Product Selectivity in Catalytic Conversion of Benzyl alcohol in Mesitylene using Meso-/Microporous Zeolites
Dongxia Liu1, Aditya Bhan1, Michael Tsapatsis1, and Saleh Al Hashimi2
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN 55455, USA
- Chemical Engineering Program, The Petroleum Institute, Abu Dhabi, United Arab Emirates
Meso-/microporous zeolites couple the catalytic features of micropores and the improved access and transport provided by the mesopores. The connectivity between the meso- and micropores could be an important factor determining the performance in catalysed reactions. This talk highlights the catalytic behavior of three acidic meso-/microporous zeolite materials (pillared MWW, pillared MFI, and 3DOm-i MFI) studied using catalytic conversion of benzyl alcohol with mesitylene as probe reactions. As expected, the apparent rate constant for the catalytic conversion of benzyl alcohol in mesitylene on materials processing dual meso- and microporosity was higher than those of the corresponding conventional microporous materials. Interestingly, the selectivity of the catalytic probe reaction in the zeolites possessing meso- and microporosity was comparable to that of the microporous analogue, but remarkably different for each type of zeolite: MWW zeolites favor alkylation of benzyl alcohol with mesitylene, while MFI zeolites favor etherification of benzyl alcohol. Chemical titration using 2,6-di-tert butyl pyridine during the catalytic conversion of benzyl alcohol over the catalysts revealed that alkylation and etherification of benzyl alcohol occurred in mesoporous environments and external surface for both MWW and MFI zeolites; However, due to interconnected micropore and mesopore structures in MFI, the etherification reaction selectively occurred within micropores of MFI zeolite as well. These results indicate that the difference in product selectivity is determined by the different micropore structures of MFI and MWW along with the corresponding differences of meso-/micropore connectivity.
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