Synthesis of biodiesel fuel using an electrolysis method

Abstract

The paper details the first use of a simple electrolysis method to produce biodiesel fuel (BDF) from corn oil and waste cooking oil at room temperature. This novel process exhibited a high fatty acid methyl ester (FAME) yield (>97%) even in the presence of a relatively high water content (as high as 2 wt.% of the total reaction mixture) when using a low concentration of sodium chloride (<1.2 wt.% based on oil weight). FAME yield was influenced by methanol/oil molar ratio, the amount of cosolvent addition, water content, NaCl concentration and electrolysis voltage. With the proceeding of electrolysis, the pH value of the electrolyte rapidly increased from 7 to 12, but the conductivity of the reaction mixture decreased. When the electrolysis was stopped on the way, the transesterification reaction was still continued, but the reaction rate became lower than that when continuing the electrolysis in the case of high water content. During the electrolysis process, no chlorine molecule in the evolved gas was detected (<0.5 ppm).