A new zinc hydroxide nitrate heterogeneous catalyst for the esterification of free fatty acids and the transesterification of vegetable oils

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.