Effects of co-solvents on the transesterification reaction time, temperature, and free glycerin content of crude methyl ester produced from coconut (Cocos nucifera L.) oil
2006
Sastri, A.V.B.
Transesterification of coconut oil was carried out with different cosolvents namely hexane, petroleum ether and diethyl ether to investigate their effect on the reaction time and temperature, and free glycerol content of crude methyl ester. Reactions were carried out with different cosolvent-to-methanol ratios (1:20, 1:10, 1:6.7, 1:5 and 1:4) at room temperature (30 deg C) and at 60 deg C. For all the reactions, methanol-to-oil ratio was maintained at 0.28:1 and sodium hydroxide catalyst added was 0.5 percent of the amount of oil taken. Washing the crude methyl ester by bubble wash and mist wash was done to compare the washing time and amount of water required, respectively, to lower the percentage free glycerol content of crude methyl ester obtained from different ratios of cosolvent to methanol, to the same level, and the effects of salts (sodium chloride, calcium chloride and potassium iodide), glycerol and temperature on the breaking of emulsions formed after washing, were also studied. The percentage yield of crude methyl ester increased with increase in cosolvent:methanol ratio. It was found out that 1:5 cosolvent to methanol ratio was the optimum ratio and the room temperature (30 deg C) was the optimum temperature. Volume of water required for mist wash and the time required to bubble wash the crude methyl ester reduced with the increase in cosolvent to methanol ratio. Mixing of the glycerol was very effective in breaking of emulsions formed during the washing.
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