Production of methyl esters from fried soybean oil using dimethyl carbonate with hydrobromic acid

Energy demand is increasing dramatically because of the fast industrial development, rising population, and economic growth in the world. To fulfill this energy demand, a large amount of fuel is widely used from different fossil resources. Burning of fossil fuels has caused serious detrimental environmental consequences. The application of methyl esters has shown a positive impact in resolving these issues. The objective of this study, methyl esters were produced by transesterification of fried soybean oil with dimethyl carbonate using hydrobromic acid as catalyst. Optimized several factors that affected the reaction efficiency including the fried soybean oil to dimethyl carbonate ratio (1:4 v/v), 3.5 % v/v catalyst concentration, a reaction temperature of 80 ºC for 50 min with 300 rpm agitation speed. The methyl esters yield was 94 % obtained using these optimized conditions. Methyl esters were purified by ion exchange resin amberlite-732, and purified methyl esters were analyzed by GC–MS. We then characterized important physical properties of methyl esters such as kinematic viscosity, density, flash point, cloud point, and pour point. These properties were found to have met with the quality standard defined under ASTM D6751-02 and compared with diesel fuel. In this research, a novel method was developed for the production of methyl esters under mild conditions using dimethyl carbonate and hydrobromic acid.