Alternative Route for Biodiesel Synthesis with Co-Production of Glycerol Carbonate

Abstract

As an alternative route from the conventional alkali-catalyzed biodiesel production, the supercritical dimethyl carbonate method had been proven to successfully produce biodiesel with the co-production of glycerol carbonate in a one-step and two-step non-catalytic methods. Biodiesel or fatty acid methyl esters (FAME) obtained were high in yield, comparable with supercritical methanol method and satisfy the international standards for use as biodiesel in engines. In this paper, key parameters for the processes such as reaction temperature, pressure, time, molar ratio of dimethyl carbonate to oil, the FAME yield, thermal decomposition, degree of denaturation, tocopherol content, oxidation stability and fuel properties were discussed. The optimized condition for supercritical dimethyl carbonate method is at 300°C/20MPa/20min/42:1 molar ratio of dimethyl carbonate to oil with a satisfactory yield of FAME at 97.4wt%. The extensive approach in this study is very important to complement mathematical model for optimization in the literatures, and to ensure that only high-quality biodiesel could be produced by supercritical dimethyl carbonate method under an optimized condition.