The effects of calcination temperature and preparation method of TiO2-ZrO2 mixed oxide on catalytic performance of B2O3/TiO2-ZrO2 catalysts were investigated. TiO2-ZrO2 mixed oxides with the same molar ratio of 1:1 were prepared by co-precipitation method, homogeneous precipitation method, sol-gel method and physical mixing method; each oxidewas calcined at a temperature between 110 and 700℃. Catalytic synthesis of ε-caprolactam from cyclohexanone oxime was evaluated in a fixed-bed flow microreactor at 300℃ and atmosphere pressure. Characterization of catalysts was carried out using adsorption of nitrogen, X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR) and temperature-programmed desorption of ammonia (NH3-TPD) techniques. The experimental results reveal that the calcination temperature in the range of 110-500℃ had only a slight effect on the catalytic performance, but after calcination at 700℃, the ZrTiO4 crystallite was formed and accounted for the decrease of acidity and catalytic performance. The co-precipitation method provided the catalyst with the highest reactivity while the physical mixing method resulted in the worst catalyst. Catalytic performance of the B2O3/TiO2-ZrO2 catalyst was closely related to its acid strength distributions and pore size.

The TS-1/diatomite catalyst was prepared for the hydroxylation of phenol with H2O2 in the fixed-bed reactor and the effects of pretreatment on the properties of TS-1/diatomite were studied by FT-IR, XRD, UV-vis, ICP-AES, BET surface area and NH3-TPD techniques. It is shown when the catalyst is pretreated by the KAc, NaAc, NH4Ac, NH4Cl or HNO3 aqueous solution, the framework structure of TS-1 is not destroyed and titanium in the framework is not removed. The surface area of catalyst has no obvious change compared with that of the untreated catalyst. But the extra-framework TiO2 can be removed partly, which leads to the slight increase of the crystallinity of catalyst and the decrease of acid concentration on the surface of the TS-1/diatomite catalyst. As a result, the activity, selectivity and utilization of H2O2 for hydroxylation of phenol are improved. After the TS-1/diatomite catalyst is pretreated by the NH3•H2O, Na2CO3 or Na3PO4 solution, its framework silicon is dissolved partly in the base solution and the framework structure of TS-1 is destroyed. While the crystallinity and surface area of catalyst decrease and the concentration of acid sites on the surface of catalyst increased slightly. As a result, the catalytic activity of the TS-1/diatomite catalyst for hydroxylation of phenol descended or deactivated completely.

As a novel support of immobilizing penicillin G acylase (PGA), MCM-48 and Co-MCM-48 molecular sieves were synthesized and characterized by XRD, N2 adsorption, NH3-TPD, FT-IR and so on. The studies show that MCM-48 and Co-MCM-48 has well ordered long-range structure, narrow pore size distribution, larger surface area and higher concentration of the weakly acidic silanol groups on their surface. PenicillinGacylasewas immobilized on MCM-48 or Co-MCM-48 by interacting silanol groups on the surface. The presence of cobalt in the framework of MCM-48 increases the amount of the weak acid sites. For the hydrolysis of penicillin G catalyzed by PGA/Co-MCM-48 (Co/Si=0.01), its specific activity reaches 1682U/g. After used for six cycles, PGA/MCM-48(0.01) can keep 1375U/g of the specific activity. If MCM-41 was used as the support, the activity of immobilized PGA is only 402U/g.

Pure TiO2, ZrO2 and TiO2-ZrO2 mixed oxides with various compositions were prepared by the co-precipitation method. Catalysts containing 12wt.% boria were prepared using these oxides and their catalytic performance for vapor-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam was determined.With increasing zirconia content in the mixed oxide, the specific surface area and the temperature of the phase transformation increased; maximum values were obtained for a mixed oxide having a Ti and Zr molar ratio of 1/1. XRD results indicated that TiO2-ZrO2 became amorphous after calcination at 500℃ if neither the content of TiO2 nor that of ZrO2 was less than 25%. The yield of lactam increased with increasing zirconia content in mixed oxide and reached a maximum value for the B2O3/TiO2-ZrO2 (1/1) catalyst.With further increase in zirconia content, the lactam yield decreased; the lowest value was observed for the pure ZrO2-supported catalyst. The acidic property and the pore characteristics of the catalyst were key factors that affected its performance. The influences of the operating parameters on the performance of B2O3/TiO2-ZrO2 (1/1) catalyst were also investigated.

Epoxidation of propylene to propylene oxide bymolecular oxygen was studied over amodifiedAg-MoO3 catalyst. The results showthatMoO3 plays an important role in improving the efficiency of the catalyst, and a suitable content of MoO3 is 40-50wt%. XPS reveals that some of the silver and molybdenum in the catalyst exist as Ag