Reaction of cellulose nitrate with carboxylic acid chlorides

Reaction of NC with carboxylie acid chlorides

1429

12. Yu. K. YUR'EV, Praktichoskie raboty pc organichoskoi khimii (Practical Papers on Organic Chemistry). p. 58, Izd. MGU, 1961 13. I. P. LOSEV and O. Ya. FEDOTOVA, Praktikum pc khiraii vysokopolimornykh soyedanenii (Practical Handbook on the Chemistry of High Polymors). p. 98, Goskhimlzdat, 1962 14. HOUBEN-WEYL,Metody organicheskoi khlmii (Methods of Organic Chomistry). p. 191, Izd. "Khimiya", 1967 (Russian translatiou)

REACTION OF CELLULOSE NITRATE WITH CARBOXYLIC ACID CHLORIDES * ilk. I. POLYAKOV and V. V. SMAGIN Irkutsk Institute of Organic Chemistry, Sibeman Sectmn of the U.S.S.R. Academy of Sciences (Received 3 November 1970)

DESPITe. the fact t h a t it has been shown in the literature t h a t homolytic and heterolytic decomposition of nitrate esters is possible under the influence of inorganic acids [1], no systematic studies have yet been conducted on this question. The fact, shown in reference [2], t h a t bromal, chloral, sulphur dioxide and malonitrile react with cellulose nitrate (NC) indicates t h a t other compounds t h a t are considerably less electrophilic t h a n mineral acids can take part in such reactions. Studies in this area are continued in the present paper, where the reaction of NC with acetyl, trichloroacetyl and benzoyl chlorides is discussed. In order to eliminate the possibility of reaction occurring between hydroxyl groups in NC with the acid chlorides we used aeetylated cellulose nitrate (ANC) [2] and cellulose trinitrate (TNC [3], which are free from hydroxyl groups. Preliminary experiment showed t h a t elimination of nitrate groups does not occur at an appreciable rate when ANC is treated with acetyl chloride (AC). W h e n the reaction is carried out in the presence of catalytic amounts of BF 3. •O(C~Hs) ~ rapid denitration of ANC and TNC does not occur with freshlyprepared AC, whereas if the reagent is stored for several months it reacts readily under similar conditions (Table, experiments 1-5). The most probable products with a co-catalytic effect t h a t could be formed when AC is stored, are acetic anhydride and hydrogen chloride. I t was found t h a t neither acetic anhydride nor a 4.6% solution of HC1 in ethyl acetate brought * Vysokomol. soyed. A14: No. 6, 1278-1282, 1972.

]430

A . I . POLYAKOVand V. V. SMAGI~

about removal of nitrate groups from A_NO in the presence of B F a. O(C~tts) 2. On the other hand in the reaction of AC with ANC the reaction, occurs readily in the presence of B F 3. O(C2Hs) 2, HC1 and acetic anhydride (Table, experiments 1 and 2). This suggests that both HC1 and acetic anhydride take part in the reaction. According to a suggestion made previously [2] the reaction can be represented as follows (CH.CO)sO+HOl~CH.COOH-+-CHaCOCl C H s C O O H + BF." O(C.Hs). ~ [CH.CO0 •B F . ] - H + + (C.H5)20 *

/~-}-- +/N~oO- r ~NO'] A/R'COONO' Ill + BC| (i)

--~ IR-oc--Cll - - - K [CH3COO-BFs]H + 4~-20----C'---CI "" IR'

'l

J II

ROCOR' + CINO2 IV

I where R is the rest of ANC or TNC and R ' is CH3, CC18 or C6H5. Of the two possible ways of decomposition of the ortho-ester derivative II, according to reference [6] route B is the more probable, and this is in good agreement with the results of elementary analysis (Table, experiments 11 and 13)t. In view of the high polarity of the C--C1 bond, it is not possible without further s t u d y to exclude the possibility of production of compounds containing chlorine (Table, experiments 1, 2, 4 and 13) as follows +/oR//.O~Jl N~x~tO~

I~'~ONO~ + RCI

(2)

C R' U O Finally chlorine can be introduced b y scission of the 1,4-acetal bond of ANC under the influence of AC in the presence of BFs" 0(C~H5)2, as has been observed previously in the reaction of AC with cellulose and its derivatives [7]. Only if this is so can the formation of a labile C1--C1 bond in the course of splitting explain the fact that the main hydrolysis product is glucose. * According to reference [5] the reaction can follow a more complex route, with forma. tion of BFa" C2H~OH or BFs" H,O, which are strong acids. t In addition it is shown that benzyl nitrate reacts with AC (catalyst BFa.O(CsHs),, 97°, 15 hr), forming a mixture consisting, according to gas-liquid chromatographic analysis, of 54 ~o of benzyl acetate, 38 ~/o of benzyl nitrate and 8 Yo of unidentified products.

Reaction of NC with carboxylic acid chlorides

1431

R E A C T I O N OF N(~ WITH ACID CHLORIDES AT 9 7 °

A n a l rsis

Reaction mixture, g

C1

.4

1 2 3 4 5 6 7 8 9 10 11 12 13

0.2 0.2 0.2 0-2 0-2 0.2 0.2 0.2 1.0 1.0 1-0 0-2 0.2

5.5 5-5 5-5 5.5 5.5 4.0 4-0 20.0 20-0 15.9 9.7 9-7

0'05 0"O5 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0"05 0.05

0'04 0"04

0.03 0.03

1'4 b04 ).04 ).04

0.03 0.03 0.03

)-04

0.03

).04

0.03

1.5 3.0 1.5 3-0 5.0 5.0 3.0 3.0 6.0 6.0 1.5 1.5 9"0

1.82; 1.76 4.69; 4.60 0.45; 0 . 4 6 2.23; 2.26 Traces No 14.57; 14.65 13.93; 13.66 18-37; 18.39 16.03; 16-09 3.95; 4.01 1.33; 1.05 5.06; 5.59

N

1"59; 1"85 No l l ' 1 8 ; 11"163 No 6'58; 6"57 7'06; 7 ' 0 8 No Traces No No No 5.23; 5.35 No

0-1 0"16 0.23 0.16 a 0"2 0.18 ¢ 0-1 0"1 0"8 0-7 0.56 0"2 0.167

1) Found %: C 30'16; $0.32; H 3.38; 3.45; N 10.59; 10.86. C6ttTO~(OCOCHI)o.7(ONOs),.,. Calculated %: C $0-11; H 3"08; N 10.92. 2) R=CHI (experiments 1-5); CCIi (experiments 7-10); Cells (experiments 12, 13). In experiments 11 a mixture of CClsCOC1(4.9 g) and Ctf,COC1, (11-0 g) was used. I) Undistilled AC was used. *) Found %: C 37"98; 37.67; H 4.16; 4.02. C,HTOt(OCOCHl)~.bb(ONOgh.,(OH)0.os. Calculated %: C 37.64; H 4.03; N 6.76. ~) TNC used here [3]. e) Found %: C 47.25; 46.91; H 5-49; 5.69. C,H~O~(OCOCHa),. Calculated %: C 50-00; H 5.55. 7) Found %: C 63.09; 62.66; H 4-52; 4.89. C,HTO,(OCOCH,)0.7(OCOC,H~),.I. Calculated %: C 63.6; H 4.53.

The nitronium chloride formed by decomposition according to scheme (1) can, according to reference [8], form the beginning of a radical mechanism of the reaction, leading to the formation of acetates and of products of oxidation of cellulose RCH2ONO2+C1COCH 3 -~RCH~OCOCHs~-C1NO~ C1NO2-~CI'~-N02 ; CI'~-C1COCHa -~CHsCO'-~ C12 RCH2ONO~-~CI" -~RCH20"-~C1NO~ ; RCH20" ~-CHsCO" ->RCH20-~ COCH 8 RCH~ONO~-~RCH20"-~NO~; RCH20"~NO~-~RCHO~HNO2 [9] RCHO ~-NO2 ->RCOOH ~-NO In fact analysis of the product {Table, experiment 2) showed the presence of 3.4% of COOH groups. The low content of COOH groups is evidently due to the

1432

A . I . POLYAKOVand V. V. S~ozN

f a c t t h a t the oxides of nitrogen formed in the reaction can react with the excess A C as follows [10, 11] NaO~

. . . . . . .

OH3OOOl~

CHsCOCI

urlsuut)1~o~

(CHsCO)~O

2CHsCOONO~-F 60HaOOOl ->4(OHsOO) sO -{-2NOCI ~- 2Ol~ Some unexpected results were obtained when ANC and ThTC were reacted ~rith trich]oroacetyl chloride. The degree of substitution (a) with respect to 'OOOCCla groups, calculated from the chlorine content, was found to be consider.ably lower than a of the products of reaction with AC and benzoyl chloride. Elementary analysis shows that the end products of the reaction do not con$ain nitrogen (Table, experiments 7-10), and are completely soluble in dilute 1

I

I

I

I

I

I

I

I

I

I

I

I

f

I

I

I

I

38

3q

32

30

28

18

18

FI

12

801 2

I/~%~,1

r

80 O0 8O L/O

80 O0 80 #0

ltO 0

I

I

I

10 8 6 VxlO-~ crn-I

Infrared spectra of the reaction products. The figures on the spectra correspond to the sample numbers in the Table; la---sample 1 eon~ning 3~o of 1~ and 1~/o of C1.

Reaction of NC with carboxylic acid chlorides

1433

solutions o f alkalis (0.5 ~ N a O H ) , forming homogeneous, yellow solutions, like those f o r m e d b y monocarboxycellulose. After hydrolysis, analysis of t h e h y d r o l ysis p r o d u c t b y p a p e r c h r o m a t o g r a p h y , t o g e t h e r with t h e hydrolysis p r o d u c t f r o m a monocarboxycellulose (14.7% COOH), gave identical c h r o m a t o g r a m s . F u r t h e r m o r e t h e results of analysis of t h e p r o d u c t of reaction of AI~G w i t h a m i x t u r e of a c e t y l and trichloroacetyl chlorides (Table, e x p e r i m e n t 11) also confirm t h e high r e a c t i v i t y of ANC. T h e lack of c o n f o r m i t y with t h e previously established relationship b e t w e e n t h e r e a c t i v i t y of a reagent on t h e electrophilic s t r e n g t h o f t h e s u b s t i t u e n t at t h e reaction centre [2], is e v i d e n t l y due to sterie factors. T h e a b o v e e x p e r i m e n t a l results are in good a g r e e m e n t with t h e results o f infrared spectroscopic analysis. T h e p r e d o m i n a n t f o r m a t i o n according to s c h e m e 1 o f cellulose acetate as the main p r o d u c t (Figure, spectra 1, 2 a n d 11) is confirmed b y t h e increase in i n t e n s i t y o f t h e b a n d s in t h e 1750, 1240 a n d 600 cm -1 regions (OCOCH3 group). T h e b a n d at a b o u t 900 cm -1 (Table, e x p e r i m e n t s 1 a n d 2) can obviously be assigned to t h e m e t h y l e n e group [12]. T h e i n t r o d u c t i o n of t h e OCOCC1 a g r o u p in the reaction of trichloroacetylchloride with ANC and TIqC is confirmed b y t h e presence in t h e s p e c t r u m of the reaction p r o d u c t s (spectra 8 a n d 9) o f t h e two b a n d s at 680 a n d 845 cm -1, assigned to v i b r a t i o n s of the CC13 g r o u p in trichloroacyl residues [13]. Moreover the considerable change in t h e s p e c t r u m of these p r o d u c t s in t h e 1380 a n d 1420 cm -1 regions (levelling out of t h e 1420 cm -~ band) indicates changes t a k i n g place at the Ce a t o m of t h e cellulose unit ( - - C H 2 0 -> - ~ C O 0 - - ) [12]. T h e results of e l e m e n t a r y and infrared analysis show t h a t at first t h e r e a c t i o n follows r o u t e (1) a n d only after a certain induction period, during which t h e nitron i u m chloride accumulates, does t h e radical m e c h a n i s m become operative. I t was f o u n d t h a t the use of A1C1a , SnC14" ZnC12 and TIC14 as catalysts r e s u l t e d in considerable d e g r a d a t i o n and resinification of the reaction products, a n d HgCl~ a n d (C6Hs)~SnCI 2 did n o t catalyse t h e reaction u n d e r t h e given conditions. EXPERIMENTAL

Nitrogen was determined by the Dumas method and carboxyl groups by the calcium acetate method [14]. Cellulose acetate-nitrate was prepared as in reference [2]. The white, fibrous product was soluble in AC, ethyl acetate, acetone and tetrahydrofuran, and insoluble in petroleum ether and trichloroacetyl chloride. Infrared spectrum: 1750, 1240, 600 cm -1 (OCOCHs); 1640, 1280, 840 cm -I (ONOz). Cellulose trinitrate was prepared from cotton fibre by the method of reference [3]. Infrared spectrum: 1640, 1280, 840 cm -1 (O1~O~). Reaction of cellulose acetate-nitrate with acetyl chloride (typical experiment). Cellulose acetate-nitrate (0.2 g was placed in au ampoule and 5.5 g of AC, 0.05 g of BFa-O(CzHs)s, 0.04 g of acetic anhydride and 0"03 g of methanol were added. The ampoule wa~ sealed and heated in a boiling water bath for 3 hr. After 5-10 min brown oxides of nitrogen were evolved. The reaction mixture was poured into dry diethyl ether or petroleum ether and the precipitate was filtered off, extracted with dmthyl ether in a Soxhlet apparatus for 10 hr and dried to constant weight over P20~ in vacuo at 80% The resulting white powder was soluble in acetone and ethyl acetate, contained 4"69~o of chlorine and was free from nitrogen. Yield 0-16 g.

1434

A. I. Po~rAxov and V. V. SMAGII~

ttydro~sis of the products was carried out by the method of reference [2]. Paper chromatographic analysis, by the descending and ascending methods, was carried out in the systems ethyl acetate-acetic acid-saturated aqueous boric acid solution (9 : 1 : 1) and n-butanol-acetic acid-water (4 : 1 : 5). The paper was from the Leningrad "Goznak" factory and the developers were potassium metaperiodate-benzidine and acid aniline phthalate.

CONCLUSIONS I t is s h o w n t h a t c a r b o x y l i c a c i d c h l o r i d e s r e a c t w i t h cellulose n i t r a t e s , w h e r e b y t h e p r e d o m i n a n t r e s u l t is r e p l a c e m e n t of t h e n i t r a t e g r o u p b y t h e a c y l g r o u p . A m e c h a n i s m of t h e r e a c t i o n is suggested.

Translated by E. O. p~T.T.TPS REFERENCES 1. R. BOSCHAN, R. T. MERROW and R. W. VAN DOLAN, Chem. Rev. 55: 485, 1965; R. A. SLAVINSKAYA, Zh. obshch, khim. 27: 844, 1957; R. BUSCKAN and A. LANDIS, J. Org. Chem, 25: 2012, 1960 2. A. I. POLYAKOV and L. N. SPIRIDONOVA, Vysokomol. soyed. B10: 637, 1968; (Not translated in Polymer Sci. U.S.S.R.) Izv. Akad. Nauk SSSR, ser. khim., 1562, 1969; M. F. SHOSTAKOVSKII, A. I. POLYAKOV, L. A. POLYAKOVA and N. A. LANDINA, Izv. Akad. Nauk SSSR, ser. khim., 2625, 1969; A. I. POLYAKOV and M. S. DOBRZHINSKAYA, Izv. Akad. Nauk SSSR, set. khim., 1919, 1970 3. A. BOUCHONNET, M. TROM:BE and G. PETITPAS, Compt. rend. 197: 63, 1933 4. K. HESS, W. WELTZIEN and S. MESSMF_~, Liebigs Ann. Chem. 435: 44, 1924 5. S. V. ZAVGORODNII, Zh. obshch, kbJm. 22: 1781, 1952; A. V. TOPi]HIEV, S. V. ZAVGORODNII and Ya. M, PAUSH]K1N, Ftoristyi bor i ego soyedineniya v organiehoskoi khimii (Boron Trifluoride and its Complexes in Organic Chemistry). Izd. Akad. Nauk SSSR, 1956 6. L. HESLINGA, G. J. KATERBERG and J. F. ARENS, Rec. tray. chim. 76: 969, 1957 7. H. S]~tAUP and E. GEINSPERGER, Monatsh. Chem. 26: 1905, 1969; K. HESS, W. WELTZIEN and S. M]BSSMER, Liebigs Arm. Chem. 485: 44, 1924 8. R. H. SHECHTER, F. CONRAD, A. L. DAULTON and R. B. KAPLAN, J. Amer. Chem. Soc. 74: 3052, 1952; J. BRAND and J. STEVENS, J. Chem. See. 629, 1958 9. Ye. D. KAVERZNEVA and A. S. SALOVA, Tzv. Akad. Nauk SSSR, ser. khim., 344, 1959 10. N. V. SVETLA]KOV, N. N. STEPANOVA and N. K. SKAFIGULLIN, Zh. org. khim. 5: 2246, 1969 11. O. DIELS and H. OKADA, Ber. 44: 3333, 1911 12. R. G. ZHEANKOV, Infrakrasnye spektry tsellulozy i eye proizvodnykh (Infrared Spectra of Cellulose and its Derivatives). Minsk, 1964 13. L. B ~ , ~ f r a k r a s n y e spektry sloztmykh molekul (Infrared Spectra of Complex Molectdes). Foreign Literature Publishing House, 1963 (Russian translation) 14. G. DAVIDSON, J. Textile Inst. 39: 59, 1948