Effects of Bronsted and Lewis Acidities on Catalytic Activity of Heteropolyacids in Transesterification and Esterification Reactions

摘要

Some salts of H3PW_(12)O_(40)-M_(x)H_(3_x)PW_(12)O_(40) (abbreviated as M_(x)H_(3-x)PW) were prepared and used as acid catalysts for transesterification and esterification reactions. These catalysts have double acidity properties, i.e., Lewis acidity and Bronsted acidity, that are suitable for the conversion of waste cooking oil into biodiesel. The highest efficiency was 59.2 % and 94.7 % corresponding to transesterification and esterification reactions by Ti_(0.6)H_(0.6)PW with moderate Lewis acidity. The relationship between the acidic properties and the catalytic activity is discussed in detail.