酸性质调控对Pd/MIL-100(Cr)催化苯甲醇一步氧化制缩醛性能的影响  

Effect of Acid Property Regulation on the Performance of Pd/MIL-100(Cr)Catalyzed One-step Oxidation of Benzyl Alcohol to Acetal

作　　者：李子鹏 耿佳鑫 刘颖雅 孙志超[1,2] 王瑶 王安杰[1,2] LI Zipeng;GENG Jiaxin;LIU Yingya;SUN Zhichao;WANG Yao;WANG Anjie(State Key Laboratory of Fine Chemicals,Dalian University of Technology,Dalian 116024,China;School of Chemical Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学精细化工国家重点实验室,大连116024 [2]大连理工大学化工学院,大连116024

出　　处：《高等学校化学学报》2023年第8期150-159,共10页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:22271038,22172012,22172015,21972014);国家重点研发计划项目(批准号:2016YFE0109800)资助.

摘　　要：采用水热法合成了金属有机骨架材料MIL-100(Cr),通过双溶剂浸渍和氢气还原制备了双功能催化剂Pd/MIL-100(Cr).以苯甲醇一步氧化制缩醛为模型反应,研究了载体表面酸性质对催化性能的影响.结果表明,串联反应可以有效提高苯甲醇氧化反应的速率,不同还原温度及活化温度均对MIL-100(Cr)的酸性质有影响,进而影响缩醛产物的选择性.吡啶吸附红外光谱(Py-FTIR)及氨程序升温脱附(NH3-TPD)表征结果表明,升高催化剂处理温度,L酸中心增加,B酸中心减少,B酸中心对提高缩醛选择性有利.在最优条件下,70℃反应12 h,苯甲醇的转化率大于99.9%,缩醛的选择性为76.2%.采用X射线光电子能谱(XPS)表征了Pd物种及载体MIL-100(Cr)的电子性质,考察了催化剂的循环稳定性;通过X射线粉末衍射仪(XRD)、场发射扫描电子显微镜(SEM)、氮气吸附-脱附等温线及NH3-TPD表征分析了催化剂失活的原因.MIL-100(Cr)was hydrothermally synthesized and used as a solid-acid catalyst support.Pd nanoparticles were impregnated on MIL-100(Cr)by a double-solvent approach followed by hydrogen reduction to obtain Pd/MIL-100(Cr).One-step tandem conversion of benzyl alcohol to acetal was selected as a model reaction,and the influence of acid property of MIL-100 on the product distribution was investigated.The results showed that Pd/MIL-100(Cr)catalyzed tandem reaction could accelerate the benzyl alcohol oxidation,and different reduction and activation tem⁃peratures had an impact on the acid properties of MIL-100(Cr),which in turn affected the selectivity of acetal.The acid properties were characterized by pyridine adsorption infrared spectroscopy(Py-FTIR)and temperature pro⁃grammed desorption of ammonia(NH3-TPD),the result showed that increasing the catalyst treatment temperature,the L acid sites increased,the B acid sites decreased,and the B acid sites was beneficial to improve the selectivity of acetal.Under optimal conditions,a benzyl alcohol conversion of 99.9%and acetal selectivity of 76.2%can be achieved at 70℃in 12 h.X-ray photoelectron spectroscopy(XPS)analysis was used to characterize the electronic properties of the Pd species and the MIL-100(Cr),the cycling stability of the catalyst was investigated,and the rea⁃sons for the deactivation of the catalyst were analyzed by powder X-ray diffraction(XRD),scanning electron micros⁃copy(SEM),N2 adsorption-desorption isotherms and NH3-TPD.

关 键 词：MIL-100(Cr) 钯 苯甲醇 缩醛 串联反应 

分 类 号：O643.3[理学—物理化学]