Effect of MgAl2O4 on the structure, acidity as well as the catalytic performance of Nb2O5/-Al2O3 catalyst for ethylene oxide hydration was studied using IR, XRD, NH3-TPD, CO2-TPD and catalytic reaction. Modification of Al2O3 support with MgAl2O4 led to an increase in both basicity and mechanical strength of the support. As a result, the density and strength of the acidity of the niobium oxide catalyst supported on the MgAl2O4 modified -Al2O3 reduced in comparison with that supported on the pure -Al2O3. The acidity of 10% Nb2O5/MgAl2O4/-Al2O3 decreased with increasing loading of MgAl2O4. Catalytic test showed that EO conversion decreased monotonously with increasing MgAl2O4 loading, whereas the selectivity to MEG exhibited a maximum of 90.6% at MgAl2O4 loading of 2.23%. In terms of MEG yield, optimal MgAl2O4 loading should be around 2%. Durability test emonstrated that 10% Nb2O5/MgAl2O4/-Al2O3 catalyst exhibited excellent stability within 1000 h time-on-stream.

The effects of pore structure on the reaction rates and selectivities in the liquid-phase hydrogenation of 2-ethylanthraquinone over Ni-B amorphous alloy catalysts prepared by the reductant-impregnation method were studied using regular (HMS, MCM-41, and SBA-15) and commercial mesoporous silicas as supports. The composition, particle size, and location of the Ni-B particles were profoundly influenced by the pore structure of the supports. It is found that the location of the Ni-B particles depended on the pore size of the supports, whereas the uniformity of particle size was related to the interaction between the Ni-B particles and the supports. The hydrogenation rate was much faster on Ni-B catalysts with pore diameters exceeding 5 nm than on the narrow-pore catalysts, whereas the selectivity to 2-ethyldihydroanthraquinone, the carbonyl group hydrogenation product, was higher on Ni-B catalysts supported on regular mesoporous silicas. The best activity and selectivity were achieved when using SBA-15 as the support, which is attributable to the formation of more uniform active sites due to the unique pore structure of SBA-15.

Niobium oxide (Nb2O5) supported on alumina (-Al2O3) prepared by impregnation was studied for hydration of ethylene oxide. The effects of niobium oxide loadings, calcination temperature and molar ratio of water to ethylene oxide (EO) on the reaction performance were investigated. The structure and acidity of the catalysts were characterized by using X-ray diffraction (XRD), differential thermal analysis (DTA)-thermogravimetric (TG) and infrared (IR) of pyridine adsorption. A durability test of niobic acid and Nb2O5/-Al2O3 catalyst was carried out over a period of 1000h. It was found that Nb2O5/-Al2O3 demonstrated very high activity and selectivity for hydration of ethylene oxide to monoethylene glycol (MEG) under mild conditions. Compared with the result of non-catalytic reactions, the conversion of ethylene oxide was increased from 34 to 99.8% on keeping monoethylene glycol selectivity almost unchanged when the hydration was carried out over 10wt.%Nb2O5/-Al2O3 catalyst. The yield of monoethylene glycol over Nb2O5/-Al2O3 was higher than that obtained over other solid acid catalysts. Moreover, the supported niobia catalyst demonstrated excellent stability and no deactivation was observed within 1000h of time-on-stream.

Reaction mechanism of skeletal isomerization of n-butane over Cs2.5H0.5P W12O40 catalyst was studied using 13C MAS NMR.The reaction proceeds mainly via a monomolecular mechanism at 80℃. The contribution of the bimolecular mechanism becomes more significant as the reaction temperature is increased to 150℃. Hydrogen suppresses the bimolecular mechanism, in particular on Pt-promoted Cs2. 5H0. 5P W12 O40 catalyst. The latter catalyst is highly selective to isobutane in the presence of H2 even at 220℃. The kinetics of the monomolecular isomerization reaction and the reaction schemes of 13C scrambling and n-butane isomerization are discussed.

Solid-state 13C NMR spectra of graphite oxide GO. and its derivatives prompt us to propose a new structural model. The spectra of GO treated with KI and the course of the thermal decomposition of GO reveal the presence of epoxide groups, responsible for the oxidating nature of the material. GO is built of aromatic'islands' of variable size which have not been oxidized, and are separated from each other by aliphatic 6-membered rings containing C-OH, epoxide groups and double bonds. The carbon grid is nearly flat; a small degree of warping is caused by the carbons attached to OH groups, which are in a slightly distorted tetrahedral configuration.