Improved Low-Temperature Properties of Chemically Modified High Free Fatty Acid Castor Oil-Methyl Esters: Blending and Optimization Study

摘要

A castor oil fatty acid methyl ester (COFAME) epoxide was prepared by structural modification of high free fatty acid castor oil. The process involved epoxidation of COFAMEs using hydrogen peroxide as an oxygen donor and IR-120 as a heterogeneous acid catalyst. Response surface methodology was implemented to optimize the epoxidation process variables and to maximize COFAME conversion to oxirane oxygen content (OOC). The effect of the process parameters on epoxidation was examined. The best optimum conditions inferred were as follows: H2O2 molar ratio, 2.34; temperature, 50 degrees C; catalyst loading, 19.43% by weight; and reaction time 5.26h. The experimental OOC value at optimum conditions was 4.38%, which agreed closely with the model-predicted value (4.44%) with a percentage error of 1.35%. The completion of epoxidation was confirmed by C-13-NMR. Molecular weight, oxidative stability, and rheological properties were determined by standard methods. The blending study results revealed that epoxide blended with COFAME showed an improved pour point compared with pure epoxide.