Effects of Catalyst and Solvent on the Chloromethylation of Non-crosslinked Polystyrene

On the chloromethylation of polystyrene in chloromethylether (CME) by Friedel-Crafts catalysts, effects of catalyst and solvent on the reaction rate and on the formation of crosslinkingwere studied. For the low concentration of polystyrene in CME (0.873mol/l), the chloromethylationreaction at 40°C by anhydrous zinc chloride, aluminum chloride and stannic chloride ascatalyst were found to be of first order at the initial stage of reactions. In the case wherezinc chloride was used as reaction catalyst, the chloromethylation rate is slower than othertwo cases. The rate constants obtained in the former case were proportional linearly to theamount of catalyst, while in the latter two cases they were proportional logarithmically totheir catalyst concentration. Crosslinking formation in zinc chloride catalyzed reaction is much smaller than those inother two catalyzed reactions. But in all three cases, the relationships of degrees of chloromethylationand catalyst concentrations to the crosslinking formation rates was linearlyproportional. The presence of ethylenedichloride as solvent has influenced especially on the aluminumchloride catalyzed reaction to decrease the chloromethylation rate and to promote remarkablyits crosslinking formation.