Production of alkyl aromatic hydrocarbons

摘要

Alkyl aromatic hydrocarbons useful as chemical raw material, solvents and the like are provided in high purity by hydrocracking of a fraction rich in alkyl aromatics and lean in aliphatic hydrocarbons over a particular zeolite catalyst associated with a hydrogenation/dehydrogenation component. The charge stock is characterized by substantial absence of benzene and lighter hydrocarbons. The technique is particularly well suited to production of maximum xylenes from a fraction containing higher boiling and lower boiling alkyl aromatics. Toluene derived from the hydrocracking reaction is disproportionated in the presence of hydrogen over a zeolite catalyst and the disproportionation effluent is processed through the same recovery train as the hydrocracked product.