Other

Serafima Borisovna Makarova

Valery Y Semeny

Ljudmila A Tikhonova

Jury A Leikin

Anatoly V Smirnov

Sergei Borisovich Savvin

Galina I Korelskaya

Galina Vladimirovna Myasoedova

Eleonora M Pakhomova

Alla Lvovna Bratslavskaya

Antonin P Polikarpova

Vera Ivanovna Seraya

Andrei A Ilinsky

Roman Yakovlevich Mushy

Olga N Vlasovskaya

The method for preparing cross-linked vinylaromatic polymers containing nitro groups having the general formula ##STR1## where R' is H, NO.sub.2, COOH, SO.sub.3 H, P(O)(OH).sub.2, or P(O)H(OH), m is from 60 to 99 and n is from 40 to 1, consists in treatment of the starting cross-linked polymers having the general formula ##STR2## where R is H, COOH, SO.sub.3 H, P(O)(OH).sub.2, or P(O)(OH), m is from 60 to 99 and n is from 40 to 1, with a mixture of an alkali metal nitrate and an acid agent, at a temperature from -5.degree. to 95.degree. C. The quantity of the alkali metal nitrate in the nitrating mixture is from 0.1 to 8 moles per mole of the starting cross-linked polymer. The method provides conditions for preparing cross-linked vinylaromatic polymers, containing nitro groups, having higher mechanical strength, high osmotic stability, and their volume in an ion-exchange column changes insignificantly as acid media are changed for alkaline, and vice versa.

Method for preparing cross-linked vinylaromatic polymers containing

In accordance with the present invention, a copolymerization product of N-vinylmethylpyrazole with a divinyl cross-linking agent has the following formula of its elemental unit: ##STR1## wherein R is CH.sub.3 in the position 3 or 5; A is a divinyl cross-linking agent, viz. divinylbenzene, diallylmaleate, ethyleneglycol dimethacrylate, diethyleneglycol dimethacrylate, triethyleneglycol dimethyacrylate; it has a sorption capacity with respect to the platinum group metals and silver: E.sub.Au = 420 to 785 mg/g of the sorbent E.sub.Ag = 320 to 450 mg/g of th sorgent, E.sub.Pd = 130 to 170 mg/g of th sorbent, E.sub.Pt = 180 to 230 mg/g of the sorbent and a swelling factor in water of 2 to 4 ml/g. The method for preparing said copolymerization product of N-vinyl methylpyrazole with a divinyl cross-linking agent according to the present invention comprises reacting N-vinylmethylpyrazole of the formula: ##STR2## wherein R is CH.sub.3 in the position 3 or 5, with a divinyl cross-linking agent, viz. divinylbenzene, diallylmaleate, ethylenglycol dimethacrylate, di ethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate in the pesence of a radicaltype initiator at 70.degree.-100.degree. C in a suspension medium, followed by isolation of the desired product.

Copolymerization product of N-vinylmethylpyrazole and divinyl

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Moscow, Russia

Serafima Borisovna Makarova