Density Functional Theory Studies On Solvent Effect Of Pyruvic Acid Isomerization Reaction And Response Properties Of Polymer Modified Surface

Chemical reaction regulation can improve the utilization rate of raw materials,save energy consumption,reduce the discharge of three wastes,improve the reaction rate to a certain extent and realize the green production.In the liquid-liquid interface environment,the interface can be controlled by selecting the reaction solvent,so that some chemical reactions can be greatly affected.Thus,the study of the influence of solvent on the reaction mechanism is the basis of reasonable selection of reaction solvent.In the solid-liquid/solid-gas interface reaction system,the interface can be controlled by changing the properties of the solid surface,so that some chemical reaction processes can be enhanced accordingly.The common means of controlling the interface is to modify the polymer by riveting it on the solid surface,so the key of controlling the performance and improving the process efficiency is to master the structure-activity relationship of the polymer.Density functional method(DFT)was used to study the effects of chemical reaction regulation on chemical processes in different environments(liquid phase environment,liquid-solid and gas-solid multiphase interface system)at the molecular level.Firstly,the influence of solvent in liquid phase environment on the reaction was studied,and the isomerization reaction of pyruvic acid was selected as the research system.This reaction is a typical proton transfer reaction,which plays a vital role in chemical and biochemical systems,and has been the focus of extensive research in recent years.Then,the response characteristics of the grafted polymers to environmental parameters and the adsorption characteristics of the modified solids were studied at the molecular level,so as to understand the regulation mechanism at the molecular level,providing an effective regulation means for the multiphase reaction system.The main contents of this paper are as follows:(1)In this paper,the multi-scale reaction density functional theory coupling quantum density functional and molecular density functional was used to study the influence of solvent on the isomerization of pyruvic acid,explore the microscopic reaction path,and explain the influence mechanism of solvent on the reaction.The results show that the water molecule act as catalyst to participate in the reaction by receiving/giving protons to form a six-membered ring in the transition state.Due to the formation of the six-membered ring,the solute configuration changes little during the reaction process,thus reducing the reaction energy barrier,which is conducive to the reaction.The assistance of water molecules plays a major role in the reduction of the reaction energy barrier,and both the assistance of water molecules and the solvation effect are very important in the whole reaction process.(2)In this paper,the response characteristics of grafted polymers were studied by using the polymer density functional method.The behavior characteristics of polymer are understood from the molecular level by studying the influence of different parameters on the behavior of polymer.It is found that the behavior of polyelectrolyte chain is highly responsive to the change of parameters.Polymer density functional theory was applied to the study the influence of surface modification on the adsorption characteristics of hydrogen and oxygen at room temperature based on the response characteristics of polymers.The polymer was grafted onto the substrate surface of the commonly used catalyst.The adsorption of hydrogen and oxygen on solid surface was studied by changing the graft density and chain length of the polymer.The results showed that the change of the graft density and chain length of the polymer significantly changed the density distribution near the substrate.The small molecules near the substrate were repelled by the polymer and the penetration was blocked under the high graft density and the long chains.Both the low graft density and the short chains facilitate the infiltration of hydrogen and oxygen.However,there is selective adsorption of hydrogen and oxygen near the substrate,so appropriate chain length and graft density should be selected according to the purpose of chemical reaction in practical applications,so as to effectively regulate the adsorption of small molecules on the substrate surface and make the chemical reaction proceed in a favorable direction.The study of typical chemical reactions by density functional theory can analyze the reaction mechanisms from the molecular level,explore the core factors and key function range that affect the reaction,and provide theoretical basis and strengthening mechanism for related engineering applications.