Optimization of the epoxidation of linseed oil using response surface methodology

Abstract

Epoxidized vegetable oils are widely used in the chemical industry. Their production requires the optimization of process conditions to maximize the epoxy yield. Therefore, the epoxidation of linseed oil with peracetic acid generated in situ in the presence of an ion exchange resin as a catalyst was optimized using response surface methodology combined with Box-Behnken design. The effects of temperature (65–85 °C), hydrogen peroxide-to-oil unsaturation mole ratio (1.1:1–1.5:1), catalyst amount (10–20 wt.%), and reaction time (5–13 h) on the epoxy yield were studied. According to analysis of variance, the developed regression model was significant with a coefficient of determination (R2) of 98.95%. Temperature of 70.6 °C, hydrogen peroxide-to-oil unsaturation mole ratio of 1.5:1, catalyst amount of 20 wt.%, and reaction time of 7 h were determined as the optimal process conditions using the model. At these conditions, a relative epoxy yield of 84.73±0.07% was achieved, which agreed closely with the predicted value of 87.60%. The epoxidized linseed oil with high epoxy oxygen content (8.27±0.01%) and low iodine number (4.22±0.49 g iodine/100 g oil) was obtained approximately isothermally in a batch process and under relatively mild and safe conditions.