甘油催化转移氢解制备丙二醇及其反应机理

The study of catalytic transfer hydrogenolysis of glycerol to propylene glycol and it's mechanism

以Raney Ni为催化剂,甲醇为供氢体,水为溶剂,对甘油催化转移氢解反应进行了研究,探讨了反应温度和甘油浓度对氢解反应的影响,并对甘油催化转移氢解反应机理进行了初步探索.与传统氢解方法相比,甘油催化转移氢解在较为温和的条件下得到了1,2-丙二醇.在温度为210℃,甘油初始浓度为0.64mol/L,反应时间为12h的条件下,甘油转化率达到54.7%,1,2-丙二醇的选择性为74.1%.一般情况下,在Raney Ni的催化作用下,甘油优先脱去伯位的羟基生成丙酮醇,随后加氢生成1,2-丙二醇.

Catalytic transfer hydrogenolysis （CTH） of glycerol was carried out over Raney Ni catalyst in aqueous media with methanol as the hydrogen donor. The effects of the temperature and initial molar concentration of glycerol on the reaction were investigated. A reaction mechanism was proposed. In comparison with the glycerol hydrogenolysis using hydrogen gas, the CTH of glycerol could be carried out under relatively mild reaction conditions. At 210 ~C a 54. 7% conversion of glycerol was achieved after 12 hour reaction with an initial glycerol concentration of 0.64 mol/L, and the selectivity of 1,2-propylene glycol was up to 74. 1%. In general, the cleavage of the primary hydroxyl group was in preference to the secondary one over Raney Ni catalyst to produce acetol, which could be hydrogenated further to become 1, 2- propylene glycerol.