Ru/C catalyst was used in hydrogenation of levulinic acid to produce γ-valerolactone. The conversion rate and the selectivity of levulinic acid to γ-valerolactone with Ru/C as catalyst were higher than those with Pd/C, Raney nickel, and Urushibara nickel. The optimum preparation conditions of γ-valerolactone by hydrogenation of levulinic acid catalyzed by Ru/C were as follows: temperature at 130 °C, hydrogen pressure at 1.2 MPa, dosage of catalyst at 5.0% (based on the mass fraction of levulinic acid), the solvent being methanol, and a reaction time of 160 min. The conversion rate of levulinic acid to γ-valerolactone was found to be 92%, and the selectivity of γ-valerolactone was 99%. The surface structure variations of the fresh and used catalysts were characterized by XRD and XPS. Furthermore, the reaction pathway for the hydrogenation of levulinic acid was proposed.

Metal–organic frameworks (MOFs) are highly versatile materials that find applications in several fields. Highly stable zirconium/hafnium-based MOFs were recently introduced and nowadays represent a rapidly growing family. Their unique and intriguing properties make them privileged materials and outstanding candidates in heterogeneous catalysis, finding use either as catalysts or catalyst supports. Various techniques have been developed to incorporate active species into Zr-MOFs, giving rise to catalysts that often demonstrate higher performances or unusual activity when compared with their homogeneous analogues. Catalytic functions are commonly incorporated at the zirconium-oxide node, at the linker, or encapsulated in the pores. Representative examples are discussed, and advantages in adopting Zr- and Hf-MOFs in catalytic applications are highlighted.

The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3), exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed.

We report the synthesis and characterization of a water-stable zirconium metal-organic framework (MOF), NU-1003, featuring the largest mesoporous aperture known for a zirconium MOF. This material has been used to immobilize the nerve agent hydrolyzing enzyme, organophosphorus acid anhydrolase (OPAA). The catalytic efficiency of immobilized OPAA in nanosized NU-1003 is significantly increased compared to that of OPAA immobilized in microsized NU-1003 and even exceeds that of the free OPAA enzyme. This paper highlights a method for rapid and highly efficient hydrolysis of nerve agents using nanosized enzyme carriers.

lett.8b00154. Details on experimental and computational methods as well as adsorption isotherms, isosteric heats of adsorption, and PXRD patterns (PDF)■ AUTHOR INFORMATION