Vapour-phase O-methylation of catechol with methanol has been investigated over Ti-containing aluminium phosphate catalysts (denoted as Al0.77TixP, where x is between 0 and 1.15) prepared by non-uniform precipitation method. The catalytic activities increase with the increase of Ti/P ratio in the range 0-0.23, while further increase of Ti content leads to the decrease of activities. Meanwhile, the selectivity to guaiacol decreased gradually with the increase of Ti/P ratio. The results of various means of characterization demonstrate that the addition of titanium considerably affects the structure of the catalysts, as well as the strength and amount of the acidic and basic sites. The presence of stronger Lewis acidic and/or basic sites in the higher Ti content catalysts should be responsible for the formation of side products (C-alkylation products) and coke, thus quickening the deactivation process of the catalysts. On the other hand, the weak acidic-basic characteristics of the lower Ti content catalysts result in the high selectivity to mono-O-methylation product (guaiacol), and the excellent durability of the catalysts.

The adsorption properties of nitrogen monoxide (NO) on various metal ion-exchanged zeolites were examined by adsorption-desorption measurements in a fiied bed flow adsorption apparatus. Among the samples used, the copper ion-exchanged ZSM-5 zeolites showedthe greatest ability for reversible adsorption of NO; therefore, it has been studied in more detail. The amounta of reversible and irreversible adsorption of NO per copper ion exchanged increased with decreasing aluminum content of the zeolite, and were constant, independent of the ion exchange level. The NO species adsorbed on the zeolite were characterized by infrared (IR) and temperature-programmed desorption (TPD) techniques. Most of the NO reversibly adsorbed is the NO+ adsorbed on Cu2+, and the NO irreversibly adsorbed is the residual of NO+, nitrate (NO3-), nitrite (NOz-1, and NO2+. The irreversibly adsorbed species gave the desorption peaks at 400, 463, and 663K. The total amount of NO desorbed in the TPD experiment is in good agreement with the amount of irreversible adsorption of NO evaluated from the adsorption-desorption measurement.

A series of samples have been prepared from high dispersion of CuCl2 into NaZSM-5 and HZSM-5 zeolites, and characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), hexane isotherms, and IR spectroscopy. The catalytic activity in selective reduction of NO shows that CuCl2/HZSM-5 catalyst exhibits higher conversion at 3008C than that of CuZSM-5 prepared from an ion-exchange method. Correlation of catalytic data with infrared spectra for CuCl2/HZSM-5, CuCl2/NaZSM-5, and CuZSM-5 samples suggested that the catalytic sites can be assigned to synergetic effect of protons and copper species.

Au/ZnO catalysts prepared by co-precipitation method with different Au: Zn atomic ratios have been studied for room-temperature CO oxidation in the presence/absence of water in the feed stream. The catalysts exhibited excellent catalytic activity and stability compared with pure ZnO. Furthermore, it was found that the lifetime of Au/ZnO catalysts was improved significantly by increasing CO concentration but decreased by addition of H2O in the feed stream. The deactivation may be related to the sintering of metallic gold and the accumulation of carbonate-like species in the catalyst.