Study On The Synthesis Of Epoxidized Fatty Acid 2-ethylhexyl Esters

In order to meet the green and functional demand of the current plastic products industry,it is an inevitable trend to develop a series of bio-based plasticizers to substitute traditional petroleum-based phthalate plasticizers.Epoxidized fatty acid 2-ethylhexyl esters?Ep-FAEtHE?is an environmentally friendly,high performance and cost competitiveness green plasticizer.However,there are few reports on the synthesis of Ep-FAEtHE.In addition,for the system of epoxidized oils synthesized by formic acid?FA?-hydrogen peroxide autocatalytic method,the study of liquid-liquid phase equilibrium of epoxidized oils-FA-water is of great significance for the product washing separation process and the design of extraction equipment.Therefore,this work studies the key technical problems of the reaction and separation process in the production of Ep-FAEtHE through the combination of experiment and modeling method.The specific contents and main achievements are as follows:?1?Firstly,the reaction process of the preparation of Ep-FAEtHE by FA autocatalytic method was studied.The effects of the amount of formic acid,the amount of hydrogen peroxide,the reaction temperature and the reaction time on the epoxidation reaction were researched.The results shown that the double bonds conversion was99.11%and the epoxy yield can reach 90.14%at the following conditions:reaction temperature of 75?,fatty acid 2-ethylhexyl ester?FAEtHE?double bonds:H₂O₂:FA molar ratio of 1:1.5:0.25,reaction time of 3 h.Furthermore,the effects of different carbon chain structures of fatty acid alkyl esters on the epoxidation reaction were also investigated.The results shown that the longer carbon chain and a branched structure of FAEtHE made its epoxy yield higher and the product more stable.?2?The ring-opening side reaction during the epoxidation reaction is the main reason to affect the epoxy yield.In view of the characteristics of the higher epoxy yield and more stable product for Ep-FAEtHE,the effects of FA,performic acid and water on the ring opening kinetics of Ep-FAEtHE system were explored.The concentrations of FA,performic acid and epoxy group were determined under different experimental conditions.The experimental data were fitted to obtain the kinetic rate constants of FA,performic acid and water at 90°C of 0.002934,0.04494 and 0.000363 L?mol^-2?min^-1,respectively.The activation energies were 33516.2,531771.7 and 551201.6 J?mol^-1,respectively.It was found that the effect of performic acid on the ring-opening reaction was greater than that of FA,and water had almost no effect on the ring-opening reaction.In addition,the study also found that the ring-opening rate constants of the Ep-FAEtHE system were much smaller than that of the epoxidized fatty acid methyl ester?Ep-FAME?system.?3?In view of the product separation process of the epoxidized oils,this work reported experimental data for the liquid-liquid equilibrium of three systems,i.e.,Ep-FAME+FA+water,Ep-FAEtHE+FA+water and epoxidized soybean oil?Ep-SBO?+FA+water,in the temperature range of 303.15 to 348.15 K.The results indicated that the liquid-liquid equilibrium constant of FA in the systems followed the order of Ep-FAEtHE>Ep-FAME>Ep-SBO.Moreover,the obtained experimental data were correlated by NRTL and UNIQUAC models.The maximum root mean square deviations?RMSD?values as low as 0.0052 and 0.0263 were estimated for the NRTL and UNIQUAC model,respectively.The NRTL model was more suitable than the UNIQUAC model to describe the liquid-liquid equilibrium behavior of these ternary systems.