金属卟啉和金属卟啉MOFs材料催化CO2与C-H键羧化反应

CO2 is a cheap, abundant, safe and non-toxic C1 resource, which can be converted into a variety of energy sources, materials and materials. Fatty acid is a necessary kind of chemical raw material and drug intermediate, the synthesis reaction conditions of fatty acid is harsh in existing methods. The synthesis of fatty acids by directly inserting CO2 into C-H bond is a method with 100% atomic economy, which is a valuable application of CO2 as carboxylation reagent. CO2 has very high thermodynamic and kinetic stability and C-H bond is inert, so that it is very difficult to directly carboxylation reaction between CO2 and C-H bond. Based on the characteristics of C=O bond for CO2 and C-H bond, the project will utilize metal porphyrin and metalloporphyrin MOFs materials as catalysts, under the action of additives, such as alkali and oxidant, to catalyze the carboxylation reaction of CO2 and C-H bond. It will use the combination of experimental study and theoretical calculation to research how metalloporphyrin and metalloporphyrin MOFs materials capture and activation CO2, to predict and verify the possible reaction paths, to determine the catalytic role of metalloporphyrin catalyst and the synergy role of metalloporphyrin and MOFs materials for capturing, adsorbing and activating CO2, and to summarize the catalytic law of metalloporphyrin and metalloporphyrin MOFs materials. It will enrich the theory of the carboxylation reaction of CO2 and C-H bond, save fossil energy and solve the problem of fatty acid demand as well.

CO2是廉价丰富、安全无毒的C1资源，可以转化为多种能源、物质和材料。脂肪酸是一种重要的化工原料和药物中间体，现有合成方法反应条件苛刻。将CO2直接插入C-H键合成脂肪酸是原子经济性100%的方法，是CO2作为羧化试剂的重要应用。CO2具有极高的热力学和动力学稳定性，以及C-H键的惰性，二者很难直接发生羧化反应。针对CO2的C=O双键和C-H键特点，本项目以金属卟啉和金属卟啉MOFs材料作为催化剂，在氧化剂、碱等助剂的作用下，催化CO2和C-H键羧化反应，利用实验探究和理论计算相结合的方法，研究金属卟啉和金属卟啉MOFs材料如何捕捉、活化CO2，预测和验证可能反应路径，确定金属卟啉的催化作用和金属卟啉MOFs材料在同时捕捉、吸附、活化CO2的协同作用，总结催化规律。本项目将丰富CO2和C-H键羧化反应的理论，能节约化石能源和解决脂肪酸需求问题。

烃类C-H键高效，选择性的催化官能团化，是化学工业的一个重要转化过程，如C-H键的催化羧基化和氧化官能团化。上述过程将方便易得的烃类化合物转化成高附加值精细化工产品和中间体，显著提高了烃类化合物的利用效率，并缩短了烃类化合物的利用路径。本项目尝试以金属卟啉和金属卟啉MOFs构筑催化体系，催化CO2羧基化烃类C-H键合成烷基羧酸。研究发现，所构筑的金属卟啉和金属卟啉MOFs并没有转化C-H键为羧基，所得主产物为C-H键的部分氧化产物。虽然经过长时间尝试，均未成功。根据实际研究情况，及时对研究体系进行了调整，设计构筑了金属卟啉钴(II)/Zn(OAc)2二元催化体系，3D MOF PCN-222(Co)/Zn(OAc)2二元催化体系，催化O2氧化烃类C-H键。对工业上重要的环己烷催化氧化，环己烷的转化率和KA油的选择性分别达到了6.21%和95%，5.51%和94%，显著高于目前工业上环己烷氧化过程KA油的选择性。本研究不仅对环己烷的选择性催化氧化制备KA油具有重要的参考价值，对其它烃类C-H键的选择性官能团化也具有一定的指导意义和参考价值。