STUDIES ON pow-(mm: ANHYDRI‘DE co STYRENE) Thesis forth. Dog"... of M. S.- I f " MICHIGAN STATE umvmsm ‘ . ' EvejrethIeoffrey Moyér ‘ I 1965- M ' ' I ”EDI: (1.2. " ? éuhéx : 4.1 ,. s. immune, fin: STUFIES CK lClY—(IALEIC ANEYDRIDE CC chREKE) by Everett Geoffrey Meyer AN ABSTRACT Submitted to the School of Graduate Studies of Kichipan State University in partial fulfillment of the requirements for the degree of MASTER CF SCIENCE Department of Chemistry 1965 r ” )j / ./ .1, K/ - [ 7 Approved .//§g£?<24 g Nit/beofy ABSTRACT Copolymers of maleic anhydride and styrene have been prepared with average molecular weights of the following orders of magnitude: 5000, 6000, 9000, 15,000, and 20,000. Polymerization conditions to produce copolymers in these various molecular weight ranges have been described. The f 3 lowest molecular weight poly-(maleic anhydride co styrene) ‘ i was prepared in dimethoxymethane solvent using 0.8 percent benzoyl peroxide as the initiator. The various copolymers were reacted with gaseous am- monia to yield the ammonium salt of the half amide of the l3a‘ho“ *M--‘ —-—-.- dicarboxylic acid moieties. Total nitrogen content of the ammoniated copolymers was determined by the Kjeldahl method. Ammonium salt nitrogen was determined by a method employing high frequency titration. This method involved the dis- placement of ammonium ion from the ammonium salt linkages by a strong acid and evaluation of the carboxylate groups thus liberated by the strong acid titrant. Anhydrous tetrahydrofuran was shown to be a suitable solvent in which to carry out ammoniation of the anhydride copolymers. The ammoniated copolymers were insoluble in tetrahydrofuran and insoluble in acetone. Acetone, a good solvent for the copolymers, was shown to be reactive with gaseous ammonia and yield ammoniated copolymers contam- inated with light unstable, dark colored, acetone soluble materials. Infrared spectra were determined on the various co- POlymers and their ammoniated derivatives. Analysis and comparison of these spectra indicated the presence of the anhydride linkage in the poly-(maleic anhydride co styrene) samples; and the presence of amide and carboxylate groups in the ammoniated derivatives. Infrared spectra have been used to distinguish copolymer samples from their ammonia derivatives. Several polymaleic anhydrides were prepared by the homopolymerization of maleic anhydride. These homopolymers were converted into the ammonium salt of the half amide of the dicarboxylic acid moiety. Homopolymaleic anhydride samples and their ammonia derivatives were then character- ized by high frequency titration and nitrogen analysis. ‘L'... STUDIES ON POIY-(NALEIC ANHYDFIDE CO STYRENE) by Everett Geoffrey Meyer : 4 A THESIS Submitted to the School of Graduate Studies of Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Chemistry 1965 Ital...lb.l....«m.. .1. “Us... .1 V...fi»«-..w.£.3 _\ ~ v'avt : a]. .1‘1Hqfiulh‘ » 11 * 1.“: r3" ACKNOWLEDGEMENT I would like to thank Dr. Ralph Guile for his guidance, encouragement, 3 ‘ '- ‘ ‘3‘" and patience. I wish to dedicate this thesis to my parents who also have been patient. E. Geoffrey Meyer TAEIE CF CCNTEKTS IntrOduCtiODOOOOOOO0......00......00.0.00... HistoricalOOOOOOOOOOOOOOOOO0.00...00.0.00... Experimental A. B. C. D. Reagents and Instrumental............. The Coyolymer of Naleic Anhydride and Styrene......................... Preparation of the Copolymer.. holecular Neights............. High Frequency Titrations..... Infrared Spectrum............. Preparation of the Low Nolecular O Neiglit COI’Olb’nero o o o o o o o o o o o o o o o o Discuss'ionOOOOOOOOOOIOIOOOOOOOOOO SuCCiniC AnhydridGOOOOOOOOOCOCOI... Reaction with Armenia Reaction with Ammonia Nitrogen Analysis of Ammonia in Acetone. Derivative-(300000000000000000000000. Synthesis of Succinamic Acid....... Ammonium Nitrogen Analysis by High Freouency Titration........... Ammonium Nitrogen Analysis by Colorinetry................... Infrared Spectra.............. Discussion.................... Ammonia Treatment of Poly—(maleic anhydride co styrene)............. Preparation of the Ammonia Derivatives of the Corolyher....................... O in Tetrahydrofuran. .20 .25 .25 .26 .27 .28 .50 7. 0/- .55 .5? ii .Ihv,"'_~‘w .MO..0~.1--4r- “-24.. _...—_ .4 Y ”‘7‘ e *3: t- I «,f The Effect of Extraction ..................43 ACGtone By-PrOdUCtS ocean's-000000.00.0.00044 Total Nitrogen Determination ..............45 Ammonium Nitrogen Determination............46 Molecular Weights Infrared Spectra o.000.000.00.00...0.0000048 ooooooooooooooooooooooooooso Discussion .000... ooooooooooooo coco-0.0000053 E. Polymaleic Anhydride. Preparation OO0.000.000.00000000000059 OOOOOOOOOOOOOOOOOO0.00.00.00.0060 High Frequency Titration.,,,,,,,,,,,,.,.,,61 Preparation of Ammonia Derivatives ........63 Nitrogen Analysis of Ammonia Derivatives 64 Discussion................................65 F. Conclusions.................................67 G. Literature CitedOOCOOC......................69 4 .ll l'x‘ -'*<‘—dF—J. “La-n. .a....- m; INTRCDUCTION This work is a continuation of the studies in this laboratory on the copolymers of maleic anhydride with st- yrene and their derivativesl’g. Poly-(maleic anhydride co styrene) with an average molecular weight in the order of 50,000 had been reacted with ammonia to produce a nitrogen containing material of unknown structure that exhibited some anti—carcinogenic activity. The work reported in this thesis was initiated to pre- pare copolymers of maleic anhydride with styrene of differ- ent but known average molecular weights and to convert these copolymers into their ammoniated derivatives. The structures of the ammoniated derivatives were to be studied and their number average molecular weights determined. Some commercial samples of the poly-(maleic anhydride co styrene) were available from Sinclair Petrochemicals, Incorporated. These samples were advertized to be of rel- atively low molecular weights based on the property of relatively low solution viscosity. No information was ob- tainable relative to the method of preparation of these samples, the values of their number average molecular weights, or their structure and purity. The commercial samples were to be used as an immediate source of copolymer material for study and as comparison samples with any that were prepared in the laboratory. Since the Michigan State Chemistry Department had re- cently acquired a Vapor Pressure Osmometer - Mechrolah .Model 502, which can effectively be used to determine num- ‘beI‘average molecular weights in the order of 100 — 20,000 it was decided to measure the number average molecular weights of‘the commercial samples and to attempt to prepare poly- (maleic anhydride co styrene) with number average molecular r « .rfz-i ..., 0‘- .2 .n lags-r. M- _ weight that would fall within the limits of measurement of the above mentioned instrument. It was also a part of the problem to ammoniate the commercial sarples and to determine the structure and molecular weight of these ammoniated derivatives. The production of lower molecular weight copolymers and their ammoniated derivatives with average molecular weights in the order of 500 to 5000 was very desirable for several reasons. Low molecular weight polymers would in general be more soluble, more easily produced in the lab- oratory, more easily reacted and more compatable with bio- logical systems. Since some of the ammonia derivatives of the poly— (maleic anhydride co styrene) have been shown to be anti- carcinogenic a variation in molecular weight might effect the toxicity and effectiveness. It was hoped that low molecular weight polymers would prove less toxic and more effective. Any samples of known structure and known molecular weight resulting from this investigation would be submitted for evaluation in certain anti-cancer screens. Within the course of this work, it was found desirable to prepare and ammoniate polymaleic anhydride. This work also describes the results of the ammoniation of succinic anhydride as a model reaction for the investigation of the reaction of the maleic anhydride moiety in a copolymer. ”A- ‘uno--.—_-._‘_‘n—-_. J HISTORICAL Copolymers of maleic anhydride and styrene have been treated with ammonia under varying conditions to yield several products. Aqueous ammonia produces the mono- or diammonium salts of the poly—(maleic anhydride co styrene) 3 4 6 . . «’ ’5’ . When heat was applied during the treatment with aqueous ammonia followed by heating the initial reaction product in vacuo the imide of poly-(maleic anhydride co styrene) was formed7. Ammonium salts of poly-(maleic anhydride co styrene) "‘9‘“ 4-...___A_.-.__A_l U . i ‘2 l A .. . . were also prepared by dry blending equivalent amounts of ammonium carbonate or ammonium bicarbonate with the cepolymerS. When the copolymer was dissolved in an anhydrous med- ium and gaseous ammonia passed through the solution the amide of poly—(maleic anhydride co styrene) was formede. It also has been reported that reacting the copolymer with gaseous ammonia in anhydrous tetrahydrofuran yielded the ammonium salt of the half amideq. Poly-(maleic anhydride co styrene) dissolved in an- hydrous acetone and reacted with gaseous ammonia under pressure quantitatively formed the imideg. Orange colored amidated polymers were formed when the copolymer of maleic anhydride and styrene in acetone sol- ufionves treated with p-aminobenzoylacetanilide or benzoyl acetic acid p—aminoanilidelo. Likewise, anidation pro- ducts were the result of reacting poly-(maleic anhydride co styrene) with N-methylaurylamine or N-methyloctylaminell. While the copolymer of maleic antydride and styrene has been prepared in this laboratory, little work has been doneon the reaction of these copolymers with raseous armoniaand the characterization of these ammonia derivatives The synthesis of polymaleic anhydride was reported re- cently and a search of the literature revealed no pub— . - . . . . l? lished data on its reaction With easeous ammonia . k . 1,2 .. u...“ _...1 Mg.__—__ PART A REAGENTS AND INSTRUMENTAL -+— W -—. -—a«.—_- __ rift—emf; 2.- 7.1.5..” L. as. _. 32.1.03ad REAGEFTS l. Benzene Thicphene free benzene was dried over sodium metal and distilled; boiling range 80-8100. 2. Acetone The acetone was purified by washing with silver nitrate and sodium hydroxide. The acetone was then filtered and stored over calcium chloride. Finally it was distilled from potassium permanganate; boiling range 56-5700. 3. Tetrahydrofuran J Tetrahydrofuran obtained from Eastman Chemicals was stored t over potassium hydroxide, refluxed with lithium aluminum hydride, and distilled; boiling range 65-6600. 4. Methanol Absolute methanol was dried by refluxing with mag- nesium turnings and distilled; boiling point 64.500. 5. Chloroform The chloroform was dried over calcium chloride, dis- tilled, and stored over calcium chloride; boiling range 60-6100. 6. Benzoyl peroxide Eastman Kodak, Reagent grade. 7. Haleic anhydride The maleic anhydride (Fisher Scientific Co., Reaeent grade) was purified by distillation; melting point 5500. 8 . Ammonia The Matheson Company, Anhydrous. C3. Succinic Anhydride The succinic anhydride was purified by recrystallization .froniacetyl chloride; melting point 12000. lO. Styrene The styrene monomer (Dow Chemical Company) was dis- tilled to remove the inhibitor. The sample was free of polymer, as indicated by the absence of a precipitate on the addition of methanol. ll. Dimethoxymethane Eastman Organic Chemicals, Reagent grade. 12. Dioxane Technical grade dioxane was refluxed with 1.8 N HCl under a flow of nitrogen gas and Stored over KOH pellets. It was then refluxed with sodium metal and dis- tilled from the sodium metal; boiling range 101-10200. INSTRUNENTAL 1. pH Meter A Beckman H2 pH meter, with glass-saturated calomel electrode pair. 2. Infrared Spectrophotometer A Perkin-Elmer 237B Double Beam Recording Infrared Spectrophotometer. 3. Vapor Pressure Csmometer A Mechrolab Vapor Pressure Csmometer - Model 302 was used. The operation temperature was 37°C. for all deter- minations. The K value for acetone solvent was determined with benzoic acid and found to be 375. The K value for water solvent was determined with potassium acid phthalate and found to be 132. 1!. .lpl. tout”... fink. , tr, .f .. nJ 7w 535;; ’- Q. PART B THE CCPOLYNER CF MALEIC ANHYDRIDE AND STYFENE . . . . I; d r. .\ firmed . I fill-P J'H .. . v! w. ‘n. 1.4nw‘vo. .V. 5 — .i—W.._ .. . 1 u i... H .. l \D PREPARATION CF THE COPOLYNER CF NALEIC ANFYDRIDE AND STYRENE The copolymerization of maleic anhydride and styrene was carried out in a one liter, three neck, round bottom flask with ground glass joints. The flask was equipped with a mechanical stirrer, a reflux condenSer, and a gas inlet tube. A 50:50 mole ratio of maleic anhydride and styrene was reacted in five hundred milliliters of the appropriate solvent. Benzoyl peroxide iritiator was used at 0.5 weight percent, based on the total monomer weight. Since approximately 42 grams of copolymer were needed for studies 0.2 mole of each monomer was copolymerized. At 100 percent conversion, this would yield the required amount of coyolymer. The appropiate weighed amount of maleic anhydride was dissolved in refluxing solvent. When the maleic anhydride had dissolved completely,the styrene was introduced into the flask and allowed to mix with the maleic anhydride solution for a few minutes. After this the benzoyl per- oxide initiator was added and the reaction allowed to pro- ceed until a good yield of copolymer was evident as in- dicated by the amount of precipitation which had occured. Purified nitroeen was introduced into the flask by means of the gas inlet tube prior to the addition of the maleic anhydride and a constant flow of nitrogen gas was maintained through the reaction mixture during the entire ,procedure to insure a nitrogen atmosphere at all times. (The reaction was carried out at the refluxing temperature of the solvents. Upon completion of the polymerization, the copolymer imas filtered by suction and washed four times with the smnne solvent in which it had been prepared. The c0polymer vwas then dried in a desiccator under vacuum. .P, . . .I.rti o ..‘ 1.9.2.9-kuj only .3‘ be" .0...- x; .f The dried c0polymer was extracted with benzene in a Soxhlet extractor for at least 168 hours. After the extraction,the copolymer was again dried under vacuum in a desiccator. Analytical samples were further dried in vacuo in an Abderhalden drying pistol heated by refluxing acetone (B.P. 56.5OC.) for a period of 24 hours. Poly-(maleic anhydride co styrene) was prepared in 13 chloroform, dimethcxyvettane, benzene , and tetrahydro- furan13 by the above procedure. The samples of poly-(maleic anhydride co styrene) which were acquired from Sinclair Petrochemicals, In— corporated,were subjected to Soxhlet extraction with ben- zene for at least 17? tours,followed by drying in vacuo in a desiccator. Samlles for analysis were dried in vacuo in an Abderhalden drying pistol heated by refluxing acetone (B.P. 56.50c.). aide. a. the a .e. instead _ x ll MOLECULAR WEIGHT 0F POLY-(MALEIC ANHYDRIDE CO STYRENE) Number average molecular weights for various samples of poly-(maleic anhydride co styrene) were determined using a Mechrolab Vapor Pressure Osmometer. The copolymer samples were dissolved in acetone for the determination. The results are listed in Table I and representative curves are shown in Figures 1 and 2. Sample Calculation Number averaee molecular weight = K K = calibration constant. AR/C(c--.)0) A R = Resistance. c = Concentration (grams/liter). Table I Molecular Weight of Poly—(maleic anhydride co styrene) Sample Preparation Molecular Number Solvent Weight lE* Dimethoxymethane 5,540 2E Benzene 20,400 3E Chloroform 9,200 4E Tetrahydrofuran 6,640 Sinclair Resin 2000A** 1,790 Sinclair Resin 3000A 2,100 Sinclair Resin 4000A 670 Sinclair Resin 5000A 23,400 Sinclair Resin 7000A 12,900 ‘ The E designation indicates poly-(maleic anhydride co styrene). ** The solvent and method of preparation of the Sinclair Resins was unknown. 7.. .vf . n-_RK.. - .9.)- L a.» ‘1' Figure l. 12 .100 O 0 ® Vapor Pressure Osmometer Molecular Neieht Determination. Poly-(maleic anhydride co styrene), lE. O ..5 P- o -0- 0‘ .9 O 4 d In 0 as O 3’ 0 ch 0 c0 9 ‘WS 9 ‘r 3 °. 2. A g ' ° 0 3! £3 1} :3 ‘§ ClFl/CL .‘Boq (w..r*-o.rn:3 /11‘er) Concehh-J3Hh Figure 2. 13 Vapor Pressure Osmometer Nolecular Weight Determination. ‘ Poly-(maleic anhydride co styrene), 3E. .4 1 J J fl 1 l L 1 4L *1 o to .9 A o B 3 3_ Z % g g lR/c 8&0 70 .0 b0. O 50.0 “(0.0 10.0 10.0 0.0 Hier) '.Y 1:)“ |. 4‘. ’ COHCQHJ‘ rel.’ 14 HIGH FREQUENCY TITRATION OF POLY—(MALEIC ANHYDPIDE CC STYRENE) Accurately weighed (i 0.0001 gram) samples of approx- imately 0.1 gram of poly—(maleic anhydride co styrene) were refluxed with absolute methanol until the copolymer dissolved. The following copolymer derivative was formedl4: CH CH-————-—CH CH t 2 u n )2“ F9 9:0 OH OCH 3 Fifteen milliliters of 0.1000 N NaCH were added to the product in order to form the sodium salt of the half ester. This was then titrated with 0.1C00 N HCl. The titration was followed with a pH meter and a high frequency ti— trimeterlq’lS. The results are listed in Table II. Figure 3 shows a representative curve. Calculation equivalent weight of maleic anhydride moiety. number of equivalents of carboxylate groups EW NE from titration. W = weight of sample in grams. LEgggNEl x 100 = percent maleic anhydride moiety in the poly—(maleic anhydride co styrene). 936...... 3......- 2.1...» .3“; 4... 13.... .. Table II :OIHI. 0") -L th E ‘ ‘ I. iiigii Expeyimental Percent Tl iE———_ "filelc Anhydride koietl ngiiiiticil P§rcent A 47-5 ; hydride ”019:1 CE #9.? 4b°5 2. 4 '. /E 48.1 F.5 5000.11 52 1 48°5 48.5 7000A g? 5 48,5 Figure 5. High Frequency Titrimeter Dial I \ g t I { L\Jl \ttxl.) pf ti " 4 « \ \ \J.4\fiJ\) o 0 ° 0 g 83 F3 5:“ r e_\la ' ' 7 T " \\\\G . O ‘1' Carboxylate group 9 -+ r. q C 4 e 9 E NaOP §—’ xcess . G —1 0 4 d 0 - O '1 5 -—4>—. High Frequency Titration curve _._ pH curve - °. "‘ '3’ High Frequency Titration of Poly-(maleic anhydride costyrene)1 3 Half Ester Technique Sample 7000A ‘ l 1 l 1 l l I 1 l 1 O. 0, 9 ‘1 e 0. 0 0° II: n_ VOI ume L‘fif 17 INFRARED SPECTRUM An infrared Spectrum was recorded for a sample of poly-(maleic anhydride co styrene). A mineral oil mull l to 750 cm.- range and a Flurolube mull sample was used to record the 4000 cm.’1 are placed beside the spectrum (Figure 4 and 5). sanple was employed to record the 2000 cm.“ 1 to 1250 cm.-1 range. The instrument settings Figure 4. 18 <;___ <:::;_::> The Infrared Spectrum of Poly—(maleic anhydride co styrene), 5E. Flurolube hull 5 Minute Scan Slit 5 0.0 Absorbdnce ‘5000 1900 9.000 “300 VJOJVEL PQLLHXK*;V' 3:00 3 I Fipure 5. l9 L The Infrared Spectrum of Poly-(maleic anhydride co styrene), 5E. E"? Mineral Oil Mull 3 Minute Scan Slit 5 (I OD Absorbonce cx34L_Lum._s~Wllwmi,uw ii \000 800 n00 IMOO W0-» $600 {$00 (en/Cl) ng\ \ hyLlil‘ 20 PREPARATION OF LON MOLECULAR WEIGHT POLY-(MALEIC ANRYDRIDE CC STYRENE) The copolymerizations of the maleic anhydride and styrene were carried out in ground glass 250 milliliter round bottom flasks. The flasks were equipped with mag- netic stirrers, reflux condensers, and gas inlet tubes. Approximately 0.04 mole of each monomer was dissolved in about 100 milliliters of dimethoxymethane. After the monomers had dissolved,the initiator was introduced and the reaction allowed to run at the boiling temperature of dinettoxyrethane (4400.) for 24 hours. The reactions were allowed to cool with constant stir- ring for 2 hours. After the cooling period,the copolymers were filtered with suction and washed several times with an- hydrous benzene. They were finally dried in vacuo. After drying the copolymers were wasted twice with hot anhydrous benzene and again dried in vacuo. Benzoyl peroxide was used as the initiator in all these polymerizaticns with varying concentrations. The atmos- phere in which the 00polymerizations were run was pre- purified nitrogen. A summary of the various experiments and the conditions under which they were carried out is given in Table III. The number average molecular weights of the poly— (Ualeic anhydride c0 styrene) were determined with a Nechrolab Vapor Pressure Csmoneter. The determinations were made in acetone solvert. The results are given in Table III. Figure 6 slows a representative graph. A sample calculation of a molecular weight is given on page ll. ?1 Table III Experimertal Conditions and Molecular Height of Low Molecular Weight Poly—(maleic anhydride co styrene) Percent Initiator Sample Based on Total Molecular Number Monomer Weight Weight lE* 0.4 3,540 BR 0.8 2,980 SE 1.5 19.750 7E 1.6 15,600 t This coyolymer was prepared under the procedure described on page 9 of this thesis. Figure 6. R) f\ Vapor Pressure Csmometer Molecular Neight Poly—(maleic anhydride co styrene) Sample 7E Determination $0.0 co.o 'ms / liter) 40.0 0 l0.0 .05 L ,oq - .03 _ [\R/c, I 0; v .01 r .00 -t _ \\ .J" / 'rolkph oneenl ’ I) t \J 23 DISCUSSICN The purpose of this series of experiments was to determine, if possible, the optimum conditions under which a low molecular weight copolymer of maleic anhydride and styrene could be prepared. It was known from pre- ceding work that a relatively low molecular weight co— polymer of maleic anhydride and styrene could be prepared using dimethoxymethane as a solvent (See page 11 of this thesis). On this basis it was decided towuse dimethox - methane as solvent and vary the benzoyl peroxide in— itiator concentration. It can be seen from Table III that the lowest mole- cular weight poly—(maleic anhydride co styrene) was ob- tained from the copolymerization utilizing 0.8 percent initiator concentration. The copolymer prepared with 0.4 percent benzoyl peroxide was also quite low. How- ever, the two highest initiator concentrations yielded the highest molecular weight copolymers. There are two factors which influence the molecular weight of the copolymer. One of these is the rate of initiation and the other factor is the rate of terminationle. The faster termination takes place thelpmmr’the co- polymer molecular weight will be. Itappears that termination occurs fastest when the initiator concen- tration is between 0.4 and 0.8 percent. 0n the other hand, when the initiator concentration is in the range of 1.5 to 1.6 percent the rate of termination has decreased. This is indicated by the considerably higher molecular weights found in this range. Cne rea- son for this behavior may he that the free radical is incorporated in the polymer bulk and is. prevented from 24 reacting with other free radicals because of its restrict— ed mobility. It does continue to react with monomer be- cause there is a much higher concentration of monomer in the system. FA RT C SUCC INIC ANFYDRIDE 25 TREATFENT CF SUCCINIC ANHYDRIDE IN ACETCNE WITH AKMCNIA The reaction was carried out in a 500 milliliter three neck flask with ground glass joints. The flask was equipped with a reflux condenser, a mechanical stirrer, and a gas inlet tube. Three grams of succinic anhydride were dissolved in 300 milliliters of acetone: After the succinic anhydride dis- solved,anhydrous ammonia gas was passed into the solution for five hours. The reaction was carried out at room temperature with continuous stirring and with no protection from light. The white crystalline precipitate which resulted was filtered by suction and washed three times with acetone. The product was then dried in a vacuum desiccator. After drying, the ammonia derivative of succinic anhyd- ride was subjected to a Soxhlet extraction with acetone for 22 hours and again dried in vacuo. The product after ex— traction and drying remained white and crystalline. The melting point of the extracted and driedjammonia treated succinic anhydride was l?9.SOC. he product was assured to terammcnium succinamate produced by the following reaction: CH CF CH CH I 2 I 2 ENH I 2 I 0:0 /c—__ 0 5 cu? (Ir—:0 \0 ONE4 ran? This assumption was later shown to be correct (See page 50). t . . , . . . . . . . _ ‘m , . The ammonia derivative cf suc01n1c anhydride preparec in acetone is samfle 1G. TREATKENT CF SLCCIEIC ATEYDRIIE IL TETRAFTDRCFURAN 'NITH ALICNIA The procedure followed in this experiuent was essent- ially the same as that for the treatment of succinic ar- tydride in acetone with ammonia. The solvent in this case was tetrahydrofuran‘ and this reaction and the product were protected from light at all times. The reaction was allowed to run for 4 hours. After filtering by Vacuum and washing with tetrahydro— furan three times the product was dried in vacuo and then extracted with tetrahydrofuran in a Soxhlet extractor for 26 hours. After extraction it was again dried in vacuo. After extraction and drying the product was white and had a melting point of 122.500. The product was assumed to be ammonium succinamate formed by the following reaction: o H~——————— 7H2 ?H2 ens $‘2 932 0:0 cre ‘ 5 0:0 0:0 \0/ 01‘s is ’ ,, 4 2 This assumption was later proven to be correct (See page 50). * The ammonia derivative of succinic anhydride prepared in tetrahydrofuran is sample 20. 28 TOTAL NITFCGEN ANALYS 8 OF THE ANNCNIA DERIVATIVES CF SUCCINIC ANHYDRIDE The Kjeldahl method was employed to determine the percent total nitrogen in an accurately weighed (i 0.0001 gram) sample of ammonium succinamate of approximately 0.1 graml7. All attempts to determine ammonium nitrogen by titration of ammonia liberated from the ammonium salt by a strong base resulted in the hydrolysis of the amide and gave values for total nitrogen in the ammonium succinamate. Calculations EW = equivalent weight of nitrogen. NE = number of equivalents of ammonia determined by titration. ' W = weight in grams of the original sample. EW NE W x 100 = percent total nitrogen in sample. Table IV Percent Total Nitrogen in Ammonium Succinamate by the Kjeldahl Method Theoretical Sample Percent Total Percent Total Yumber Nitrogen Nitrogen 1C; 1(908 20.9 ?G 18.4 20.9 30 SYNTHESIS OF SUCCINANIC ACID FROM AKRONIA TREATED SUCCINIC ANHYDRIDE A sample of ammonia treated succinic anhydride was dissolved in distilled water. An excess of a 5 percent silver nitrate solution was added to the dissolved ammonia derivative of succinic anhydride and a white precipitate was immediately formed. The precipitate was filtered by suction, washed with distilled water three times, and dried in vacuo. The dry white precipitate was treated with an aqueous solution of H28. The black-brown precipitate which was formed in the reaction was removed by suction filtration. The filtrate was evaporated on a steam bath under vacuum. The colorless crystals remaining after all the water had evaporated were recrystallized three times from an acetone-ether mixture. If the ammonia derivative of succinic anhydride were ammonium succinamate, the above procedure should yield succinamic acid as the final productlB. The melting point of the recrystallized product was 156-15700. which agrees with the known melting point of succinamic acid . The following reactions occured in the above procedure: (ale—we + ewe—e2 H S wig—we 0:::C 0:::0 Ag 02:: 02:0 2 0:: 02:0 I I ——> I l ——> I I ONH4 NH2 OAg NH2 0H NHZ HIGH FREQUENCY TITRATICKS CF AUNCNIUF STCCIEAMATE To prepare the ammonia treated succirio arhydride for high frequency titration an accurately weighed sample (i 0.0001 gram) of approximately 0.1 gram was dissolved in distilled water. his was then directly titrated with 0.1000 F PCl. The titration was followed with a high frec— uency titrimeter and a Eectran glass electrode pH meter. A titration.curve is shown in Figure 7. The results are showr in Table V. Calculations EH 2 eouivalent meipht of nitrogen. NE = hunter of equivalents of ammonium ion present as determined by the titration of the carboxylate group (Figure 7). W weight in grams of sample. LEWJCNE) - 1 (W) X lCC percent ammonium nitrogen as deter- mined by high frequency titration. Table V Percent Ammonium Nitrogen in Ammonium Succinamate by High Frequency Titration Sample Experimental Percent Theoretical Percent Dhnmber Ammonium Nitrogen Ammonium Nitrogen 1G 9.18 10.4 2G 9.89 10.4 t Figure 7. High Frequency Titrimeter Dial 52 o O , 1‘ 1 6— 5 it!" In K) 1 4. a 4 5 J A and C High Frequency Titration of Ammonium Succinamate a Sample 1G -4— pH curve 9 J \\ -—o—-High Frequency Titration curve q a 1 d d} all 4 k d n 1 L, 1 1: 1 O Q 0 . 2‘ a ° who m Qua \o.o 6,0 0 A» QHO Q0 53 COLCRINETRIC DETERMINATICN CF AMMCNIUM NITRCGEN IN AKHONIA TREATED EUCCINIC AYHYDRIDE A standard solution of ammonium chloride was prepared by quantitatively dissolving an appropriate weighed amount 6 in ammonia free water to give a solution containing 6.#x10- equivalents of ammonium ion per liter. The samples were prepared by dissolving an accurately weighed sample (i 0.0001 gram) of approximately 0.1 gram of ammonia treated succinic anhydride quantitatively in 100.0 milliliters of ammonia free water. Cne milliliter of this solution was then diluted with ammonia free water to 50.0 milliliters and treated with 5.0 milliliters of Nessler's Reapcnt* (Prepared by the Keck and Neckin Nethod ) and allowed to stand for 15 minutes. The same treatment was given to 50.0 m'lliliters of the stand- 1r“: ard solution /. The transmittance of tte solutions was then determined on a Bausch and Iorb Spectroric 20 Colorimeter at a wave— C1- iength of 5C0 microns ’. Calculations If colorimeter experiments utilize matched cells, the same solvent, temperature, ard wavelength for all samples and the standard solution, then the following relationship is 'true: 0 =K log l/T where c is some concentration term for the colored sub- stance,l{ is a constan , and T is the transmittance. * "inolv furnished by Dr. Bans Lillevik. .‘ '2 " h...nF« Since A is constart in all cases the following re- lationship is truel/ lrg l/T log l/TX Cs Cx where subscript 5 refers to the standard solution and sub— script X refers to the sample. Data and results are shown in Table VI. The follouing is the method for calctlatirg the percent ammonium ritrogen from transnittance: cX = eruivalerts/liter cf avnonium ritroge n from transmittance. EN = ecuivalent weight of ritrcgen. W =weight of sample in prams. (EN)(CX )(5 0) (N77 X 100 = percent ammonium nitrogen. Table VI fercent Ammonium Nitrogen in Ammonium Succinamate by Colorimetry Experimental Equivalents of Percent Sample Ammonium Nitrogen Ammonium Number Transmittance Per Liter Nitrogen Standard .526 6.4 x 10"6 1G .266 13.2 x 10’6 8.90 2G .270 13.0 x 10"6 8.78 The theoretical percent ammonium nitrogen succinamate is 10.4 percent. for ammonium '7 y 94 a. ’ nun M. Li:-‘;.. .‘m.-' .— W's—int. [IA '*-. ' :3 1“ .. ‘ 35 INFRARED SPECTRA Infrared spectra were recorded for samples of succinic anhydride and ammonium succinamate. A mineral oil mull sample was employed to record the 2000 cm.-1 to 750 cm.- range and a Flurolube mull sample was used to record the 4000 cm.“ are placed beside the spectra (Figures 8 and 9). l to 1250 cm.- range. The instrument settings r< ‘ -o-...-.-— c~.J’€M‘.—!- 1 1 F“: .- twin-st b, Figure 8. 36 The Infrared Spectrum of Succinic Anhydride Flurolube Mulls 5 Minute Scan Slit 5 The Infrared Spectrum of Ammonium Succinamate,fi 2G. “ 0.0 Absorbdnce T leoi E 3500 Emoo \A/cwe Number (Cir-.71 \ Figure 9. B The Infrared Spectrum of Succinic Anhydride Mineral Oil Mulls 3 Minute Scan Slit 5 The Infrared Spec— trum of Ammonium 4 Succinamate, 2G. 0.0 [\bSKDrNDOLhJLGL looo 80° \zoo ( , til lQoo Wave Number [boo \Boo ‘ ‘i 9 0.. .fi-‘t h..’:-.-.ua‘ph sun’s-‘o '-.-I~r‘ 58 DISCUSSION Reacting succinic anhydride with dilute aqueous ammonia yields ammonium succinamate from which it is possible to . . . l8 prepare suCCinamic a01d . Since it was suspected that the product which resulted ; s -, . .2 my from reacting succinic anhydride and gaseous ammonia in an anhydrous medium was ammonium succinamate the preparation of succinamic acid from this product was attempted. The colorless crystals which resulted had a melting point of 3 156-15700. The melting point of succinamic acid is 1570C.18. § It was concluded from this that the product which re- ; sults from treating succinic anhydride with gaseous ammonia 1 I... “II—g... is ammonium succinamate. O H H4NO C CH2 VH2 0:0 --¢Hl 2 Kjeldahl analysis for total nitrogen gave 19.8 percent nitrogen on the sample prepared in acetone and 18.4 percent nitrogen for the sample prepared in tetrahydrofuran. The theoretical percent total nitrogen is 20.9 percent (Table IV). Colorimetric determination of percent ammonium nit— roeen yielded 8.90 percent and 8.78 percent (Table VI). The theoretical percent ammonium nitrogen is 10.4 percent. The method is relatively straightforward with compounds which dissolve to form colorless solutions. However, some of the ammonia treated copolymers form solutions that ‘vary from yellow to brown. This color would cause diff— irnilties in applying a colorimetric method to the ammon- iatefl.copolymers. The high frequency titration of the samples gave a cnxrve with one break (Figure 7). If we assume that this 59 break is the titration of the cartoxylate group then we can calculate the percent ammonium nitrogen. The percent ammonium nitroren calculated from the high frequency titration curves is 9.18 percent and 9.89 percent. The theoretical percent ammonium nitrogen is 10.4 percent (Table V). From these results it can be seen that high frequency titration is an acceptable method for deter- mining percent ammonium nitrogen in ammonia treated an- hydrides. i. “ain't... PART D AMMCNIA TREATEENT CF THE CCPOLYMERS OF NALEIC ANHYDRIDE AND STYRENE 4O 'Q’L‘s .u. cut-.I—A IZ" — — -in—n. “Luv ' u‘ f 41 PREPARATION OF THE AMMONIA DERIVATIVES OF PCLY-(MALEIC ANHYDRIDE CO STYRENE) A 10 percent (weight/volume) solution of poly-(maleic anhydride co styrene) in an anhydrous solvent was placed in a three neck round bottom flask fitted with a mechanical stirrer, a reflux condenser, and a gas inlet tube. Anhydrous ammonia gas was passed into the solution with continuous stirring. In all cases the reaction was carried out at room temperature. A summary of the various experiments and the conditions of each are given in Table VII. Table VII Experimental Conditions for the Ammonia Treatment of Poly-(maleic anhydride co styrene) Sample Protected Reaction Number Reactant From Light Solvent Time-Hburs lM‘ Resin 7000A No Acetone 48 3M Resin 5000A Yes Acetone 6 4M Resin 7000A Yes Acetone 6 5M 1E Yes Acetone 2 6M 2E Yes Acetone % 7M 5E Yes Tetrahydrofuran 5 8M 4E No Tetrahydrofuran 4 In all experiments a white gelatinous precipitate re- sulted. This precipitate was separated from the solvent by «centrifugation and decantation of the supernatent solvent. {Dhe precipitate was repeatedly washed in the centrifuge * The designation M in the sample number indicates ammonia derivatives of poly-(maleic anhydride co styrene). '. .‘ 9-. ;‘ ..‘wfil-Q .I-c .md . Kc- ‘~0.‘-.'*~ -- In ’ I _.J . -’~" 13:37:! 42 tube and separated from the wash solvent by centrifugation. The white gelatinous precipitate was then dried in vacuo. After drying it was subjected to Soxhlet extraction for 24 hours with the same kind of solvent in which it had been pre- pared. The extracted product was dried in vacuo. In all the experiments the product recovered following centrifuging was a white gelatinous substance. However, the products prepared in acetone turned brown during vacuum dry— ing. The darkest product was obtained from experiment 1M which was exposed to light. The two experiments carried out in tetrahydrofuran yielded final products considerably lighter in color than any of those prepared in acetone. The reaction in tetra- hydrofuran which was protected from light gave a perfectly white product while the experiment not protected from light yielded a substance which was slightly yellow. The latter was considerably lighter than any prepared in ace- tone. Soxhlet extraction removed some of the colored sub- stances from all the colored products but even after ex- traction considerable color remained. 43 THE EFFECT OF EXTRACTION ON THE NITROGEN CONTENT Since Soxhlet extraction removed colored products from the ammonia derivatives of poly-(maleic anhydride co styrene), the effect of the extraction on the total nitrogen content of the unextracted derivatives was determined. The percent total nitrogen was determined by the Kjeldahl method on an accurately weighed (1 0.0001 gram) sample of approximately 0.1 gram . The percent total nitrogen was determined on a sample before extraction, after extraction for 24 hours, and after extraction for 48 hours. The results are given in Table VIII. Table VIII The Effect of Extraction on the Nitrogen Content Percent Total Percent Total Percent Total Sample Nitrogen Nitrogen Nitrogen Number Before Extraction After 24 Hours After 48 Hours 1M 7.45 4.96 4.89 5M 7.79 6.54 6.59 4M 7.86 6.50 6.62 It can be seen from the results in Table VIII that ex- traction does remove some nitrogen-containing substances and.the ammonia derivatives of poly-(maleic anhydride co Styrene) reach a constant nitrogen content at least after Ekxxhlet extraction for 24 hours. .__ .__ l ._‘.f .. 7 A- 44 BY-IRCDUCTS FRCM ATNCNIA TREATKENT CF ACETCNE Gaseous anhydrous ammonia was passed into acetone in an attempt to see if the colored products formed during the ammonia treatment of the copolymers were due to the acetone reacting with the ammonia. Three hundred milliliters of acetone were placed in a ground glass, three neck, round bottom, 500 milliliter flask equipped with a reflux condensor, a mechanical stirrer, and a gas inlet tube. Gaseous anhydrous ammonia was pass- ed through the acetone for 6 hours with constant stirring. There was no observable reaction or change of color. at. . . ‘0’ Pu" ‘-‘l§.l-wk_..c“_—. - I .A: 45 TOTAL NITROGEN DETERNIRATICN CF ANNONIA TREATED COFCIYTEPS CF NALEIC ANEYDRIDE AND STYRENE The total yercent nitrogen in the ammonia derivatives of poly—(maleic anhydride co styrene) was determined by the Kjeldahl method using an accurately weighed (i 0.0001 gram) sample of approximately 0.1 graml7. The results are shown 5 in Table IX. - 3 4b HIGH FREQUENCY TITRATIONS OF AMMONIA TREATED POLY-(MAIEIC ANHYDRIDE CO STYRENE) Previous experiments showed that high frequency ti— trations are a valid method for analyzing the percent am- monium nitrogen in the ammonium succinamate (See page 51 vide infra). Therefore, it was concluded that this method could be used to determine the percent ammonium nitrogen in the ammonia derivatives of poly-(maleic anhyd— ride co styrene). Accurately weighed (i 0.0001 gram) samples of approx- imately 0.1 grams of the ammonia derivatives were dissolved in distilled water. The dissolved samples were titrated directly with 0.1000 N HCl. The titration was followed with a high frequency titrimeter and a Beckman glass electrode pH meter. The method of calculation for percent ammonium nitrogen is given on page 5L. A typical titration curve is shown in Figure 10. The results are given in Table IX. Table IX Percent Total Nitrogen and Percent Ammonium Nitrogen in Ammonia Derivatives of Poly—(maleic anhydride co styrene) Percent Theoretical Percent Theoretical Sanmde Total Percent Total Ammonium Percent Ammonium ZNumber Nitrogen Nitrogen Nitrogen Nitrogen 1M 4.96 11.9 2-77 5.95 am 5.54 11.9 2.72 5.9 4m 6.50 11.9 2.75 5.9 5M 4-59 11.9 5.59 5.95 em 4.80 11.9 5.04 5.95 7M 5.50 11.9 2.91 5.95 am 5.54 11.9 2.84 5.95 Figure 10. ”A High Frequency Titrineter Dial 47 0 g 0 1L: 3 1 T L {2‘ n “1' 9 +2 I High Frequency Titration of Ammonia Derivatives of Poly-(maleic anhydride co styrene) fl‘? ‘5 Sample 7M 4 O 4:" -—®—— High Frequency Titration Curve A -—~-- pH Curve 0 49‘ 9 1m 4:: Carboxylate EF::E) 4 4-2 °. ‘N 1 .1 1 1 1 1 3 0 <3 0 ° 0 Q :5 03 3 77' "A o I]: (mlS) H C 1 Volume of 0.1000N MOLECULAR WEIGHTS OF THE AUMONIA DERIVATIVES OF POLY—(MALEIC ANHYDRIDE CO STYRENE) The molecular weights of the ammonia derivatives of poly-(maleic anhydride co styrene) were determined using a Mechrolab Vapor Pressure Osmometer. The determinations were carried out in water solution. A sample calculation of molecular weight is shown on page 11. A typical curve is shown in Figure 11 and the results are listed in Table X. Table X Molecular Weights of the Ammonia Derivatives of Poly—(maleic anhydride co styrene) Number Average Number Average Molecular Sample Molecular Weight of Weight of Copolymer fromiflrufl1 Number Ammonia Derivative Ammonia Derivativefiflas Prepared 4M 1,100 12,900 5M 1,640 3,540 7M 856 9,200 8M 1,590 6,640 Figure ll. l1 Vapor Pressure Osmometer Molecular 0 Weight Determination 0 -:§ Ammonia Derivative of Poly- (maleic anhydride co styrene) Sample 4M q 0 dci n 9 “§ 0 "9 l k i 1 1 I t g m “‘- 3 3 “Q: ‘3. ‘63 ’lR/c J (:OnCerdWwiTUDH Gardnus/lifer) SO INFRARED SPECTRA Infrared spectra were recorded for the samples of the ammonia derivatives of the poly-(maleic anhydride co styrene). A mineral oil mull sample was employed to record the 2000 cm.-1 sample was used to record the 4000 cm.— to 750 cm.-1 range and a Flurolube mull l to 1250 cm."1 range. Since the infrared spectra for the ammonia derivatives of the 00polymer were, qualitatively speaking, identical a representative spectrum is illustrated in Figures 12 and 13. The instrument settings are placed beside the spectra. Figure 12. Flurolube Null 5 Minute Scan Slit 5 The Infrared Spectrum of the Ammonia Derivative of Poly-(maleic anhydride co styrene) Sample 8M QO AbSOPbQHCE Qooo |§Oo QEOO (L‘A‘rL—l) 5000 Wave Num l 3500 Vs Figure 15. The Infrared Spectrum of the Ammonia Derivative of Poly- (maleic anhydride co styrene) Sample 8M 4 .1 Mineral Oil Mull 5 Minute Scan Slit 5 A a emf—’7 (l0 Absorbdnce Boo Woo Rea N00 law 13, m 1.. r“ Wave DISCUSSION The color which was formed when the poly-(maleic an— hydride co styrene) was reacted with gaseous ammonia in ace- tone could be due to the reaction of the acetone with am- monia. Ammonia reacts with ketones to form imines, which are stable only in solution and form trimers or more complex molecules when their isolation is attemptedgo. CH5 H+ CH5 :;c:0 + NH5 . _a H20 + ;0:NH-_ >trimer CH5 CH5 The acid which is required to catalyze the formation of the imine could very well have come from acid impurities in the anhydride c0polymer21. The color is probably due to the formation of complex molecules which are formed when the solvent is removed by drying/since the color does not appear to any great degree until the ammonia derivative is dried. Since the color was more intense when the reaction was exposed to light, it leads one to believe that the formation of these colored products is enhanced by light. The fact that ammonia derivatives prepared in tetra- hydrofuran were white supports the argument that the form- ation of these colored substances is characteristic of a reaction involving acetone. Since these colored by-products contain nitrogen if they originate from imines,it would be expected that the total nitrogen content of the ammonia derivative would de— crease when some of the colored by-products are removed by Soxhlet extraction. This was found to be the case (See page 45). Because this thesis was concerned primarily with developing a technique for preparing the ammonia derivatives of poly-(maleic anhydride co styrene) and not investigating the reaction of acetone with ammonia to form imines and other complex molecules no further study on the composition of the colored matter was carried out. A 100 percent reaction of the copolymer to form the half ammonium salt half amide would yield a product which would have a total nitrogen content of 11.9 percent. None of the poly—(maleic anhydride co styrene) which was treat- ed with ammonialmui 11.9 percent total nitrogen. Apparently not all the anhydride rings in the copoly- mer are available for reaction with the ammonia at any given time. This would appear reasonable since the polymer chains are probably coiled in soluticmzand some of the an- hydride rings stereically protected from the ammonia. Once the gel precipitate begins to form one would expect that some of the anhydride rings in the copolymer would be shielded by adjacent polymer molecules. If all the anhydride rings were available for reaction with the ammonia a precipitate should form almost immediately because of the electrolytic properties of the ammonium salt part of the copolymer molecule. However, precipitation does not begin to occur until ammonia has been passed into the solution for at least 20 minutes. , There does appear to be some correlation between the length of time the 00polymer is reacted with gaseous am- monia and the percent total nitrogen. It can be seen from Table VII and Table IX that the longer the gaseous ammonia ‘was allowed to pass through the reaction mixture the high- eI'the percent total nitrogen.in the product. The exception to this was sample IN. I would point out that this part— icular experiment was carried out while exposed to light and a considerable amount of colored material was formed in the final product. The same 00polymer (Resin 7000A) was reacted with ammonia while protected from light (Sample 4M). In this case the percert total nitroren does correlate with time of reaction. In samples 5M and 6N there was a greater percent of ammonium nitrogen than non ammonium nitrogen (Total ni- trogen - ammonium nitrogen = non ammonium nitrogen). Cne explaination of this may be that some hydrolysis of the anhydride ring to form the dicarboxylic acid took place prior to the reaction with ammonia. The water which hydrolyzed the anhydride ring could have come from two sources. The first possibility is the reaction of acetone with ammoniago. CH 5‘0—0 m: H+ CH5\ __ 5 The second possible source of water would be from the con- densation products of acetone22. CH CH CH CH 5\_ base .5 C55 .5 (EH; 2 C—0 ____, CH—CmCHr- =0—9 CH—CZCH—C=0 + H 0 CH? 5 a d 5 2 The dicarboxylic acid then could have reacted with ammonia to form the diammonium salt. ———CH-—-—- CH— — CH -—CH — —- CH —— CH — l H O - / \ _ NH / x _. : : 2 O—C C—0 5 OTC C-0 0 \o/C 0 ——+ ‘0H Ho/ —’ \oma H 1:0 The percent ammonium nitrogen decreases as the reaction time increases. A possible explaination for this behavior 0 would be the formation of the imide’. \D Q) -—— CH- CH-—- -——CH~———CH-—- —-CH——-CH—— ' ' -H 0 __ __ ._ = :; 2? 0:0 C—O O—C C—O NHOH 0 (I: ('10 a I, J. , \1/ + 4 03314 Ox‘m4 OF1'134 £ng DVH Normally, however, these reactions to form the imide re— quire much higher temperatures than were attained under the reaction conditions7’22. The reactions carried out in tetrahydrofuran yielded ammonia derivatives which had approximately twice as much percent total nitrogen as percent ammonium nitrogen. This would indicate that the product is the half ammonium salt half amide of poly-(maleic anhydride co styrene). —-~ CH -— CH2—-————-b ecu—— CH ' 020’ >020 ,9; ‘01-2134 11 m n Since tetrahydrofuran is inert in the présence of gaseous ammonia the possibility of water forming by condensation reactions is eliminated. The absence of the colored substances and the reason- able nitrogen analysis when the copolymer is reacted with gaseous ammonia in tetrahydrofuran indicates that the side reactions occuring in acetone have been eliminated by the use of tetrahydrofuran. Molecular weights determined for the ammonia derivatives of the various samples of poly-(maleic anhydride co styrene) are considerably lower than the molecular weights of the original copolymers. The reason for this may be that fractionation-occurs. Fractionation would occur if the formation of the ammonium salt takes place at the same rate regardless of the size of the molecule. If this is the case,the low molecular weight fraction would acquire a greater percentage of ionic character in a given time. \n \3 Thus the low molecular weight fraction would precipitate out first. Future work investigating the molecular weight of ammonia derivatives precipitated in a given time inter- val would be interesting (Eee Table X). The interpretation of the infrared spectrum of poly— (raleic anhydride co styrene) has been discussed by Curticeé. The infrared spectrum of poly-(maleic anhydride co styrene) (See page 17 of this thesis.) was compared to the infrared spectra of the ammoria derivatives of the poly-(maleic an- hydride co styrene) (See page 48?)23’2#’25. Three new bands were observed in the ammonia derivatives of the copolymer (Figures 12 and 13). A band at 1550 cm..-1 can be attributed to asymmetrical stretching of the car- boxylate group. A strong absorption occured at 1650 cm."1 which was due to the 0:0 in the primary amide. This band is refered to as the Amide I hand. The third band appear- ed at 3150 cm.-l. This was a weak band and not readily observable in all the ammoniackrivatives. This absorption is assigned to both the ammonium ion and primary amides. A band at 1220 cm."1 the poly-(maleic anhydride co styrene) was completely elim— due to the cyclic arhydride in inated in the spectra of the ammonia derivatives of the copolymer. Two other bands which are due to cyclic an— hydrides were observed in the spectra of the ammonia de— l and 1850 cm.-1. Since none of the copolymers treated with gaseous ammonia reacted rivatives. These were at 1775 cm.- 100 percent, it is to be expected that absorption due to the anhydride ring would be present in the infrared spectra of the ammonia derivatives. The Spectra of the ammonium succinamate (See page 55 and Figures 8 and 90 when compared to the spectrum of succinic anhydride (See page 55 and Figures 8 and 9) also ’3 revealed three new bands25’LQ’25. \fl As in the case of the ammonia derivatives of the COpolymer the bands occured at 1650 cm.’1, 1550 cm.’1, and 3150 cm.‘l. These absorptions can be assigned to the primary amide, the carhoxylate ion, and the primary amide or ammonium ion respectively. All the characteristic cyclic anhydride bands (1220 cm.-l, 1775 cm.-1 the spectrum of succinic anhydride were not observed in the spectrum of the ammonium succinamates. , and 1850 cm.—l) present in Since imides fbsorb in the save region as cyclic -1 o . -1 . . .. anhydrides (1770 cm. to 1775 cm. ) it was imp ssiole to draw any conclusions concerning the formation of imides from the infrared spectra. Pa RT E PCLYMALEIC ANKYDRIDE \J'l vfi \l. . J\ C) PREPARATION CF POLYNALEIC ANHYDRIDE The preparation of polymaleic anhydride has been re- portedlg. The homopolymerization of maleic anhydride was carried out in a ground glass 250 milliliter round bottom flask equipped with a magnetic stirrer, a reflux condenser, and a gas inlet tube. Approximately 0.5 moles of maleic anhydride was dis- solved in 150 milliliters of benzene and the polymerization initiated with 5 percent benzoyl peroxide, based on the weight of the monomer. The polymerization reaction was continued for 64 hours under a continuous flow of prepur- ified nitrogen gas. After 15 to 20 minutes the solution turned a dark red and then eventually almost black. The dark brown precipi- tate which resulted was filtered mysuction, washed with benzene and then dried in vacuo. The homopolymer was subjected to Soxhlet extraction for 72 hours and dried again in vacuo. The polymerization was repeated with 150 milliliters of 1-4 dioxane as the solvent. A dark brown precipitate was formed in this case also. After the Soxhlet extraction and drying the homOpoly- mer prepared in benzene was light brown and the homopolymer prepared in dioxane was light pink. Number average molecular weights determined with the Mechrolab Vapor Pressure Csmometer using acetone as a sol- vent showed that the polymaleic anhydride polymerized in benzene had a molecular weight of 1050. The homopolymer prepared in dioxane had a molecular weight of 691. n1 HIGH FEBRUEECY TITRATICK CF PCllhALEIC ANHYDRIDE l The percent maleic anhydride in polymaleic anhydride was determined by accurately weighing (i 0.0001 gram) a sample of approximately 0.1 gram. This sample was then re- fluxed in absolute methanol until all the honopolymer dis— solved. The product formed by this esterification isl4 qH———-qH ' 0==C 0==0 I OH OCH5J n This was treated with 15.00 milliliters of 0.1000N NaCH and titrated with 0.1000N HCl. The titration was followed with a Beckman glass electrode pH meter and a . . . 14 l . high frequency titrimeter ’ 5. Sample calculations are shown on page 14 and a typical titration curve is shown in Figure 14. The results are given in Table XI. Table XI The Percent haleic Anhydride Noiety in Polymaleic Anhydride Experimental Theoretical Preparation Percent Maleic Percent haleic Sample Solvent Anhydride Anhydride Polymaleic Anhydride Dioxane 96.5 100.0 Folymaleic Anhydride Benzene 98.5 100.0 Figure 14. Carboxylate ‘é:/.group High Frequency Titration of Polymaleic Anhydride (Dioxane) Half Ester Technique L No.0 “4.0 042 m ~ (am. - 613 >— i‘iiii“. Rossini—meg T!“ Wit-)6“ Dial J / 1'1"": \- d 3 N‘- N WI! 1 I .~I\‘ ’I' J" Volume OF 0.1 65 AriCNIA DFRIVATIVE CF P01YhALEIC ANEYDRIDE The half anide half ammonium salt of the polymaleic acid was prepared by passing ammonia gas into a ten percent (weight/volume) solution of the polymaleic anhydride in tetrahydrofuran. The reaction was carried out in a 250 milliliter ground glass, round bottom flask equipped with a magnetic stirrer, a reflux condenser, and a gas inlet tube. The reaction was carried out at room temperature with constant protection from light. As soon as the amronia gas was passed into the solution, a dark brown precipitate was formed. After 5 hoursjthe reaction was stopped and the chocolate brown precipitate vas removed by centrifugation. The supernatant solvent was discarded and the precipitate was washed with tetrahydro— furan in the centrifuge tube three times. After the last washing and centrifugatiorfthe precipitate was dried in vacuo. The precipitate was still chocolate brown after drying. The dried product was then subjected to Soxhlet ex- traction with tetralydrofuran for 72 hours. The tetrahydro- furan remained clear and colorless throughout the extract- ion. When the extraction was completed)the product was again dried under vacuum. The final dried product retain- ed the chocolate brown color. 64 NITROGEN ANALYSIS OF THE AMMONIA DERIVATIVES OF POLYMALEIC ANFYDRIDE The total nitrogen content of the ammonia derivatives of polymaleic anhydride was determined by the Kjeldahl methodl7. The ammonium nitrogen was determined by dissolving an accurately weighed (i 0.0001 gram) sample of the ammonia derivative of approximately 0.1 gram in distilled water. The dissolved ammonia derivative was then directly titrated with 0.1000 N HCl. The titration was followed with a high frequency titrimeter and a pH meter. A typical curve is shown in Figure 15 and the results are given in Table XII. The method of calculation for the percent ammonium nitrogen is given on page 51. Table XII Percent Total Nitrogen and Percent Ammonium Nitrogen in the Ammonia Derivatives of Polymaleic Anhydride Percent Theoretical Percent Theoretical Sample Total Percent Total Ammonium Percent Ammonium Number Nitrogen Nitrogen Nitrogen Nitrogen 9‘ 17.2 20.9 8.67 10.5 10‘ 16.7 20.9 8.52 10.5 ‘ The sample number 9 designates the ammonia derivative of the homopolymer prepared in dioxane and 10 refers to the derivative of the homOpolymer prepared in benzene. Figure 15. Moo High Frequency Titration of the Ammonia Derivative 4 of Polymaleic Anhydride Sample 10 4 q q d Carboxylate . ‘F~*group i 1 .4 l J 1 J l L l J l 1 o 0 c Q .3, «3; 3 .3: d a; Hlj‘H Frequehgu Kirk‘rr-th-x‘ DKO.\ .z J Ike 6.0 3.0 /0.0 ’va “(,0 3 .' .x I: |. iT‘ ‘ L '2 .\I 4m 13 Q0 ! Q \J g: 7". ‘/\ I‘fi‘ ‘\ ! t ‘ } I" J ' \' i .' ‘\ \hD‘LLTHEi CA 66 DISCUSSION The preparation of a homopolymer of maleic anhydride has been repertedlg. The polymerization of maleic anhydride was attempted and the products which resulted were found to lave high enough molecular weights to show that the maleic anhydride did polymerize (See page 59). The composition of the polymers was determined by high frequency titration and found to beIVIOO percent maleic anhydride moiety (See Table XI). The homopolymers cf maleic anhydride which were pre- pared had relatively low molecular weigh s. This low molecular weight may reflect the reluctance of the maleic anhydride monomer to react with a free radical of similiar structure26’97. The ammonia derivatives of the polymaleic anhydride were found to be half ammonium salts half amides (See Table XII). The theoretical percent total nitrogen for a com- plete reaction of the polymaleic axhydride with the gaseous ammonia is 20.9 percent. Neither of the two homopolymers which were reacted with gaseous amnonia reacted completely. The lower molecular weight horopolymer of maleic anhydride had a higher percentage of total nitrogen which may be due to greater accessibility of the anhydride ring in the lower molecular weight homopolymer. PART F CONCLUSIONS 6. CCNCLUSIONS Relatively low molecular weight poly—(maleic anhydride co styrene) can be prepared in dimethoxymethane solvent with 0.# to 0.8 percent benzoyl peroxide initiator concentration. 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