Bindhu, Jacob; Dr.Sugunan, S(Cochin University of Science & Technology, February , 1998)
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Abstract:
In this thesis an attempt has been made to compare the catalytic activity of
some medium and large pore zeolites in a few alkylation and acylation reactions. The
work reported in the present study is basically centered around the following zeolites
namely, ZSM-5, mordenite, zeolite Y and beta. The major reactions carried out were
benzoylation of o-xylene, propionylation of toluene and anisole and benzylation of 0xylene.The programme involves the synthesis, modifications and characterization of
the zeolite catalysts by various methods. The influence of various parameters such as
non-framework cations, Si/AI ratio of zeolites, temperature of the reaction, catalyst
concentration, molar ratio of the reactants and recycling of the catalysts were also
examined upon the conversion of reactants and the formation of the desired products
in the alkylation / acylation reactions.The general conclusions drawn by us from the results obtained are summarized
in the last chapter of the thesis. Zeolite beta offers interesting opportunities as a
potential catalyst in alkylation reactions and the area of catalysis by medium and large
pore zeolites is very fascinating and there is plenty of scope for further research in this
field. Moreover, zeolite based catalysts are effective in meeting current industrial
processing and more stringent environment pollution limits.
Description:
Department of Applied Chemistry, Cochin
University of Science and Technology
One-pot acetalizations of cyclohexanone. acetophenone and benzophenone were carried out using methanol over H-montmorillonite clay
(a mesoporous material). silica, alumina, and different zeolites such as HFAU-Y.HBeta, H-ZSM-5, and H-mordenite. In all the cases a single
product-the corresponding dimethylacetal-was obtained in high yields. Hemiacetal formation was not observed with any catalyst. A
comparison of catalytic activity indicated that montmorillonite K-10 is the most active catalyst for the reaction. As evidenced by the reaction
time studies, the catalyst decay is greater over the zeolite catalyst than over the clay.