Abstract
4-Chlorbmethylstyrene has been synthesised, by a known route, from p-tolunitrile. This monomer has been polymerised by initiation with azobisisobutyronitrile. Polystyrene has been chloromethylated to yield a soluble polymer containing one chloromethyl group substituted in each benzene ring. Substitution, which was slightly in excess of monochloromethylation, has been shown to be largely para to the main chain. The polymers were characterised by determination of their intrinsic viscosities in toluene at 25°. Chloromethylated polystyrene has been reacted with triethylphosphite and several tertiary amines to yield polymers containing benzyldiethyl-phosphonate and benzyltrialkyl ammonium groups respectively. The second-order rate constants for the reaction between triethylamine and benzyl chloride, cuminyl chloride, the chloromethyl polymers and a styrene: 4-chloromethylstyrene copolymer in benzyl alcohol at 75° have been determined. The rates of the polymeric quaternizations progressively fall after about 25% reaction due to the formation of electrostatic charges on the macromolecules. The values of the rate constants are unaltered by changes in polymer molecular weight, and (initially) by spacing out the reactive groups by inert styrene units. The deceleration is similar for both poly(4-chloromethylstyrene) and chloromethylated polystyrene. A similar, though less marked, fall in the rate of quaternization of poly(4-chloromethylstyrene) with triethylamine at 75° in sulpholane was observed, but in dimethylformamide solvent no deceleration occurred. The kinetic results are discussed in relation to polar and solvation effects and to the structure of the macromolecules.