Corrosion Inhibition Performance And Inhibition Mechanism Of Penicillins

Adding inhibitor is the most common way to protect metals from corrosion, particularly in the pickling solution. With the increasing demand for the green inhibitor all around the world, inhibitor drugs, as a new kind which is less polluted and degradable, are attracting more and more attention from the public. Therefore, in recent years, scientists at home and abroad have carried out measurement about inhibitor drugs performance. After some studies, it’s sure that they have excellent corrosion properties, but studies of the drug inhibitor are relatively few in our country, just in the very beginning. After a series of researches, it is certain that they have excellent properties in corrosion relief. However, the surveys into drug inhibitors are relative few domestically, for we are still in a fledging period.In this paper, we have chosen four penicillin inhibitors, they are (PenicillinG)[3,3-dimethyl-7-6-[(2-phenylacety) amino]-(2S,5R,6R)-4-Thia-l-azabicyclo [3.2.0] heptanes-2-carboxylic acid].(Oxacilin)[3,3-dimethyl-6-[[(5-methyl-3-phenyl-4-isoxazolyl) carbonyl] ami-no]-7-ox0-4-Thia-1-azabicyclo [3.2.0] heptanes-2-carboxylic acid].(PenicillinV)[3,3-d-imethyl-7-oxo-6-[(2-phenoxyacetyl)amino]-(2S,5R,6R)-4-Thia-l-azabicyclo[3.2.0]heptanes-2-carboxylic acid].(Amoxicillin)[6-[[(2R)-2-amino-2-(4-hydroxyphenyl) acety] amino]-3,3-dimethyl-7-oxo-(2S,5R,6R)-4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid]. And thro-ugh many methods such as weight loss method, scanning electron microscopy (SEM), polarization curves, quantum chemical calculations, molecular dynamics simulation, we researched into the corrosion relief performance of four kinds of inhibitors towards carbon steel melted in1mol/L HCl, analyzed their inhibition mechanism, and made possible adsorption model.From the results of experiment through weight loss method, polarization curves and scanning electron microscopy, we know that four kinds of inhibitor in HC1solution have significant inhibition effect on carbon steel, corrosion inhibition efficiency increases by the increase of the concentration of inhibitor. At an experimental the concentration of10-3mol/L, the rate of oxacillin inhibition reached93.4%. The test by polarization curves shows that the corrosion inhibition is a fixed inhibitor based on cathode suppression. The process of corrosion inhibitor adsorbing on the surface of carbon steel is endothermic, abiding by the Langmuir Isotherm equation, which is a single-molecule adsorption. From SEM, we can see that in the protection from B inhibitor molecule, the metal surface is complete, with little corrosion. And the theoretical arguments are proved by quantum chemical calculations and molecular dynamics simulations. The result of theoretical calculations through the method combining the quantum chemical calculations with molecular dynamics simulation shows that all of the four kinds inhibitor molecules have multiple reactive sites, which focuses on the Phenyl and nitrogen’s heterobicyclic, and the reactive sites of oxacillin inhibition is the most. Molecular dynamics simulation in the interaction of the inhibitor molecules and the metal surface further confirms that oxacillin inhibitor’s adsorption on metal surface is the most stable one.Conclude from the results of four kinds of measurement, four kinds of corrosion molecules orders by the efficiency of molecule inhibition:Oxacillin> amoxicillin> Penicillin V> Penicillin G. Experiment results of corrosion performance coincide with theoretical analysis.