Preparation Of Nickel Based Bimetallic And Chiral Modified Nickel Based Bimetallic Nanomaterials Nanomaterials Applied In Electrocarboxylation Of Acetophenone

In recent decades,people have released more and more CO₂ in industrial production and life,resulting in a gradual increase in the"greenhouse effect".Therefore,how to reduce and utilize CO₂ has always been a great concern of people.Electrochemical catalytic synthesis,as one of the methods of fixing and utilizing CO₂,has great development potential because of its simple,gentle and convenient conditions.Traditional asymmetric catalytic synthesis has been the main synthesis method of chiral compounds with the advantages of high yield and high selectivity.However,because the traditional asymmetric catalytic synthesis is a homogeneous catalytic synthesis,there are some main problems in the homogeneous system,such as the difficulty of separating and recovering the catalyst in the solution and the harsh reaction conditions,so that the cost of traditional asymmetric catalytic synthesis is higher and difficult to be applied to industrial production.This makes electrochemical asymmetric catalytic synthesis begin to receive people's attention,especially after combining fixation and utilization of CO₂,which makes electrochemical asymmetric carboxylation a promising research direction in the field of green chemistry.Electrochemical asymmetric carboxylation is a non-homogeneous catalytic synthesis,and the most important part in heterogeneous catalytic synthesis is the use of catalysts with high catalytic properties.Therefore,the search for a catalyst with excellent catalytic properties is an important research content in electrochemical asymmetric carboxylation.In recent years,because bimetallic nanomaterials can use the synergistic effects between two different metals?including electron and geometric effects?to improve the catalytic properties of materials,it has been widely used in the field of catalysis.In this paper,a simple and gentle method was used to prepare the nickel system and its chiral modified bimetallic nanomaterials,and it was applied to the asymmetric electrodeposition reaction of acetophenone to study its catalytic properties.The main research contents are as follows:?1?Preparation of nickel silver bimetallic nanomaterials and their application in asymmetric electrocarboxylation of acetophenoneWe explored a simple and mild hydrothermal method to prepare nickel bimetallic nanomaterials such as Ni/Ag,Ni/Cu and Ni/Fe by using cheap and readily available transition metal salts,and the corresponding bimetallic nanomaterials with different metal molar ratios could be prepared by changing the feeding ratio.We utilized XRD,SEM and SEM-EDX to analyzing the composition structure,surface morphology and elemental distribution of bimetallic materials.The corresponding material electrodes were prepared by using these materials,which can be applied into catalyze the asymmetric electrocarboxylation reaction of acetophenone.We have examined and optimized the reaction conditions such as the categories of nanomaterials electrodes,the types and quantities of chiral inducers,electrolytic power and current density and temperature of different bimetallic nanomaterials.It is found that under optimal reaction conditions,when cinchonidine?CD?is used as chiral inducer,using Ni/Ag 5/3bimetallic nanomaterial to catalyze the asymmetric electrocarboxylation reaction of acetophenone,we obtained the highest yield and optical activity?ee value?of R-2-hydroxy-2-phenylpropionic acid?atrolactic acid?.?2?Preparation and application of tartaric acid modified nickel bimetallic nanomaterials in asymmetric electrocarboxylation of acetophenoneA chiral modified nano-composite material was prepared by modifying tartaric acid to nickel bimetallic nanomaterials.XRD and SEM characterization show that tartaric acid modification will not affect the composition structure and surface morphology of the composites.The successful modification of tartaric acid in bimetallic nanomaterials was proved by FT-IR and TGA characterization.Then,the modification amount of tartaric acid in the composites was determined by ultraviolet spectrophotometry.Finally,the catalytic properties of bimetallic nanocomposites modified by different configurations of tartaric acid were studied by using chiral modified composites in asymmetric electrocarboxylation of acetophenone,and the reusability of composites was also investigated.