scholarly journals Electrochemical and quantum chemical study to assess the role of (2E)-2-(furan-2-ylmethylidene) hydrazine carbothioamide as inhibitor for acid corrosion of mild steel

2021 ◽  
Author(s):  
V. R. Adinarayanan ◽  
P. Preethi Kumari ◽  
Suma A. Rao
Keyword(s):  
Mild Steel ◽  
Quantum Chemical ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
Acid Corrosion ◽  
Quantum Chemical Study ◽  
Activation Parameters ◽  
Chemical Study ◽  
Clear Insight

AbstractSynthesis and inhibition effectiveness of (2E)-2-(furan-2-ylmethylidene) hydrazine carbothioamide (FMHC) as an inhibitor for corrosion of mild steel in 0.5 M H2SO4 is reported. Experiments were conducted at various temperatures (303–323 K) by adopting potentiodynamic polarization and electrochemical impedance spectroscopy. Readings obtained demonstrated that percentage inhibition efficiency (% IE) improved with the upsurge in the concentration of FMHC, while it decreased with a rise in temperature. The highest % IE observed was 60% for 2.5 × 10–4 M FMHC at 303 K. FMHC worked moderately as a mixed inhibitor. FMHC obeyed the Langmuir model of adsorption and the mode of adsorption was physisorption on the mild steel surface which was further endorsed by examining the surface using the scanning electron microscope. A clear insight into the mechanistic features of corrosion inhibition by using FMHC was acquired. Calculation of activation parameters helped to suggest an appropriate mechanism for the adsorption of FMHC on mild steel through quantum chemical calculations using density functional theory (DFT). Graphical abstract

AN EXPERIMENTAL AND THEORETICAL CORRELATION OF INHIBITION EFFECT OF SOME DIHIDROPYRIDINE ON MILD STEEL IN 1M HCL

2021 ◽  
Author(s):  
Ismail Fahim ◽  
Malika Tridane ◽  
Said Belaaouad
Keyword(s):  
Mild Steel ◽  
Quantum Chemical ◽  
Electrochemical Impedance ◽  
Quantum Chemical Study ◽  
Steel Corrosion ◽  
Chemical Study ◽  
Chemical Parameters ◽  
Langmuir Adsorption ◽  
Tafel Polarization ◽  
Acidic Bath

The corrosion inhibition of mild steel in 1 M HCl solution by some dihydropyridine has been studied using gravimetric, electrochemical impedance spectroscopy, potentiodynamic polarization techniques and quantum chemical study. The results of weight loss and Tafel polarization measurements showed that among the studied compounds, Isradipine has good inhibiting properties for steel corrosion in acidic bath, with 98% inhibition efficiency at optimum concentration 400ppm. The inhibition is of a mixed anodic–cathodic nature. The adsorption behaviour of the investigated compounds is found to obey Langmuir adsorption isotherm. Quantum chemical parameters, were correlated with the experimental results.

Corrosion Inhibition of 45# Mild Steel in Acidic Solution by Some Norfloxacin

2011 ◽  
Vol 194-196 ◽  
pp. 44-51
Author(s):  
Fei Ran Xu ◽  
Sheng Tao Zhang ◽  
Xiao Li
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Mild Steel ◽  
Corrosion Inhibition ◽  
Quantum Chemical ◽  
Electrochemical Impedance ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Adsorption Model ◽  
Tafel Polarization

The corrosion inhibition of 45# mild steel in 3%HCL solution by norfloxacin has been studied by weight loss measurement, Tafel polarization, electrochemical impedance spectroscopy (EIS) and quantum chemical study. The inhibitor of norfloxacin shows 93.2% inhibition efficiency at optimum concentration 400mg/L. The polarization studies suggest that norfloxacin is the mixed-type inhibitor for 45# carbon steel in 3%HCL. Electrochemical impedance spectroscopy techniques are also used to investigate the mechanism of corrosion inhibition. What is more, the adsorption model obeys Langmuir adsorption isotherm at 298K. And the calculated quantum chemical also suggests that norfloxacin have excellent inhibition properties.

Electrochemical and quantum-chemical study on newly synthesized triazoles as corrosion inhibitors of mild steel in 1 M HCl

2016 ◽  
Vol 43 (5) ◽  
pp. 3145-3162 ◽  
Author(s):  
Ying Yan ◽  
Xiaoxiao Lin ◽  
Lehua Zhang ◽  
Hao Zhou ◽  
Laiming Wu ◽  
...  
Keyword(s):  
Mild Steel ◽  
Quantum Chemical ◽  
Corrosion Inhibitors ◽  
Quantum Chemical Study ◽  
Chemical Study

Quantum chemical study on the formation of isopropyl cyanide and its linear isomer in the interstellar medium

2020 ◽  
pp. 1-11
Author(s):  
Keshav Kumar Singh ◽  
Poonam Tandon ◽  
Alka Misra ◽  
Shivani ◽  
Manisha Yadav ◽  
...  
Keyword(s):  
Amino Acids ◽  
Interstellar Medium ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Dark Cloud ◽  
Water Ice ◽  
Hydrocarbon Radicals

Abstract The formation mechanism of linear and isopropyl cyanide (hereafter n-PrCN and i-PrCN, respectively) in the interstellar medium (ISM) has been proposed from the reaction between some previously detected small cyanides/cyanide radicals and hydrocarbons/hydrocarbon radicals. n-PrCN and i-PrCN are nitriles therefore, they can be precursors of amino acids via Strecker synthesis. The chemistry of i-PrCN is especially important since it is the first and only branched molecule in ISM, hence, it could be a precursor of branched amino acids such as leucine, isoleucine, etc. Therefore, both n-PrCN and i-PrCN have significant astrobiological importance. To study the formation of n-PrCN and i-PrCN in ISM, quantum chemical calculations have been performed using density functional theory at the MP2/6-311++G(2d,p)//M062X/6-311+G(2d,p) level. All the proposed reactions have been studied in the gas phase and the interstellar water ice. It is found that reactions of small cyanide with hydrocarbon radicals result in the formation of either large cyanide radicals or ethyl and vinyl cyanide, both of which are very important prebiotic interstellar species. They subsequently react with the radicals CH2 and CH3 to yield n-PrCN and i-PrCN. The proposed reactions are efficient in the hot cores of SgrB2 (N) (where both n-PrCN and i-PrCN were detected) due to either being barrierless or due to the presence of a permeable entrance barrier. However, the formation of n-PrCN and i-PrCN from the ethyl and vinyl cyanide always has an entrance barrier impermeable in the dark cloud; therefore, our proposed pathways are inefficient in the deep regions of molecular clouds. It is also observed that ethyl and vinyl cyanide serve as direct precursors to n-PrCN and i-PrCN and their abundance in ISM is directly related to the abundance of both isomers of propyl cyanide in ISM. In all the cases, reactions in the ice have smaller barriers compared to their gas-phase counterparts.

HYDRATION AND DISSOCIATION OF CALCIUM HYDROXIDE IN WATER CLUSTERS: A QUANTUM CHEMICAL STUDY

2007 ◽  
Vol 06 (03) ◽  
pp. 595-609 ◽  
Author(s):  
CLARA JIAYUN MEN ◽  
FU-MING TAO
Keyword(s):  
Calcium Hydroxide ◽  
Quantum Chemical ◽  
Density Functional ◽  
Water Clusters ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Structure Stability ◽  
Water Molecules ◽  
Aerosol Formation ◽  
Hydrated Clusters

The structure, stability, and properties of the hydrated clusters of calcium hydroxide, Ca ( OH )2( H 2 O )n, n = 1–6, were investigated using density functional and ab initio quantum chemical methods. The results show that six water molecules are needed to result in the complete dissociation of Ca ( OH )2. The stable and ionic conformer of Ca ( OH )2( H 2 O )6 has C 3 symmetry. Its surprising stability and high IR activity render hydrated clusters of Ca ( OH )2 potentially significant in the nucleation of noctilucent clouds in the mesosphere. Trends in the interaction energies (ΔEe) of the complexes show that water molecules in the first shell of Ca 2+ are highly stable, further alluding to the role of hydrated Ca ( OH )2 in aerosol formation.

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