Rational Design Of Nitrogen?Phosphine-Functionalized Microporous Organic Polymers-Supported Palladium Catalysts For The Oxidative Carbonylation Of Glycerol To Glycerol Carbonate

The rapid development of biodiesel industry has brought a large number of by-product glycerol, in order to avoid pollution and resource waste, so converting glycerol to high value-added chemicals, such as glycerol carbonate, has become the focus and hotspot in the field. In the multiple synthetic routes of glycerol carbonate, the oxidative carbonylation of glycerol not only has high utilization rate of atoms, but also realizes the greening of the synthesis. It conforms to the principle of environmention friendly and sustainable development. At present, for the oxidative carbonylation of glycerol to glycerol carbonate, homogeneous catalysts can play a catalytic activity, but homogeneous catalysts have problems on separation difficult. And heterogeneous catalysts reported for the reaction are a few, mainly focus on the supported palladium catalysts, but effect of the structure of support on the properties of palladium catalyst is unclear. So development of new supported palladium catalysts will become the important direction for the oxidative carbonylation of glycerol to glycerol carbonate.First of all, we select some of the palladium nanoparticles catalysts supported on inorganic carriers and organic carriers in our lab, and find that microporous organic polymers with high surface area supported palladium catalysts have good catalytic activity. On this basis, we synthetize the five kinds of nitrogen, phosphine functionalization of microporous organic polymers, namely using 1,10-Phenanthroline monohydrate and benzene, and 1,3,5-Triphenylbenzene to prepare microporous organic polymers containing nitrogen atom, and using triphenylphosphine and benzene, and 1,3,5-Triphenylbenzene to prepare microporous organic polymers containing phosphine atom, and using 1,10-Phenanthroline monohydrate and triphenylphosphine to prepare microporous organic polymer containing both nitrogen and phosphine atoms. By comparing the catalytic performance of the five palladium catalysts supported on different types of microporous organic polymers, we study the interaction between the support and palladium. We find that the activities of microporous organic polymer containing nitrogen atom supported palladium catalysts are significantly higher than microporous organic polymer containing phosphine atom supported palladium catalysts, and Pd0 is formed as the major phase on the surface of the support for the former, while the latter mainly exists in Pd²⁺. So we can see that Pd0 plays a key role in the reaction. Then, through the comparative study of different types of supports and effect of catalyst loading on the oxidative carbonylation of glycerol to glycerol carbonate, we select the best catalytic performance of heterogeneous catalysis system, SMP?phen-PhPh₃?-Pd?0?/NaI. In the reaction, glycerol:Pd =1000:1?molar ratio?, N,N-dimethyl acetamide, 3MPa?Pco:Po2=2:1?, 135?, 1.5 h, and realize the efficient conversion of glycerol?95.3%?, and glycerol carbonate with high selectivity?99.9%? and high TOF value?636h-1?. Catalytic system SMP?phen-PhPh₃?-Pd?0?/NaI can realize the selective synthesis of glycerol carbonate, and the catalyst can be reused for three times, but the catalytic activity gradually decreases.