Construction And Application Of Polymer-based Oxazoline Nanoreactor

In recent years,homogeneous catalysts have received extensive attention and application due to their high catalytic activity.There also are several problems,high cost,and difficulty in separation from the catalytic system,which will pollute the environment to a certain extent.In nature,many chemical reactions often occur in a small domains ranging from a few nanometers to tens of nanometers of enzymes Inspired by nature,chemists have attempted to build a variety of nanoreactors to achieve efficient chemical conversion using small size effects,surface effects,confinement effects,and synergistic effects in nanoreactors.The introduction of heterogeneous catalysts into the nanoreactor can achieve the advantages of homogeneous and heterogeneously catalysis,as well as the special effects of nanoreactors.The nanoreactor has high local catalyst concentration,high catalytic efficiency,and convenient separation and recovery.In this thesis,polymer was used as a carrier of the catalyst,the amphiphilic polymer loaded with oxazoline was prepared and self-assembled in solvent to form nanoreactor.The research contents are as follows:Topic 1:Macromolecular initiator was synthesized by Reversible Addition-Fragmentation Chain Transfer Polymerization(RAFT).The monomer of methyl acrylate(PyOx)containing small molecular organic non-metallic catalyst(2-phenyl-4,5-dihydrozole-5-yl)methyl acrylate were prepared by organic synthesis.In chloroform,a nanoreactor with the organic catalyst PyOx in the core was prepared by polymerization induced self-assembly(PISA)via RAFT polymerization.Its structure and particle size were characterized by 1H-NMR,DLS and IR.The nanareactor was applied to the asymmetric hydrosilylation of aromatic ketones in chloroform solution.The results showed that the amount of catalyst needed decreased after the catalyst was included into nanoreactor.Topic 2:In this study,oligopoly(ethylene glycol methyl ether methacrylate)(OEGMA300)was used as temperature sensitive monomer to synthesize polymer carrier by RAFT polymerization.A chiral oxazoline-palladium metal complex was anchored in the end of the polymer chain forming an amphiphilic polymer.Then,the amphiphilic polymer was self-assembled in the water,offering a nanoreactor,which was successfully applied in the asymmetric synthesis of flavanone in water.Under low palladium loading(0.5 mol%),flavonoids with excellent yield(98%)and high enantioselectivity(82%)were successfully synthesized.The catalyst can be recovered by simple increasing temperature,the catalytic efficiency almost didn’t decrease after reuse for 5 times,began to decrease slightly at the 6th cycle.