Amelioration of Factors Limiting the Use of Lipid-Based Diesel Products

High-purity oleate esters can decrease the melting points and improve the oxidative stability of lubricants. High-oleic soybean oil (HOSO) was esterified to butyl or isopropyl esters. Fractional distillation and low-temperature crystallization were applied to improve the purity of oleate of HOSO esters. Although the purity of butyl esters of HOSO attained 91.8% by fractional distillation, the rate of distillation must be slow which made this approach not very feasible. After subjecting the esters to a two-step crystallization at reduced temperatures, the percentage of oleate in the HOSO esters was increased from 83.2 to 92.5%. The percentage of saturated fatty acids decreased to less than 2.2%, but polyunsaturates percentage remained almost unchanged.