Biodiesel Production From Transesterification of Vegetable Oils Over Zeolite-Like Catalysts Synthesized From Diatomite Clay

In this study, cost-effective clay catalysts were prepared from natural diatomite clay to catalyze transesterification of triglycerides/vegetable oils in excess methanol for biodiesel production. These effective catalysts were found to possess characteristics of zeolites. In a typical experiment, this zeolite-like material was obtained after aging a mixture of raw diatomite clay, sodium hydroxide, aluminum salt and deionized water for 0.5 h in ambient environment, followed by hydrothermal reaction at 220 °C for 12 h. Various instruments such as XRD, FT-IR, SEM, EDS, SS MNR and TGA were applied to characterize the as-synthesized catalyst. The obtained catalytic material was advantageous not only in easy preparation, but also as a low-cost solid catalyst that can effectively catalyze transesterification of triglycerides in excess methanol for production of methyl oleate and other fatty acid methyl esters as biodiesel. Over 95% of soybean oil transferred to biodiesel under optimal conditions of 63 °C and 2 h.