The Application Of Theoretical Calculation In The Study On Inhibition Mechanism

At present,although theoretical calculation,especially quantum chemistry calculation have been widely applied in research of inhibition mechanism of inhibitors,but some parameters such as E_HOMO,E_LUMO,?E are not agreement with the results of experiment.So it is necessary to develop a more reliable and holistic calculation model to explore corrosion mechanism in microcosm,thus estimating corrosion inhibition properties of molecules.This will help in developing new types of corrosion inhibitors that perform well in a low-cost and effective way.In order to reduce the time of optimize the geometries of corrosion inhibitors and obtain accurate initial configurations,firstly,the influence of indented skeleton atoms,balme indented skeleton atoms of long carbon chain and the use of tools on the panel of GaussView5.0 upon the initial structures of molecules has been discussed to acquire rules of building up initial structures in this paper.Then in order to futher explain the corrosion inhibitor mechanism and investigate the relationship between the molecule microstructure and corrosion inhibition properties and find an universal and reliable method to elaborate the corrosion inhibiton mechanism,the frontier orbital density distribution,Fukui function,molecular electrostatic potential?MEP?and some quantum chemical parameters such as frontier orbital energy(E_HOMOOMO and E_LUMO),energy gap??E?of some corrosion inhibitors M1,M2,S1,S2,PTU,TTU and DPTU were caculated by Gaussian09.In addition,the adsorption model and the binding energy between corrosion inhibitors and the metal sueface were also figured up by molecular dynamics simulation.At last inhibitors with a better performance were designed according to the corrosion inhibiton mechanism of M1,M2,S1,S2,PTU,TTU and DPTU.Besides,a new type of inhibitor was designed by forecasting the corrosion inhibition performance of the molecular fragment functionalized graphene oxide molecule.The results showed that accurate initial structures can be obtained if the atoms the skeleton atoms of the carbon chain are arranged serrated and the toolis used when building up initial molecules.The method of explaining microscopic mechanism with use of theoretical calculation can be summarized as following:?1?Get the frontier orbital density distribution firstly;?2?Analyze the active adsorption sites of inhibiotors with combinations of Fukui function population;?3?Caculate quantum chemical parameters energy gap??E?,global softness???,electron transfer number??N?and electric index???,corrosion performance can be determined in this way.?4?Simulate molecular dynamics for further verification and obtain adsorption model.Moreover,inhibitors named M1b-2 and DTTU-1 with a better performance and a new type of inhibitor GO5-f-EDA were designed.