Reactions of macromolecules. Part VIII. Kinetics of the alkaline hydrolysis of poly-(m-acetamidostyrene) and related amides
Two poly-(m-acetamidostyrene)s, the first approximately twice the molecular weight of the second, and a 2·35:1 styrene–m-acetamidostyrene copolymer have been prepared by acetylation of the corresponding m-aminostyrene polymers. Rates of hydrolysis of the amido-groups of the above polymers, and of acetanilide and N-acetyl-m-cumidine, in benzyl alcoholic potassium hydroxide at 145°, have been determined. Second-order rate constants for these amides, in the order named, are 5·32, 5·53, 10·1, 20·1, and 17·9 = 10–4 l. mole–1 sec.–1. For the homopolymers it is inferred that change in molecular weight has little effect on the rate of hydrolysis, and that the rate is reduced by intramolecular hydrogen bonding; in the copolymer such bonding is lessened by spacing-out with inert styrene units.