Study On The Catalysts Of Tungsten System For Synthesis Adipic Acid From Cyclohexene Directly In A Green Way

Adipic acid is an important chemical raw materials used in the synthesis of Nylon 66, Nylon 46 and polyurethane products. However, clean and efficient synthesis of adipic acid is still an important research subject at present. Therefore, this thesis examined in detail the influence of reaction conditions that synthesis of adipic acid by oxidation cyclohexene with H2O2 catalized by sodium tungstate and phosphotungstic acid, and the containing tungsten species with better catalytic properties was optimized. Minewhile, solid load test for the optimized species containing tungsten was carried out. The influence of carrier catalyst on the reaction performance was inspected for selecting appropriate solid catalyst carrier, so as to provide basis for the research of green industrial catalyst in this reaction.The possibility in thermodynamic that synthesis of adipic acid by oxidation of cyclohexene with H2O2 and the influence of reaction conditions on reaction were examined. The calculation results showed that reaction is spontaneous reaction and reaction can almost completely reach the equilibrium state in temperature range of 298.15K~373.15 K. The low temperature and H2O2 / cyclohexene(mole ratio) controlled between 4:1 to 5:1 is conducive to the production of adipic acid.The influence of reaction conditions in the synthesis process of adipic acid by oxidation of cyclohexene with H2O2 for catalyzed Na2WO4 was examined. The results showed that influence of three factors of reaction temperature, heating reflux time of Na2WO4 and H2O2 and heating reflux temperature of Na2WO4 and H2O2 on the yield of adipic acid weakened in turn. When the material ratio of Na2WO4 ? 2 H2O: H3PO4: H2O2: C6H10 = 5:20:400:100(mmol ratio) as well as heating reflux of Na2WO4 with H2O2 in 60 oC for 30 min and reaction in 102 oC for 2 h, the yield of adipic acid reached as high as 63%.The affect of reaction conditions of synthesis of adipic acid by oxidation of cyclohexene with H2O2 catalyzed by hosphotungstic acid on reaction performance and compared with that of Na2WO4. The results showed that yield of adipic acid on phosphotungstic acid higher than at least 10% that of Na2WO4 under conditions of W:H2O2:C6H10 =3:400:100(mmol ratio) and lower temperature(<95oC). So the phosphotungstic acid is suitable for the reaction as active component of catalyst.The affect of immobilized carrier, such as TS-1 molecular sieve, Si O2, Al2O3 and TiO2, on synthesis of adipic acid by oxidation of cyclohexene with H2O2. The results indicated that high yields of adipic acid were obtained on PW/ SiO2 and PW/ Al2O3 under conditions of 90 oC and 10 h on stream, whose yields above 30%. Therefore, SiO2 and Al2O3 can be used as appropriate carrier for immobilizing phosphotungstic acid.