Benzene is known to be readily alkylated with alkyl halides, alkanols or alkenes in the presence of acid catalysts. This alkyation, however, occurs on the benzene ring even if the benzene were already substituted with an alkyl group. There would be a significant advantage to a process that could take a common solvent such as methylbenzene and alkylate it with methanol on the methyl side chain rather than on the benzene ring. The instant process provides such a process wherein methyl-substituted benzenes can be converted to ethylbenzene and styrene by alkylation with methanol.
It has been recognized by the art that alkali metal substituted zeolites can be useful for alkylating methylbenzene with methanol. See for example U.S Pat. No. 4,115,424, issued Sept. 19, 1978; Yashima, et al, J. of Catalysis 26, 303-312 (1972)., and Undland et al in "Catalysis of Organic Reactions", edited by W. R. Moser and published by Marcel Dekker, Inc. The instant process provides for an improvement over the use of conventional ion exchanged zeolites.
The term "alkali(ne-earth) metal" as used hereinafter refers to a metal selected from the group consisting of alkaline earth metal and mixtures of alkaline earth metal and alkali metal, that is, it refers to alkaline earth metal and includes one or more alkaline earth metals and to a mixture of alkali metal(s) and alkaline earth metal(s) containing at least one alkali metal and at least one alkaline earth metal.