Jinxu Xi,Daqian Ding,Yi Shao,Xiaohui Liu,Guanzhong Lu,Yanqin Wang
The efficient usage of lignocellulosic biomass is of great significance for large-scale low-cost biomass conversion to biofuels and other useful chemicals. Here, an interesting catalytic process was reported related to converting cellulose into ethylene glycol (EG) and ethylene glycol monoether (EGME) in methanol over a Ru/NbOPO4 catalyst, with the cleavage of a C–C bond by NbOPO4 and further hydrogenation by supported Ru particles. The influence of reaction temperature, hydrogen pressure, and reaction time was systematically investigated and showed that a 54.5% total yield of EG and EGME could be obtained at 220 °C in 3 M Pa H2, which was an exciting result. Meanwhile, the effect of solvent was also studied in detail. It was shown that methanol played an important role in the production of EG and EGME, especially in the cleavage of the C–C bond. Methanol could protect the C═O bond in glucose produced from cellulose through acetalization, thus prevent its hydrogenation, and led to the production of EG and EGME. Furthermore, the influence of dopants (W, Sn, Ni, Cu) was further investigated, and it was found that only the Ru–Ni/NbOPO4 catalyst was more effective through limiting the further hydrogenolysis of products (EG and EGME) to CO and alkanes, and as high as 64% total yield of EG+EGME was achieved. Moreover, the Ru–Ni/NbOPO4 catalyst showed good reusability, which can be reused at least four times with a little loss in EG and EGME yield.
Lignin, as an important biomass resource, has significant research value in its oxidative cleavage process. Nickel-based metal catalysts could selectively depolymerize lignin. A series of heteropolyacid doped nickel based bimetallic catalysts Ni 4 Mo 1 -MOF-x（x represented heteropolyacid）were prepared by hydrothermal method, which were calcined to catalyze the oxidative cleavage of lignin model compound (2-phenoxy-1-acetophenone). The catalyst Ni 4 Mo 1 -MOF-SiWA-0.1(500) showed the best catalytic performance in methanol solvent under conditions of 160 °C, 4 h, 0.5 MPa oxygen pressure, where the conversion rate was nearly 100 % and the yields of phenol and benzoic acid were 54.5 % and 23.3 %, respectively. The catalysts were well characterized to explore the catalytic performance during the oxidation of lignin dimer. This study could provide some interesting and useful information for the catalytic oxidation of lignin to biomass-derived chemicals.
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