| Epoxy plasticizer was considered as a new kind of plasticizer and widely used in polyvinyl chloride (PVC) industry, due to its innocuity, good coMPatibility, biodegradation and renewability. Epoxy plasticizer mainly included epoxy fatty acid methyl ester(FAME) and epoxy soybean oil(ESO). The production of epoxy plasticizer was a heterogeneous reaction. On an industrial scale, there were some problems in preparing epoxy plasticizer: long reaction time, poor production quality, high energy consumption and equipment corrosion. In order to solve above problems, a new method to prepare epoxy plasticizer was developed by utilizing hydrodynamic cavitation in formic acid autocatalytic system, and the process of mass transfer and reaction was studied in detail. The main content as well as the achieved conclusions is as follows:(1) Experimental study on preparation of epoxy FAME with hydrodynamic cavitation technology in formic acid autocatalytic system. The effect of the circulation rate, volume ratio of oil phase to aqueous phase(VROA), and upstream pressure were investigated with single factor experimental method. The effect of hydrodynamic cavitation and mechanical stirring was also studied. The experimental results showed that the higher circulation rate could result in much more cavitation times of the system, which favored the epoxy reaction. The optimized conversion of FAME was obtained when volume ratio of oil phase to aqueous phase was 2.4:1. The higher upstream pressure led to a better emulsification and higher conversion of FAME. However, too much of the upstream pressure would result in the degradation of epoxy FAME. The optimum experimental conditions were: circulation rate was 0.3 L/min, VROA was 2.4:1, upstream pressure was 0.4 MPa. CoMPared with mechanical stirring at the optimum conditions, hydrodynamic cavitation could provide better mass transfer rate in a liquid-liquid system, and the reaction time and energy consumption were reduced more significantly, the iodine value and oxirane% of the product were 3.2 g/100g,4.51%.(2) Experimental study on preparation of epoxy ESO with hydrodynamic cavitation technology in formic acid autocatalytic system. The effect of 4 main parameters on epoxidation of ESO were investigated with orthogonal experimental method, which included the circulation rate, HCOOH, temperature, and H2O2. The effect of HCOOH, VROA, and upstream pressure were investigated with single factor experimental method. The effect of hydrodynamic cavitation and mechanical stirring was also studied. The experimental results showed that the degree of the influence on epoxidation reaction was circulation rate> HCOOH> temperature> H2O2. The optimum experimental conditions were:the mass ratio of soybean oil to HCOOH to H2O2 was 170/25/117, circulation rate was 50 mL/min, VROA was 2.5:1, upstream pressure was 0.5 MPa, temperature was 70℃, reaction time was 6 h. CoMPared with mechanical stirring at the optimum conditions, hydrodynamic cavitation could provide better mass transfer rate in a liquid-liquid system, and the reaction time and energy consumption were reduced more significantly, the iodine value and oxirane% of the product were 2.7 g/100 g,6.24%.(3) Experimental study on mass transfer and reaction kinetic of epoxidation ESO in formic acid autocatalytic system. The partition coefficient and mass transfer coefficient of HCOOH between the soybean oil and aqueous phase were measured in double-stirred cell, the mass transfer and reaction model between the oil and aqueous phase was built. Moreover, the effect of HCOOH, H2O2, and phase interface was simulated based on the model with polymath. It was found that the result trend calculated from the built model anastomosed with the experimental result, it would be the basis for qualitative analysis of epoxidation of soybean oil process... |
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