Mechanism of aromatic transalkylation in ZSM-5

Journal Article · Sun Jun 01 04:00:00 EDT 1986 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(86)90357-X· OSTI ID:5269443

Santilli, D S

The ZSM-5-catalyzed transalkylation of ethylbenzene, which yields benzene and diethylbenzenes, occurs by acid-catalyzed cleavage of the ethyl group followed by addition of the ethyl group to another ethylbenzene. Xylenes transalkylate much more slowly because methyl groups are more difficult to cleave than ethyl groups due to their decreased carbonium ion stability. When a mixture of xylenes and ethylbenzene reacts, diethylbenzenes are produced preferentially to dimethylethylbenzenes if the ZSM-5 crystallites are in a size range that allows the disubstituted benzenes to diffuse out of the zeolite crystallites much faster than the trisubstituted benzenes. The dimethylethylbenzenes (produced by ethyl group addition to the xylenes) diffuse so slowly from the larger crystallites that the added ethyl group is cleaved and xylene exits, apparently unreacted.

• Research Organization: Chevron Research Co., Richmond, CA (USA)
• OSTI ID: 5269443
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 99:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
ALKYLATED AROMATICS
ALKYLATION
AROMATICS
BENZENE
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CATALYTIC REFORMING
CHEMICAL REACTIONS
HYDROCARBONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MINERALS
ORGANIC COMPOUNDS
PURIFICATION
REFORMER PROCESSES
XYLENES
ZEOLITES