxygen 61 none 1:1 02-N2 Mixture 61 75 c e l l temperature 37°, pressure 11 p . s . i . , <5Hfcell temperature 38°, pressure 15 p . s . i . , 67.5 flow r a t e 10 flow rate 11 I t was concluded from these data that the product of the oxidation i s a gas which behaves as nitrogen with respect to the molecular sieves used for t h i s examination. In order to f u r th e r cement the contention th a t the gaseous product of the oxidation was nitrogen, a gas sample was co llected and an in frared spectrum was taken. The sample showed no absorption and thus must consist of molecules containing id e n tic a l atoms. In l i g h t of the f a c t th a t the re te n tio n time of the second peak fo r a l l samples matched th a t of nitrogen, th a t the gas must tru ly be nitrogen. it i s concluded III. RESULTS OP OXIDATIONS 20 III. RESULTS OP OXIDATIONS A. Sodium Azid© Sodium azide, being about the simplest of nitrogen compounds, was chosen as a s ta r tin g point in the study of cerium(IV) oxidations of nitrogen compounds in g la c ia l acetic acid. The oxidation of hydrazoic acid and various a l k a l i azides in aqueous solution has been done with a number of oxidizing agents. Among those reported to give q u a n tita tiv e evolution of nitrogen are iodine (18), potassium permanganate (19), and cerium(’TV) s a lt s (14,21). The oxidation with cerium(IV) requires one equiv­ a len t of cerium per mole of azide according to the equation 2 NaN3 + 2 Ce(IV) -------> 3 Ng + 2 Na* * 2 Ce(IIl) For oxidation by cerium(IV) in g la c ia l acetic acid, the sodium azide was dried at 110°C. f o r a minimum of two hours. A quantity was then weighed and dissolved in acetic acid and made up to a volume such th a t the f in a l concentration was approximately one molar. Prior to doing any cerium(lV) oxidations in g la c ia l acetic acid the azide solution was analyzed via the in d ire c t cerium method of Martin (14) content. to determine the actu al azide 21 The f i r s t attempts to oxidize sodium azide in acetic acid as a d ir e c t t i t r a t i o n with the cerium(IV) reagent were unsuccessful. rap id ly a t f i r s t The reaction proceeds very and then becomes ra th e r sluggish as the equivalence point is approached. I t appears as though the explanation fo r t h i s behavior l i e s In the s im ila r ity of the ionization constants of acetic and hydra zoic acids. All oxidative methods fo r the determination of azide in aqueous media c a l l fo r the presence of strong acid, so t h a t the azide Is present e s s e n tia lly as hydrazoic acid. In the acetic acid medium, however, the ionization _ c — c constants being 1.8 x 10 and 2.6 x 10 for acetic and hydrazoic acids resp ectiv ely , it seems quite possible that the sodium azide would not be completely converted to the acid instantaneously. On th is basis i t would appear th at in order to achieve a q u an titativ e oxidation by means of a d ir e c t t i t r a t i o n , be hydrazoic a c id . the active species must This is not necessarily true, however, I f one uses an excess of oxidizing agent and then deter­ mines the excess. Oxidation of azide by the use of excess cerium(IV) and subsequent determination of the excess by t i t r a t i o n with oxalate, has been found to be applicable In g la c ia l acetic From a solution approximately one molar in acid. sodium azide, a series of one ml. aliquots were withdrawn and oxidized in the manner previously described* As the data in Table 4 show, the oxidation i s complete a f t e r t h i r t y minutes under these conditions. The oxidation is q u a n tita tiv e and consumes one equivalent of cerium(IV) per mole of sodium azide, as is shown in Table 5, TABLE 4 SODIUM AZIDE BY EXCESS CERIUM Mg,NaN3 taken Reac tion Time, Min. 62.16 15 61.73 30 Ave. Percent Error 61.77 61.75 .66 62.23 62.08 62.16 .12 45 62.19 62.08 62.14 .10 60 62.15 62.15 62.15 .02 90 62.19 62.19 62.19 .05 Mg. NaN3 Found TABLE 5 SODIUM AZIDE STOICHIOMETRY M eq. Ce(lV) Mmol. NaU3 Mmol. NaUg taken Meq. Ce(IV) used 0.9560 .9570 1.001 .9 564 1.0004 .9 558 .9998 .8975 .9996 .89 37 .9931 .8964 .9961 0.9000 23 The oxidation produces a gas as evidenced by the build-up or pressure in the stoppered iodine f la s k . The gas was l a t e r shown to be nitrogen. I t was necessary to proceed with some caution when removing the stopper l e s t some of the acetic acid used fo r the seal be blown out by the gas escaping from the f la s k . The gas produced by the oxidation of a 0.5 ml. sample, as delivered from a 500> micropipet, was collected and measured according to the procedure as given in the section on gas co llec tio n and I d e n tif ic a tio n . measurements. Table 6 shows the r e s u lts of the gas I t can be seen from these data th a t a q u a n tita tiv e evolution of nitrogen is achieved. TABLE 6 GAS MEASUREMENTS FOR SODIUM AZIDE Mmol. NaN3 taken 00 • .45 Since i t Vol. N2 Collected M mo1. N2 Collec ted Mmol. Ng Mmol. RaN3 16.18 .722 1.502 16.46 .735 1.53 14.89 .665 1.48 14.9 5 .668 1.482 Is always more desirable to have a d ir e c t method of determination ra th e r than an in d ire c t one, a tte n tio n was focused on making the oxidation of the azide In acetic acid instantaneous and thereby workable 24 as a d ir e c t titr a ti o n * As was stated previously, it appeared th a t in order to get a rapid oxidation i t was necessary fo r the azide to be present in the form of hydrazoic acid* I t was found that I f the acetic acid used as the solvent fo r the oxidation of the azide samples was made approximately one normal In perchloric acid, the oxidation could be carried out as a d ire c t t i t r a t i o n using cerium(IV) in g la c ia l acetic acid* An excess of only one drop caused a considerable galva­ nometer deflectio n and thus the end point was r e a d ily d e te c ta b le . That t h i s is a quantitative oxidation can be seen in the r e s u l t s as shown in Table 7. TABLE 7 DIRECT TITRATION OP SODIUM AZIDE Mg. NaNg tak en 58.50 Ml. of Ce(IV) Ce(IV) Normality 16.52 0.0543 Mg. NaN-z found Per cent error 58.36 - .24 58.29 - .36 58.41 - .15 19.73 58.56 4 19.69 58.45 - .08 16.50 19.68 0.0456 .10 In li g h t of the stoichiometry achieved in the oxidation and the amount of nitrogen collected i t may be concluded th a t the oxidation of sodium azide with 25 cerium(lV) in g la c ia l acetic acid proceeds according to the equation: NaN3 + Ce(IV) -------> 1 . 5 Ng * Ce(III) 4 Na+ B. Hydrazine Because of i t s somewhat peculiar behavior towards oxidizing agents in aqueous media, hydrazine was chosen as the next nitrogen compound to be subjected to oxidation by cerium(lV) in g la c ia l acetic acid. The samples were aliquots of a hydrazine hydrate-acetic acid mixture. The hydrazine was obtained as a 64 per cent so lu tion in water corresponding to 100 per cent hydrazine hydrate. I t was analyzed independently by the in d irect iodate method of Bray and Cuy (4 ). A solution of hydrazine hydrate in g la c ia l acetic acid was prepared by adding a known weight of the analyzed hydrazine hydrate to a volume of acetic acid. hydrate was not removed. The water of the Aliquots of th is solution were then treated with the cerium(IV) reagent. The reaction with cerium(IV) was much too slow to be used as a d ir e c t t i t r a t i o n . All attempts to increase the r a t e of oxidation of the hydrazine and i t s d e ri­ vatives by the addition of perchloric acid were unsuccessful. Samples were then allowed to re a c t with the cerium(IV) reagent in the dark f o r various lengths of time. In th is manner i t was found t h a t the reaction 26 was wcom.pl©t e u a f t e r four hours in th a t the number of m illleq u iv alen ts of cerlum(IV) used was e s s e n tia lly constant fo r a reaction time of four to ten hours. Thus a l l subsequent samples of hydrazine were allowed to r e a c t for four hours. As Table 8 shows, the oxidation consumed three equivalents of cerium(lV) per mole of hydrazine. This stoichiometry was also found when samples of hydrazine acetate were allowed to stand in acetic acid fo r a long period of time before oxidation. was highly unexpected, This odd stoichiometry and therefore an attempt was made to determine what the end products of the oxidation might be. I t was evident from the build-up of pressure within the iodine f la s k that a t l e a s t one product was a gas, which was shown to be nitrogen. All attempts to i s o la te a second product, presumably one in which the nitrogen would be present In an oxidation s ta t e of minus one, were unsuccessful. Assuming the pressure build-up to be the r e s u l t of the production of nitrogen, gas measurements were made to determine ju s t how much gas was being produced. The r e s u l ts , as shown in Table 9, in d i­ cated th a t as a f i r s t approximation one-half of a mole of nitrogen was being produced per mole of hydrazine. This seemed to indicate even more strongly that another product with nitrogen in the minus one s ta te must be produced. 27 TABLE 8 PRELIMINARY HYDRAZINE - CERIUM STOICHIOMETRY Mmol. N2H4 taken 0.07 Meq. Ce(lV) Used Meg. Ce(lV) Mmol. NgH4 0.1969 2.82 0.2153 3.07 0.2150 3.07 Ave. 0.12 0.3544 2.95 0.3752 3.12 0.3302 2.75 Ave. 0.20 0.6110 2.9 4 3.05 0.6359 3.18 0 . 5698 2.85 Ave. 0.30 2.9 5 0.8534 3.02 2.84 0.9213 3.07 0.9680 3.22 Ave. Combined Ave 3.04 2.99 28 TABLE 9 PRELIMINARY GAS MEASUREMENT Mmol. N2H4 taken Ml. N2 STP Mmo1. N2 STP Mmol. N2 Mmol. N2H4 to • o 4.09 0.18 0.60 0.3 4.06 0.18 0.60 0.3 3.60 0.16 0.53 In order to r e - e s ta b lis h the id e n tity of the s t a r ti n g m aterial a portion of the solution of hydrazine hydrate in acetic acid was d iluted ten-fold with ethyl eth e r. Treatment in th is manner produced a massive white p re c ip ita te which was n eu tral to both perchloric acid in g la c ia l acetic acid and sodium methoxide in benzene-methanol solvent. After re p re c ip ita tio n from a 1:1 chloroform-ethanol solution the material had a melting point of 138-140°C. This corresponds to l i t e r a t u r e values of 138°C. (22) and 140°C • (17) reported for symmetrical diacethydrazide. The obvious conclusion to be drawn from th is obser­ vation i s that a solution of hydrazine in g la c ia l a c e tic acid is not sta b le . As w ill be shown in a l a t e r section, hydrazine hydrate in g lac ia l acetic acid is present as the s a l t , hydrazine a cetate, a f t e r standing only two hours. A solution of the s a l t i s also in s ta b le . This i n s t a b i l i t y of the solution made i t necessary to prepare 29 and p u rify hydrazine acetate, acethydrazide, and the symmetrical diacethydrazide and t r e a t each separately with the cerium(IV) reagent. The procedures used f o r the preparation of these materials are given in the preceeding section dealing with chemicals. Subsequent studies with acethydrazide in acetic acid showed th a t i t disproportionates to hydrazine and symmetrical diacethydrazide very rapid ly. necessary time of oxidation i . e , , to the r a te of disproportionation, Due to the four hours, compared i t was deemed unprofitable to continue any fu rth er oxidative studies with the acethydrazide. Attention was then turned to the oxidation of the hydrazine acetate and symmetrical diacethydrazide, 1* Hydrazine Acetate Oxidation Solutions of hydrazine acetate, milligrams per ml., containing four in a cetic acid were prepared and subjected to oxidation with the cerium(IV) reagent. These solutions were prepared fresh each day that they were to be used, and a l l samples were removed from the stock solutions within four hours a f t e r preparation. This was done in order to insure th a t the material would be in i t s o rig in al form fo r the oxidation. Table 10 shows the stoichiometry achieved in the oxida­ tion of the hydrazine a c e ta te . On the basis of visual 30 observation there appeared to be no gas evolved from th is oxidation* Xn order to prove or disprove th is observation a sample was placed in the reaction vessel connected to the nitrometer tube, and the oxidation was carried out while sweeping with carbon dioxide* In th is manner i t was found th a t a gas, subsequently shown to be n itrogen, was being produced a t the ra te of 0.5 moles of gas per mole of hydrazine oxidized, as can be seen in Table 11. TABUS 10 HYDRAZINE ACETATE - CERIUM STOICHIOMETRY Mmol. S a lt Taken 1 0.215# Meq. Ce(IV) Used Meq. Ce(lV) Mmol. S alt 0.416 1.93 2 0.474 2.20 3 0.498 2.30 4 0.480 2.22 5 0.491 to • to Trial 6 0.462 2.14 7 0.456 2.11 8 0.490 2.26 Ave. # 2 0 m g# 2.18 31 TABLE 11 HYDRAZINE ACETATE GAS MEASUREMENTS Vol. N2 Collected STP Mmol. N2 Mmol. N2] 0.114 0.521 2.50 0.112 0.520 0.110 0.512 0.129 0.567 2.51 0.112 0.520 • 2.56 C O • C J 0.215 Mmol. N2 STP to Mmol. N2H4*H0Ac Taken lvalue calculated on basis of Ce(IV) consumption- 0.545 The oxidation of hydrazine in aqueous solution has been d e a lt with by a number of inv estig ato rs (10,11,5) with the r e s u l t th a t several mechanisms have been proposed. These mechanisms are based on oxidations performed with i r o n ( I I I ) rath er than cerium(IV). Both are c l a s s if i e d as one electron tran sfer agents, however, and thus would be expected to re a c t in the same manner. Included among these are 2 H2 H4 2 e q . ■> 2 N 2 H3 2 N2 H3 ------------* NH2 -H H -N H -N H 2 UH2 -N H -N H -N H 2 ------------» HN=K-NH2 A NH3 + H N -N -N H 2 NH2 N=EH 2 N2H4 2 e(3—> 2 NH3 + N2 --------- » NH3 4- Ng 32 N2 H4 1 . . M > NgHg N2 H3 i —2 3 —> N2H2 n 2 h2 B g _ e a , l> N2 N2 H4 1 . 2 3 2 N2 H4 c 2 > N2 eq , 2 H gH 3 > N 2 H2 N2 g - e- 3 - > 2 N 2 H3 N gH g 4 N gH 4 N2H4 1..2.3, > H2 Mechanism B and A requires C require one equivalent per mole while both four equivalents per mole. The following mechanism i s also included in the review of Cahn and Powell (5). 2 N2 H4 4 e <* > 2 NHsNH 2 NHZNH ------------ > N H =N -NH -N H g N H -N -N H -N H g ________> HN3 4 NH 3 I f th is were the path the reaction takes i t would not stop at th is p oint. I t has already been shown the cerium(IV) in g la c ia l acetic acid oxidizes hydrazoic acid q u a n tita tiv e ly to nitrogen. Thus in the above mechanism a fourth step would be required. HN3 1 e 3 > 1 . 5 Ng This would r e s u l t in a stoichiometry of of cerium(IV) per mole of hydrazine. 2 .5. equivalents 33 The studies of Higginson and Sutton (10) and Cahn and Powell (5) were carried out by use of radioactive 15 N labeled hydrazine* By this means i t was found t h a t h a lf of the nitrogen evolved was formed from two hydrazine molecules and h a lf from one hydrazine molecule, This would suggest th a t reaction A above would actually be: H g N -N H g * H g N -N H g g H g N -N H * •H N -N H g ------------- » 4 -* H g N -N H • 4- • H N -lIH g H g N -N -N -flfe g HH HgH-N-N-lfeg HH H N IN -N H g 4- 4 NH 3 NH 3 4 H o N -N Z N H ± h 2 n -n = n h h n = n -n h 2 nh n E n '* 3 4 n sn ' nh3 The stoichiometry achieved in the oxidation of hydrazine acetate by cerium(IV) is 2.21 i in g la c ia l acetic acid *09 equivalents of cerium(IV) per mole of hydrazine a c e ta te . A combination of the foregoing proposed mechanisms can be devised which w ill y ield such a stoichiometry. Such a combination f a i l s , however, when the r e s u ltin g amount of nitrogen produced is compared to the amount actu ally collected. I t w ill be noted th at oxidation of hydrazine acetate to give one mole of nitrogen as the only product, by e ith e r reaction B or G above, requires four equivalents of oxidizing agent 34 per mole of hydrazine. If i t is assumed th a t nitrogen i s the only product of the oxidation and the sto ic h io ­ metry i s a r e s u l t of incomplete reaction, then the th e o re tic a l amount of nitrogen to be collected becomes 0.545 millimoles per millimole of hydrazine acetate used. A comparison of the values obtained experimentally with the th e o re tic a l y ield shows th at the evolution of nitrogen is very nearly q u a n tita tiv e . 2* Symmetrical Diacethydrazide Oxidation In a like manner solutions of symmetrical d ia c et­ hydrazide In acetic acid were prepared and allowed to react with the cerium(lV) reagent. The oxidations did not consume 1he expected number of m illiequivalents of cerium(IV) as can be seen from the data in Table 12; however, the r e s u lts were quite reproducible. I t was evident from the gas escaping upon opening the reaction vessels t h a t a pressure was developed in these oxida­ tio n s. Subsequently, gas measurements were made on the oxidation of symmetrical diacethydrazide. these gas measurements is seen from the data, be nitrogen, The data fo r shown in Table 13. As can be the volume of gas which was shown to is about three-fourths the amount necessary fo r a q u a n tita tiv e y ie ld . I f , however, the volume of nitrogen collected is compared with the number of m illiequ ivalen ts of cerium(IV) consumed by the oxidation, a q u a n tita tiv e yield r e s u l t s . The lo g ic a l conclusion to 35 b© derived from these data is t h a t the oxidation is incomplete* The proposed route of the oxidation i s AcNHNHAc 4 2 Ce+ 4 -----------* AcH=NAo 4 2 Ce* 3 4 2 H4" AcHrNAc -----------> CH3 C0C0CH3 4- U2 CH3 C0C0CH3 4- 2 Ce+ 4 4 2 OH" -----------> CH3 COOH 4 2 Ce+3 This produces a stoichiometry of four equivalents of cerium(IV) consumed per mole of symmetrical d iac et­ hydrazide, and one mole of nitrogen produced. The amount of water present in the g la c ia l acetic acid i s s u f f ic ie n t to provide the hydroxyl ion. TABLE 12 DIACEOHYDRAZIDE - CERIUM STOICHIOMETRY Mmol• Sample Meq. Ce(IV) Used Meq. Ce(lV) Mmol • Sample 0.581 3.38 0.574 3.34 0.578 3.36 0.586 3.41 0.578 3.36 0.580 to • to 0.581 3.38 Ave. 3.37 36r TABLE 13 GAS DATA FOR DIACETHYDRAZIDE Mmol. Sample Taken 0,344 Vol. H2 STP Mmol. N2% Meq.^ellV) Mmol• N2 STP 6.46 0.288 0.855 6.31 0.282 0.840 6.34 0.283 0.842 6.42 0.287 0.853 6.38 0.285 0.847 lvalu e calculated on basis of Ce(IV) consumption^.860 This type of reaction in which nitrogen i s s p l i t from the molecule has been shown by Carpino (V) to take place when acid hydrazides are oxidized with chlorine in the presence of excess hydrogen chloride* The products of such a reaction are the acid chloride and nitrogen. An example of h is work i s the oxidation of benzhydrazide to benzoyl chloride in the following manner: C6H5C0NHNH2 4 HC1 -----------> CgH5C0HHHH3Cl C6H5G0 g6H5C0NHNH3C1 * C12 -----------* S c6h5coci 4 N2 A Kries color t e s t (16) for d iac ety l, using 1 per cent phloroglucinol in ethyl ether, was p ositive i f an in s u f f ic ie n t amount of cerium(IV) was added to the sample. 37 Attempts to prepare a solid derivative were unsuccessful, however. Treatment of both the acetic acid used as solvent and the cerium(IV) reagent with the Kries reagent produced negative r e s u l t s . The f a il u r e to secure a so lid d eriv ativ e for the d iac ety l, however, does not n ecessarily mean th a t i t i s not present. Under the operating con­ d itio n s being used diacetyl is very rapidly oxidized by cerium(IV) as was determined experimentally. The oxida­ tion requires approximately two equivalents of cerium(IV) per mole. Therefore, eith er readtion 1 or 2 above must be the lim iting reaction . In e ith e r case the amount of d ia c e ty l present at any time, even when an in s u ff ic ie n t quantity of cerium(IV) is used, w ill be very small. Thus the preparation of a d eriv ative would be quite d i f f i c u l t and f a ilu re to do so can not be considered a negative re su lt. H Y D R A Z IN E -A C E T IC A C ID R E A C T IO N 38 I V , HYDRAZINE-ACETIC ACID REACTION As previously noted, a solution of hydrazine in g la c ia l a c e tic acid i s not sta b le . Because of th is I t was considered necessary to study the reaction between hydrazine and acetic acid . All such reactions reported between hydrazine and acetic acid or acetic anhydride have been carried out a t elevated temperatures, S tolle (22) has prepared d i- , tri-, and tetraacethydrazide by the reactio n of hydrazine hydrate and acetic anhydride a t elevated temperatures. There was no record found of any study being made at room temperature, nor any evidence t h a t such a reaction would proceed a t room temperature ♦ E a rlie r experiments showed th a t the end product of the reaction was symmetrical diacethydrazide. material i s neutral This to acid and base and I t s production necessarily r e s u l t s in a decrease in to ta l b a sic ity of the so lution . Since both hydrazine acetate and acet- hydrazide can be t i t r a t e d by perchloric acid in g la c ia l acetic acid, i t was considered p ra c tic a l to follow the reaction by means of such a t i t r a t i o n . A solution, approximately two molar with respect to hydrazine in g la c ia l acetic acid, was prepared. various time in te rv a ls a one ml. At sample was withdrawn 39 and t i t r a t e d with, perchloric acid in g la c ia l acetic acid* Simultaneously a second sample of 0,15 ml. was allowed to r e a c t with cerium(IV). There was no apparent change in the hydrazine content fo r the f i r s t twenty-four hours or so, and then the acid t i t e r began to f a l l off a t a regular r a t e . At various times twenty-five ml. samples were removed and d ilu te d ten-fo ld with ethy l ether in an e f f o r t to is o la te solution a t some of the material present in the that p a r tic u la r time. With the e a rly samples th is treatment l e f t about five to ten ml. of o i l . cooling on dry ice, it By was possible to obtain a precip­ i t a t e from th is o i l which, a f t e r r e c r y s ta lliz a tio n from a 1:1 chloroform-ethanol mixture, had a melting point of 96-97°C. A search of the l i t e r a t u r e fa ile d to yield a value close to th is ; however, Semishin (20) had reported a melting point of 87.5° for hydrazine a c e ta te . A t i t r a t i o n of the re c ry s ta lliz e d m aterial with perchloric acid in g la c ia l acetic acid to the blue-green color of c r y s ta l v io le t yielded an equivalent weight of 91.54, and a t i t r a t i o n with sodium hydroxide in water gave an equivalent weight of 92.62. the l a t t e r In connection with t i t r a t i o n i t was necessary to continue t i t r a t i n g u n t i l no furth er change in color of the phenoIphthalein in d icato r could be observed. equivalent weight, 92.07, The average corresponds to the mono s a l t , 40 ^2^4*H0Ac , and the previously reported melting point i s therefore assumed to be in erro r. After twelve days the samples treated with ether gave a p r e c ip i ta te of symmetrical diacethydrazide as evidenced by a melting point of 138-40°C. a f t e r r e c r y s t a l li z a ti o n from 1:1 chloroform-ethanol. quantity of this The p re c ip ita te increased with time during the remainder of the study. At no time during the study was there any indication of the presence of the lo gical intermediate i . e . , is acethydrazide. Since th is compound also t i t r a t a b l e with perchloric acid, the acid t i t e r could conceivably have been a combined one. In order to gain a clearer insight into the reaction, i t was obviously necessary to devise some method for distinguishing between hydrazine acetate and acethydra­ zide. I t was thought that there might be a distinguishing difference in th e ir r e a c t i v i t y toward various oxidizing agents. ganate, Several were t r ie d , iodine, including sodium perman­ chromic oxide, and f e rric perchlorate, without success. The next step involved treating the two compounds with salicylaldehyde to form the corresponding S e h iff's base and then t i t r a t i n g with perchloric acid in gla cial a c e tic acid to a potentiometrie end point. This was done in hope of finding a useable difference in b a s ic ity between the two compounds. This method was unsuccessful 41 in i t s e l f but did point the way to the f i n a l so lu tion . Xt was observed th a t the reaction of hydrazine acetate with salicylaldehyde imparted a lig h t yellow color to the so lution. tr a n s f e r to The a g ita tio n re su ltin g from the t i t r a t i n g vessel, fo r the perchloric acid t i t r a t i o n , caused a p re c ip ita te to form. In a lik e manner a p r e c ip ita t e formed in the solution containing the acethydrazide and salicylaldehyde; however, in th is case there was no color imparted to the solution. c o lle c tio n and drying, Upon the p re c ip ita te s gave melting points of 212-14°C. and 196-98°C. respectively . compare to values of 213-14°C., These and 201°C. as reported in the l i t e r a t u r e fo r disalicylaldhydrazine (3) and acetic acid salicylidenehydrazide (9) respectively. A colorim etric method, described previously, fo r the d e te r­ mination of hydrazine in the presence of acethydrazide was based on th is reactio n . Once the colorimetric procedure had been developed the time study was repeated in duplicate. Hydrazine hydrate was used for one and hydrazine acetate fo r the oth er. Both were made approximately two molar with respect to hydrazine in acetic acid, placed in glassstoppered f la s k s , and immersed in a water bath at 25 i 0.5°C. By using the two d iff e r e n t materials the e f f e c t of water on the reaction could be observed and also i t s e ffe c t on the cerium(lV) oxidations would be 42 indicated* For the colorimetric measurements d ilu tio n s were made in such, a manner th at the f i n a l solution f o r measurement had a concentration of approximately milligram hydrazine As can be seen 0.4 acetate perml* from Figure 2B, the reaction between hydrazine acetate and acetic acid follows f i r s t order k in e t ic s . Figure 2A shows th at there is some production of acethydrazide during the reaction but i t s t r a t io n i s never large enough to allow i t by the procedure being used. concen­ to be iso la te d Similar p lo ts fo r the reaction with hydrazine hydrate are e ss e n tia lly the same, with the exception that the slope of the log concentration versus time is s l ig h tl y le s s . This shows that the water slows the rate somewhat but does not change the k in etics of the reactio n . A second s e t of duplicate time studies was then prepared, using acethydrazide as prepared according to the previously mentioned procedure of Curtius (8). One solution was made two molar in water, corresponding to the amount of water produced by a two molar solution of hydrazine a cetate reacting to yield acethydrazide and water. The second solution was made four molar in water to correspond, in the same manner, to the previous t r i a l in which hydrazine hydrate was used. In Figure 3B shows, the reaction between acethydra­ zide and acetic acid follows second order k in e tic s . In CONC. M L" 45 20 (DAYS) LOG CONC. M L“ TI ME 20 TIME (DAYS) FI G. 2 A. H Y D R A Z I N E - A C E T I C A C I D R E A C T I O N S - S A L T CONCENTRATION M - ACETHYDRAZIDE CONCENTRATION B. F I R S T O R D E R PLOT FOR HYDRAZINE A C E T A T E 44 1.5 Li s 1.0 d z o o 0 .5 50 TIME (HRS.) TIME 40 (HRS.) _i o 1.0 FIG. 3 A. D I S P R O P O R T I O N A T I O N OF A C E T H Y D R A Z I D E M - ACETHYDRAZIDE S-SA L T x - 2 M H20 o - 4 M H20 B. S E C O N D O R D E R P L O T FOR A C E T H Y D R A Z I D E 45 t h i s case, as in the previous one, the presence of water slows the reaction to a very s l i g h t extent but does not change the o v e r- a ll k in e t ic s . The complete data for a l l time stu d ies may be found in the appendix. As a comparison of Figures 2A and 3A shows, the reactio n of hydrazine with acetic acid is very slow in comparison to the reaction r a te of the acethydrazide. The r e s u lts of the time stu d ies show th a t the disappearance of the hydrazine is f i r s t order, and the disappearance of the acethydrazide is second order. This would suggest t h a t the reactio n of hydrazine with acetic acid proceeds according to the following set of equations • * HOAc H 2H 4 - H0A c - li — 2-----» 2H2 KNHAo -JE2 » N2H4*H0Ac HgNKHAc + H2 0 > AcNHNHAc t- N2H4 Since hydrazine acetate could be prepared merely by mixing hydrazine hydrate with acetic acid and cooling, be concluded th a t k^ » k2 < as a method fo r obtaining a symmetrical secondary acid hydrazine from a primary acid hydrazine. Whereas the present study was done a t room temperature, a l l previous reports of such a reaction state th at i t takes place a t elevated temperatures and i s usually done near the melting point of the primary acid hydrazine. SUMMARY 46 v. summary Cerium( IV) in g la c ia l acetic acid can be used fo r the oxidation of some simple nitrogen compounds* Among those which have been treated with t h i s reagent are sodium azide, hydrazine acetate, symmetrical diacethydrazide. azide is acethydrazide, and Of these only the sodium q u a n tita tiv e ly oxidized. This oxidation to nitrogen can be done by dissolving the sample in g la c ia l acetic acid alone, adding excess cerium(IV) reagent, allowing to stand for one-half hour and then determining the excess cerium(IV) by using sodium oxalate. I t may also be accomplished as a d ir e c t t i t r a t i o n with the cerium(lV) reagent, provided th a t the g lac ia l acetic acid used as solvent i s made at l e a s t one normal i n perchloric acid . As has been shown, the acethydrazide i s too unstable in g la c ia l acetic acid to lend any meaning to the values obtained in I t s oxidation. Oxidation of both hydrazine acetate and the symmet­ ric a l diacethydrazide yielded odd values of stoichiometry. Both stoichiom etries were quite reproducible however. As might be expected, the values obtained in the oxidation of the symmetrical diacethydrazide were more consistent than those achieved in the oxidation of the hydrazine 47 ace ta te • This would be expected since the symmetrical diacethydrazide, being the end product of the hydrazine- acetic acid reactio n , is stable in the g la c ia l acetic acid while the hydrazine acetate does react on standing* In both cases i t appears th a t the oxidation r e s u l ts in the formation of nitrogen as the only product. The amount of nitrogen produced i s not q u an titativ e a t f i r s t glance. However, i f the amount of nitrogen c o llec te d i s compared to the r a t i o of m illiequivalents of cerium(lV) actually used to t h a t required for oxida­ tio n to nitrogen as the only product, the evolution i s q u a n ti ta t iv e . It can be concluded t h a t under a set of standardized conditions, the stoichiometry achieved in the oxidation of hydrazine acetate Is 2.21 i Sim ilarly, the stoichiometry in .09 Ce(IV) Z NgH^/HOAc. the oxidation of symmetrical diacethydrazide Is 3.37 f .03 Ce(IV) = CH-zCNHNHCCH^. For the l a t t e r oxidation the following O il M *-> 0 o route i s proposed: CH3 CNHNHCCH3 4 2 Ge(lV) -------» CH3 CN=NCCH3 4 0 0 0 0 2 C e(IIl) 4 CH3 CN-NCCH3 ---------» CH3 CCCH3 4 N2 0 0 CH3 CCCH3 4 00 00 2 OH" 4 2 Ce(IV) ---------4 2 CH3 COOH 4 2 C e(IIl) 2 H* 48 Hydrazine and acethydrazide can both be t i t r a t e d with perchloric acid in g la c ia l acetic green color of c r y s ta l v io le t . acid to the blue- Each requires one equivalent of acid per mole. Hydrazine may also be determined colo rim etrically by re a c tio n with salicylaldehyde and measurement of the r e s u ltin g color at 4 1 8 ^ . The apparent lim it of con­ cen tra tio n of hydrazine is determined by the s o lu b ility of the reaction product, d isalicy lalh y d razin e* L IT E R A T U R E C I T E D 49 LITERATURE CITED 1* Audrieth, L. P ., and Ogg, B., "The Chemistry of Hydrazine,” Chapter 7, John Wiley & Sons, I n c ., 19 51, New York. 2 . Autenrieth, W., and Spiess, P ., Ber., 3 4 , 187 (1901). — 3. Borsche, W., Ber., 3 4 , 187 (1901). 4. Bray, W. C., and Cuy, E. J . , 858-875 (1924). J. Am. Chem. Soc., 46, 5. Cahn, J. W., and Powell, R. E., 76, 2568 (19 54). J. Am. Chem. Soc., 6 . Caronna, G., and Sansone, B., Gazz. chem. I t a l . , 739-744 (1939). 7. Carpino, L. A., J . Am. Chem. Soc., 79_, 96 (19 57). 8 . Curtius, Th., and Hofmann, T. S., 55, 524 (1896). 9. Grammaticakis, 690-698. P., Bull. J . prak. Chem. soc. chim. Prance, 10. Higginson, W. C. E., and Sutton, B., 19 55, 1380. 11. I b i d . , 69, 2 19 50, J . Chem. Soc. 1402. 12. Hinsvark, 19 54. 0 ., Ph.D. Thesis, Michigan State University, 13. Kolthoff, I . M., and Belcher, R., "Volumetric A n alysis,” Vol. I l l , pp. 663-665, Interscience Publishers, I n c ., 1957, New York. 14. Martin, J . , J . Am. Chem. Soc., 49, 2133 (1927). 15. Niederal, J . B., and Niederal, V., "Organic Quantita­ tiv e M icroanalysis,” 2 nd Ed., pp. 301-310, John Wiley & Sons, I n c ., 19 48, New York. 50 16. Patton, S ., Keeney, M., and Kurtz, 0 *, Chemists Soc., 28, 391 (19 51). 17. P e l l i z z a r i , 18. Raschig, F ., G., Gazz. chim. i t a l . , 39^ I , 536 (1909). Z. angew. Chem., 23, 972 (1910). 19. Riegger, H. E., (1911). 20. J. Am. Oil J. Am. Chem. Soc., 33, 1569-1576 Semishin, V. I . , J. Gen. Chem. U. S. S. R. 13, 632-642 (1943) C. A., 39, 456. 21. Sommers, F ., (1915). 22. S to lle , R., and Pincas, H., Ber., 48, Ber., 32, 796 (1899). 1963-1969 a p p e n d ix e s 51 APPENDIX A A q u a lita tiv e study of the effect of the perchloric acid concentration on the ra te of decomposition of Hie ceriumflV) reagent was carried out. In this study a volume of standardized cerium(IV) reagent was added to 50 ml, of g la c ia l acetic acid of varying perchloric acid concentration in an iodine fla sk much the same as fo r the oxidations. A series of such samples were prepared and allowed to stand in the dark for varying lengths of time. At the end of a specified length of time the remaining cerium(IV) was determined by t i t r a ­ tion with sodium oxalate. Pour such se rie s were run varying the perchloric acid concentration from zero to approximately one normal. The following table contains the data from th is study. A p lo t of l/C vs. time fo r the concentration of cerium(IV) y ield s a s t r a ig h t lin e for each of the four series run. The slopes vary with the concentration of the perchloric acid. A p lo t of the slope vs. l/C of the perchloric acid also produced a s t r a i g h t lin e . In this manner i t was found th at the decomposition of the cerium!IV) reagent was second order with respect to the cerium(IV) and also second order with respect to the perchloric acid . There e x is ts , however, the 52 p o s s i b i l i t y th a t th is e ffe c t may be due to the presence of water from the perchloric acid and not the acid alone* This point w ill bear f u rth e r in v estig a tio n on a more q u a n tita tiv e b a s is . CERIUM(IV) DECOMPOSITION DATA Time (min. ) T ria l T 0 HC104 Meq. Ce(IV) T rial 2 Trial 3 «25N HC104 • 5N HC104 T rial 4 IN HC104 0 1.544 1.558 1.594 1.544 15 1.530 1.484 1.187 1.207 30 1.530 1.457 1.032 0.998 60 1.534 1.341 0.816 0.727 90 1.534 1.287 0.646 0.672 120 1.538 1.260 0.672 0.432 An attempt was also made to find a su ita b le nonaqueous d ilu en t so as to study the e ffe c t of the acetic acid c one en tr ation on the decomposition of the reagent. Among the mat e r i al s used were carbon te tra c h lo rid e , acetone, hexane, dioxane, dimethyl formamide, ethyl a c e ta te , chloroform, a c e t o n i t r i l e , and dimethyl ether of ethylene glycol (1,2 dime thoxyethane) • Of these l a t t e r was the only one to show any re a l promise. the All of the others e ith e r reacted with the cerium(IV) of the reagent themselves, or caused p re c ip ita tio n of the 53 cerium(lV) s a l t . At the time of this Investigation the supply of 1 ,2 dime thoxy ethane was very lim ited, there being only enough f o r one d ilu tio n . As mentioned, th i s one attempt appeared promising but fu r th e r work was n o t done. A P P E N D IX B D A T A PROM T IM E S T U D I E S OP H Y D R A Z IN E - A C E T IC A C ID R E A C T IO N 54 • 1—1 C• rH Hydrate 1.88M* O £CO • 00• rH rH to 00 CM • 03• o O P O rH t— J eS O3 wu o S3 * o rH rH o a m 03 03 O o 03 • O t• rH to to • rH to to • rH in CO • rH to 00• 00• c00• in o o o 03 00 • i—1 in 00 • rH in rH a t• rH rH o• rH rH O • rH in 00• in 00• to 00• rH rH 00• rH rH «—1 o 00• oo• 1 i— 1 1— o in 03• o o 03• o to 03• o to 03• o O CO o • 00• c -• co CO 1C O — 1 rH rH 03 to • O O in rH rH rH 00 03• o to to 03• o CO to 03• o o to 03• o CO in 03* o o to 03• o 00 03• o CD O• rH rH to rH rH rH • o CD o> rH i—1 CD rH • NF rH to 00 in to - • i—1 £> to i—t to i— • • sh 1— 1 co • 1—1 rH • • rH m — i 1 03 HI • • 1 1 — to rH 03 03 CO CD < £ » 03 o 03 03 i—J Eh &S3 to rH o- 000• 00• (— 1 rH d © co e OhS aj »H H • OhO 03 o o page P rH cti CO rH 03 to CD to s to to 03 CO rH to next o Eh 03 rH • o P ACID SUMMARY I - Hydrazine Concentration to 1—1 • a H Tim® Study Original to rH • Continued ♦ o s o 55 02 02 • O LO 02 • o CD CO • i—1 rH to • r "1 CD • t—1 to • rH 05 to • rH rH to • i—1 LO iH CD • (H • iH rH to * iH to LO • 1—1 05 c• .H co CM • o CO to 02 • O CD 02 02 • O to • i—t to 02 02 • O . to 05 rH • o LO CD rH • o Tt* 02 • O iH 1 LO 02 • iH 05 • rH 1 o • rH CO rH • 1 o to * o 02 GO r-t • o o o to • o 1—1 io o o rH 05 1— 1 05 to • o • o to GO o * t• o cIO o • o o o • • 02 • o O o LO CO • • CO rH •*** SSe 02 OO i— i o o X 05 • iH 1—1 • o SUMMARY - Continued ACID • 02 H LO to • 02 rH to rH • 02 i—1 LO LO • io rH h iG C Q o • o 05 • rH CO to • LO O o 05 rH • LO O • IO CO • 'Sf 1— 1 LO • c02 • to • rH m a • 09 ci to 1-1 i— ! • O • LO • •sr> to 05 o 05 • O o rH to 02 • to 1—I 05 o to o CO LO • to 1—1 • o £> 02 • o • 05 o c02 • o • o to • o rH LO LO LO to c- iH O £> 02 rH rH LO 1—1 to rH t> rH rH rH CD LO trH 05 rH ^ £ > C O O L O t O t >~00 C S 5 r H .H 0 2 02 02 02 C0 »— 1 Or HCv j e o - ^ i Oc o i r 0 2 0 2 0 2 0 2 0 2 0 2 0 2 0 2 1:250 1:100 O rH • O factor factor o rH • o ■JHfdilution oo • o # dilution io o • o 56 © OlrH © CM O trco CO CO • rH o 02 rH • CM CO 02 • i—1 1 IO CO • CM • CM to co CLO 02 CO • o C- o o to E '­ en o 00 • • CM M o CO ♦ d o* © © 02 • -P 0*< 5h ©© SL -1 • TJ & © © d SSd Time CERIUM(IV) SUMMARY Study I - Hydrazine Hydrate S 13 rH CM tIO • CO CM rH IO • rH 05 IO • o o to c- o C-• o 02 cCM • r-1 d to to co IO LO • LO e LO LO • o o o o 1—1 CM CO t- 00 CO £CO e- o o c-• to rH CM t- 1—1 02 CO CO o o o o o C- CM C- to 02 CM CD CM • rH to 1 —1 CM © rH IO LO CM CM • rH C O co oi • CM • rH 00 LO CM • i rH • 1 e CLO tr­ © to o LO © CO io o o o o LO CM CM CM • rH to 1— 1 02 rH t- O CO CO CO LO CO ©■ e e rH i— I CM o o rH CM ECM e l— 1 CO tr­ • o CD i—1 LO io• 1 i CO CM 02 CO —1 CO 1 co CM • rH rH CM • i—1 • © © © ft 8 © *H rH EH Cl O CM CM to C O CtO o to © H * Pi o 1 525 t/3 CM CO LO CO co cn CM rH to Continued next page CM CM 02 ♦ rH 00 o 57 CM CT rH H 02 CM • TJ a*0 0 ra S 13 O • -P LQ tr­ tO io O » rH cr•* *0d SUMMARY - Continued CERIUM(IV) 0 rH • ft O ^ 825 CO CO to co o C" 1—1 CO CO • rH 0 0 S *H Eh O J • a1O h 0 0 'd 0 W ft at «-H m CO CM OS oo as • o 00 OS CM • CM CO ct to • CM OS to o rH CO t" c- to• o o CO rH CM os oo OS * o CO CO to CO CO rH rH • CM CM C0 OS to • to CO • o O OS • CM to OS • CM O CO to 00 OS rH CM 00 • o rH o to 00 • o • CM CO rH 1 • o o o to rH CO rH 00 os o O o o C- O o o os CO • i—t CM « i—1 • CO • 1 —1 to 1 CO OS CM • CM C- • • CO I to • E*• CM CO • o o 1—1 rH CO • CO o CM to o to CM • CM O • CO 00 o• CO CO 00 to 00 • ct00 • o o to o o to • i—! rH • CO to co co • o CM CO CO • CM Os • o o o O o o CO lO rH CO CO c- o to o £> 00 O rH rH rH rH 1—1 CO • rH ci—1 00 1—I o to CO CM CCM CO rH O l CO to CM to CM rH • • • • 0 • 0 Sh to to 1 to I> 1—1 o 1—1 to to c- CM rH to to sH rH C** i—1 os rH CO os o CM 01 CM CM CM CM CM 00 O' CM a 02 O* O o• o -p i—t C0 CO 00# 02 co* 1—1 rH rH Gj co 00• CD rH r -i CD to to 02+ o u o Tim© Study Original ACID SUMMARY II - Hydrazine A ce ta te Concentration 1.86M. o Eh tO 02 -p O 1-4 i— I cd 02 o i— t o • LO o o 00 IO CO CO oo • O • o «o oo 02« o o 00 o 02 CD - O o LO Ol o rH o o • • 00 to c- 1— 1 • CO rH • o o C D CO CD CD CD o o CO CO c- CD CD IO LO 00 00 to oo 02 00 r— I o 00 00 CO CD CO CO lO to 02• o o 02• CD O 02• o to 02• O to rH • 02• o o to 02• o rH « rH • O CO to cn to CO 02 02♦ o 02 02 o 02 t- C - LO CO 02 02♦ o 02 02• O CD O O tO rH Bg o £3 o • I— II— I OS w to o• i—I c- o• rH 02 O• i—1 to o>• to 1—1 £> 00 CO o> • 00• CO CO CO rH O IT- to • tO rH • Ci—1 LO 02• Er—1 rtf CD 09 ® ft s C(f *H r-i EH i— I • ft O §^ co il 02 02 CO ^ CO IO 00 CD 02 02 00 tO i—1 CD CO * to CO i— I 02 rH CO rH next o Continued . « page 58 59 • o P o s • 45 to rH • • 03 o- tO to 5? to to 00 05 o o o 03 o O CO to • • o % to rH r— I i— I o * o to o• o i—! • O * V to 05 rH o> I—1 00 E> 03 LO O >> 45 O H i 1 OS — o s H3 sn O ACID SUMMARY - C ontinued £5 o • rH i—1 f^S-4 O *=3 W 00 03* rH rH O • t- i—1 O rH to to £> * to to to rH O O LO O 03 rH «* *« t5 O O eS oS * + h d d O O •H *H -P 4-> 2 3 e rH • Ph o g £5 CO rH to rH to rH t> — r I 00 05 O 03 iH 03 03 03 rH iH •H *H T3 $ 60 © to « 03 to • 02 to 03 • 02 LO 05 o 05 O I tO < M I— to* to to 03 03 • 03 to 03 « 03 O to • 02 1 00 CO * 03 CO i—1 to • m 03 02 02 o 02 05 03 to CO • T3 O© © 09 P • -P 0 • o 03 lO to • i—1 to rH O O • rH LO to to • rH ■ CO to CO O • i—t 03 tr­ io to • rH rH rH to O • rH o 00 03 O • 1—1 00 05 o LO to • rH o rH ■^L to • to to • tO CO to • o cto ♦ o LO 1 to 03 t>* o .H to CO t>• o o LO CO 1—1 o • 1—1 to to o• o LO 05 to to LO to rH 1 • rH to LO LO o oo lO • 1—1 1 rH LO CO • rH 1— to i—I rH •^}i • rH 03 1 LO CO to # to o 05 £cr> o 1 LO LO • lO LO o o ^ o> o rH 02 oi 00 i— I 03 Time CERIUM(IV) SUMMARY Study II - Hydrazine A c e ta te S 00 •O © ©© Ps LO IO • OS *rl rH EH 03 00 03 02 E> 03 00 o> • CO to CO 00 H LO 02 to © rH • PH O S^ 00 02 to ^ lO to Continued next page o' © 61 CrfrH •u O4< D ©m a4ft ©© S 1-4 • 13 a 4© © i3 CERHJM(IV) SUMMARY - Continued S 13 «« 13 © 09 © ft a * ft O a }s; Q co rH o> £> L O 02 02 02 to 05 to • o L O c1 — 1 !>• • o o 1 —1 LO LO • 02 rH to o 05 00• 02 O to 02 00 o 00» o o CO 00• o 5> to to rH 02 00 o o E>• to 02 • O 05 1 • to • rH • • • o to to LO rH • to to 02• to to 02 02 to CO rH 00• 05• o o 00 £> to tO 02 to 00• o 05 co 05 £> o o 05 C ■sO h to• • 05 CO * o o O o 02 O to 05 rH rH 00 D~ C O o1—1 02 o C O 05 to j—1 o- i—1 CO O• to• LO to• • • 1—1 1—I rH rH rH 02 rH tO LO to £- 00 i— I tO • rH 05 02 • rH m GO L O LO to • to o & 13 rH O - LO rH o 02 02 05 I— 1 o 02 02 02 tO to 02 02 02 ■P CT rH < Da rH 05 to 03 ACID SUMMARY Time Study III - A ceth yd razid e Original Concentration 1.88M. OS 03 03 • oo iH • to -P o Eh i— I to rH LO o 03 to o o • rH <£> LO o CD LO to O O O o •P H V H O rH i— I aj rH 03 O • o 03 to+ o> 03 • i—! 03 — C* to• f 1 • o o o Ip LO LO C O £> L O LO • o to CM « rH rH rH • 05 05 • o o 05 05 o o * • to # o LO LO • rH iH to 03 to to • • o o LO o 05 co • to CO CO • o o to L O to • to • to to to • to CM • 00 o> o o o o o o o o CM 00 • CM rH i—! • o CM 00 LO to 05 LO CO CM rH rH 05 CO cto • CO 03 • tO • to * to • to • 05 to • • o rH C M to O 00 C O rH L 00 LO C O o C O o o I—! 8g o o • rH rH o S w 1—1 LO o> • to rH LO i—1 LO rH o co o i[c 01 a> CO • H o CO rH o> to • o • to o> • to rH rH rH CM • • 05 • 05 to • • • • CO to to • o • 0 2 • O to • 0 • £> • rH CO • 0 2 o • o 0 2 £> ♦ p ACID 0 2 • r r - • • o - rH o 0 2 • • 0 # o o to o o rH rH * • O o 00 ^•h o i— i « — IO S o S ffl P h O |25 • 0 2 0 2 • 0 2 o o i—1 rH O ^ to 0 2 0 0 to• < 0 0 o o CO LO 01 • • GQ rH to o I—I I—I ♦ o tO rH • CO > 05• to • CO rH • LO 9 0 lO o 02 rH • • «« o -P +3 a 05 CO 02 rH O LO CO to rH I—1 O 05 rH 02 02 lO 02 o o ai of s a o o P © rH • ft O & & Of CO P 0 $ rH LO rH to rH O rH 00 05 i— I o CVJ rH 02 02 02 r0 'O ❖ 3j! = Je 64 •st* 03 • 03 O • to to 03 • 03 to 03 • 03 CD rH *> LO to CO 00 to rH O 03 03 03 CO CO • » o o 03 m 03 o ID 03 • 03 to 03 • 03 03 03 • 03 1 to 03 • 03 rH 03 CO CO • o ID LO to CO ♦ o oID 03 00• o 1 03 to 0oo03 00 CO • o o o 03 03 03 rH CO • 03 © 01 CERIUM(IV) SUMMARY Time Study III - A ceth yd razid e S £> O oo to 00 oH <^ rH © © • o co to CO to co 03 ID• • LO LO • • O o o CO to LO LO CO 03 • +3 • 'd o4© ©*d a 'd <*! •d © ©© 9I5Eh i— W Pho a©S23 CO fc- 03 i 1 • i—1 03 rH * rH • rH to i—1 03 'St* * rH 1 03 000 ID • o 1 CO to rH f • rH 03 • H ■ o• C- rH • LO CO • rH 03 o o• o 03 o> t"- to 1—1 ID 03 02 o 03 03 03 1 CO • o 03 to • 1--1 1—I 03 CO • 1—I a •H a LO LO • o 03 03 03 to CO to co to 02 rH 02 03 03 00 03 o to to oo rH 03 60 i— I LO to I— I Continued ** C T CT1 © next page • • © CT i—i © o a a a 65 • • © c? rH © O to CO * CM e • cr* ® © ra rH rH • CO CO £> • CM rH rH • CO o LO o CM CO o to 05 to 05 CO c- co 3 P 05 • • +» 0 * CO ♦ • o o o o o rH rH CM 05 £> o LO o • o O rH O • CO o LO 05 • to 05 00 to CO • o o • o CO CO CO CO to c- CO to • o o o o CO • • to L O I— 1 rH O C M L M £> C O C • • • — 1 1— 1 rH * o D4® © ^ id <4 CERIUM(IV) SUMMARY - Continued O CO • CM • • ' CM CM CO • o c1—( o LO • o C M L O < 7 > C O rH rH L O L O O C O L iH C O * • • • I—I rH rH H T# © 03 © ft a CtJ *H rH EH ft O i ^ CO lO O to sH C*~ 05 05 IO tO 00 CM rH rH 05 o rH rH CM CM CO 05 o i— I o CO LO to I— I CM CM LO CM CM CM © © Time ACID SUMMARY Study IV - Acethydrazide * Water Original Concentration 1.88M. CO i—1 © -P O Eh HQ o © rH rH O ^ rH rH • rH CO Os • O o 00 o co rH to • rH ID 1—1 02 • r-1 • 1-- 1 * 1—1 CO • rH ID to CV2 00 O CO rH * ID i—1 02 • ■ o« o rH • o CO • o • o O oo c• o 1—I 1—1 CO 0• 02 rH 03 ■sf to * o CO ID 02 •. O to 00 • • 02 1 1 o CO 02• 1-- 1 00 pH • rH CO 00 02 • 1 o • • 00 CO • ID CO • CO CO • rH CO • o O o o o o ID • CO ID • O LD • CO ID « o LD ID • O o o ID ID • O rH c- o> OS OS os CO o o O c- CO OS o o o • (—I co cCO • o • 00 CO * o 03 • to • • • 00 • o page CD to • rH rH i—1 • O CO • o OS CO • OS 00 CO • o o o o os 00 o 1—1 rH • O 02 OS • ID rH w i—I 00 o O i—1 rH O W O • o• o O -P to ID o> • to rH i—1 OS CO • rH i—! CO 02 • O rH LD rH • os <0 CO CM rH c- 02 os !> • 00 rH CO • 00 O O C- • 00 • 00 • ^ 02 oo 02 02 CO CO CO 00 ID ID oo OS o 1—1 rH 02 rH CO rH • © TO © © »H i—1 Eh • •H s ja o rH i—1 02 02 © rH • P. O § CO to ^ id co rH next • -P CT rH ID to • rH Continued • o £ o 67 • o O 09 03 • O LO LO • i—1 o o LO 00 o 00 o o o oo to to a to s o 4-> rH od CO • o • cf O EH 09 << to 003 • O to LO 09 m • • to 03 CO • o o • • to to • • 03 # o o o o to 09 to to to 09 in • o o o o 00 to to O' 03 • o in 03 • • • • 03 • to to to o o o o o CO 03 03 • O o to E" o co • LO « m • in IO 00 o £> 03 • O 00 o 03 • O 03 • • • • 00 * • ■ 03 • rH • +3 O r -i rH oS O w O £21 * rH rH O s w ACID SUMMARY - Continued o 5 © 09 © 0H § 0(5 •H rH EH t © 1—1 « Q* ° £ ^ CO LO to • C" 00 rH • £> E> • 03 • to to 09 to to • h Jd o to to o- rH LO 1—1 o o rH to rH 03 GO o 03 iH rH i—i rH E> rH rH oo 09 i—1 O 03 to 09 68 • © CT i— © o 00 rH m O•i to to tO to to LO rl CO CO C- O 4 05 • • o o 00 to o rH • rH C“o CO 00• o to to o cs> I— I CO o o• 02 I—1 LO 05 05 00 00* • o rH • rH 03 CO CO rH rH rH • rH • 03 0- O 00 00• o 00 to CO 0-• I to CO 00* o 05 r> LO E> rH • i—1 to 00 1 I—i o> rH 03 to O C- O 00 oo 05 £- CD 02 i-H O 00 i— I 00 O C- to to r ’l i—i CO 05 • 1—1 00 00 LO rH • r—1 00 03 03 03 to • o to o• 1— 1 co o tO 03 to £• o CO 1 o LO rH l> 05 00 o o 1 CO 05 I— 1 • rH Time Study CERIUM(IV') SUMMARY IV - Acethydrazide ♦ Water ©© S t=> O co 00 oo• o © ©© Pi £3 Of nH 1-4E H W P •H s u & o 03 03 ■ si* 03 03 03 to to tO co to 03 to LO © — I • Pi O § $21 CO 03 tO C O 00 05 o rH Continued next i page • 69 • • © c r rH • O rH 00 00 • o CO o 1—1 • o o 1—1 oo • o o 00 1—1 05 CM to 00 • o CD • rH • © a *h EH © rH • ft o g £5 CO CM O • *d © ID 00 LO • o rH <• CM 05 * u & CD ID £> o o f—1 CD CM rH i—1 LQ rH CD rH i—1 o C*» CO o CM rH 1—1 rH co 05 rH O rH 05 CM