Heteropoly acid supported modified Montmorillonite clay: An effective catalyst for the esterification of acetic acid with sec-butanol

Esterifications of acetic acid with sec-butanol catalysed by supported dodecatungstophosphoric acid, H3PW12O40 (DTP) on acid modified Montmorillonite clay (AT-Mont) matrix have been carried out. A series of catalysts having 5%, 10%, 20% and 30% loading of DTP on different AT-Mont (15 min to 4h) were synthesized and evaluated as catalysts: 20% DTP loaded on acid activated (15 min) clay showed the highest catalytic activity with about 80% conversion, having nearly 100% selectivity towards sec-butyl acetate. The high catalytic activity may be due to a high dispersion of the DTP on AT-Mont, providing more surface area (120 m(2)/g) and active sites than pure HPA. The variation of different reaction parameters, such as reaction temperature, reaction time, mole ratio of acid and alcohol and catalyst amount, on the conversion of acetic acid were studied. The samples were characterized by surface area, cation exchange capacity (CEC) measurements, TGA-DTA and FTIR spectroscopy. (C) 2010 Elsevier B.V. All rights reserved.