Epoxidation Of Methyl Oleate And Isomerism Etherification Of Soybean Oil Catalyzed By Br?nsted Acid Ionic Liquid

Vegetable oil is excellent green lubricant material. Modifying vegetable oil for its poor thermo-oxidative stability and low temperature properties can broaden its range of application. Br?nsted acid ionic liquids have been successfully used in many organic catalytic reactions as catalysts, and are getting more attention from researchers in the aspect of substituting homogeneous and heterogeneous catalysts. In this paper, using homemade sulfonic acid(-SO3H) Br?nsted acid ionic liquids as catalyst for epoxy modifying and isomerism etherification modifying of vegetable oil was studied, in order to improve the thermo-oxidative stability and low temperature properties of vegetable oil and to provide a green approach for the development of new technology for vegetable oil modification.The effect of reaction conditions on the epoxidation reaction of methyl oleate catalyzed by Br?nsted acid ionic liquid [HSO3-(CH2)3-mim][HSO4] was investigated by single factor experiments, and then optimized by orthogonal experiments. The results showed the primary and secondary factors affecting the epoxidation ratio: amount of hydrogen peroxide > amount of formic acid > catalyst dosage > reaction temperature. The optimal reaction conditions were as follows: n(30% hydrogen peroxide):n(C=C)=2.6; n(formic acid):n(C=C)=0.7; catalyst dosage was 4%; reaction temperature was 80 ℃; reaction time was 60 min. Under the optimal epoxidation conditions, acid value of the product was 0.32 mg KOH/g, iodine value was 7.2 g I2/100 g, and the epoxidation ratio came up to 83.4%. Br?nsted acid ionic liquid catalyst could be easily separated from the product and reused. When it was reused for the sixth time, the epoxidation ratio of the product could still maintain at about 80%.Under the condition of different alcohol-oil ratio, fatty alcohols of different chain lengths were used to isomerism etherification modify soybean oil. The isomerism etherification soybean oils were characterized by FTIR, 1H NMR and TG. Pour point and viscosity index were determined. The results indicated that isomerism etherification modifying reaction involved an epoxy group ring-opening reaction, accompanied by transesterification at the triacylglycerides. When the alcohol-oil ratio was 5:1, the isomerism etherification ring-opening time of methanol, butanol and 2-ethylhexanol was shorter than that of alcohol-oil ratio 2:1, referring 5 h, 6 h, 8 h respectively. The low temperature properties and thermal stability of isomerism etherification soybean oils were improved, and the isomerism etherification soybean oils from alcohol-oil ratio 5:1 were better. Among them, the 2-ethylhexanol isomerism etherification soybean oil exhibited the best low temperature properties and thermal stability. Its pour point was-18 ℃, viscosity index was 111 and starting temperature of thermal decomposition was 415 ℃, which improved the low temperature properties and thermal stability of soybean oil and broadened the application of soybean oil as green lubricant base oil.