摘要
采用等体积浸渍法制备了负载型乙酸锌催化剂。当采用活性炭(AC)为载体,反应温度170℃,反应时间3 h时,催化碳酸二甲酯(DMC)与2,4-二氨基甲苯(TDA)反应制备2,4-甲苯二氨基甲酸甲酯(TDC)的效果最好,TDC的产率达86％。用TiO2对活性炭表面进行了改性,制备了TiO2包覆活性炭负载乙酸锌催化剂,170℃下反应1 h,TDC的产率较使用未改性载体的催化剂提高7％。TiO2的生成方式不同,对催化剂活性影响很大。采用XRD、XPS对各种催化剂进行表征。结果表明,造成活性炭负载乙酸锌催化剂失活及其与表面改性载体负载催化剂活性差异的原因是由于表面Zn所处的化学环境发生了改变,从而影响了TDC合成反应的催化活性,即随着Zn2p结合能的增加,Zn周围电子云密度降低,催化剂活性降低。
Supported catalysts for the synthesis of 2,4-toluene dicarbamate (TDC) using zinc acetate as active substance were prepared. Activated carbon (AC) was the best support among those examined. TDC yield was 86% at 170°C for 3 h when using AC supported catalyst. A new zinc acetate supported catalyst was prepared that AC was surface-coated by titanium dioxide. The coated catalyst was more active than the previous AC support catalyst. The TDC yield at 170°C for 1 h was 7% higher than the previous one. XRD and XPS were used to characterize the catalysts. The deactivation of the supported catalyst and the variation between the surface modified catalyst and the normal catalyst were due to the change of the chemical environment of atom Zn on the catalyst surface. That is to say, with the increase of the binding energy of Zn2p, the electron density around atom Zn declined and activity of the catalysts for TDC synthesis decreased at the same time.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2004年第2期35-40,共6页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家自然科学基金资助项目(29976010)
河北省自然科学基金资助项目(298034)
