清洁溶剂中的绿色合成及催化加氢反应研究

Green synthesis and catalytic hydrogenation in clean and green solvents

超临界CO2(scCO2)作为绿色溶剂具有传统有机溶剂无法比拟的特性,即可调变的物理化学性质.如在临界点附近,改变压力或温度可以调变其密度、黏度、传热、传质系数、介电常数等.scCO2作为绿色溶剂在材料合成、催化反应等领域的研究相当活跃,并取得了一些创新性的研究成果.催化加氢是scCO2绿色溶剂中最具产业化前景的化学反应.近年来,本研究组对此类反应进行了广泛的研究并取得了一些有意义的研究结果,如不饱和醛的选择性加氢,苯甲酸、苯酚的环加氢反应,顺酐加氢以及硝基化合物加氢等反应.这些反应在scCO2中的反应速率均随着CO2压力的增加而显著提高,而且可以通过调变CO2压力来控制产物的选择性.本研究组研究了scCO2中催化加氢反应的新规律、新现象,讨论了加氢反应速率及产物选择性的变化规律及其机理.此外,还对scCO2中纳米材料的合成及其形成机制进行了讨论和研究.

Supercritical carbon dioxide（scCO2） as a green solvent has a characteristic feature that is tunable chem-physical properties, which is incomparable by the conventional organic solvents. For example, its viscosity, density, coefficient of mass and heat transfer, dielectric constant can be adjusted by altering pressure or temperature slightly near the supercritical point. The material synthesis and catalysis reaction in green solvent of scCO2 have been paid more attention, and achieved some progresses in these years. Catalytic hydrogenation is one of the most prospective reactions in scCO2. We have made a wide study on the selective hydrogenation reactions in scCO2, and some interesting results have been obtained, such as hydrogenation of unsaturated aldehydes, hydrogenation of benzoic ring of benzoic acid and phenol, hydrogenation of maleic anhydride and the nitro-compounds. The reaction rates of these reactions increase significantly with increasing the pressure of CO2, and the product selectivities depend on the CO2 pressure also. My group focuses our study on the new advancements and new situations of the catalysis hydrogenation in scCO2, discuss or reveal the effects of CO2 pressure on reaction rate and product selectivity as well as the influencing mechanism. Moreover, we also investigate the nanomateirals synthesis in the presence of scCO2, and pay more attention to the forming process of the metal oxides and metal nanoparticles.