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1011-eschange resins a s membranes and in granular form have been prepared by the copolyn~erization of divinylbenzene with various esters of p-styrenesulphonic acid and subsequent hydrolysis. T h e synthesis of the sulphonated styrene illonomers is described. Equilibri~l~n data for the sodium-hydrogen ion exchange on a resin prepared in this manner are discussed in terms of post~~lated variations of sulphonate group environment.

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Based on systematic investigation of mononitroimidazoles, selective polarographic and spectrophotometric methods for determination of nitrazole compounds in reaction mixture are proposed. It was proved that the selectivity is based on the different properties of the nitro group due to the effects of the nitro group position in the ring, the type and position of the other substituents and on the fact whether the compound is N-substituted or not. The proposed methods can be successfully used for monitoring the synthetic procedures and decreasing the number of experiments for optimization. Based on the anticipated and proved behaviour of the nitro compounds of pyrazole, novel mononitropyrazole derivatives were synthetized in a new way and with high yields. Applying the polarographic method it was discovered that during N-substitution of tautomeric mononitroimidazole and mononitropyrazole substrates other byproducts were obtained besides the main products and undesired isomers. The products were identified and then a correct and more complete N-substitution scheme could be given. Following quantitatively these N-substitution processes conclusions which directly concern the mechanism of reactions were drawn.