Preparation of Mesoporous Solid Acid SO42-/ZrO2/MCM-41 and Its Catalytic Activity for Synthesis of Biodiesel

摘要

SO42-/ZrO2/MCM-41 solid acid catalysts were prepared by an impregnation-calcination method with mesoporous molecular sieve MCM-41 as the supporter. MCM-41 was synthesized by hydrothermal reaction with cetyl trimethyl ammonium bromide as template and tetraethoxysilane as silicon source in an alkaline environment. The catalysts and their supporter were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Used as raw material to simulate the high acid value raw materials for biodiesel, oleic acid was reacted with methanol. The influences of preparation conditions of catalyst, ratio of methanol to oleic acid, reaction temperature, reaction time and amount of catalyst were investigated in the esterification reaction. The experimental results showed that SO4 2-/ZrO2/MCM-41 had the best catalytic properties when the ZrO2 loading amount was 40%, the concentration of sulphuric acid was 1.5 mol/L and the calcination temperature was 873K. The conversion ratio of oleic acid reached 84.8% with 6hreaction under the conditions of 363K, 6:1 methanol/oleic acid mole ratio, and 5% (wt/wt oleic acid) catalyst amount. SO4 2-/ZrO2/MCM-41 solid acids were suitable catalysts for the esterification of the high acid value raw materials in the biodiesel production.