Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate

›› 2011, Vol. 19 ›› Issue (2): 292-298.

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Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate

TENG Hui, WANG Jun, REN Xiaoqian, CHEN Demin

State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineer-ing, Nanjing University of Technology, Nanjing 210009, China

Received:2010-06-28 Revised:2011-01-22 Online:2011-04-28 Published:2011-04-28
Supported by:
Supported by the Key Natural Science Foundation for Universities of Jiangsu Province(06KJA53012);the National Natural Science Foundation of China(20776069,20976084)

Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate

腾晖, 王军, 任晓乾, 陈德民

State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineer-ing, Nanjing University of Technology, Nanjing 210009, China

通讯作者: WANG Jun,E-mail:junwang@njut.edu.cn
基金资助:
Supported by the Key Natural Science Foundation for Universities of Jiangsu Province(06KJA53012);the National Natural Science Foundation of China(20776069,20976084)

Abstract

Abstract: Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS (tetraethyl orthosilicate).Various parameters for preparing catalysts were changed to investigate the suitable conditions.The resulting cata-lysts were tested in a pressured fixed bed reactor and characterized by SEM (scanning electron microscopy).The conversion of toluene and para-xylene selectivity were influenced remarkably by the n(SiO₂)/n(Al₂O₃) ratio of ZSM-5 zeolite,the type and amount of deposition agent,acid and solvent used,and the time and cycle of deposition treatment.TEOS was proved to be a more efficient agent than the conventional polysiloxanes when the deposition amount was low.The catalyst prepared at the suitable conditions exhibited a high para-xylene selectivity of 91.1% with considerable high conversion of 25.6%.SEM analyses confirmed the formation of a layer of amorphous silica on the external surface of ZSM-5 zeolie crystals,which was responsible for the highly enhanced shape-selectivity.

Key words: shape-selective catalysis, ZSM-5 zeolite, disproportionation of toluene, chemical liquid deposition, tet-raethyl orthosilicate

摘要： Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS (tetraethyl orthosilicate).Various parameters for preparing catalysts were changed to investigate the suitable conditions.The resulting cata-lysts were tested in a pressured fixed bed reactor and characterized by SEM (scanning electron microscopy).The conversion of toluene and para-xylene selectivity were influenced remarkably by the n(SiO₂)/n(Al₂O₃) ratio of ZSM-5 zeolite,the type and amount of deposition agent,acid and solvent used,and the time and cycle of deposition treatment.TEOS was proved to be a more efficient agent than the conventional polysiloxanes when the deposition amount was low.The catalyst prepared at the suitable conditions exhibited a high para-xylene selectivity of 91.1% with considerable high conversion of 25.6%.SEM analyses confirmed the formation of a layer of amorphous silica on the external surface of ZSM-5 zeolie crystals,which was responsible for the highly enhanced shape-selectivity.

关键词: shape-selective catalysis, ZSM-5 zeolite, disproportionation of toluene, chemical liquid deposition, tet-raethyl orthosilicate

TENG Hui, WANG Jun, REN Xiaoqian, CHEN Demin. Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate[J]. , 2011, 19(2): 292-298.

腾晖, 王军, 任晓乾, 陈德民. Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate[J]. , 2011, 19(2): 292-298.

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Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate

Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate

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