High-silica Hβ zeolite catalyzed methanolysis of triglycerides to form fatty acid methyl esters (FAMEs)

Transesterification of biomass-derived triglycerides with methanol (methanolysis of triglycerides) is a promising method for the industrial production of the biodiesel fuel, fatty acid methyl esters (FAMEs). Herein, we present a simple heterogeneous catalytic method for the selective transformation of triglycerides into FAMEs. For the methanolysis of trilaurin under reflux of methanol, a commercially available high-silica HI3 zeolite (H beta-75, Si/Al = 75) showed a higher yield of methyl laurate than other zeolite catalysts, metal oxides, and conventional heterogeneous and homogeneous catalysts. Under the optimized conditions, the method was widely applicable to the transformation of various triglycerides (C4-C18 frames) into the corresponding FAMEs (yields of 87-93%). The catalyst was furthermore reusable. Quantitative relationships between acidity, hydrophobicity, and reaction rates versus Si/Al ratio of H beta zeolite catalysts show that a low affinity to glycerol, which arises from the hydrophobicity of the high-silica zeolites, is an important factor for controlling the catalytic activity.