Selective esterification of glycerol to bioadditives over heteropoly tungstate supported on Cs-containing zirconia catalysts

Esterification of glycerol with acetic acid was carried out over tungstophosphoric acid (TPA) supported on Cs-containing zirconia. The catalysts were prepared by impregnation method and characterized by FT-infrared spectroscopy. X-ray diffraction and temperature program desorption of NH3. The catalysts exhibited more than 90% conversion within a short reaction time. The catalytic activity depends on the amount of exchangeable Cs with TPA on zirconia, which is in tern related to the acidity of the catalysts. The acidity of the catalysts varied with the presence of residual protons of TPA. The effects of various parameters, such as reaction temperature, catalyst concentration and molar ratio of glycerol to acetic acid, were studied and optimized reaction conditions are established. (C) 2010 Elsevier B.V. All rights reserved.