Transesterification of soybean oil and analysis of bioproduct

Biodiesel produced by the transesterification reaction of soybean oil using potassium hydroxide (KOH) catalytic is a promising alternative fuel to diesel regarding the limited resources of fossil fuel and the environmental concerns. In order to decrease the operational temperature and increase the conversion efficiency of methanol, a novel idea was presented in which a co-solvent dichloromethane was added to the reactants. The results showed that the yield of methyl ester was improved when dichloromethane was coexistence. The effects of the co-solvent, molar ratio of methanol/oil, reaction temperature, and catalyst on the biodiesel conversion were investigated. With the optimal reaction temperature of 45 °C, methanol to oil ratio of 4.5:1, co-solvent dichloromethane of 4.0%, a 96% yield of methyl esters was observed in 2.0 h at the condition with 1.0 wt.% potassium hydroxide. The characterization and analysis of biodiesel were obtained by FT-IR, gas chromatograph and inductively coupled plasma atomic emission (ICP–OES) spectroscopy methods. The cetane number, flash point, cold filter plugging point, acid number, water content, ash content and total glycerol content were investigated.