Studies On The Synthesis And Asymmetric Catalytic Properties Of The Chiral Polymer Heterogeneous Catalysts

Drugs are essential for human to overcome the disease and prolong the life,and they are very important to our lives.The pharmaceutical industry usually involves the asymmetric homogeneous catalysis.Asymmetric homogeneous catalysis has the advantages of high activity and high chiral selectivity.However,the homogeneous catalyst is difficult to be separated,and it will cause the pollution of the drugs such as metal residues.The strategy of homogeneous catalyst immobilization can greatly improve the service life of the catalysts,which not only improves the efficiency,but also alleviates the pollution.The methods of homogeneous catalyst immobilization mainly include grafting and polymerization.The polymerization method has attracted increasing attention because it leads to more active centers and better activity.However,the chiral selectivity of heterogeneous polymer catalyst is usually not as good as that of homogeneous catalyst.In addition,there exists the phenomenon of swelling,poor stability and depolymerization of polymer catalyst in the reaction process.So far,it is still a challenge to prepare high performance heterogeneous asymmetric catalysts with high stability.In this thesis,the main research work is to construct the heterogeneous catalysts with polymerization strategy,and to study their performance in the asymmetric catalytic reaction.It includes the three parts as follows:1.The functionalized chiral Bis(oxazoline)ligands have been successfully synthesized.The polymer catalysts were obtained by copolymerizing the functionalized chiral Bis(oxazoline)ligands.In order to improve the stability of catalysts,we treat the polymer catalysts at high temperature for partial carbonization.The study of asymmetric catalytic Henry reactions showed that chiral selectivity of the chiral polymer heterogeneous catalysts was nearly the same as homogeneous catalysts.The effects of high temperature treatment on the performance of catalysts were also studied,and we found that heat treatment could improve the stability of catalysts.2.A kind of stable heterogeneous catalysts with well-defined structure was obtained by copolymerizing the functionalized chiral Bis(oxazoline)ligands and the terephthaloyl dichloride.The study of asymmetric catalytic Henry reactions showed that the catalytic activity of the chiral polymer heterogeneous catalyst is comparable to that of homogeneous catalyst,and the chiral selectivity is up to 79%EE,which is better than that of the homogeneous catalyst and the previously reported values.The catalyst is reused more than 7 times without any decay in the activity and selectivity.3.The chiral phosphoric acid catalyst monomer(1,1’-Binaphthyl-2,2’-diyl hydrogenphosphate)functionalized in the 33’ position was successfully synthesized.Then,a new kind of chiral porous polymer catalyst was prepared based on the catalyst monomer.A series of characterizations of the catalyst were carried out.The specific surface of the novel catalyst reached up to 572 m2/g.The novel catalyst is expected to find applications in many asymmetric catalytic reactions.