Molecular Design Of Thiazole Schiff Base And Corrosion Inhibition Of Copper

Metals are easily corroded during storage and use.Metal corrosion causes losses at a slight level and serious accidents at a high level.Copper and copper alloys are widely used in various fields,so it is necessary to study the behavior of copper corrosion and the protection of copper corrosion.In this paper,the corrosion inhibition performance and structure-activity relationship of thiazole-based Schiff base corrosion inhibitor for copper are studied.The main research contents are as follows:1.Synthesis and characterization of non-hydrocarbon-based aromatic aldehyde-thiazole Schiff base(A1,A2,A3,A4)and corrosion inhibition of copper in an aqueous solution of 3.5%sodium chloride were studied.Four Schiff base was synthesized:2-amino thiazole-salicylic aldehyde(A1)2-amino thiazole-vanillin(A2)2-amino thiazole-hydroxy benzaldehyde(A3)and 2-amino thiazole-adjacent vanillin(A4).Using self-assembly method at room temperature,respectively,in deal with copper electrode with corrosion inhibitor,corrosion inhibitor film electrode surface,and through electrochemical method of corrosion inhibitors on copper in3.5%NaCl aqueous solution.Schiff base A1 self-assembled film best assembly condition as:25?,10 mmol/L assembly solution was assembled for 4 hours.The optimal assembly condition of Schiff base A2:under 25?,assemble in 15 mmol/L assembly solution for 6hours;The optimal assembly condition of Schiff base A3 self-assembled membrane is:at25?,assemble in 20 mmol/L assembly solution for 6 h;Schiff base A4 self-assembled film best assembly condition as:25?,20 mmol/L assembly in 12 h Tafel curves determined results show that the corrosion current density decreases,suggests self-assembled film inhibits the corrosion of copper electrode,the efficiency of the corrosion A2>A1,for A3and A4,corrosion current density of anodic polarization area reduced,the cathodic polarization current is added,that self-assembled film only inhibit the anodic process of copper based on electrochemical impedance spectroscopy analysis,four kinds of corrosion inhibitors on copper surface membrane layer significantly increase the dissolved oxygen in the copper surface reduction of charge transfer process,but the corrosion of A3 A4performance worse than A1 A2.2.Synthesis and characterization of hydrocarbon-based aromatic aldehyde-thiazole Schiff base(B1,B2,B3)and corrosion inhibition of copper in an aqueous solution of 3.5%sodium chloride.Three Schiff base were synthesized:2-aminothiazole-p-methylbenzaldehyde(B1),2-aminothiazole-4-ethylbenzaldehyde(B2)and 2-aminothiazole-cuminaldehyde(B3).The optimal assembly conditions of Schiff base B1 self-assembly film were:25°C,15 mmol/L assembly solution for 12 h;the optimal conditions for the B2 self-assembly film of Schiff base were:25?,15 mmol/L assembly solution for 6 h;the optimal conditions for self-assembly of Schiff base B3 self-assembly film were:25?,10 mmol/L assembly solution for 4 h.After processing of copper electrode current cathodic area decreased obviously,and the anode area current changed little,indicated that three kinds of Schiff base contained the cathode of the electrode reaction process.Three kinds of corrosion inhibitors on copper surface membrane layer are increased the charge transfer process of dissolved oxygen on the surface of copper reduction,and the corrosion inhibition efficiency was B1>B2>B3.3.Synthesis and characterization of hydrocarbon-based aromatic aldehydes-benzothiazole Schiff base(C1,C2,C3)and corrosion inhibition of copper in 3.5%sodium chloride solution were studied,and compared with B1,B2,B3.Three Schiff base were synthesized:2-benzothiazolamine-p-methylbenzaldehyde(C1),2-benzothiazolamine-4-ethylbenzaldehyde(C2)and 2-benzothiazolamine-cuminaldehyde(C3).After treatment,the cathode current of the copper electrode decreased,and the anode current did not change much,indicating that the three Schiff base significantly inhibited the cathode reaction process of the electrode.The film formed by the three corrosion inhibitors on the copper surface obviously increase the charge transfer process of dissolved oxygen reduction on the copper surface,and the corrosion inhibition efficiency is C2>C1>C3.4.Use Materials Studio Dmol~3 module of all corrosion inhibitor molecules in the experiment of molecular orbital parameters is calculated,and then using the density functional theory to molecular orbital energy and molecules of atoms in the forefront of the charge distribution in the calculation,get the distribution of HOMO and LUMO inhibitor molecules,charge distribution and the frontier orbital energy.Substituent power stronger,Schiff base-C=N-groups and N atoms of the stronger the electronegativity,when after the introduction of thiazole ring in benzene ring form new conjugated system,frontier orbital energy difference value decreased?E,are more likely to participate in the coordination bonding.