PROCESS FOR THE PRODUCTION OF SIX TO EIGHT CARBON-ATOM AROMATIC COMPOUNDS

摘要

Certain acidic heterogeneous catalysts produce large yields of benzene, toluene and xylene from alkyl aromatics of at least nine carbon atoms by a mechanism different from the classical disproportionation reaction characteristic of acid catalysts. These catalysts are characterized by a zeolite of the ZSM-5 type or zeolite ZSM-12 or zeolite ZSM-21. The reaction has the unique function of providing aliphatic by-products of higher molecular weight than is to be expected by splitting side chains from benzene rings. Typically, aromatic mixtures so derived from such charge stocks have unusually low content of ethyl benzene, thus greatly simplifying separation of xylene isomers.