Esterification Of Glycerol Using Heteropolyacids As Catalysts

At present, glycerol was used as raw materials to produce more and more types of glycerides, triacetin, glycerin fatty acid ester, oleic acid ester compounds etc are widely used as chemicals. In modern studies, using heteropoly acid instead of sulfuric acid catalyzed esterification reaction has become a trend. Since heteropoly acid is high yields, little pollution, the use of heteropoly acids (salts) as acid catalysts are increasingly attracted researchers'interest.In this thesis, we synthesized and characterized In_x/3H_3-xPW₁₂O₄₀(x=1.5, 1.8, 2.4, 2.7, 3.0) and Zn_x/2H_3-xPW₁₂O₄₀(x=0.8, 1.2, 1.6, 2.0, 2.4,3.0), and the catalytic activity of these catalysts was studied by esterification of glycerol with acetic acid. 1. A solid catalyst indiumdodecatungstophosphate In_x/3H_3-xPW₁₂O₄₀(x=1.5, 1.8, 2.4, 2.7, 3.0) was synthesized and characterized by FTIR, XRD, elemental analysis, Hammett acid strength (Ho), NH3-TPD and FTIR pyridine adsorption spectroscopy. The catalytic activity of the catalyst was studied by esterification of glycerol with acetic acid. The conversion of the glycerol can reach 94.3% with In_0.6H_1.2PW₁₂O₄₀, glycerol to acetic acid molar ratio 1:4.0, at 120℃for 6h.2. A solid catalyst zincdodecatungstophosphate Zn_x/2H_3-xPW₁₂O₄₀ (x=0.8, 1.2, 1.6, 2.0, 2.4,3.0) was synthesized and characterized by FTIR, XRD, elemental analysis, Hammett acid strength (H_o), NH3-TPD and FTIR pyridine adsorption spectroscopy. The catalytic activity of the catalysts was studied by esterification of glycerol with acetic acid. The conversion of the glycerol can reach 92% with Zn0.6H1.8PW12O40, glycerol to acetic acid molar ratio 1:3.5, at 120℃for 4h.