An Alternate Green Route to Synthesis of Mono and Diesters using Solid Acid Catalysts

摘要

The conventional catalysts used in esterification reactions are liquid acids that are not environment friendly. Keeping with global trends, in the present endeavour, an effort has been made to replace the conventional homogeneous liquid acid catalysts by heterogeneous solid acid catalysts. M(IV) Phosphotungstates [M(IV)= Zr, Ti and Sn] which possess inherent acidity have been synthesized by sol-gel route whereas, 12-Tungstophosphoric acid (12-TPA) has been supported onto ZrO_(2), TiO_(2) and SnO_(2) resulting in 12-TPA/ZrO_(2), 12-TPA/TiO_(2) and 12-TPA/SnO_(2) which possesses induced acidity have been synthesized by process of anchoring and calcination. All the catalysts have been characterized for elemental analysis by ICP-AES, TGA, FTIR, SEM, EDX, XRD, surface area (by BET method) and surface acidity (by NH_(3)-TPD method). The potential utility of these materials as solid acid catalysts have been explored by studying esterification as a model reaction wherein mono and diesters have been synthesized. The catalytic activity of synthesized materials has been compared and correlated with acid properties of the materials.