摘要
The directly selective hydrogenolysis of xylitol to ethylene glycol (EG) and 1,2-propylene glycol (1,2-PDO) was performed on Cu-Ni-ZrO2 catalysts prepared by a co-precipitation method. Upon optimizing the reaction conditions (518 K, 4.0 MPa H-2 and 3 h), 97.0% conversion of xylitol and 63.1% yield of glycols were obtained in water without extra inorganic base. The catalyst still remained stable activity after six cycles and above 80% total selectivity of glycols was obtained when using 20.0% xylitol concentration. XRD, TEM and ICP results indicated that Cu-Ni-ZrO2 catalysts possess favorable stability. Cu and Ni are beneficial to the cleavage of C-O and C-H bond, respectively. To reduce the hydrogen consumption, isopropanol was added as in-situ hydrogen source and 96.4% conversion of xylitol with 43.6% yield of glycols were realized. (C) 2018 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
