Study On The Synthesis And Properties Of Vegetable Oil Based Lubricant

With the progress and development of society,people pay more and more attention to environmental protection,and put forward higher requirements for the performance of lubricats.Traditional mineral lubricants cannot meet the requirements of industrial production due to their toxicity,non-renewability and poor biodegradability,so research on environmentally friendly lubricants has become a development trend.Vegetable oil has the characteristics of easy biodegradation,no biological toxicity or little toxicity to the environment.At the same time,it has high viscosity index,low volatility and excellent lubrication performance,which has attracted more and more people's attention.In view of the shortcomings such as poor oxidation stability and low temperature fluidity of vegetable oil,the chemical modification of epoxidized soybean oil was carried out by transesterification and ring opening reaction in this paper.Two kinds of base oils were synthesized: epoxy soybean oleate methyl ester and ethoxy fatty acid methyl ester.The technological conditions were optimized,and the oxidation stability,rheological properties and friction properties before and after modification were investigated which provide basic data for the development of new green lubricants.First,the base oil epoxy soybean oleate methyl ester was synthesized by transesterification from epoxy soybean oil and methanol.Through single factor experiment,the optimum conditions of transesterification were obtained: reaction temperature 55 ?,reaction time 60 minutes,molar ratio of alcohol to oil 6:1,catalyst amount 1.1%.Under this condition,the yield of epoxy soybean oleate methyl ester was 91.32%,and the reaction process had no obvious effect on the epoxy value of the product.In addition,the product structure was characterized by IR.Then,the epoxy soybean oleate methyl ester synthesized above was further reacted with ethanol under the catalysis of tetrafluoroboric acid to synthesize the base oil ethoxy fatty acid methyl ester.Through the orthogonal experiment,the optimum technological conditions of the epoxidized ring opening reaction were obtained: reaction temperature 55 ?,reaction time 90 min,molar ratio of alcohol to oil 4:1,catalyst amount 0.5%(accounting for the total weight).Under this condition,the conversion rate of epoxy soybean oleate methyl ester was 99.52%,and the structure of ethoxy fatty acid methyl ester was characterized by IR.By examining the tribological properties of the raw materials and the two synthetic base oils,it is found that the friction coefficient of epoxy soybean oleate methyl ester and ethoxy fatty acid methyl ester is smaller,and the friction reduction effect is better.With the change of rotating speed,the friction coefficient remains relatively stable,which is better than epoxy soybean oil.The antiwear and bearing capacity of epoxy soybean oil decreased after transesterification reaction,but the antiwear and bearing capacity of epoxy soybean methyl oleate increased after ring-opening reaction.The rheological properties research found that compared with epoxy soybean oil,the viscosity of epoxy soybean methyl oleate decreased,the viscosity index increased,and the low-temperature fluidity improved.After the ring-opening reaction between methyl epoxy soybean oleate and ethanol,the viscosity increased significantly,the viscosity index increased,and the low-temperature fluidity was better.By examining the oxidation stability of the two base oils synthesized,the results showed that the transesterification reaction did not destroy the oxidation stability of the epoxy soybean oil and improved,the oxidation stability of the product of ethoxy fatty acid methyl ester was further improved after the ring opening of epoxy group.