ZnO催化对苯二甲酸脱羧制苯的反应历程  

Catalytic Decarboxylation Mechanism of Terephthalic Acid to Benzene Over ZnO Catalyst

作　　者：庄岩[1] 蒋斌波[1] 王靖岱[1] 阳永荣[1] 

机构地区：[1]浙江大学化学工程联合国家重点实验室,浙江杭州310027

出　　处：《石油学报（石油加工）》2015年第3期698-704,共7页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家自然科学基金项目(21176208);国家高技术研究发展计划项目(2012AA030304)资助

摘　　要：通过比较不同金属氧化物催化对苯二甲酸脱羧制苯的活性及反应产物分布情况,优选ZnO作为脱羧催化剂。采用FT-IR、XRD和Py-GC/MS表征了催化对苯二甲酸脱羧反应前后的ZnO催化剂及对苯二甲酸锌配合物。同时还对对苯二甲酸锌配合物进行了TG-DTA及DTG分析,以探讨ZnO催化对苯二甲酸脱羧反应机理以及催化剂积炭的原因。结果表明,当反应温度为550℃、质量空速为0.48h-1时,ZnO催化对苯二甲酸脱羧的转化率达到100%,产物中苯的质量分数达40%。ZnO催化对苯二甲酸脱羧反应分两步进行,首先对苯二甲酸化学吸附在ZnO表面形成对苯二甲酸锌配合物,然后再热分解生成苯、CO2等。对苯二甲酸锌配合物的热分解温度在410~530℃,在N2中热分解时发生的深度脱氢反应导致积炭的形成。Several metal oxides catalysts were prepared for catalytic decarboxylation of terephthalic acid（TPA）, and then ZnO was selected after comparison of their catalytic activities and reaction products distribution of TPA decarboxylation. FT-IR, XRD and Py-GC/MS were used to characterize the ZnO samples before and after catalytic decarboxylation and zinc terephthalate （TP-Zn）, which was also analyzed by TG-DTA and DTG, to study the mechanism of the decarboxylation and coke formation. The results showed that conversion of TPA decarboxylation over ZnO was about 100% and the content of benzene in products was over 40% at 550℃ and MHSV of 0.48 h 1. TP-Zn intermediate was identified on ZnO after its catalyzing decarboxylation. The TPA decarboxylation over ZnO involved two steps, in which the first step was chemical adsorption of TPA on ZnO to form TP-Zn and the second step was thermal decomposition of TP-Zn to produce benzene and CO2. The decomposition temperature of TP-Zn was between 410℃ and 530℃ in N2 atmosphere. The decomposition companied with deep dehydrogenation of TP-Zn resulted in carbon deposition on ZnO surface.

关 键 词：对苯二甲酸(TPA) 氧化锌(ZnO) 脱羧 苯 

分 类 号：TQ032[化学工程]