مطا لعه نظری و تجربی سینیتیک واکنشهای چند جزئی جدید همراه با مطالعه نظری میزان بازدارندگی تعدادی از ترکیبات روی خوردگی کربن استیل

In the first research work, kinetics and mechanism of the reaction between 4-methylbenzaldehyde (1), 4-boromoaniline (2) and methyl acetoacetate (3) in the presence of La(NO3)3.6H2O as a catalyst in acetonitrile solvent was investigated. UV/vis spectrophotomery technique was used to determine the kinetic parameters of this reaction. The proposed mechanism was investigated based on the obtained experimental data and the second step of the reaction was recognized as the rate determining step. In the second research work, kinetics and mechanism of the reaction between para-substituted Anilines (1), diethyl acetylenedicarboxylate (2) and benzaldehyde (3) in formic acid (as solvent and catalyst) was investigated by UV/vis spectrophotometery. Useful information was obtained from studying the effects of solvent, temperature, substitution and concentration of reactants on the reaction rates. Results show that the first step of the reaction is the rate determining step. The proposed mechanism was confirmed on the basis of experimental data. In the third research work, kinetics and mechanism of the reaction between benzaldehyde (1), 4-ethylaniline (2) and diethyl acetylenedicarboxylate (3) in ethanol (as solvent) was investigated using UV/vis and Stopped-Flow spectrophotometry techniques. The rate constant of the fast step was obtained using stopped-flow spectrophotometry. Also the number of reaction intermediates was determined and the mechanism approved by the UV/vis was confirmed. In the fourth research work, theoretical study of kinetics and mechanism of the reaction between 4-methylbenzaldehyde (1), aniline (2) and methyl acetoacetate (3) in the presence of Tartaric acid as a catalyst in methanol solvent was investigated using quantum mechanical calculations. The profile of the potential energy surface was constructed at the HF/6-31G (d,p) level of theory and kinetics data including k and Ea, activation parameters (ΔG‡, ΔS‡ and ΔH‡) and thermodynamic parameters (ΔG, ΔS and ΔH) were calculated in solution phase (the B3LYP/6-31G(d,p) level of theory) for all steps of the two mechanisms. In both proposed mechanisms, the second Step was identified as the rate determining step. Between the two proposed mechanisms, one of them was c kinetically more acceptable. This results agree well with the experimental data obtained from the previous studies (first research work). In the fifth research work, theoretical study of kinetics and mechanism of the reactionsbetween benzaldehyde (1), 4-ethylaniline (2) and diethyl acetylenedicarboxylate (3) in ethanol solvent was investigated using quantum mechanical calculations. The profile of the potential energy surface was constructed at the HF/6-31+G* level of theory and the kinetics of the reaction was investigated in solution phase for various steps of the mechanism. In the proposed mechanism, the first step was identified as the rate determining step. This results agree well with the experimental data obtained from the previous studies (third research work). In the sixth research work, theoretical study of corrosion inhibition efficiencies of amino acid derivatives [tryptophan (B), tyrosine (C), and serine (A)] have been studied using global properties at the B3LYP/ 6-311++G** level of theory in gas and solution (water) phases. Also, active sites for electron donors and electron acceptors of inhibitors was determined by local properties. In the continuing the adsorption aehavior of inhibitors on the surface of Fe (110) was investigated using molecular dynamics simulations. Consistent with experimental data, theoretical results showed that the order of inhibition efficiency is tryptophan (B) > tyrosine (C) > serine (A). In the seventh research work, theoretical study of the corrosion inhibition efficiencies of benzothiazole derivatives have been studied using global properties at the B3LYP/6-311++G** level of theory in gas and solution (water) phases, consistent with experimental data, theoretical results showed that the order of inhibition efficiency is TBTA > MBTA > BTA. In the eighth research, theoretical study of the corrosion inhibition efficiencies of penicillin G, methicillin and nafcillin have been studied using global properties at the B3LYP/6-311++G** level of theory in gas and solution (water) phases. Consistent with the experimental data, the theoretical results showed that the order of inhibition efficiency is nafcillin>methicillin>penicillinG.