氮氧吡啶-钌基催化剂催化乙炔氢氯化的研究  

Study on Ru-based catalysts coordinated with pyridine N-oxide for acetylene hydrochlorination

作　　者：胡嘉琦 王富民[1] 张旭斌[1] HU Jiaqi;WANG Fumin;ZHANG Xubin(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学化工学院,天津300350

出　　处：《化学工业与工程》2023年第4期1-14,共14页Chemical Industry and Engineering

基　　金：国家重点研发计划(2016YFF0102503)。

摘　　要：针对目前钌基催化剂在乙炔氢氯化应用中活性和稳定性不足的问题,利用湿法浸渍技术制备了氮氧吡啶配位的新型钌基催化剂,并优化了配体添加量。其中性能最好的催化剂含氮氧吡啶10%,在温度170℃、乙炔空速360 h^(-1)、氯化氢与乙炔流量比为1.15条件下,转化率高达96.1%,且20 h内只下降了0.8%。动力学分析显示,该反应活化能从34.95 kJ·mol^(-1)下降至25.58 kJ·mol^(-1)。TEM和XRD结果证明钌在催化剂中呈高分散状态。H_(2)-TPR和XPS结果揭示了氮氧吡啶可以削弱氧化态钌物种在反应过程中的还原。由BET和TG数据可知,氮氧吡啶的引入抑制了反应过程的积碳。TPD图谱证明配体的引入增强了催化剂对反应物的吸附。同时基于前线轨道理论分析发现,钌的引入可以作为电子转移的中转站,大大降低了其能量差,而配体的引入,进一步降低了钌向氯化氢提供电子的能量差,这可能是协同作用的微观机理。该研究为钌基催化剂的进一步研发提供了理论启发。To enhance the activity and stability of Ru-based catalysts for acetylene hydrochlorination,wet impregnation technology was used to prepare a new Ru-based catalyst coordinated with pyridine N-oxide,and the dosage of ligand was optimized.Under the conditions of 170℃,GSHV(C_(2)H_(2))=360 h^(-1)and V(HCl)/V(C_(2)H_(2))=1.15,the activity of the catalyst with the optimal dosage of 10%pyridine N-oxide ligand reaches the conversion of 96.1%,which only decreases 0.8%within 20 h.Kinetic analysis shows that the activation energy of the reaction decreases from 34.95 kJ·mol^(-1)to 25.58 kJ·mol^(-1).The results of TEM and XRD prove that Ru is highly dispersed in the catalyst.Furthermore,H_(2)-TPR and XPS re-sults certify that the pyridine N-oxide weakens the reduction of oxidized Ru species during the reaction.Moreover,the introduction of pyridine N-oxide inhibits the coke deposition,according to BET and TG da-ta.TPD result confirms that the ligand enhances the adsorption of reactants on catalysts.Besides,theo-retical calculations based on the frontier molecular orbital theory indicate that Ru can act as a transfer of electrons and greatly reduce the energy difference.And the introduction of ligand further weakens the en-ergy difference of Ru donating electrons to HCl,which may be the microcosmic mechanism of the syner-gy,consistent with the experimental results.It can provide theoretical inspiration for designs and applica-tions of Ru-based catalysts in acetylene hydrochlorination.

关 键 词：乙炔氢氯化 钌基催化剂 氮氧吡啶 密度泛函理论 前线轨道理论 

分 类 号：TQ032.4[化学工程]