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A novel process based on cyclohexene esterification–hydrogenation for the production of cyclohexanol, the key intermediate in the production of ε-caprolactam, was devised and validated for the first time. In this process, cyclohexene obtained from the partial hydrogenation of benzene is esterified with acetic acid to cyclohexyl acetate, followed by hydrogenation to cyclohexanol. The experimentally determined equilibrium conversion of cyclohexene for cyclohexene esterification at the stoichiometric ratio is always ≥68% in the temperature range of 333–373 K over the commercial Amberlyst 15 catalyst, which is substantially higher than that of cyclohexene hydration. The apparent activation energy (Ea) for the esterification of cyclohexene with acetic acid is 60.0 kJ mol−1, which is lower than that of cyclohexene hydration. In the hydrogenation of cyclohexyl acetate to cyclohexanol, high conversion of 99.5% and high selectivity of 99.7% are obtained on the La-promoted Cu/ZnO/SiO2 catalyst prepared by the co-precipitation method. This process shows both a high overall atom economy of 99.4% comparable to that of the cyclohexene hydration process and a much higher catalytic efficiency than the phenol hydrogenation process. On the basis of the above fundamental works, a pilot-scale demonstration unit with a capacity of 8000 tonnes per annum was developed and operated smoothly for more than 1000 h with no indication of deactivation. [ABSTRACT FROM AUTHOR]

It has been documented that W-modified Pt catalysts with relatively high tungsten contents are effective for the catalytic transformation of biodiesel-derived glycerol to 1,3-propanediol (1,3-PDO). Herein, we report a new finding that Pt/W–SBA-15 catalysts with extremely low W/Si atomic ratios (≤1/80) exhibit excellent catalytic performance in the hydrogenolysis of glycerol to 1,3-PDO. In particular, a Pt/W–SBA-15 catalyst with the W/Si ratio of as low as 1/640 (Pt/W–SBA-15(1/640)) gave rise to the highest 1,3-PDO selectivity of 70.8% at a high glycerol conversion of 86.8% and thus afforded the highest yield of 1,3-PDO of 61.5%. A combination of characterization techniques evidenced that tungsten was homogeneously incorporated into SBA-15 in the form of isolated tetragonal WO4 and only displayed Lewis acidity. The particle size of Pt evolved in a reverse volcanic curve with the W/Si ratio, with the smallest size being observed for Pt/W–SBA-15(1/640). Control experiments indicated strong synergy between Pt nanoparticles (NPs) and WO4 in the hydrogenolysis of glycerol. A probe reaction suggested that Brønsted acid sites were generated in situ on the Pt/W–SBA-15 catalysts in a H2 atmosphere by the reaction between WO4 and spillover H atoms from the Pt NPs. It is plausible that the hydrided WO4 functioned as a highly selective active centre in the hydrogenolysis of glycerol to 1,3-PDO, whereas the Pt NPs played the role of a reservoir of spillover H atoms. Thus, a good match between the isolated WO4 and the small Pt NPs was responsible for the superior catalytic performance of Pt/W–SBA-15(1/640). [ABSTRACT FROM AUTHOR]

The ever-increasing industrial demands for nylon-6 and nylon-66 and the more and more stringent regulations on particulate emission in exhaust gases necessitate the development of an energy-efficient and environment-friendly method for saturation hydrogenation of benzene and its derivatives. However, the hydrogenation of benzene is usually conducted at a high temperature and/or under high H2 pressure, which is energy-consuming and of low environmental safety. Here, we prepared amorphous Ru–B/MIL-53(Al, Cr, and AlCr) catalysts via the wetness impregnation–chemical reduction method, which were comprehensively characterized by a combination of techniques. We found that the Ru–B/MIL-53 catalysts could catalyse the hydrogenation of benzene to cyclohexane under mild reaction conditions of 30 °C and 1.0 MPa of H2 with high efficiency, among which the Ru–B/MIL-53(AlCr) catalyst exhibited the highest turnover frequency (TOF) in terms of benzene of 6.4 s−1. Moreover, this catalyst showed good recyclability and high activities in the hydrogenation of toluene, o-xylene, m-xylene, p-xylene, and mesitylene as well, which shows promise for the application of the Ru–B/MIL-53 catalysts in the industrially important and environmentally desirable hydrogenation reaction of benzene and its derivatives. [ABSTRACT FROM AUTHOR]

In the challenging crotonaldehyde hydrogenation to crotyl alcohol, an Ag–In/SBA-15 catalyst fabricated by a modified “two solvents” strategy shows an unprecedentedly high yield of 86% at a selectivity of 87%, which exceeds the best results on Pt-, Au- and other Ag-based heterogeneous catalysts reported so far. [ABSTRACT FROM AUTHOR]

Square and round single crystalline SnO platelets have been prepared in a solution-based chemical route aided with sonication at room temperature.

A nanosized amorphous Ni-Cr-B catalyst prepared by the chemical reduction method exhibited superior thermal stability and selectivity in hydrogen peroxide synthesis via the anthraquinone route.