Low-melting-point biodiesel derived from corn oil via urea complexation.

The objective of this research was to improve the cold-flow property of biodiesel (fatty acid methyl ester, FAME) made from corn oil by urea complexation. Effects of processing conditions on the yield of low-melting-point biodiesel and its fatty acid composition were investigated. The optimal conditions were as follows: 50 degrees C stirring temperature, 40 min stirring time, 1:1 (w/w) ratio of urea to FAME, 5:1 (v/w) ratio of methanol to FAME, 20 degrees C crystallization temperature, and 2 h crystallization time. Under these conditions, the maximum yield of non-urea complexes with a melting temperature range from -52 to -45 degrees C was 53%, and the fatty acid profiles of non-urea complexes were 0.3% palmitic acid, 23.7% oleic acid, 75.1% linoleic acid, and 0.9% linolenic acid. Results also showed that oxystearin was helpful in further improving the cold-flow property of low-melting-point biodiesel.