过渡金属助剂改性Ca-Zr催化剂上甲醇与碳酸丙烯酯反应制备碳酸二甲酯  

Synthesis of dimethyl carbonate from methanol and propylene carbonate over the Ca-Zr catalyst modified by transition metals

作　　者：陈美娟 杨金海[1] 赵宁[1] 肖福魁[1] CHEN Mei-juan;YANG Jin-hai;ZHAO Ning;XIAO Fu-kui(State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001 [2]中国科学院大学,北京100049

出　　处：《燃料化学学报（中英文）》2023年第6期804-811,共8页Journal of Fuel Chemistry and Technology

基　　金：山西省科技重大专项(202005D121002);山西省中央引导地方科技发展资金项目(2020SW26)资助。

摘　　要：采用溶胶凝胶法制备了一系列由过渡金属助剂改性的Ca-Zr催化剂,对其低温下甲醇与碳酸丙烯酯(PC)酯交换反应合成碳酸二甲酯(DMC)的催化性能进行了研究。结果表明,系列过渡金属改性的Ca-Zr催化剂上DMC选择性的顺序依次为Co-Ca-Zr>Cu-Ca-Zr>Ca-Zr>Fe-Ca-Zr>Ni-Ca-Zr>Zn-Ca-Zr。其中,Co改性的Co-Ca-Zr催化剂在35℃、甲醇/PC物质的量比为15及催化剂用量为4%的条件下反应2 h,PC的转化率可达84.3%,DMC的选择性可达94.5%。结合XRD、FT-IR、XPS和CO_(2)-TPD等表征结果发现,催化剂的碱性位强度增加可以提高PC的转化率,而总碱性位含量提高则降低DMC的选择性。Co改性的Ca-Zr催化剂具有最少的碱性位和最高的强碱性位站比,因而表现出较高的PC转化率和DMC选择性。A series of Ca-Zr catalysts modified by different transition metals were prepared by the sol-gel method and their catalytic performance in the synthesis of dimethyl carbonate(DMC)from methanol and propylene carbonate(PC)by transesterification at low temperature was investigated.The results indicate that the selectivity to DMC of various transition metal-modified Ca-Zr catalysts follows the order of Co-Ca-Zr>Cu-Ca-Zr>Ca-Zr>Fe-Ca-Zr>Ni-Ca-Zr>Zn-Ca-Zr.For the transesterification over the Co-Ca-Zr catalyst,in particular,the conversion of PC reaches 84.3%with a selectivity of 94.5%to DMC after reaction for 2 h under 35℃,a methanol/PC molar ratio of 15,and catalyst amount of 4%.Combining with the XRD,FT-IR,XPS and CO_(2)-TPD results,it is revealed that increasing the strength of basic sites can raise the conversion of PC,whereas increasing the density of basic sites leads to a decrease of the selectivity to DMC.As a result,the Co-modified Ca-Zr(Co-Ca-Zr)catalyst,with the lowest density of surface basic sites but the highest fraction of strong basic sites,exhibits a high conversion of PC and a high selectivity to DMC for the transesterification of PC with methanol at a low temperature.

关 键 词：过渡金属改性 Ca-Zr 酯交换 碳酸二甲酯 碳酸丙烯酯 甲醇 

分 类 号：TQ225[化学工程—有机化工]