Quantum chemical study on the inhibition efficiencies of some sym-triazines as inhibitors for mild steel in acidic medium (original) (raw)
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Molecules, 2016
Triazine derivatives, namely, 2,4,6-tris(quinolin-8-yloxy)-1,3,5-triazine (T3Q), N 2 ,N 4 ,N 6-tris(pyridin-2-ylmethyl)-1,3,5-triazine-2,4,6-triamine (T3AMPy) and 2,2 1 ,2 11-[(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)] tris(ethan-1-ol) (T3EA) were synthesized and their inhibition of steel corrosion in hydrochloric acid solution was investigated using electrochemical techniques. The corrosion protection of the prepared compounds increased with increasing concentration and reached up to 98% at 250 ppm. The adsorption of T3Q, T3AMPy, and T3EA on the steel surface was in accordance with the Langmuir adsorption isotherm. The electrochemical results revealed that T3Q, T3AMPy and T3EA act as excellent organic inhibitors and can labeled as mixed type inhibitors. The efficiencies of the tested compounds were affected by the nature of the side chain present in the triazine ring, where T3EA gave the least inhibition while T3Q and T3AMPy gave higher and almost the same inhibition effects. The inhibition efficiencies obtained from the different electrochemical techniques were in good agreement.
ACS Omega
We observed our newly developed tetrahydro-1,2,4triazines, including triazene moieties (THTA), namely, 6-((1E)-1-((2E)-(4-(((Z)-1-(2,4-diphenyl-2,3,4,5-tetrahydro-1,2,4-triazin-5yl) ethylidene) triaz-1-en-1-yl)piperazin-1-yl) triaz-2-en-1-ylidene) ethyl)-2,4-diphenyl-2,3,4,5-tetrahydro-1,2,4-triazine (THTA-I), and 1-((E)-((E)-1-(2,4-diphenyl-2,3,4,5-tetrahydro-1,2,4-triazin-6yl) ethylidene) triaz-1-en-1-yl) naphthalen-2-ol (THTA-II), as effective inhibitors for the corrosion protection of N80 carbon steel metal in 5% sulfamic acid as the corrosive medium via electrochemical approaches such as potentiodynamic polarization and electrochemical impedance spectroscopy. Furthermore, the tested steel exterior was monitored using X-ray photoelectron spectroscopy after the treatment with the investigated components to verify the establishment of the adsorbed shielding film. The investigated compounds acted as mixed-type inhibitors, as shown by Tafel diagrams. The compounds considered obey the Langmuir adsorption isotherm, and their adsorption on the steel surface was chemisorption. When the tested inhibitors were added, the double-layer capacitances, which can be determined by the adsorption of the tested inhibitors on N80 steel specimens, decreased compared with that of the blank solution. At 10 −4 M, the inhibitory efficacy of THTA-I and THTA-II achieved maximum values of 88.5 and 86.5%, respectively. Density-functional theory computations and Monte-Carlo simulation were applied to determine the adsorption attributes and inhibition mechanism through the studied components. Furthermore, the investigated inhibitors were considered to adsorb on the Fe (1 1 0) surface. The adsorption energy was then measured on steel specimens.
Egyptian Journal of Petroleum, 2013
The main objective of this work was to examine the corrosion inhibition ability of three novel surfactant molecules synthesized from 1,3,5-triethanolhexahydro-1,3,5-triazine, which named (I, II and III). The chemical structure of these surfactants was confirmed by FT-IR and 1 H NMR spectroscopy. Also the surface active properties for the synthesized compounds were calculated. The effect of these surfactants on carbon steel in a solution of 1 M HCl was studied using mass-loss and electrochemical measurements. Protection efficiencies were found to be 93.1%, 90.7%, and 87% for III, II, and I, respectively. The order of increasing inhibition efficiency was correlated with increasing the number of ethylene oxide units. Potentiodynamic polarization curves indicated that the prepared surfactants acted as mixed type inhibitors. Adsorption of the inhibitor obeys the Langmuir isotherm. Quantum chemical calculations based on ab initio method were performed on I, II and III. The molecular structural parameters, such as the frontier molecular orbital energy HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital), the charge distribution and the fraction of electrons (DN) transfer from inhibitor to carbon steel were calculated and discussed. ª 2013 Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute.
Arkivoc, 2006
A quantum chemical study of the efficiency of some o-, m-, and p-substituted benzohydrazides, cinnamohydrazide, and Schiff bases derived from salcylaldehyde with o-substituted anilines, psubstituted benzaldehydes with 2-aminopyridine and 2-aminopyrimidine, benzaldehyde and cinnamaldehyde with p-phenylenediamine as corrosion inhibitors of steel in the presence of 1M HCl is presented. The AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods were used. A possible correlation between corrosion inhibition efficiencies and structural properties was searched to reduce the number of compounds to be selected for testing from a library of compounds. Quantum parameters, total negative charge (TNC) on the molecule, energy of highest occupied molecular orbital (E HOMO), energy of lowest unoccupied molecular orbital (E LUMO), dipole moment (µ), total energy (TE), and linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π*) were correlated to corrosion inhibition efficiency of the studied compounds. The results were used to predict the corrosion inhibition of some related aromatic hydrazide derivatives with correlation coefficient r > 0.96.
2008
ABSTRACT. A quantitative structure property relationship (QSPR) analysis of some organic compounds (imines or Schiff bases) is studied. The corrosion inhibition efficiencies of these imines have been studied by using AM1 (Austin model 1) Hamiltonian SCF-MO method and QSPR analysis. One of the most promising semi-empirical methods for predicating geometries and electronic properties is AM1. The geometry of all compounds 1-11 was optimized and all data obtained for building the multiple regression model. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds was obtained from the regression coefficients for the model.
Bulletin of the Chemical Society of Ethiopia, 2009
A quantitative structure property relationship (QSPR) analysis of some organic compounds (imines or Schiff bases) is studied. The corrosion inhibition efficiencies of these imines have been studied by using AM1 (Austin model 1) Hamiltonian SCF-MO method and QSPR analysis. One of the most promising semiempirical methods for predicating geometries and electronic properties is AM1. The geometry of all compounds 1-11 was optimized and all data obtained for building the multiple regression model. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds was obtained from the regression coefficients for the model.
Adsorption and corrosion inhibiting behavior of a new S-triazine derivative
Protection of Metals and Physical Chemistry of Surfaces, 2015
Abstarct-The inhibiting effect of 4, 6 bis (5 mercapto 1, 3, 4 thiadiazol amine) 2 phenylamino 1,3,5 tri azine BMTDT on the corrosion of mild steel in acidic media has been investigated by weight loss and elec trochemical methods. Results obtained reveal that this organic compound is a very good inhibitor. BMTDT is able to reduce the corrosion of steel more effectively in 1M HCl than in 1M H 2 SO 4 . The effect of polariza tion studies show that the adsorption of BMTDT follows physical adsorption in both acids without changing the mechanism of the hydrogen evolution reaction. Surface analyses were also carried out to establish the mechanism of corrosion inhibition of mild steel in acidic media. The adsorption of this inhibitor on the mild steel surface in obeys the Langmuir absorption isotherm in 1M HCl and Frumkin adsorption isotherm in 1M H 2 SO 4 . The corrosion behavior of mild steel with addition of different concentration of BMTDT was studied in the temperature range 308-333 K. The associated activation parameters and adsorption free energies have been determined and discussed.
Results in Physics, 2018
One of best method, which was used to prevent the mild steel from corrosion, was through employed natural or synthetic organic chemical compounds. Here in, we displayed a Schiff base derivative which has nitrogen, oxygen and sulfur atoms as corrosion inhibitor for MS "mild steel" in 1 M HCl "hydrochloric acid" solution. Synthesized inhibitor was characterized by using of FT-IR "Fourier transform infrared" and NMR "Nuclear magnetic resonance" spectroscopies in addition to CHN analysis technique. The weight loss and SEM "Scanning electron microscope" studies showed that inhibitor have the ability to prevent the alloy surface from corrosive solution by adsorbing on MS surface to form stable adsorbed layer that results in the higher inhibition efficiency. The inhibition influence of the synthesized inhibitor was increased parallel with increasing concentration and decrease with rising temperature degrees. Furthermore, DFT "Density function theory" has been employed to calculate quantum chemical parameters "Energy, highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and electronegativity (χ)" which performed on synthesized corrosion inhibitor to determine the relationship between the structure of synthesized inhibitor molecule and inhibition performance.
Journal of the Turkish Chemical Society Section A: Chemistry, 2019
Density Functional Theory (DFT) calculation at B3LYP level of theory and 6-31G* basis set was applied on some triazole derivatives of pyrimidine which led to the optimization of their structures, generation of electronic and other important Quantum chemical descriptors such as the energy of the highest occupied molecular orbital (EHOMO), the energy of the lowest unoccupied molecular orbital (ELUMO), energy band gap (ΔE), Dip E), Dipole Moment (μ)), chemical hardness (η),), chemical softness (σ)), global electronegativity σ =1η = − (2 (EHOMO − E L U M O)) (χ) and number of transferred electrons (ΔE), Dip N) using SPARTAN'14 Software. The obtained results shows a good correlation between the chemical structures of the inhibitors and their experimental inhibition efficiencies (%IEs). The ranking of these efficiencies (%IEs) nicely matched with the order of a good number of the generated descriptors but with a varying degree of correlation as majority of the descriptors indicates that I-4 is the best inhibitor among the data set. Furthermore, molecular dynamic (MD) simulations were carried out to search the best adsorption configuration of the inhibitor on the steel (1 1 0) surface using Material Studio 8.0. The obtained results of MD simulations suggest that the interaction was as a results of the chemical adsorption on the steel surface, since the binding energy > 100 Kcalmol-1 for all the inhibitors and the best adsorption energy was found to be-488.07 Kcalmol-1 (I-4). This observation are in good agreement with the DFT results and the experiment findings. Thus; this study provides a valuable approach and new direction to novel steel corrosion inhibitor discovery.
Corrosion Science, 2012
The abilities of phthalazine derivatives, including phthalazine (PT), phthalazone (PTO) and phthalhydrazide (PTD), to inhibit the corrosion of mild steel in 1 M HCl at 30 °C were studied using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. Theoretical calculations were performed to investigate the electronic structures of the PT derivatives. Our results showed that the inhibition efficiencies of these derivatives improved with increases in concentration. The data also showed that PTD < PT < PTO in terms of the inhibiting efficiency. Theoretical calculations also revealed that PTO is expected to be the best inhibitor among the studied phthalazine derivatives.