催化学报 ›› 2018, Vol. 39 ›› Issue (2): 309-318.DOI: 10.1016/S1872-2067(17)63006-7

• 论文 • 上一篇    下一篇

镁铝酸碱双功能氧化物催化剂上醇胺氧化耦合合成亚胺性能

宋金玲a, 于贵阳a, 李玺a, 杨胥微a, 张文祥a, 闫文付b, 刘钢a   

  1. a 吉林大学化学学院, 表面与界面化学吉林省重点实验室, 吉林长春 130021;
    b 吉林大学无机合成与制备化学国家重点实验室, 吉林长春 130012
  • 收稿日期:2017-11-13 修回日期:2017-12-25 出版日期:2018-02-18 发布日期:2018-02-10
  • 通讯作者: 张文祥, 刘钢
  • 基金资助:

    国家自然科学基金(21473073,21473074);吉林省科技发展计划项目(20170101171JC);吉林省教育厅"十三五"科学技术研究项目(2016403);国家重点实验室无机合成和制备化学的开放项目(201703).

Oxidative coupling of alcohols and amines to an imine over Mg-Al acid-base bifunctional oxide catalysts

Jinling Songa, Guiyang Yua, Xi Lia, Xuwei Yanga, Wenxiang Zhanga, Wenfu Yanb, Gang Liua   

  1. a Key Laboratory of Surface and Interface Chemistry of Jilin Province, College of Chemistry, Jilin University, Changchun 130012, Jilin, China;
    b State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, Jilin, China
  • Received:2017-11-13 Revised:2017-12-25 Online:2018-02-18 Published:2018-02-10
  • Contact: 10.1016/S1872-2067(17)63006-7
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21473073, 21473074), the Development Project of Science and Technology of Jilin Province (20170101171JC), "13th Five-Year" science and technology research of the Education Department of Jilin Province (2016403) and the Open Project of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry (201703).

摘要:

亚胺是一类重要的含氮有机化合物,由于具有不饱和C=N双键,可以作为一种有效的氮源,用于一系列含氮衍生物的合成.目前合成亚胺的工艺路线主要是通过羰基化合物和一级胺在强酸条件下缩合;与该路线相比,醇和胺在空气或氧气存在条件下耦合是一条更为绿色的工艺路线,其副产物只有水产生.目前的报道表明,一些具有氧化还原性质的催化剂,如负载型贵金属催化剂和负载型过渡金属氧化物催化剂在该反应中表现出一定催化性能,但很少关注表面酸碱性质对该反应性能的影响.在本工作中,我们尝试将具有酸碱双功能性质的Mg-Al复合氧化物作为催化剂用于该反应中,考察了Mg/Al比、焙烧温度和后处理条件对催化性能的影响.结果显示,Mg/Al=3的催化剂在反应中表现出最优的催化活性;NH3-TPD和CO2-TPD显示,随着镁含量的增加,样品表面碱性中心的数量呈现出先增加后减少的趋势,其中Mg/Al=3的样品表面酸、碱总量最大,而且该样品表面弱碱中心数量也最多;我们通过焙烧和探针分子吸附等后处理手段进一步调控了催化剂表面的酸碱性质,初步结果表明在酸碱中心的协同作用下可以有效地催化醇和胺的氧化耦合反应;其中弱碱性位可能是活化醇的主要活性中心,而醇的氧化是该反应的速控步骤,因此可以推测表面弱碱中心的数量在一定程度上决定着催化剂在该反应中的性能.

关键词: 氧化耦合, 亚胺合成, 醇氧化, 镁铝复合氧化物, 酸碱催化

Abstract:

A series of Mg-Al mixed oxide catalysts are prepared and introduced as efficient irreducible catalysts for the oxidative coupling of alcohols and amines to imine. The structure and surface properties of Mg-Al oxides are modulated by changing the Mg/Al ratios, calcination temperature and treatment with probe molecules. Detailed characterization, including X-ray diffraction, 27Al magic angle spinning nuclear magnetic resonance spectroscopy, N2-adsorption, NH3-temperature-programmed desorption, CO2-temperature-programmed desorption and X-ray photoelectron spectroscopy are carried out to determine the physicochemical properties of these catalysts. The Mg-Al oxides with Mg/Al=3 exhibit the highest activity in the reaction, which possess a large number of surface weak basic sites and a relatively small number of weak acidic sites. The role of the acidic and basic sites in the reaction process is systematically investigated, and are shown to serve as adsorption and activation sites for amines and alcohols, respectively. Under the synergistic effect of these acid-base centers, the oxidative coupling process successfully occurs on the surface of Mg-Al mixed oxides. Compared with the acidic sites, the weak basic sites play a more important role in the catalytic process. The acidic sites are the catalytic centers for the benzyl alcohol activation, which control the reaction rate of the oxidative coupling reaction.

Key words: Oxidative coupling, Imine synthesis, Alcohol oxidation, Mg-Al mixed oxides, Acid-base catalysis