The Effect of Temperature on Oxirane Oxygen in the Epoxidation of Rice Bran Oil Methyl Ester by Resin Catalyst

Unsaturated fatty acid in vegetable oils can be converted into epoxide. Rice bran oil is a byproduct of rice milling. It contains unsaturated fatty acid that can be epoxidized. First of all, rice bran oil is converted into methyl ester, followed by the epoxidation reaction. As a result, epoxidized methyl ester is produced. It can be used both as a base oil or lubricant additive. This research aims to synthesize the epoxidized methyl esters from rice bran oil methyl ester, the product of transesterification and to find the effect of temperature on oxirane oxygen, as well as on iodine value. Epoxidation is performed in situ using IR-120 resin catalyst. This process is expected to produce a higher oxirane, to simplify the separation between product and catalyst, and to ease the purification of product. In this research, the temperature is varied from 40 °C, 50 °C, 60 °C, 70 °C, to 85 °C for 4 hours. The effect of temperature on the oxirane oxygen and iodine value shows that the temperature increases up to a certain point, resulting in an increase of oxirane oxygen and a decrease of iodine value. The highest oxirane oxygen is 4.06% (which is 68.58% of oxirane conversion) at 70 °C. Product identification using Fourier Transform Infrared shows that there are oxirane groups at 820–843 (cm⁻¹).