Transesterification of rapeseed oil in the presence of basic zeolites and related solid catalysts

The transesterification of rapeseed oil with methanol was performed by reflux of methanol over cesium-exchanged NaX faujasites, mixed magnesium-aluminum oxides, magnesium oxide, and barium hydroxide for different methanol-to-oil ratios. Over cesium-exchanged NaX faujasites and mixed magnesium-aluminum oxides, a long reaction time and a high methanol-to-oil ratio are required to achieve both high oil conversion and high yields in methyl esters. However, over a 300 m²/g magnesium oxide, methanol-to-oil ratios and reaction times are significantly reduced to obtain both high oil conversion and high yield in the methyl esters, particularly when the hydroxide precursor is calcined at 823 K. Finally, preliminary results with other basic solids such as barium hydroxide have shown a very high activity and a very high yield in esters. This catalyst is particularly effective since, for a methanol-to-oil ratio of 6, at reflux of methanol and after a reaction time of only 1 h, the oil conversion is about 80% with a nearly quantitative ester molar fraction. Part of this work was presented at the 91st AOCS Annual Meeting, San Diego, California, April 2000.