The chemical structure of polysylvan

Chemical structure of polysylvan

65

(5) T h e s t r u c t u r e of the acid residue also affects t h e p o l y m e r i z a b i l i t y of t h e v i n y l a l k y l esters of d i c a r b o x y l i c acids, b u t in a n opposite m a n n e r : t h e adipic acid esters p o l y m e r i z e m o r e r a p i d l y t h a n those of t h e succinic a n d glutaric acids. Tra~slated by V. ALFOR1) REFERENCES

1. 2. 3. 4. 5. 6. 7.

K. W. EBERSBACH and K. H. MICHL, Kunststoffe 49: 513, 1959 M. F. SHOSTAKOVSKII et al., Zh. prikl, khim. 30: 816, 1957 C. E. BARNES et al., J. Amer. Chem. Soc. 72: 210, 1950 V. KARNOJITZKY, Chimica e industria 81: 895, 1959 A. I. VOLKOVA, M. M. KOTON et al., Vysokomol. soyed. 2: 805, 1960 F. GRABAK, Coll. czeehoslov, chem. commun. 25: 829, 1960 H. BRAUER, Rukovodstvo po preparativnoi neorganicheskoi khimii. (Directions for Preparative Inorganic Chemistry.) M., 213, 1956 8. G. N. FREIDLIN, S. M. ZHENODAROVA, N. V. FOMINA and A. P. CHUKUR, Zh. obshch. khim. 32: 795, 1962

THE CHEMICAL STRUCTURE OF POLYSYLVAN* K H . F . KHAIDAROV, A. A. ABDUVALIYEV a n d A. S. SULTANOV Institute of Polymer Chemistry, Uzb. S.S.R. Academy of Sciences (Received 18 December 1961)

I N [lJ it w a s r e p o r t e d t h a t the m o s t p r o b a b l e s t r u c t u r e o f p o l y s y l v a n w a s

•

. .

•

This is s u p p o r t e d b y the ease of t h e r e a c t i o n in t h e 2, 5 f u r a n ring positions: f o r m a t i o n o f a n a d d u c t w i t h maleic a n h y d r i d e , o x i d a t i o n of f u r a n to maleie d i a l d e h y d e b y nitric acid in t h e presence of acetic a n h y d r i d e [2], a n d t h e f o r m a t i o n of maleie acid as a result of t h e o x i d a t i o n o f 2 , 5 - d i b r o m o f u r a n [3]. T o p c h i y e v , G o l ' d f a r b a n d K r e n t s e l [4], w h o c o m p a r e d t h e r e a c t i o n of t e t r a h y d r o f u r a n a n d p o l y s y l v a n w i t h sulfonyl chloride, a n d showed t h a t if s t r u c t u r e I is correct for the p o l y s y l v a n t h e n it is to be e x p e c t e d t h a t SO 2 w o u l d be f o r m e d b y r e p l a c e m e n t o f t h e chlorine a t o m s in t h e sulfonyl chloride b y the o x y g e n a t o m s f r o m t h e p o l y s y l v a n , as is o b s e r v e d in the ease of t e t r a h y d r o f u r a n . H o w ever, this w a s n o t found. Therefore, these a u t h o r s s u g g e s t e d t h a t t h e m o r e p r o b a b l e s t r u c t u r e o f p o l y s y l v a n is I I or I I I . • Vysokomol. soyed. 5- No. 7, 1012-1015, 1963.

66

KH. F. KHAIDARO¥et al.

To find out which structure was correct, we subjected polysylvan to ozonization followed b y degradation of the ozonidc by hydrogen peroxide. I f structure I were correct, formation of the methylvinyl polyester would be expected, COOH COOHCOOH COOHCOOH COOH

I

t--°l

I

CH3

o I I

!

o ~

I

CH3

....

CH3

which, on reaction with hydriodic acid, should give methyltartaric acid. However, the product obtained did not react with H I and remained an insoluble and infusable polymer, showing the absence of an ether bond in the molecule of the product of the degradation of polysylvanozonide. This means that the polymerization of sylvan is not the result of a transfer of a double bond to position 3,4 and cross-linking to positions 2, 5, which confirms Topchiyev's proposition that polymerization is probably due to one of the double bonds of the furan ring. Perhaps polysylvan has structure III. CHa

,i i, In this ease degradation of the polysylvanozonide should lead to the formation of an acctyl derived polymer of unsaturated oxycarbonie acid; COOtt OCOCI-I3 COOH OCOCI-I3 COOH OCOCI-I3

I

I

I

I

I

I

However we were not able to discover an aeetyl group in the product of the decomposition of polysylvan ozonide and, consequently, structure I I I was not confirmed. I f structure II is regarded as a correct one the ozonide should decompose with elimination and formation of the carboxy-polymericoxycarbonie acid: 0--0\

j

o

CH

[CH /

-- - - C - -

CI-I3 n

I J CH3

+nCO v

(iv)

n

We found that the ozonide degradation proceeds with vigorous evolution of carbon dioxide, which should not occur in the case of structures I and III. Determination of the hydroxyl and earboxyl groups showed that at each entry

67

Chemical structure of polysylvan

unit of the ozonide degradation product there is one carboxyl and one hydroxyl group. The I R absorption spectrum of the degradation product also confirms t h a t it contains hydroxyl groups, which are characterized by absorption bands in the 3400 cm -~ range. The strong absorption band 1702 cm -1 is dependent on C = O valence vibrations of the carboxyl groups and, finally, the absorption band of 1437 cm -1 and the slight step on the absorption band in the 2950 cm -~ range shows the presence of methyl groups* (see Fig.).

r

201

I

3200

I

I

I

Y

I

I ~'J

2400 f700 1300 Fmquenc#(cm-1)

I

BOO

,

Il¢ absorption spectrum of the ozonide degradation product. These data permit the assumption t h a t polysylvan has structure II. And indeed, the proximity of the m e t h y l group to a double bond has a marked effect on the strength of its u bond, which means t h a t sylvan is polymerized only because of the one C = C bond in the methylated carbon atom. EXPERIMENTAL

To study the structure of the polymer, polysylvan was used which had been obtained by the polymerization of sylvan in the presence 2 mole °/o of the complex ionic catalyst Sb[(CHa)2SiC12]2C1a. To remove the monomer and catalyst the polymer was reprecipitated from an acetone solution of distilled water, filtered and dried in vacuo at 50 ° to constant weight. Ozonization of polysylvan. 2 g of finely ground polysylvan were dissolved in 40 ml of dry chloroform and ozonized at 0 ° by passing a mixture of oxygen and ozone containing 2.5 to 3.5% ozone, at the rate of 50 to 60 ml/min. During the ozonization the polymer mixture first changed into a very viscous mass, which then gradually precipitated on to the walls of the vessel. The ozonization was halted because the solution turned blue, and after this the chloroform was distilled off at reduced pressure. Ozonidc degradation. The ozonide was degraded by heating it at 80 to 90 ° in a water bath with 30 ml 3 ~o solution of hydrogen peroxide. There was vigorous separation of carbon dioxide and formation of a brittle sponge-like mass. After this 10 ml of water was added and the water was distilled off in a vacuum of * The IR absorption spectra were taken by Yu. T. Tashpulatov and Yu. P. Pitiyev in the analytical laboratory of the Institute.

68

KH. F. KHAIDAROV et al.

10 mm at 40 °. The product remaining was treated several times in 10 ml of water and each time the water was distilled right off in order to completely eliminate traces of HC1 and formic acid formed as a result of the destruction of the chloroform in the process of ozonization. After the water had been removed a brittle, light yellow polymer remained. Determination of the carboxy group concentration in the ozonide degradation product was carried out b y titrating it in solution with dioxine, with an alcoholic alkali. The mean acid number of two determinations was 23.1. Determination of the hydroxyl group concentration was carried out according to the Verley method. The mean of two determinations was 17.1%. Determination of the aeetyl group concentration. A weighed sample of the polysylvan ozonide degradation product was put in to a 250 ml conical flask and then 25 ml 0.5N alcoholic solution K O H was added drop b y drop through a pipette. A check experiment was carried on simultaneously without a weighed sample. A counter flow condenser was connected to the flask and heated in a water bath for 3 hr, after which, without cooling, the contents of the flask were titrated with 0.5N HC1 solution until the rosy colour of the phenolphthalein disappeared. The determinations showed that the ether number was zero.

Counting the number of carboxyl and hydroxyl groups from the elementary units. For the elementary units H

I

...--C

CH 3 ]

I

C--...

the calculated concentration of hydroxyl groups was 16.6 ~/o (experimental 17-1%) and the acid number was 21.8 (experimental 23.1). Spectral analysis confirmed the presence of the carboxyl, hydroxyl and methyl groups and the absence of acetyl groups. CONCLUSIONS

Chemical and spectral studies of the product of polysylvan ozonide degradation has established that the sylvan is polymerized at the C----C bonds of the furan ring with a methylated carbon radical. Translated by V. ALFOI~D REFERENCES

1. V. V. KORSHAK, A. S. SULTANOVand A. A. ABDUVALIYEV, Uzb. khim. zh. 4 : 39, 1959 2. H. S. F R E N K and T. B. JOHNSON, J. Amer. Chem. Soc. 55: 4197, 1933 3. Yu. K. YUR'YEV, Prakt. rab. pc organicheskoi khim. (Practical Organic Chemistry Work.) 3, Izd. MGU, p. 181, 1961 4. A. V. TOPCHIYEV, Yu. Ya. GOL'DFARB and B. A. KRENTSEL', Vysokomol. soyed. 3: 870, 1961