206
Vol. 63
J. B. ANDELMAN, G. K. HOESCHELE AND HARRY P. GREGOR
METAL-POLYELECTROLYTE COMPLEXES. VI. PREPARATION AKD PROPERTIES OF A NEW POLYCHELATEPOLYVINYLMETHYLGLYOXIME BY JULIAN B. AND ELM AN,^ GUENTHE~R K. HOESCHELE AND HARRY P. GREGOR Contribution f r o m the Department of Chemistry of the Polytechnic Institute of Brooklyn, New York, N . Y. Recebved Julg SO, 1968
Polyvinylmethylglyoxime was prepared by treating polyvinyl ethyl ketone with ethyl nitrite and converting the a ketomonoxime to the glyoxime with hydroxylamine hydrochloride. The acid dissociation constants and some metallic ioii binding constants were determined in 4/1 dioxane-water solutions for the polymer and its monomeric analog, dimethylglyoxime. Using a modified Bjerrum technique, formation constants were calculated for the displacetnent of a proton from the chelate acid by the metallic cation. On this basis it was found that both the polymer and its monomeric analog bound u?i(II) to approximately the same extent; weaker binding was observed with both Nd(II1) and Pr(II1) for the polymer. Binding to Ni(I1) was weak relative to UOz++,but stronger than with the rare earth cations.
Previous papers2t3 in this series discussed the chelating properties of polymers. This contribution concerns itself with the synthesis and properties of n new polychelate, polyvinylmethylglyoxime (PMG), the polymeric analog of dimethylglyoxime. Experimental Preparation of Polymer.-The polymer was prepared by treating polyvinyl ethyl ketone with ethyl nitrite so as to add an a-oxime group to the carbonyl, followed by the addition of hydroxylamine hydrochloride to convert the carbonyl to an oxime. First, polyvinyl ethyl ketone was obtained by free radical polymerization of vinyl ethyl ketone a t 90" using 0.5% benzoyl peroxide as a catalyst. Ethyl nitrite was prepared by slowly adding a mixture of an aqueous ethanol solution (8.5y0 by volume; 125 ml.) and 22 g. of concentrated sulfuric acid to 32 g. of sodium nitrite dissolved in 125 ml. of 8.5% ethanol in water. The gaseous ethyl nitrite was passed for a period of one hour into a solution of 35 g. of polyvinyl ethyl ketone in 120 ml. of ethanol containing 2% (by volume) concentrated hydrochloric acid. The reaction temperature was maintained a t 40-50'. The resulting reaction mixture was agitated for an additional hour, and then added slowly with constant stirring to 700 ml. of water. After suction filtering and drying the resulting precipitate, a yellow-brown powder was obtained. As a chemical analysis indicated that only half of the theoretical nitrogen content was introduced, the nitrosation procedure was repeated and the polymer t,hen was found to contain 9.11 % nitrogen. A calculation indicated that 67.4y0of the monomeric units were converted to t8woprobable nitrosation products, I1 and I11
This reaction is analogous to the nitrosation of ethyl isopropyl ketone reported by Aston, et ul.4 They found that nitrosation occurred in both positions a to the carbonyl, the relative amounts of the two products depending on the reaction conditions. '4 mixture of 5 g. of the composite polymer ( I , I1 and I I I ) , 5 g. of hydroxylamine hydrochloride and 10.8 g. of anhydrous sodium acetate was refluxed for 5 hours in 100 ml. of absolute ethanol. In the course of the reaction the deep red solution became yellow and precipitation occurred. The cooled reaction mixture was poured into water with stirring and then centrifuged. The brown precipitate (forms IV, V and VI) was washed with water and dried under varuum. The 5 g. yield contained 14.99% nitrogen. A calculation indicates that a t this stage of the reaction, oxime formaqion took place with a yield of 84.7% of the theoretically poss!ble conversion. This polymeric product was soluble In dmyane, dioxane-water mixtures containing less thnn .50% water by volume, alcohol, dimethylformamide, pyridine, acetone and tetrahydrofuran. I t was slightly soluble 111 ethyl acetate and insoluble in ether, carbon disulfide, carbon tetrachloride, chloroform and water. Forms I , I1 and 111 all could have reacted with the hydroxylamine hydrochloride to give
r-CH2-Y
H-
IV
i
1
K=O
r
I
V
r,,2-7H1 C=N-OH
L
I
CHs An I
VI
11
I11
( 1 ) A portion of this work is ahstracted from t h e Dissertatiori of
Juliaii B. Andelitian to be submitted i n partial fulfilliiient of the requireiiients f o r the degree of Doctor of Philosophy in Cheniistry, Polytechnic Institute of Brooklyn. (2) H. P. Qregor, with L. B. Liittinger and E. R 1 . Loehl, THla J O U R N A59, L , 34, 3Gti, 559, 990 (1055). (3) G. I
