Electrolysis Approach of Fatty Acid Methyl Ester Production Using Alkali Hydroxides and Their Alkoxides

Abstract

The depletion of fossil fuels and environmental concerns have led to the search for alternative fuels (biodiesel) derived from renewable resources. Electrolysis is a promising method of fatty acid methyl ester (FAME) synthesis that can be maintained at room temperature. Nevertheless, the low reaction rates have been commonly accelerated using a combination of catalysts and electrolytes. This work proposed a novel electrolyte-free electrolysis approach for biodiesel synthesis from soybean oil using alkaline hydroxide (NaOH, KOH) and alkaline methoxide (NaOCH3, KOCH3)catalysts. Though all of them demonstrated high biodiesel yield, KOCH3 exhibitedthe highest efficiency. Based on response surface methodology, the highest FAME yield of 97.11% was achieved at optimal electrolysis voltage of 18.76V, water amount of 1.97 wt.%, KOCH3 amount of 3.17 wt.%, and methanol/oil of 21.33:1 molar, and reaction time of 60 min. The fuel properties of synthesized biodiesel agreed with international standards.The findings of this work suggest that electrolyte-free electrochemical using alkaline hydroxides and alkaline methoxides as catalysts could be a useful alternative to conventional transesterification method for producing biodiesel. Keywords: Alkaline catalysts, Biofuel, Box–Behnken Design, Electrochemical approach