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We report the synthesis, characterization, and catalytic performance for gas phase propane dehydrogenation of single-site Co2+ ions supported on silica. Spectroscopic characterization by resonance Raman, electron paramagnetic resonance, and X-ray near-edge and extended absorption fine structure revealed that tetrahedrally coordinated Co2+ ions are chemisorbed into the trisiloxane rings on the surface of amorphous silica. In situ XAS shows that Co is not oxidized by air nor reduced by hydrogen even at 650 °C. For catalytic propane dehydrogenation, single-site Co2+/SiO2 exhibits selectivities >95% at 550 °C and >90% at 650 °C with stable activity over 24 h. Calculations with hybrid density functional theory support a non-redox mechanism for activation of C–H and H–H bonds by Co2+ similar to that previously reported for single-site Zn2+/SiO2.

The effect of alcohol as a solvent on the acid-catalyzed conversion of furfuryl alcohol ( FA ) into polymerized furfuryl alcohol ( PFA ) has been studied by UV Raman spectroscopy. The major peak intensity ratios were compared to gain quantitative information about the extent of polymerization in various solvents. The reaction rate of the polymerization has been found to significantly decrease with increasing concentrations of ethanol or butanol ( n -butanol and iso -butanol). Compared to ethanol, longer or branched chain alcohols such as n -butanol and iso -butanol can marginally reduce the acid-catalyzed polymerization at room temperature. The plot of reciprocal intensity of the characteristic Raman band of FA vs. the reaction time suggests that the polymerization reactions follow second-order kinetics.

Fifteen distinct MgOV 2 O 5 , MgOMoO 3 , MgOV 2 O 5 MoO 3 , and V 2 O 5 MoO 3 compositions were prepared using sol–gel chemistry and their selectivities and conversions for propane oxidative dehydrogenation (ODH) to propylene were measured. The vanadates were more active than the molybdates at lower temperatures; however, the molybdates exhibited higher selectivities at similar conversions. An increase in both ODH conversion and selectivity with molybdenum substitution on vanadium sites was also observed. These results demonstrate the importance of the bulk structure on the ODH reaction. In general, propylene selectivities increased with increasing conversions at temperatures above 673 K when oxygen depletion in the reactant stream occurred. Visible and UV Raman spectroscopy corroborates this result and helps focus attention on critical surface-specific information. A new Raman peak was observed for the partially reduced MgMoO 4 and is associated with a three-coordinate surface oxygen.

An infrared matrix isolation study has been performed for sodium and benzene mixtures in solid argon at 9 K. In contrast with the earlier report, sodium was evidence to form complexes with benzene. Although the exact nature of the complexes is not certain, ab initio quantum mechanical calculation indicated clearly that the 1:1 NaC 6 H 6 complex should be as stable as the 1:1 LiC 6 H 6 complex. The tentatively assigned peak frequencies for the 1:1 NaC 6 H 6 complex were also inv fair agreement with the theoretical values.