氮、硼共掺杂碳催化四氢喹啉等含氮杂环氧化脱氢

Heterocycles account for about one-third of all the organic compounds. Of which N-heterocyclic compounds is an important branch. The catalytic dehydrogenation of N-heterocycles constitutes an important and fundamental process in organic synthesis. For example, in recent years, many homogeneous and heterogeneous metal catalytic systems have been successfully employed in the catalytic oxidative dehydrogenations of tetrahydroquinolines. Metal-free catalytic systems are of great potential due to distinct advantages over metal-based catalysts such as no metal pollution, low cost as well as environmental friendliness. In view of important application of N-heterocyclic derivatives in pharmaceutics and life sciences, this project plans to develop metal-free heterogeneous catalytic system for oxidative dehydrogenation of N-heterocycles such as tetrahydroquinolines to detour metal contaminants in the final product, particularly for the pharmaceutical reagents. Companied with simple nitrogen and boron resource, a series of nitrogen, boron-codoped hierarchical porous carbon materials have been derived from biomass. The codoping of nitrogen and boron of different electronic characteristics is capable of adjusting the surface electronic structure and physicochemical property, boosting the ability to activate dioxygen. Based on the discussion of the relationship between surface structure analysis and their reaction kinetics then give an insight into sructure-activity relationship of the catalyst, and study systematically the mechanism of the reaction process in order to provide theoretical foundation for the ideal metal-free catalytic oxidative dehydrogenation of N-heterocycles. Some preliminary results have been obtained.

有机化合物中，杂环化合物占了大约三分之一，而含氮杂环是杂环化合物中的一个重要分支。含氮杂环化合物氧化脱氢是有机合成中非常重要的反应。以四氢喹啉氧化脱氢为例，针对该反应研究学者已开发多种均相和多相金属体系。相较于金属催化剂，非金属催化体系因无金属污染、成本低且环境友好而具有强大的潜在发展优势。鉴于含氮杂环衍生物在医药、农药及生物技术方面的广泛应用，本项目拟开展非金属多相催化四氢喹啉等含氮杂环氧化脱氢研究，以避免杂环药物中间体中的金属残留问题。以廉价易得生物质为碳源，同时引入电负性差异较大的氮、硼杂原子合成共掺杂多级孔碳材料。不同电子特性的硼和氮杂原子共掺杂可调节碳材料表面电子结构和物理化学性质，从而提高其对分子氧的活化能力。结合化学反应动力学与表面分析数据，深入研究催化剂构效关系，系统研究催化氧化脱氢反应机理，为实现含氮杂环氧化脱氢的非金属催化过程提供理论基础。目前已获得一些初步实验结果。

氮杂芳烃作为最通用的分子结构之一，广泛存在于药物，生物活性分子和天然产物中。其可由金属催化剂催化含氮杂环氧化脱氢得到。而非金属催化剂可成功避免杂环药物合成中的金属残留问题。碳材料因不同电子性质的杂原子引入而引起电子离域，从而可活化分子氧。本项目拟围绕建立分子氧作为氧化剂含氮杂环氧化脱氢的非金属催化体系的相关问题展开研究。以廉价易得生物质为碳源，同时引入杂原子氮和多级孔结构，调节碳材料表面电子结构和物理化学性质。以其为催化剂建立高效高选择性的含氮杂环氧化脱氢体系的非金属催化体系，同时在研究催化剂结构与其催化含氮杂环氧化脱氢性能之间的构效关系基础上，系统研究含氮杂环氧化脱氢反应机理，进而为高效非金属催化剂的设计提供理论基础。进一步提出以杂原子引入后再离去的方式创造更多缺陷位，构造高缺陷高活性碳基催化剂，以期实现更多的有机反应多相催化过程，拓展非金属催化平台。