Solvent effect on hydrogenolysis of glycerol to 1,2-propanediol over Cu–ZnO catalyst
Solvent effect on hydrogenolysis of glycerol to 1,2-propanediol over Cu–ZnO catalyst
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DOI：
10.1016/j.cej.2014.11.113
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发表时间：
2015-03
影响因子：
15.1
通讯作者：
Cancan Wang;Hong Jiang;Changlin Chen;Rizhi Chen;W. Xing
中科院分区：
文献类型：
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作者：
Cancan Wang;Hong Jiang;Changlin Chen;Rizhi Chen;W. Xing
以共沉淀法制备的铜-氧化锌催化剂为催化剂，考察了溶剂对甘油氢解合成1，2-丙二醇催化性能的影响。所制得的铜-氧化锌颗粒为球形，由纳米颗粒组成的针状结构，比表面积为2300m2/g。所用溶剂对甘油氢解反应有明显影响。分别以水、乙醇和甲醇为溶剂时，甘油转化率逐渐提高，而1，2-丙二醇的选择性则相反。通过NH3-TPD、X射线衍射仪、扫描电子显微镜和N2O等手段对回收催化剂的物化性能进行了表征，详细分析了溶剂效应的机理。水的表面张力较大，导致铜纳米粒子严重聚集，活性中心减少，甘油转化率降低。乙醇或甲醇催化氢转化为甘油也可能是甘油转化率较高的原因。较高的水极性有利于1，2-丙二醇从催化剂表面的脱除，有助于提高1，2-丙二醇的选择性。
The present work aimed to investigate the effect of solvent on the catalytic performance of glycerol hydrogenolysis to 1,2-propanediol over a Cu–ZnO catalyst prepared by a coprecipitation method. The as-prepared Cu–ZnO particles were spherical in shape with needle-like structure formed by nanoscale particles, and had a specific surface area of 23 m2/g. The solvents used in this work had an obvious influence on the hydrogenolysis of glycerol. Glycerol conversion increased gradually while the selectivity to 1,2-propanediol changed oppositely with water, ethanol and methanol as a solvent, respectively. The mechanism of solvent effect was analyzed in detail through characterizing the physicochemical properties of recovered Cu–ZnO catalyst by NH3-TPD, XRD, SEM and N2O, etc. The larger surface tension of water brought about the serious aggregation of Cu nanoparticles, leading to less active sites and lower glycerol conversion. The catalytic hydrogen transformation from ethanol or methanol to glycerol could also be responsible for the higher glycerol conversion. The higher polarity of water facilitated the removal of 1,2-propanediol from the catalyst surface, contributing to higher selectivity to 1,2-propanediol.