25 weight% ZrO2/SBA-15 catalyst exhibits good activity in the catalytic transfer hydrogenation of levulinic acid under vapour phase conditions at atmospheric pressure.

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CO2-assisted dehydrogenation of benzyl alcohol to benzaldehyde over Cu nanoparticles dispersed on CeO2 was reported. Cu nanoparticles with an average size of ∼11.4 nm dispersed over CeO2 cubes were efficient in selective conversion of benzyl alcohol with a rate of formation of benzaldehyde of 250.99 μmol s–1 gcat –1. The high rate of reaction might be due to the miscibility of BOH in CO2, which led to enhanced diffusion of BOH reactant molecules toward active sites. The controlled surface acid–base sites were responsible for the activation of benzyl alcohol, and nearby Cu nanoparticles abstracted α-H of benzyl alcohol to form benzaldehyde. During a time on stream study, the Cu-CeO2 catalyst experienced a gradual deactivation in the presence of N2 as the carrier gas, while in the presence of CO2, it delivered constant activity for 24 h. In the presence of N2, in-situ generated hydrogen was responsible for the formation of much toluene via hydrogenolysis of benzyl alcohol. CO2 acted as a soft oxidant, which minimized the in-situ generated hydrogen via the reverse water gas shift reaction; as a result, the toluene formation and deposition of carbonaceous species were minimized.

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Vapor phase hydrogenation of levulinic acid using formic acid as a hydrogen source has been conducted over ordered mesoporous Cu/Fe 2 O 3 catalysts prepared by hard template method using mesoporous silica, SBA-15. X-ray diffraction result reveals the absence of copper peaks because of either highly dispersed state, or formation of a solid solution with iron oxides. The N 2 sorption analysis and TEM results indicate the retainment of mesoporous nature in the samples. Among the catalysts tested, 10 (wt%) Cu/Fe 2 O 3 seems to be an efficient catalyst to yield higher amounts of γ-valerolactone under hydrogen-free conditions. The results reveal the formation of spinel species, which gets reduced easily at a lower temperature (as evidenced from TPR studies), and as a consequence of this synergism, significant improvement in the catalytic performance for the synthesis of γ-valerolactone from levulinic acid and formic acid in presence of water has been achieved. The presence of water plays a crucial role in obtaining a higher yield of γ-valerolactone. This makes the catalytic system a viable methodology for hydrogenation of levulinic acid to get γ-valerolactone.