Study On The Preparation And Application Of Multiester Derivatives Based On Soybean Oil

In the catering industry and daily life of residents,more and more waste cooking oil is produced.Unreasonable disposal of waste cooking oil has caused serious environmental pollution.As a kind of available resource,waste cooking oil can be converted into green lubricant base oil by effective chemical modification.In this study,soybean oil was used as a model compound to simulate the waste oil of catering industry.Multiester derivatives were prepared by four steps of hydrolysis,esterification,epoxidation and ring opening reaction.The product thus prepared was utilized as the base oil of HM46 antiwear hydraulic oil,different additives were added,and the best formulation of HM46 antiwear hydraulic oil was explored by the comprehensive evaluation method of fuzzy mathematics.Soybean oil was hydrolyzed to fatty acids by two steps.Single factor experiment was designed to optimize the reaction conditions:hydrolysis temperature 90℃,hydrolysis time 3 h in the first step,hydrolysis time 2 h in the second step,hydrolysis rate 98.73%.The fatty acids were characterized by infrared spectrum and gas chromatography.The presence of fatty acids was confirmed.The total content of unsaturated fatty acids was 84.3%.The acid value and iodine value of fatty acids were150.69 mgKOH/g and 107 gI₂/100g,respectively.Because the ester made of alcohol withoutβhydrogen atom has better thermal oxidation stability than the ester made of alcohol withβhydrogen atom,NPG is selected to react with fatty acid to prepare fatty acid neopentyl glycol ester（FANE）.Through single factor experiment,the optimum reaction conditions were obtained:the reaction temperature was 120℃,the reaction time was 3.5 h,the ratio of alcohol to acid was 1:4,the amount of catalyst was 2%（percentage of fatty acid mass）,the amount of solvent 40%（percentage of fatty acid and NPG mass）,and the fatty acid conversion rate was 99.31%.The product was characterized by infrared spectrum,which confirmed the existence of FANE.The physical and chemical properties,thermal oxidation stability and tribological properties of FANE were determined.The results show that FANE has good antioxidant and antiwear properties.The epoxidation of fane was carried out to prepare the epoxy fatty acid neopentyl glycol ester（EFANE）,which can reduce the number of C=C double bonds and improve its oxidation resistance.The mechanism of epoxidation was discussed.The optimum reaction conditions were determined by single factor experiment:FANE,30%H₂O₂ and formic acid reacted in the mass ratio of 1:0.66:0.14,reaction temperature 60℃,catalyst dosage 6%（percentage of FANE mass）,rotational speed 2000 rpm,and epoxidation rate 82.37%.The product was characterized by FTIR,and the existence of EFANE was confirmed.Multiester derivatives（OFANE）were prepared by ring opening reaction of EFANE.Acetic acid was introduced to increase the degree of branching,so as to reduce the pour point and improve its low temperature performance.The mechanism of ring opening reaction was discussed.The product was characterized by infrared spectrum,and the presence of OFANE was confirmed.The physical and chemical properties of OFANE were determined.The acid value was 1.09mgKOH/g,pour point was-21℃,viscosity（40℃）was 357.97 mm²/s,viscosity index was 117,evaporation loss was 7.6%,oxidation induction time（150℃）was 22.03 min,which showed that OFANE had good low temperature performance and thermal oxidation stability.The test of tribological properties shows that OFANE has excellent antiwear properties.The tribological properties of OFANE were further improved by the addition of diammonic acid（DA）.HM46 antiwear hydraulic oil was finally investigated.In order to meet the viscosity requirements of hydraulic oil,OFANE and fatty acid methyl ester were mixed in proportion as HM46 antiwear hydraulic oil base oil,and different additives were added.The optimal formula was determined by fuzzy mathematics comprehensive evaluation method:base oil 98.697%,propyl gallate（PG）0.237%,butylated hydroxytoluene（BHT）0.158%,dimeric acid（DA）0.790%,triethanolamine oleate（TO）0.059%,zinc dialkyl dithiophosphates（T202）0.059%,and trace antifoaming agent.Series of performance tests showed that it can meet the national standards.