负载型KI催化甘油与CO_2合成甘油碳酸酯

Synthesis of glycerol carbonate from glycerol and CO_2 by supported KI catalysts

添加不同组分对氧化铝载体进行调变改性,再以改性氧化铝为载体,负载KI制备了一系列负载型催化剂KI/Al2O3-Mg O、KI/Al2O3-Zn O、KI/Al2O3-Ti O2和KI/Al2O3-Zr O2,并通过CO2、环氧丙烷和甘油合成甘油碳酸酯反应评价其催化活性,发现KI/Al2O3-Mg O具有最高的活性。由不同载体的CO2-TPD分析可以发现,载体表面少量碱性位的存在有利于反应进行。实验研究了不同负载量KI/Al2O3-Mg O的活性及稳定性,发现KI负载量为1.5mmol/g较为适宜。同时,实验又通过N2吸附/脱附(BET)、X射线衍射(XRD)等手段对不同负载量的KI/Al2O3-Mg O进行了表征,进一步说明了负载量过多会导致KI晶粒团聚,并阻塞载体孔道。优化了反应条件,在最佳条件下(环氧丙烷0.3mol,甘油0.1mol,反应温度130℃,反应时间2h,反应压力6.0MPa),甘油的转化率为65.5%,甘油碳酸酯的产率为60.8%。

Different components were chosen to modify alumina and then KI was loaded on the surface of modified alumina,and a series of supported KI catalysts were prepared,such as KI/Al2O3-MgO, KI/Al2O3-ZnO,KI/Al2O3-TiO2 and KI/Al2O3-ZrO2. The catalytic activities were evaluated by the reaction of CO2,propylene epoxide and glycerol to synthesize glycerol carbonate and KI/Al2O3-MgO was found to be the best one. Through CO2-TPD of diffirent supports,it could be found that a few basic positions on the surface of supports were favorable to the reaction. The catalytic activity and stability of KI/Al2O3-MgO with different loading amounts were investigated and the optimal loading amount of KI was 1.5mmol/g. At the same time,KI/Al2O3-MgO was characterized by N2adsorption/desorption （BET） and X ray diffraction （XRD）. Overfull loading amount could lead to agglomeration of KI crystals and blockage of support pores. Reaction conditions were optimized. Under the optimal conditions （propylene oxide 0.3mol,glycerol 0.1mol,reaction temperature 130℃,reaction time 2h,and reaction pressure 6.0MPa）,conversion of glycerol was 65.5% and yield of glycerol carbonate was 60.8%.