DFT-QSAR studies on corrosion inhibition efficiency of derivatives of thiadiazole, oxadiazole and triazole

The inhibiting activity of 3 sets of organic compounds ([2-[(2,3-dihydroxypropyl)sulfanyl]-N-octylacetamide (DSO), 2-[(2,3-dihydroxypropyl)sulfanyl]-N-decylacetamide (DSD) and 2-[(2,3-dihydroxypropyl)sulfanyl]-N-dodecylacetamide (DSDD)) were studied. The studied anti-corrosion compounds i.e. 2,3-dihydroxypropyl-sulfanyl derivatives were calculated using quantum chemical calculation and several descriptors (highest occupied molecular orbital energy (E HOMO), lowest unoccupied molecular orbital energy (E LUMO) and chemical reactivity indices (global electrophilicity index (ω), chemical hardness (η), electronegativity (χ), local reactivity index, electron affinity and ionization potential) which described the anti-corrosion properties of the studied compounds were obtained. Fukui Indices for nucleophilic and electrophilic Attacks for inhibitors i.e. [2-[(2,3dihydroxypropyl)sulfanyl]-N-octylacetamide (DSO), 2-[(2,3-dihydroxypropyl)sulfanyl]-Ndecylacetamide (DSD) and 2-[(2,3-dihydroxypropyl)sulfanyl]-N-dodecylacetamide (DSDD) were observed and sites for nucleophilic and electrophilic attacks for DSO were C6 (0.047) and O3 (0.170); for DSD, the utmost value for was found on C6 (0.047), and the highest value for was located on C5 with 0.099 while the greatest value for was situated on C6 with 0.047 and the highest value for is found on C3 and C4 with 0.053 each for the DSDD molecule. The molecules used in this study was calculated using quantum chemical calculation and it was achieved using Spartan 14. More so, the QSAR study using multiple linear regression method was executed using Gretl 1.9.8. The selected descriptors among the entire calculated descriptors were used in the development of quantitative structural activity relationship (QSAR) model and the developed model replicated the observed %IE. The correlation coefficient (R 2) was calculated to be 0.926, cross validation (CV.R 2) was 0.963 and adjusted R 2 was 0.852. Also, E LUMO was the predominating parameter in the corrosion inhibition property of the studied compounds.

Section: Dso Dsd Dsddmentioning

confidence: 75%

Quantum chemical studies on inhibition activities of 2,3-dihydroxypropyl-sulfanyl derivative on carbon steel in acidic media

Oyebamiji¹,

Adeleke²

2018

“…Hetero atoms in organic corrosion inhibitors increase the efficiency in the order of O ˂ N ˂ S ˂ P [1][2][3][4][5][6]. The adsorption depends on the electron density of the donor atom and of the functional group, which is influenced by the charge, type of electrolyte, and the metal surface.…”

Section: Introductionmentioning

confidence: 99%

Influence of the nanolayer’ post-treatment on the anticorrosion activity

2018

The study of self-assembled molecular layer (SAM) of undecenyl phosphonic acid amphiphilic molecule was in the focus of experiments. This molecule has a double bond at the end of the hydrophobic carbon chain, which does not allow the formation of a very compact SAM layer. The nanolayers were developed on carbon steel surface polished before layer deposition. To increase the compactness of the nanolayer, post-treatments were applied. In one case UV light, in the other case gamma-ray irradiation were used to polymerize the double bonds and form a film with net-like structure on the metal surface. The influence of the SAM layer treatments on the layer structure was followed by monitoring the change in water wettability and by atomic force microscopic (AFM) visualization of the morphological alteration. At the UV treatment the time dependence, at the irradiation the change in the dose were the altered factors. The post-treatments of the self-assembled undecenyl phosphonic acid molecular layer resulted in denser nanolayer structures and the consequence was a significantly improved anticorrosion activity. The change in the roughness parameters (maximum height of the profile, roughness average and the root means square roughness) arisen from the AFM measurements proved the influence of post treatments on the layer structure, which could be correlated with the increase in the anticorrosion ability as it is known that with increasing surface roughness the possibility of pitting corrosion increases. The increased anticorrosion activity is due to the formation of a more effective, compact barrier layer between the nanolayer-covered metal surface and the corrosive environment.

“…As a consequence, the study of effective methods to prevent corrosion has become a very important and interesting topic among researchers [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

SVET study of the interaction of 2-mercaptobenzothiazole corrosion inhibitor with Au, Cu and Au–Cu galvanic pair

2017

This study reports an electrochemical investigation of the interaction between 2-mercaptobenzothiazole (2MBT), a corrosion inhibitor, and two noble metals (Cu and Au), either isolated or under galvanical coupling. The surface reactivity of the inhibitormodified metals in chloride-containing aqueous solution of 0.1 mM NaCl was studied using the Scanning Vibrating Electrode Technique (SVET). The potential gradients in the electrolyte were detected by the SVET and converted to local ionic currents distributed at different anodic and cathodic sites, where electrochemical redox reactions are taking place. No external polarization was applied during SVET measurements, leaving the samples at the spontaneous free corrosion potential (FCP). The values of FCP showed that the metals are not protected by 2MBT. SVET revealed a moderate electrochemical activity of Au and very low in the case of Cu.