溶剂热浸渍法制备高稳定性Zn(OAc)_2/SiO_2催化剂及其催化合成苯氨基甲酸甲酯  

Preparation of Zn(OAc)_2/SiO_2 catalyst with better stability prepared by solvothermal impregnation method and its application in methyl N-phenyl carbamate

作　　者：彭向聪 王志苗[1] 李红芹 薛伟[1] 李芳[1] 王延吉[1] PENG Xiangcong;WANG Zhimiao;LI Hongqin;XUE Wei;LI Fang;WANG Yanji(Hebei Provincial Key Lab of Green Chemical Technology & High Efficient Energy Saving, School of Chemical Engineering & Technology, Hebei University of Technology, Tianjin 300130,China)

机构地区：[1]河北工业大学化工学院绿色化工与高效节能河北省重点实验室,天津300130

出　　处：《化工进展》2019年第3期1396-1402,共7页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(21236001;21776057);天津市自然科学基金(17JCYBJC20100)

摘　　要：Zn(OAc)_2对由碳酸二甲酯(DMC)和苯胺合成苯氨基甲酸甲酯(MPC)的反应具有优异的催化性能,但存在易失活、不能重复使用的缺点。为此,以DMC为溶剂,利用溶剂热浸渍法制备Zn(OAc)_2/SiO_2催化剂,并对其催化性能进行了研究。利用XRD、FTIR和TG-DTA等方法对其进行了表征,结果表明,Zn(OAc)_2/SiO_2催化剂表面存在Zn(OAc)_2和ZnO,且其在SiO_2表面分散较好;优化了Zn(OAc)_2/SiO_2催化剂的反应条件,当反应温度为190℃、反应时间为5h、苯胺与DMC的摩尔比为1∶20、催化剂与苯胺质量比为0.2时,苯胺的转化率为97.2%,MPC的选择性为89.4%。和等体积浸渍法制备的催化剂相比,溶剂热浸渍法制备的Zn(OAc)_2/SiO_2催化剂具有较好的稳定性,重复使用7次,苯胺的转化率下降至79.1%,MPC的选择性下降至79.2%。Zn(OAc)_2/SiO_2活性下降的原因是由于ZnO的生成,并对其进行了再生,再生后的催化剂活性与新鲜催化剂接近。Zn(OAc)2 exhibits excellent catalytic performance in the methyl N-phenyl carbamate (MPC) synthesis using aniline and dimethyl carbonate (DMC), but it cannot be reused. Zn(OAc)2 /SiO2 catalyst was prepared by solvothermal impregnation with DMC as the solvent in this paper. Zn(OAc)2 /SiO2 was characterized by XRD、FTIR and TG-DTA. The results suggested that Zn(OAc)2 and ZnO were well dispersed on SiO2 surface. At reaction temperature of 190℃, reaction time of 5h, nDMC∶naniline of 20∶1 and maniline: mZn(OAc)2 /SiO2 of 0.2, Zn(OAc)2 / SiO2 showed the best catalytic performance, giving an aniline conversion of 97.2% and a MPC selectivity of 89.4%. The obtained Zn(OAc)2/SiO2 showed better stability than that prepared by incipient impregnation. After the Zn(OAc)2 /SiO2 was used for the seventh time,aniline conversion and MPC selectivity were found to be 79.1% and 79.2%, respectively and the catalytic activity decrease is attributed to the formation of ZnO. The deactivated Zn(OAc)2/SiO2 can be regenerated with the catalytic activity almost the same as that of the fresh catalyst.

关 键 词：碳酸二甲酯 苯氨基甲酸甲酯 苯胺 Zn(OAc)2/SiO2 溶剂热浸渍 催化剂 稳定性 再生 

分 类 号：TQ246[化学工程—有机化工]