Three-dimensional porous chromium oxide single crystals have been prepared by aminosilylation of the surface silanols of the template, SBA-15, anchoring of dichromic acid to the grafted amine groups, thermal decomposition of inorganic and organic compounds, and removal of the silica framework with HF.

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.

Stable van der Waals-bonded C60/benzene solvates were prepared using a novel crystallization technique. Solid-state NMR measurements on highly crystalline solvate under liquid benzene show that there is very little interaction between benzene and the C60 molecules and that the rotation of C60 at room temperature is not hindered. The magnetization transfer between benzene protons and local C60 molecules is highly inefficient. Three benzene species have been found in the solvate: two, nearly freely mobile, in wide and narrow porous structures, and the third constrained by C60 molecules in lattice defects. Premelting of deuterated benzene within the C60 solvate has been observed at Tm-10.5 K.

ZEOLITES derive their catalytic activity from the strong acidity of protons attached to the negatively charged aluminosilicate frame-work, which makes the materials excellent proton donors. Unlike zeolites, the aluminophosphate molecular sieves1,2 are built from alternating AIO4 and PO tetrahedra and are thus electrically neutral. Much attention has therefore been devoted to the genera-tion of Br0nsted acidity in these materials by introducing het-eroatoms, such as Si, Mg, Fe, Co or Zn, to produce negatively charged frameworks3-6. Similar arguments apply to gallophos-phate molecular sieves7-10, of which cioverite9,to is a remarkable example. This extra-large-pore material contains pore openings in the form of a four-leafed clover, defined by a ring of 20 gallium and phosphorus atoms, some of which are linked to terminal hydroxyl groups. Here we use NMR, X-ray photoelectron spectroscopy (ESCA) and infrared spectroscopy to show that the P-OH groups in cloverite are localized versions of those in solid phosphoric acid, H3PO4. Cloverite is thus a strong Br0nsted acid even though no heteroatoms are present in its framework.

The synthesis of DPA-VPI-5 and TBA-VPI-5 and their phase transformation to AIPO4-8 have been studied by X-ray diffraction in situ. The synchrotron radiation-energy dispersive diffraction is shown to be able to monitor these two fast reactions in real time. The results indicate that nucleation may occur already during the aging of the synthesis gel. The different rates oftransformtion of DPA-VPI-5 and TBA-VPI-5 show that the microstructure of the two materials is different.