层状磷酸锆基过渡金属催化剂上烃类催化氧化性能研究

Selective oxidation of C-H bond in hydrocarbon is recognized as a problem in chemical synthesis, and the production of the corresponding aldehyde (ketone) products in a higher yield is of great strategic significance and application value. In this project, the metal component is introduced into the layered zirconium phosphate by ion-exchange method, impregnation method and in-situ doping method, thus the transition metal (Fe、Co、Mn、Ce、Ti) catalysts are obtained with synergistic effect between zirconium phosphate and the redox center of the variable valence metal. The composition, structure and the quantity and distribution of surface lattice oxygen of the catalyst were characterized. Meanwhile, the oxidation reaction of hydrocarbons was carried out by using the environment-friendly reaction system (low temperature liquid environment and molecular oxygen as oxidant) over the above transition metal catalyst, the catalytic performance of oxidation of cyclohexene, hexane and toluene are examined. The mechanism on the activation of C-H bond by the zirconium phosphate was elucidated, and the ability of different metal components to create lattice oxygen was discussed. The relationship between the composition, structure and catalytic performance of the catalyst was clarified. The synergistic catalysis mechanism of zirconium phosphate and metal components was revealed, and some new catalytic systems were explored for the selective oxidation of C-H bond of hydrocarbons.

烃类C-H键选择氧化被公认为化学合成领域的难题，以较高产率实现相应醛（酮）产物的生产具有重大战略意义和应用价值。本项目拟采用离子交换法、负载法、原位掺杂法在层状材料磷酸锆上引入金属组分，得到磷酸锆和可变价态金属的氧化还原中心协同作用的过渡金属（Fe、Co、Mn、Ce、Ti）催化剂。对催化剂组成、结构、表面晶格氧数量及分布进行表征，采用环境友好的反应体系（低温液相环境、分子氧为氧化剂），考察上述催化剂对烃类氧化（以环己烯、环己烷、甲苯氧化为探针反应）的催化性能。阐明载体磷酸锆活化烃类C-H键的作用机理，探讨不同金属组分创造晶格氧的能力，明确催化剂的组成、结构和催化性能之间的关系。揭示载体磷酸锆和金属组分协同催化反应机理，为烃类C-H键的选择氧化探索出新的催化体系。

烃类C-H键选择氧化被公认为化学合成领域的难题，以较高产率实现相应醛（酮）产物的生产具有重大战略意义和应用价值。通过本项目实施，分别合成了α和γ-磷酸锆，采用离子交换法，以Fe、Mn、Co、Ti等多种可变价金属对磷酸锆进行改性，以烯烃氧化为探针反应对磷酸锆载体和金属组分进行了初步优选；合成了MnCeOx、CoCrOx等多种还原性金属氧化物并用于甲苯氧化反应，考察不同金属塑造晶格氧的能力；进而优选Cr元素合成不同比率的CrZr-金属磷酸盐，用于环己烯氧化到环己烯酮、环己烷氧化到KA油、乙苯苯氧化到苯乙酮等多种探针反应，最终形成系列性能优良的烃类氧化催化体系。依据催化剂表征及实验数据分析，明确了催化剂的组成、结构和催化性能之间的关系，阐明了晶格氧与不同可变价金属组分 Lewis 酸性对这些烃类选择氧化反应的作用机理，建立了磷酸锆和金属中心协同与良好催化性能的构效关系。