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Isotropic Raman spectra of poly(ethylene oxide) in aqueous solution and in the melt show differences in the skeletal stretching vibration bands near 800 cm-1 and in the disordered longitudinal acoustic mode feature in the 200−400 cm-1 region. These spectra may be simulated by superposing calculated spectra resulting from a series of normal coordinate calculations performed for an ensemble of conformers. The conformational distribution for poly(ethylene oxide) in the molten state appears to favor the tgg‘ conformer, which dominates the spectrum calculated to match closely the observed isotropic Raman spectrum. It appears that the experimental data suggest that the tgg‘ conformation is present by a greater amount than is predicted by previous simulation methods. On the same basis, it appears that the aqueous solution of poly(ethylene oxide) contains mostly tgt conformers. The results for poly(ethylene oxide) were supported by measurements and computations made using 1,2-dimethoxyethane as a model.

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A series of Cu−Ni/CeO 2 -nanotube catalysts is prepared by an impregnation method for CO 2 hydrogenation to CH 3 OH. Regular CeO 2 nanotubes are perfectly formed with a tube diameter of about 30−50 nm and Cu−Ni alloy is well dispersed on CeO 2 nanotube without nanotube morphology change. There is a synergistic effect between Ni and Cu, promoting the bimetallic Cu−Ni dispersion, reducibility, CO adsorption and hydrogenation. Additionally, a strong interaction is observed between Cu−Ni alloy and CeO 2 , and it contributes to partial reduction of Ce 4+ to Ce 3+ and formation of oxygen vacancies which adsorb and activate CO 2 . It is shown that both CO 2 conversion and CH 3 OH space-time yield increase at first, reach their maximum values at a Ni/ (Cu+Ni) ratio of 2/3, and then decrease with increasing the Ni/(Cu+Ni) ratio. The CeO 2 -nanotube supported CuNi 2 catalyst gives CO 2 conversion of 17.8% and CH 3 OH space-time yield of 18.1 mmol/(g cat •h) after preliminary optimization. Furthermore, it exhibits an excellent catalytic performance within a wide range of space velocity.