| abstract |
For example, when used in the production of a fatty acid ester fuel, it is possible to suppress the formation of a fatty acid salt that causes a decrease in fuel quality, reduce the amount of basic catalyst used, and improve the production efficiency of a fatty acid ester fuel. A method for esterifying free fatty acids in oil and fat compositions is provided. An oil composition containing a free fatty acid and a monovalent lower alcohol are reacted in the presence of a solid catalyst for esterification reaction while irradiating ultrasonic waves having a frequency of 15 to 100 kHz. The monovalent lower alcohol is preferably methanol and ethanol, and the solid catalyst is preferably ferric sulfate. Moreover, as an oil-fat composition containing a free fatty acid, used edible oil-fat can typically be used. [Selection figure] None |