Shape-selective alkylation of biphenyl with propylene using zeolite and amorphous silica–alumina catalysts

Authors:  Venkat Ramana Rao Pendyala, Gary Jacobs, Wilson D. Shafer, Robert A. Keogh, Jungshik Kang, Dennis E. Sparks, Burtron H. Davis

Abstract:
The influence of zeolite structure for the alkylation of biphenyl with propylene was studied over various zeolites such as HY, HZSM-5, and dealuminated mordenite (DMOR), as well as amorphous SiO₂/Al₂O₃, in a stirred tank reactor. Biphenyl conversion was found to increase with reaction time for HZSM-5 and DMOR zeolites and reach a leveling off in 4 h, whereas for HY and amorphous SiO₂/Al₂O₃ a leveling off was reached within an hour. DMOR displayed the highest selectivity for 4,4 -diisopropylbiphenyl (4,4 -DIPB) even at temperatures as high as 300^◦C, whereas for HY, HZSM-5 and amorphous SiO₂/Al₂O₃ selectivities fell in the range of 10–35%; they were significantly lower than observed for DMOR. These differences in selectivity might be due to the structure and pore channels of the zeolites. DMOR was found to be an active catalyst, the selectivity for 4-isopropylbiphenyl (4-IPB) and (4,4 -DIPB) was high among isopropylbiphenyl (IPB) and diisopropylbiphenyl (DIPB) isomers, respectively, indicating DMOR possesses shape-selectivity. The selectivity of 4,4 -DIPB increased with time, while the corresponding selectivity of 4-IPB decreased for DMOR catalyst. Alkylation of biphenyl with propylene occurred with predominant formation of 4-IPB in the first step. 4-IPB is only a source in the second step of alkylation of biphenyl with propylene for the formation of 4,4 -DIPB, while 3-IPB does not participate in the formation of DIPB isomers.

Keywords:
Alkylation
Biphenyl
Propylene
Mordenite
Zeolites
Shape-selectivity

Published in: Applied catalysis A: General  (Volume 453, Pages 1-402, 26 February 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Shape-selective alkylation of biphenyl with propylene using zeolite and amorphous silica–alumina catalysts

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