Study On The Synthesis Of Cyclohexyl Acetate By Addition Of Acetic Acid And Cyclohexene

Cyclohexyl acetate is an important chemical raw materials and intermediates in organic synthesis, and it is widely used in paint, food additives, surface active agents, preservative fungicide and drugs. Meanwhile it also can produce cyclohexanol, adipic acid, caprolactam and nylon.At present, the addition route that acetic acid and cyclohexene synthesise cyclohexyl acetate has high atom economy, and the cation exchange resin catalysts aremainly used in this route of synthesis of cyclohexyl acetate. However they have problems such as low temperature, renewable and ease swelling. Therefore, the development and preparation of high-performance, easy recyclable and regeneration catalyst has important significance.In this paper, the catalysts that acetic acid and cyclohexene synthesise cyclohexyl acetate have been studied in the reaction tank conditions. Main contents and results are as follows:1.Investigate the reactivity of different types of zeolites catalysts, the result shows that Hβis better than others.When reaction temperature is 80 ℃, the mole ratio of acetic acid to cyclohexene is 5.5: 1, the total amount of catalyst is 3% of reactants mass and reaction time is 2h, the cyclohexene conversion is 25.3% and cyclohexyl acetate selectivity is 59.4%, which is significantly higher than HMCM-22 and HZSM-5. According to NH3-TPD and N2 ads-desorption characterization analysis results, it is obvious that quantity of total acid amount and strong acid position inthe zeolite is more benefit to the conversion of cyclohexeneand selectivity of the cyclohexyl acetate high, respectively. In addition, the larger ring of pore structure, the better the performance of catalysts.Catalytic properties of zeolites have possibilityof improvement by altering reaction conditions, but the limitation of the reaction equipment can not make the further study.2. Cation exchange resins and heteropolyacidsare chosen as the catalyst of the reaction, phosphotungstic acid has the best catalyst performance. The effect of different reaction conditions has been investigated, and the mole ratio of acetic acid to cyclohexene, amount of catalyst and reaction time are optimized. Finally, the appropriate reaction conditions are that reaction temperature is 80 ℃, the mole ratio of acetic acid to cyclohexene is 5.5: 1, the total amount of catalyst is 3% of reactants mass, reaction time is 2h. Under these conditions, the cyclohexene conversion and cyclohexyl acetate selectivity was 40.7% and 86.5%, respectively.3.Because phosphotungstic acid hydration is difficult to separate after reactions, preparing insoluble phosphorus tungstate. And meanwhile the reaction performance about different metal phosphorus tungstate and different molar ratio(Cs+ / H+) of phosphotungstic acid cesium salt catalyst are investigated. The result shows that Cs2.5H0.5PW12O40 has the best catalytic performance, cyclohexene conversion and cyclohexyl acetate selectivity is 43.6% and 91.8%, respectively. At the same time, Cs2.5H0.5PW12O40 has large specific surface area and mesoporous structure features by low temperature N2 adsorption-desorption characterization.4. To achieve continuous production in the future industrialization, the supported catalysts are prepared. MCM-41 is chosen as carrier, and Cs2.5H0.5PW12O40 is loaded. At the same time, the effect of different loadings on the catalyst performance is investigated. Finally, under 50% loading of Cs2.5H0.5PW12O40 and MCM-41 as the carrier, the catalytic property gets the best result. Cyclohexene conversion and cyclohexyl acetate selectivity is 28.6% and 88.9%, respectively.