甘油氢解合成1,2-丙二醇铜锌铝催化剂的性能

采用共沉淀法制备了铜锌铝类水滑石前驱体,经焙烧和还原后制得铜基催化剂。采用XRD、H2-TPR、H2-TPD、NH3-TPD和CO2-TPD等表征手段并结合甘油氢解反应评价,研究了类水滑石前驱体的老化对催化剂结构和性能的影响,考察了反应条件对催化剂甘油氢解反应性能的影响。结果表明,老化有利于形成结构更为完整的类水滑石前驱体,但对铜物种的还原性能未造成显著影响。与由未老化前驱体制备的催化剂相比,由老化前驱体制备的铜锌铝催化剂具有较大Cu表面及较大酸量,但表面碱中心数量较低,从而该催化剂具有较好的甘油氢解活性及稳定性。在220℃、H2压力3.0 MPa、n（H2）/n（甘油）为18.9、甘油重时空速1.26 h-1及质量分数为60%甘油水溶液的条件下,经老化前驱体制备的铜锌铝催化剂上甘油转化率接近100%、1,2-丙二醇选择性约为96%。

Performance of Cu-Zn-Al Catalyst for Hydrogenolysis of Glycerol to 1,2-Propanediol

Cu-Zn-Al and Cu-Zn-Al-no hydrotalcite precursors,which were respectively aged and un-aged during the preparation process,were prepared by co-precipitation.After the hydrotalcite precursors were calcined and reduced,Cu-based catalysts were obtained.The effect of ageing on the structure and performance of the catalysts for the hydrogenolysis of glycerol was studied by means of H2-TPR,XRD,H2-TPD,NH3-TPD and CO2-TPD and activity test.Also,the effect of the reaction conditions on the performance of Cu-Zn-Al catalyst was investigated.After calcination at 450 ℃,the hydrotalcite-like precursors were transformed to the mixed oxides without hydrotalcite-like structure,in which Cu species dispersed well.Cu-Zn-Al-no and Cu-Zn-Al had similar reducibility.After reduction at 270 ℃,the mixed oxides were converted to Cu-based catalysts.Compared with the Cu-Zn-Al-no,Cu-Zn-Al had larger active surface,more acid sites and less basic sites.Thus,in the hydrogenolysis of glycerol,the Cu-Zn-Al catalyst showed better activity,selectivity and stability than the Cu-Zn-Al-no catalyst.Under the condition of 220 ℃,3.0 MPa H2 pressure,H2/glycerol molar ratio of 18.9,space velocity of 1.89 h-1 and 60%（mass fraction） glycerol aqueous solution,the Cu-Zn-Al catalyst gave glycerol conversion of 100% and 1,2-propanediol selectivity of 96%.