Deactivated palladium catalysts in the hydrogenation of anthraquinone were regenerated with ethanol, nitric acid, hydrogen peroxide, boiling water and steam, respectively. The deactivated and regenerated catalysts were characterized by XPS, ICP, TG, FTIR, TPD, XRD, etc., and studied in the hydrogenation of anthraquinone. The results showed that the main cause of catalyst deactivation is the coverage of the active component by deposits. The treatments by hydrogen peroxide and boiling water can effectively regenerate the deactivated catalysts.Anthraquinone route, palladium catalyst, deactivation, regeneration

A new working solution consisting of 2-pentylanthraquinone (PAQ) and 6-pentyl 1, 2, 3, 4-tetrahydroantraquinone (4HPAQ) was hydrogenated and then oxidized by O2 to produce H2O2. The oxidation reaction was conducted in a well-stirred batch reactor at 30～50℃ and 0.10～0.20MPa. By measuring the concentrations of generated H2O2 by iodometry, the intrinsic kinetics for the gas-liquid oxidation of 6-pentyl-1, 2, 3, 4-tetra-hydroanthacene-9, 10-diol (4HPAQH2, the only hydrogenated product in the hydrogenated working solution) with molecular oxygen were studied. An exponential model was employed to describe the reaction rate and the kinetic parameters were obtained. The results show that the reaction rate is 0.7 and 1.4 order in the concentration of 4HPAQH2 and oxygen pressure, respectively, and the activation energy for oxidation is 41.3kJ/mol.

The extraction of hydrogen peroxide by means of deionized water from anthraquinone working solution via anthraquinone process was carried out in a gas-agitated sieve plate extraction column. The effects of the superficial velocity of air, dispersed phase and continuous phase on the overall plate extraction efficiency have been investigated. The corrections for the prediction of the overall plate extraction efficiency were presented. The correction proposed to predict the overall plate extraction efficiency in the air, water, anthraquinone working solution three-phase system agreed satisfactory with experimental data with a maximum absolute deviation of 5.6%. A new design method for gas-liquid-liquid three-phase extractors is developed based on the multistage countercurrent extraction model. The calculated data by the model agreed well with experimental data and the average relative deviation was less than 10%. Moreover, the model was used to predict a gas-agitated sieve plate extraction column for industrial production of hydrogen peroxide. The results show that the plate numbers of gas-agitated sieve plate extraction column are 30-40% less than that of liquid-liquid sieve plate column.

The possibility of the integration of the processes ofH2O2 generation through isopropanol partial oxidation and ammoximation of cyclohexanone with H2O2 and NH3 TS-1 catalysed was investigated. The ammoximation of cyclohexanone over TS-1 with isopropanol as solvent was first studied. The results show that isopropanol can be used as solvent, and the impurities in the H2O2 solution obtained through isopropanol oxidation with only acetone needing to be separated have no harmful effects on the ammoximation of cyclohexanone, suggesting that the process of H2O2 generation through isopropanol oxidation and the ammoximation of cyclohexanone could be directly integrated.

The ammoximation of acetone to acetone oxime with 30wt.% hydrogen peroxide over TS-1 has been studied. The conversion of acetone and the selectivity to acetone oxime can reach 99% and 94%, respectively. The by-products are the corresponding hydrazone, imine and small amounts of unidentified compounds. The influence of various parameters such as solvent, temperature, amounts of catalyst and the NH3 to acetone molar ratio were investigated. Keywords: Acetone oxime, acetone, ammoximation, TS-1, hydrogen peroxide