碳前驱体在全氟磺酸型碳基固体酸材料设计中的影响

Effect of the Carbon Precursor on the Design of Perfluorosulfonic Acid Functionalized Carbon Catalysts

以碳纳米管、介孔碳分子筛和氮掺杂的介孔碳为前驱体,采用全氟磺酸-全氟乙烯共聚物(PTFE)液相沉积方法制备了修饰量相同的三种全氟磺酸功能化碳基固体酸催化剂,利用N2吸附、热重分析(TG)、透射电子显微镜(TEM)、傅里叶红外变换(FTIR)光谱以及电位滴定等方法对材料的结构和酸性进行了表征.考察催化剂对于苯甲醇与苯甲醚Friedel-Crafts(F-C)反应的催化性能.结果表明,前驱体的比表面积越大,与修饰剂的相互作用越强,越有利于修饰剂在前驱体表面的分散,得到的催化剂表面酸量越多,酸催化活性越好.因此,全氟磺酸功能化的氮掺杂介孔碳在F-C反应中表现出最高的活性和稳定性.

Perfluorosulfonic acid functionalized carbon-based solid acid catalysts were prepared by liquid deposition of perfluorosulfonic acid-polytetrafluoroethylene（PTFE） copolymer using carbon nanotubes,mesoporous carbon molecular sieves, and nitrogen-doped mesoporous carbon as precursors. The obtained catalysts were characterized by N2 adsorption, thermogravimetric analysis（TG）, transmission electron microscope（TEM）, Fourier transform Infrared（FTIR） spectrometer, and potentiometric titration. Their catalytic behavior in the Friedel-Crafts（F-C） alkylation of anisole was also investigated. It was found that the surface area of the precursor and its interaction with perfluorosulfonic acid play important roles in the preparation of highly active catalysts. The highest activity as well as the best stability was observed over perfluorosulfonic acid functionalized nitrogen-doped mesoporous carbon.