Alkyl transfer of alkyl aromatics with group viii metals on zeolites

Abstract

Abstract A process for the alkyl transfer of alkyl aromatics including contacting an alkyl aromatic feed material, such as toluene, with a catalyst comprising a precious metal of Group VIII, such as platinum, palladium, rhodium, ruthenium, etc., deposited on a zeolite base at a temperature of about 700* to 1,100* F, a pressure of about 0 to 2,000 psig, and a liquid hourly space velocity of about 0.1 to 10, and in the presence of hydrogen introduced at a rate of about 1 to 10 moles hydrogen per mole of hydrocarbon feed. Promoters selected from Group I, Group II, Group IV, and the Rare Earth metals of the Periodic System may be added to the catalyst. Deactivated catalyst may be periodically rejuvenated by discontinuing the introduction of aromatic feed material and purging with hydrogen and the catalyst can be reactivated by calcination in air. Where toluene is the feed, the alkyl transfer product may be distilled to separate benzene, toluene and xylenes, the toluene may be recycled to the alkyl transfer step, the xylenes may be crystallized to separate paraxylene from the remaining xylenes, the mother liquor from the crystallization step may thereafter be isomerized to readjust the para-xylene content and the product of the isomerization may be recycled to the crystallization zone.

Inventors

• 👤 Ronald A Kmecak
• 👤 Stephen M Kovach

Bibliographic Details