Selective decomposition of cumene hydroperoxide into phenol and acetone by a novel cesium substituted heteropolyacid on clay

Phenol is industrially produced by the Hock process starting from benzene and propylene to yield cumene, which is subsequently oxidized with oxygen to generate cumene hydroperoxide (CHP) which is then decomposed with sulfuric acid to obtain equimolar phenol and acetone. Both phenol and acetone are important bulk chemicals having separate as well as interrelated markets. The last step of the Hock process is polluting and results in loss of selectivity leading to formation of by-products beside the desired products phenol and acetone. The current work reports the decomposition of CHP by using K-10 clay supported catalysts such as 20% (w/w) dodecatungstophosphoric acid (DTP)/K-10, 20% (W/W) CS2.5H0.5PW12O40/K-10, 20% (w/w) ZnCl2/K-10 and K-10, and also sulfated zirconia at 40degreesC. For the first time, the synthesis of Cs2.5H0.5PW12O40 supported on K-10 clay has been reported with complete intact Keggin anion structure. This catalyst has been found to exhibit excellent activity for decomposition of cumene hydroperoxide exclusively into phenol and acetone. Various kinetic parameters were studied over 20% Cs2.5H0.5PW12O40/K-10. The reaction follows the first order kinetics. The catalyst is stable and reusable giving 100% conversion with exclusive selectivity to 100% phenol and acetone during all the runs. (C) 2002 Elsevier Science B.V. All rights reserved.