Studies on performing chloromethylation reaction for polystyrene by micellar catalysis in aqueous surfactant solutions

This paper puts forward a new method to realize the chloromethylation of polystyrene (PS), and this is the micellar catalysis. The chloromethylation reactions of polystyrene (PS) were carried out in micellar catalysis systems, in which the CCl4 solution of polystyrene was solubilized in the micelle solutions of surfactants. The mechanism of chloromethylation reaction of polystyrene and the mechanism of the micellar catalysis were explored. The structure of chloromethylated polystyrene (CMPS) was characterized using FT-IR, and its composition was determined with Volhard method. The experimental results show that the micelle solutions of surfactants can solubilize polystyrene dissolved in CCl4, namely, polystyrene can be transferred into the micelle solutions of surfactants along with solubilization of CCl4. Micellar catalysis is an effective way to realize chloromethylation for polystyrene. The reaction between polystyrene and formaldehyde and hydrogen chloride consists of electrophilic substitution reaction and nucleophilic substitution reaction. The micellar catalysis of cationic surfactant was more effective than that of anionic surfactant, and this fact displays that the nucleophilic substitution step is a slower reaction step and it is probably the controlling step. Except the types of the surfactants, the structures of cationic surfactants also have effects on the efficiency of the micellar catalysis, and the longer the hydrophobic hydrocarbon chain of cationic surfactant is, the better its catalysis effect is.