In a process for producing cumene, benzene and a C3 alkylating agent comprising isopropanol are supplied to an alkylation zone comprising a molecular sieve alkylation catalyst under alkylation conditions such that the isopropanol reacts with the benzene to produce a reaction product comprising cumene. Subsequently, the supply of benzene and C3 alkylating agent to the alkylation zone is ceased and a gaseous stripping agent is supplied to the molecular sieve alkylation catalyst under conditions effective to remove nitrogenous impurities deposited on the catalyst during the preceding alkylation reaction. The supply of benzene and C3 alkylating agent to the alkylation zone is then reinitiated.