Graphite oxide (GO) and its derivatives have been studied using 13C and 1H NMR. The 13C NMR lines at 60, 70, and 130 ppm are assigned to C-OH, C-O-C, and>CdC<groups in the bulk of the material, respectively. The>CdC<double bonds are relatively stable, while C-OH groups may condense to form C-O-C (ether) linkages. There are at least two magnetically inequivalent C-OH sites, and the structure does not necessarily possess long-range order. Water molecules interact very strongly with the structure. The results reveal a number of new structural features.

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.

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.

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.

The synthesis of TBA-and DPA-VPI-5 has been studied in detail. Optimal synthesis conditions have been established using ternary composition diagrams for TBA-Al203-PzOs and DPA-Al203-PzO. Gel samples at different aging times have been examined using chemical analysis, X-ray diffraction, FT-IR, and solid-state NMR. Two reactions occur between H3P04 and pseudo-boehmite during gel aging. Interaction between the acid and the OH groups linking the pseudo-boehmite layers leads to the formation of an AI-0-P species in which A1 is 6-coordinated. A further reaction between the acid and the AI-O-P species results in the formation of a 4-coordinated A1 species. Because of the different aging conditions, the latter reaction begins much earlier in the TBA system than in the DPA system. The behavior of DPA in the synthesis gel is different from that of TBA. There is evidence that crystallization of VPI-5 proceedsvia a solid-state mechanism, and that nucleation in both systems occurs already during the aging of the gels.