钒氮共掺杂多孔碳催化剂上苄胺氧化偶联合成亚胺
Synthesis of Amines by Oxidative Coupling of Benzylamine over a Vanadium-Nitrogen Co-doped Porous Carbon Catalyst
作者单位E-mail
吴晓雪 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004  
齐妍妍 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004  
王盈懿 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004  
王丽 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004  
涂高美 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004  
傅仰河 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004  
陈德利 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004  
朱伟东 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004  
张富民 先进催化材料教育部重点实验室, 浙江师范大学物理化学研究所, 金华 321004 zhangfumin@zjnu.edu.cn 
摘要: 本工作以生物质壳聚糖作为牺牲模板,乙酰丙酮钒为金属钒源,ZnCl2为造孔剂,采用高温热解结合酸洗的策略制备出一种钒氮共掺杂多孔碳(V-N-C)催化剂。表征结果表明,V-N-C催化剂的比表面积高达1 470 m2·g-1,孔容为1.06 cm3·g-1,质量分数为0.19%的钒物种可能以单原子VNx形式高度分散在载体上。在苄胺氧化偶联合成亚胺的反应中,V-N-C表现出高催化性能,底物苄胺的转化率和产物亚胺的选择性均为99%,性能明显优于均相VO(acac)2和多相V2O5催化剂。此外V-N-C催化剂连续重复使用9次也未出现任何活性衰减的问题,且对一系列含有不同官能团的底物也具有优良的普适性。机理研究表明,苄胺和氧气首先分别在催化剂VNx和缺陷位点活化成苄基亚胺和H2O2中间体,然后苄基亚胺与苄胺缩合脱NH3生成目标产物亚胺。
关键词: 选择性催化氧化  多相催化  钒氮共掺杂多孔碳  氧化偶联
基金项目: 国家自然科学基金(No.21576243)资助
Abstract: Synthesis of imine compounds via benzylamine oxidative coupling has become one of the most ideal methods due to its high atom economy and environmental friendliness. The key is to develop high-performance non-noble metal-based heterogeneous catalysts. In this work, a vanadium-nitrogen co-doped porous carbon (V-N-C) catalyst was prepared via high-temperature pyrolysis (900℃ for 2 h in an inert atmosphere) combined with acidleaching (1 mol·L-1 HCl solution at 120℃ for 12 h) approach by using biomass chitosan as the sacrificial template, vanadium acetylacetonate as the source of metal vanadium, and ZnCl2 as the pore-forming agent. Various characterization techniques including a high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) investigation were used to analyze the composition, structure, vanadium species size, content, and other physical and chemical properties of the catalyst, and its catalytic performance was evaluated in the oxidative cou-pling reaction of benzylamine. The characterization results showed that the specific surface area of the V-N-C catalyst was as high as 1 470 m2·g-1, the pore volume was 1.06 cm3·g-1, and the mass fraction of the vanadium species was 0.19% that were highly dispersed on the support likely in the form of single atoms (VNx). In the oxidative selfcoupling reaction of benzylamine to the imine (reaction conditions:toluene as solvent, 110℃, 1.01×105 Pa O2, 12 h), the developed V-N-C exhibited excellent activity (99%), exclusive selectivity (99%), outperforming the homogeneous VO(acac) 2 and heterogeneous V2O5 catalysts. Moreover, V-N-C was repeatedly used 9 times without any decay in reactivity and stability. Furthermore, V-N-C presented excellent universality for a series of substrates containing different functional groups. Mechanism studies indicated that the reaction steps were involved in the initial formation of benzylimine and H2O2 intermediates by activating benzylamine and oxygen molecules, respectively, on the VNx and defect sites of V-N-C, then benzylimine and benzylamine condensed to release an NH3 molecule to gener-ate the target product imine.
Keywords: selective catalytic oxidation  heterogeneous catalysis  vanadium-nitrogen co-doped porous carbon  oxidative coupling
投稿时间:2022-01-12 修订日期:2022-04-14
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吴晓雪,齐妍妍,王盈懿,王丽,涂高美,傅仰河,陈德利,朱伟东,张富民.钒氮共掺杂多孔碳催化剂上苄胺氧化偶联合成亚胺[J].无机化学学报,2022,38(6):1049-1058.
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