Creation of Bronsted Acidity by Grafting Aluminum Isopropoxide on Silica under Controlled Conditions: Determination of the Number of Bronsted Sites and their Turnover Frequency for m-Xylene Isomerization

被引：25

作者：

Caillot, Maxime ^{[1
,2
]}

Chaumonnot, Alexandra ^{[2
]}

Digne, Mathieu ^{[2
]}

Van Bokhoven, Jeroen A. ^{[1
,3
]}

机构：

[1] ETH, CH-8093 Zurich, Switzerland

[2] IFP Energies Nouvelles, Direct Catalyse & Separat, F-69360 Solaize, France

[3] Paul Scherrer Inst, Lab Catalysis & Sustainable Chem LSK, CH-5232 Villigen, Switzerland

来源：

CHEMCATCHEM | 2014年 / 6卷 / 03期

关键词：

acidity; coverage degree; ethanol; silicates; thermogravimetry; ETHANOL DEHYDRATION; CATALYTIC-ACTIVITY; SURFACE-ACIDITY; CO ADSORPTION; ZEOLITES; MCM-41; H-ZSM-5; FTIR; IR; AL;

D O I：

10.1002/cctc.201300824

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

There is not a unique BrOnsted acid site for aluminosilicates (ASAs). IR spectroscopy following CO adsorption proves the creation of BrOnsted acid sites on Al/SiO2 ASAs, which are synthesized by the deposition of aluminum species on hydroxylated silica. These sites are active for ethanol dehydration and m-xylene isomerization. Controlled deposition under anhydrous conditions optimizes the number of sites, whereas the presence of water leads to alumina agglomerates with no BrOnsted acidity. The turnover frequency for m-xylene isomerization (4.3x10(-4)s(-1)site(-1) at 350 degrees C, atmospheric pressure, and 0.6cm(3)h(-1) of m-xylene) is approximately 3times lower than that of the BrOnsted acid sites of Si/Al2O3 and 75times lower than that of an ultrastable Y-type zeolite without extra-framework aluminum.

引用

页码：832 / 841

页数：10

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