Study On The Integrated Process Of H₂O₂ Production Through Isopropanol Oxidation And The Ammoximation Of Cyclohexanone

The ammoximation of cyclohexanone to cyclohexanone oxime with hydrogen peroxide and ammonia catalyzed by TS-1 has distinct advantages, such as mild conditions, high conversion of cyclohexanone, high selectivity to cyclohexanone oxime and no pollution. It is a new catalytic oxidation process. However, hydrogen peroxide constitutes the main cost of the final product, and the transportation and storage of hydrogen peroxide in low concentration may cause many problems. Process integration is often used as an alternative method for optimization, and the integrated process of hydrogen peroxide production and the direct ammoximation of cyclohexanone should be attached great importance to green chemical industry. Therefore, the followings have been studied in this thesis in order to integrate the processes of hydrogen peroxide production and the direct ammoximation of cyclohexanone.Firstly, the isopropanol oxidation was studied. The effects of the temperature, pressure and reaction time on the isopropanol oxidation were investigated and the optimal reaction conditions were 110(C, 1MPa, 2h. At these conditions, the yield of hydrogen peroxide was 7.5 %. The oxidation products were fractionated and the levels of some impurity compounds left in hydrogen peroxide solution after separation were determined.Secondly, the possibility of the integrated process of hydrogen peroxide production through isopropanol partial oxidation and the ammoximation of cyclohexanone in a t-butanol based solvent system was investigated. The influence of impurity compounds, such as isopropanol, acetone, acetic acid, stabilizers and corrosion inhibitors, on the ammoximation of cyclohexanone was studied in detail. The presence of these impurities in the hydrogen peroxide solution did not appreciably influence the ammoximation of cyclohexanone. In the integrated process, the hydrogen peroxide solution obtained after fractionation by isopropanol oxidation was used in the ammoximation of cyclohexanone, and the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were 99.2% and 99.9%, respectively. The results indicate that the processes of hydrogen peroxide production through isopropanol partial oxidation and the ammoximation of cyclohexanone in a t-butanol based solvent system can be integrated. Thirdly, the possibility of the integrated process of hydrogen peroxide production through isopropanol partial oxidation and the ammoximation of cyclohexanone in an isopropanol based solvent system was investigated. The ammoximation of cyclohexanone in an isopropanol based solvent system was first studied. The optimal reaction conditions were 80(C, the mass ratio of isopropanol to cyclohexanone selected at 2.3, the molar ratio of ammonia to cyclohexanone selected at 2.1. The conversion of cyclohexanone and the selectivity to cyclohexanone oxime can be improved by adding the pressure of the reaction system. At the optimal conditions, the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were 99.7% and 99.68%, respectively. The influence of impurity compounds, such as acetone, acetic acid, stabilizers and corrosion inhibitors, on the ammoximation of cyclohexanone was also studied. The presence of these impurities in the hydrogen peroxide solution did not appreciably influence the ammoximation of cyclohexanone. In the integrated process, the hydrogen peroxide and isopropanol solution obtained after fractionation by isopropanol oxidation was used in the ammoximation of cyclohexanone, and the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were 99.6% and 99.7%, respectively. The amounts of by-product, acetone oxime, in the ammoximation products can be controlled by controlling the molar ratio of hydrogen peroxide to cyclohexanone. The results indicate that the processes of hydrogen peroxide production through isopropanol partial oxidation and the ammoximation of cyclohexanone in an isopropanol based solvent system can be integrated.