Biodiesel Synthesis Catalyzed by the KF/Ca−Mg−Al Hydrotalcite Base Catalyst

Abstract

A series of solid base catalysts, KF/Ca−Mg−Al hydrotalcite (KF mass ratio of 100%) with different cation ratios, were prepared and studied in this research. Effects of the cation ratio of the Ca−Mg−Al hydrotalcite and the methanol/oil molar ratios on the fatty acid methanol ester (FAME) yield of the transesterification of palm oil with methanol were investigated. The results of the transesterification reactions showed that all of these kinds of catalysts had a very high activity for the biodiesel yields, obtaining 90% or more with 10 min of reaction under the conditions of 338 K, 12:1 methanol/oil molar ratio, and 5% (wt/wt oil) catalyst amount. In addition, the FAME yield could reach 99.6% in 10 min catalyzed by the optimal catalyst KF/Ca−Mg−Al hydrotalcite (2.2:0.8:1 Ca/Mg/Al; KF mass ratio of 100%), under the same reaction conditions as above.