A new zinc hydroxide nitrate heterogeneous catalyst for the esterification of free fatty acids and the transesterification of vegetable oils
ABSTRACT A new heterogeneous catalyst for the esterification of free fatty acids and the transesterification of vegetable oils is reported. The layered compound zinc hydroxide nitrate (Zn5(OH)8(NO3)2 · 2H2O) was very effective in the alcoholysis of palm oil and the esterification of lauric acid with m(ethanol), even when hydrated ethanol was used. Over the range of 100–140 °C, the ester yield was the highest at 140 °C, while the catalyst concentration had a much greater effect on ester yields than the molar ratio of alcohol to acid did. Total ester contents above 95 wt% were obtained in both reactions and 93.2 wt% glycerin streams were recovered as a result of methanolysis.
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ABSTRACT: a b s t r a c t Heterogeneous catalysts are now being tried extensively for biodiesel synthesis. These catalysts are poised to play an important role and are perspective catalysts in future for biodiesel production at indus-trial level. The review deals with a comprehensive list of these heterogeneous catalysts which has been reported recently. The mechanisms of these catalysts in the transesterification reaction have been dis-cussed. The conditions for the reaction and optimized parameters along with preparation of the catalyst, and their leaching aspects are discussed. The heterogeneous basic catalyst discussed in the review includes oxides of magnesium and calcium; hydrotalcite/layered double hydroxide; alumina; and zeo-lites. Yield and conversion of biodiesel obtained from the triglycerides with various heterogeneous cata-lysts have been studied.Latest developments on application of heterogenous basic catalysts for an efficient and eco friendly synthesis of biodiesel: A review. 11/2010;
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ABSTRACT: The seed of Chinese Spicehush, containing 41.87% crude oil with 24.54% saturated acids and 75.32% unsaturated acids, could potentially be an alternative source of biodiesel. The problems of water pollution and the high purification cost of biodiesel can be avoided by using solid basic catalysts. The catalytic efficiency of CaMgZn oxide for the transesterification of Spicehush oil was evaluated. Catalysts were prepared via conventional co-precipitation methods and were characterized using X-ray diffraction, scanning electron microscopy, and the Brunauer-Emmett-Teller equation. The catalyst with a Ca/Mg/Zn molar ratio of 2:1:7 exhibited excellent catalytic performance and possessed a unique mesoporous structure with a surface area of 51.35 mg and an average pore diameter of 11.6 nm. The calcination temperature largely affected the structural and catalytic properties of the catalyst. Under the optimal transesterification conditions at 65 °C (catalyst amount of 5 wt.%, molar ratio of methanol to oil of 12, reaction time of 2 h), a high conversion ratio of 92.3% can be obtained. The biodiesel conversion rate did not exhibit a linear relationship with the amount of CaMgZn catalyst and reached maximum values at the catalyst amount of 5 wt.%. The CaMgZn solid basic catalysts could be applied as an alternative to traditional homogenous catalysts.International Journal of Green Energy - INT J GREEN ENERGY. 01/2012;