Cu茁催化剂上氧化羰基合成碳酸二甲酯的原位漫反射红外光谱研究.PDF

第40卷 第10期 燃摇 料摇 化摇 学摇 学摇 报 Vol.40 No.10 2012年10月 Journal of Fuel Chemistry and Technology Oct. 2012 文章编号:0253鄄2409(2012)10鄄1212鄄10 Cu茁 催化剂上氧化羰基合成碳酸二甲酯的原位漫反射红外光谱研究 王增竹,黄守莹, 申勇立,王胜平,马新宾 (天津大学化工学院绿色合成与转化教育部重点实验室,天津摇 300072) 摘摇 要:采用原位漫反射红外光谱法研究了Cu茁 催化剂上氧化羰基合成碳酸二甲酯(DMC)的反应机理,考察了甲醇、一氧化 碳和DMC 的单独吸附及混合气吸附。 结果表明,Cu茁 催化剂上只存在一种活性位,位于六元环中;氧气能够氧化吸附态的甲 醇产生甲氧基和水;DMC吸附在Cu茁 催化剂上时,以羰基中的氧原子吸附在活性位上更加稳定;反应存在生成单甲氧基物种 和双甲氧基物种两条路径,单甲氧基物种与CO反应生成单甲基碳酸盐物种(MMC),MMC再与甲氧基反应生成DMC;CO 插入双甲氧基物种也可以得到DMC。 在Cu茁 催化剂上更倾向于进行CO插入双甲氧基物种这一路径。 关键词:Cu茁;氧化羰基;碳酸二甲酯;反应机理;原位漫反射红外光谱 中图分类号:TQ032.4摇 摇 文献标识码:A In situ DRIFTS study on the oxidative carbonylation of methanol to dimethyl carbonate over Cu茁 catalyst WANG Zeng鄄zhu,HUANG Shou鄄ying,SHEN Yong鄄li,WANG Sheng鄄ping,MA Xin鄄bin (Key Labfor Green Chemical Technology of Ministry of Education,School of ChemicalEngineering and Technology, Tianjin University,Tianjin摇 300072,China) Abstract:The mechanism of oxidative carbonylation of methanol to dimethyl carbonate (DMC) over Cu茁 catalyst was investigated by using in situ DRIFTS;the adsorption of single methanol,carbon monoxide and DMC aswell astheir mixtureson the Cu茁 catalyst were considered. Theresultsindicatedthat methoxide species are formed whenmethanolisadsorbedonthecatalystduetopresenceofCuO . Only onetypeofactive sitesthatx are located in the six鄄membered ring of茁 zeolite is found,over which adsorbed methanol can be oxidized to methoxideandwater. DMCisadsorbedonthecatalystthrough thecontact ofthe oxygenatomin carbonyl group with theactive sites. Thereweretwopathwaysfortheoxidativecarbonylation:bythemono鄄methoxidepathway, carbon monoxidecanreactwithmono鄄methoxide speciestoformmonomethylcarbonate (MMC)andMMCthen reactswith methoxide to form DMC,or by t