Preparation of 6-t-butyl alkyl-substituted phenols

A process for preparing 6-t-butyl alkylphenols from alkylphenols in high selectivity is disclosed, wherein the starting alkylphenol is a 3-alkylphenol or a 2,3-dialkylphenol and the alkyl group is a C1-C6 primary alkyl. The process comprises reacting a 3-alkylphenol or a 2,3-dialkylphenol, wherein the alkyl group is a C1-C6 primary alkyl, with isobutylene in the presence of a catalyst, which is a sulfonated polystyrene crosslinked with a divinylbenzene, at a temperature of 50 DEG to 90 DEG C.