Synthesis Of Nano Nickel/cobalt And Their Application In Electrocatalytic Asymmetric Hydrogenation Of Keto Esters

Asymmetric catalytic synthesis is one of the most important methods for the preparation of chiral compounds.Since it was discovered,more and more researchers have paid attention to it and there have been a lot of scientific research achievements about it.As an important medium for asymmetric catalytic synthesis,catalysts have been attracted more and more attention.Most of the asymmetric metallic catalysts are Pt,Pd and other platinum precious metals.However,this kind of precious metals are limited in the global reserves.Besides,there are also significant demands of them in valuable jewelry,high-tech materials and other fields.Therefore,it is of great value to develop non noble metal catalysts.As a green synthesis technology,electrochemical synthesis has many advantages,and gradually get people's attention.Particularly,a number of studies have been made on the preparation of chiral compounds by electrochemical methods.In this thesis,we mainly study the synthesis of Ni,Co nanomaterials and their application in electrocatalytic asymmetric hydrogenation of keto esters.The experimental studies were as follows:(1)Synthesis of nickel nanoparticles and their application in electrocatalytic asymmetric hydrogenation of keto estersNickel nanoparticles were prepared by liquid phase chemical reduction method,then pressed to a coin as the cathode.XRD and SEM were used to characterize the Ni nanoparticles.Nano nickel coin was used as the cathode,with alkaloid and tartaric acid as chiral inducers and H2O as hydrogen source,to study the electrocatalytic asymmetric hydrogenation of ethyl benzoylformate and ethyl benzoylacetate in an undivided cell.GC-MS was used for qualitative analysis and HPLC was used for quantitative analysis of the products.The influence of charge,co-solvent,current density and temperature on the reaction were investigated.Besides,cyclic voltammetry behavior of the two substrates on nano nickel cathode was also investigated.The experimental results showed that the application of nickel nanoparticles in electrocatalytic asymmetric hydrogenation of keto esters was effective.(2)Preparation of TA@Ni/Co chiral bimetallic nanomaterials and their application in electrocatalytic asymmetric hydrogenation of a-keto estersNi/Co nanoparticles with molar ratio of 1:1 were prepared by liquid phase chemical reduction with improved conditions on the basis of the above preparation procedure of nano nickel materials.Then,tartaric acid was modified into the Ni/Co nanomaterials by the strong interaction between Ni/Co bimetal and tartaric.After that,XRD,SEM,ICP,FT-IR were used to characterize the chiral bimetal materials.TA@Ni/Co coated on the carbon paper was used as the cathode,with alcohol as hydrogen source,to study the electrocatalytic asymmetric hydrogenation of ethyl benzoylformate and methyl benzoylformate in an undivided cell.And cyclic voltammetry behavior of ethyl benzoylformate on TA@Ni/Co cathode was also investigated.The experimental results showed that products of electrolysis by the TA@Ni/Co chiral bimetal cathode had a relatively higher yield on the basis of maintaining a certain ee value compared with the nano nickel cathode.