Hydrogenation of 3-hydroxypropanal into 1,3-propanediol over bimetallic Ru–Ni catalyst†
A series of Ni-based catalysts, including Ru/SiO2, Ni/SiO2 and Ru–Ni/SiO2, were prepared and employed in the hydrogenation of 3-hydroxypropanal (3-HPA) to 1,3-propanediol (1,3-PDO). The catalysts were systematically characterized by means of XRD, TEM, HRTEM, SEAD, XPS, H2-TPD, H2-TPR and N2-physisorption. It was indicated that the introduction of Ru onto the Ni/SiO2 not only increased the porosity of catalyst and the degree of dispersion of Ni species but also promoted the reduction of Ni2+ to Ni0 and the generation of active hydrogen species. The catalytic performance evaluation showed that the Ru–40Ni/SiO2 catalyst, among all others, could provide the largest yield of 1,3-PDO (above 99.0%) and highest TOF (4.70 × 103 S−1). The optimized reaction conditions over the Ru–40Ni/SiO2 catalyst had been established as follows: reaction temperature = 80 °C, H2 pressure = 2.0 MPa and LHSV = 0.4 h−1. In consideration of its extremely low H2 pressure and very high yield of 1,3-PDO for the hydrogenation of 3-HPA, to the best of our knowledge, the Ru–40Ni/SiO2 catalyst appeared to be the most efficient catalyst among all others reported in the literature. The good performance enabled the Ru–40Ni/SiO2 catalyst to be very promising in its industrial application.