用于邻苯基苯酚合成的Pt-K/Al_2O_3脱氢催化剂(Ⅰ):钾物种的促进作用机制  

Pt-K/Al_2O_3 dehydrogenation catalyst for synthesis of o-phenyl phenol(Ⅰ):promotion effect of potassium species

作　　者：李彦鹏 刘大鹏 刘晨光 

机构地区：[1]中国石油大学重质油国家重点实验室,山东青岛266580 [2]中国石油大学CNPC催化重点实验室,山东青岛266580

出　　处：《中国石油大学学报（自然科学版）》2012年第3期165-174,179,共11页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家“973”重点基础研究发展计划项目(2010CB226905);教育部创新团队“重质油高效转化的绿色化学与工程”项目;国家自然科学基金项目(21106185)

摘　　要：基于未改性Pt/Al2O3催化剂探索环己酮二聚物脱氢反应体系,针对反应产物的分布特点使用多种钾助剂对催化剂性能进行调变,采用吡啶吸附红外(Py-IR)、氢氧滴定(H2-O2Titration,HOT)、X射线光电子能谱(XPS)、程序升温还原(TPR)等对Pt-K/Al2O3催化剂中钾助剂的促进作用机制进行研究。结果表明:在合适的条件下使用钾助剂可以大幅提高邻苯基苯酚(OPP)的选择性(最高可达94%);钾助剂对铂基脱氢催化剂的促进作用体现为2个方面,一是削弱氧化铝载体酸性,可以通过抑制酸中心导致的副产物生成而提高目的产物OPP的选择性,二是钾与铂中心存在较强的相互作用,特别是电性促进作用(EP);碱性较强的K2CO3改性效果最好。The reaction system of cyclohexanone dimer dehydrogenation over non-modified Pt/Al2O3 catalyst was investigated. According to the reaction products distribution characteristics, a variety of potassium additives were adopted to modify Pt/Al2O3 catalysts. The promotion effect of the potassium species on the Pt/Al2O3 catalyst was studied by using several characterization methods such as pyridine adsorption infrared spectroscopy （Py-IR） , H2-O2 titration （HOT） , X-ray photoelec- tron spectroscopy （XPS） and temperature-programmed reduction （TPR）. The results show that the OPP selectivity can be greatly improved under proper dosage and kind of potassium additive. The promotion effect from the potassium species can be interpreted in two ways. Firstly, the introduction of basic potassium additives, such as K2 CO3 , can greatly suppress the acid- ity of alumina support （ confirmed from Py-IR results）, inhibit the by-products resulted from the acidic center and improve the OPP selectivity. Secondly, the potassium species has strong interactions with the Pt center, especially the electrical pro- motion （EP） effect. Basic potassium additive such as K2CO3 is more effective since it exhibits the promotion effect from both ways.

关 键 词：邻苯基苯酚 脱氢 铂 钾 氧化铝 促进作用 

分 类 号：TQ420[化学工程]