甘油选择性脱水的海绵铜基催化剂制备和表征

Preparation and characterization of sponge copper-based catalysts for selective dehydration of glycerol

采用湿混法制备了氧化物修饰的海绵铜基甘油脱水催化剂。Cu/Mg O催化剂催化甘油脱水表现出了优良的活性和选择性,借助于粉末X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、N2吸附-脱附(BET)、CO2程序升温脱附(CO2-TPD)和热重-差示扫描量热(TG-DSC)等技术对Cu/Mg O进行了表征,并考察了该催化剂在无溶剂条件下催化甘油脱水至羟基丙酮的性能。结果表明:Mg O的修饰未改变海绵铜的骨架,且形成了Cu-Mg O相,其催化甘油脱水的活性和选择性与Cu和Mg O间相互匹配密切相关。当含Cu 8%(质量分数)的催化剂用量为1.0 g(为反应原料质量的4.2%)、反应温度为225℃、反应时间为5 h下,于反应-蒸馏工艺中可催化甘油获得转化率92.3%(质量分数)的和羟基丙酮选择性90.7%(质量分数)。Mg O修饰的海绵铜能有效地催化甘油选择性脱水至羟基丙酮。

A series of sponge Cu-based catalysts was prepared by wet-mixing method and used in the dehydration of glycerol. Among those catalysts, Cu/MgO showed the excellent activity and selectivity for the catalytic dehydration of glycerol, and was characterized by means of X-ray diffraction （ XRD）, scanning electron microscopy （ SEM）, transmission electron microscopy （TEM）, Brunauer-Emmett-Teller （BET）, CO2 temperature programmed desorption （CO2-TPD）, and thermogravimetry differential scanning calorimetry （TG-DSC）, and it was also investigated that the Cu/MgO catalyst catalyzed the dehydration of glycerol to aeetol under solvent-free conditions. The results reveal that the modification of MgO does not change the sponge copper skeleton, and the Cu-MgO phase comes into being. The activity and selectivity of Cu/MgO for glycerol dehydration are dependent on the effective match between Cu and MgO. Under the reaction conditions of 4.2% mass ratio of 8% Cu/MgO （ 1.0 g catalyst） to pure glycerol, reaction temperature 225 ℃ and reaction time 5 h, the conversion and the selectivity to acetol in the reaction-distillation process reach 92.3% and 90.7% （mass fractions） , respectively. The sponge copper modified by MgO can effectively catalyze the selective dehydration of glycerol to acetol.