Synthesis of new epoxy glucose derivatives as inhibitor for mild steel corrosion in 1.0 M HCl, Experimental study: Part -1

A two non-toxic biodegradable epoxy glucose derivatives, namely 5,6-anhydro-3-O-octa-1,2-O-isopropyli-dene-α-D-glucofuranose (EGC8) and 5,6-anhydro-3-O-butadecyl-1,2-O-isopropylidene-α-D-glucofuranose (EGC14), were prepared and characterized by using spectroscopic measurements. These products were tested for mild steel corrosion inhibition in 1.0 M HCl using electrochemical measurements. It is shown that these epoxy glucose derivatives affect the cathodic branches with a shift in the cathodic direction (cathodic - type).  So, it found that their inhibition efficiency arise with concentrations to achieve a maximum of 93.2 % and 93.48 % at 10-3 M of EGC8 and EGC14, respectively, and they depends to the carbon number chain following the order : EGC14 > EGC8. Indeed, it is found that these compounds adsorb according the Langmuir’s adsorption isotherm. On the other hand, the temperature effect on the inhibition efficiency of the epoxy glucose derivatives indicated that they take them at high-rise temperature. In addition, the calculated kinetic and thermodynamic parameters have shown that EGC8 act via physical adsorption while EGC14 act via chemical adsorptions, and their process are endothermic and spontaneous

Synthesis of new epoxy glucose derivatives as inhibitor for mild steel corrosion in 1.0 M HCl: DMol3 theory and molecular dynamics simulation study: Part-2

The adsorption behaviour of (3aR,6aR)-2,2-dimethyl-6-(octyloxy)-5-(oxiran-2-yl) tetrahydrofuro[2,3-d][1,3]dioxole (EGC8) and (3aR,5R,6R,6aR)-2,2-dimethyl-5-((S)-oxiran-2-yl)-6 (tetradecyloxy) tetrahydrofuro[2,3-d][1,3]dioxole (EGC14) as inhibitors for  mild steel corrosion in 1M HCl have been investigated computationally using DFT (DMol3) calculations with the GGA functional and DNP as the base set. DMol3 calculations were centered on the neutral forms of the molecules tested, since these types of inhibitors are impossible to be protonated in an acidic environment. Quantum chemical descriptors inform that tensioactives are more chemically reactive and the local and global reactivity is concentrated in the heads of these species. Fukui indices were determined to evaluate the nucleophilic and electrophilic centers of the atoms of the molecule. The molecular dynamics (MD) simulation used show that EGC8  and EGC14 inhibitors are located vertically in relation to the surface. The values of E interaction and E binding reflect the spontaneity of the adsorption process

Elaboration of tin deposits in the presence of Bis-glucobenzimidazolone

The tin deposit was elaborated electrolytically on an ordinary steel substrate in SnSO4 based electrolyte in acid medium with and without additive (bis-glucobenzimidazolone) at ambient temperature. The influence of bis-glucobenzimidazolone on the electrochemical properties of the coating was investigated using both the stationary method and the chronopotentiometry. On the other hand, the surface state of the deposit obtained was characterized by optic microscopy. The results have shown a good surface quality of the deposit elaborated by addition of an optimal concentration of bis-glucobenzimidazolone in the electrolyte

An experimental-coupled empirical investigation on the corrosion inhibitory action of 7-alkyl-8-Hydroxyquinolines on C35E steel in HCl electrolyte

International audienceTwo 8-Hydroxyquinoline-based piperazine, 7-((4-(4-chloro phenyl)piperazin-1-yl) methyl) quinolin-8-ol (CPQ) and 7-((4-methyl piperazin-1-yl) methyl)quinolin-8-ol (MPQ) were prepared, identified and investigated as corrosion inhibiting additives of C35E steel in HCl electrolyte using experimental and theoretical tools. All outcomes findings confirm that CPQ and MPQ significantly improved anti-corrosion properties of C35E steel and CPQ performed better than MPQ and their inhibition efficiency depends on the temperature, the amount, and the chemical structure of the inhibitor. The ηmax of CPQ and MPQ reaches as much as 91.5% and 86.3% at 10−3 M, respectively. EIS outcomes revealed that the corrosion of C35E steel is controlled by only one charge transfer mechanism and the adsorbed CPQ and MPQ molecules decreased the steel dissolution by developing a pseudo-capacitive film on the steel surface. Both additives revealed mixed-type inhibitory activity, lowering of cathodic and anodic corrosion reactions rate, as proposed from the polarization investigation. The UV–Visible spectra suggest the existence of strong interaction between iron cations and 7-(4-alkylpiperazinylmethyl)-8-Hydroxyquinolines molecules. The 7-(4-alkylpiperazinylmethyl)-8-Hydroxyquinolines were chemisorbed on the C35E steel surface in accordance with Langmuir adsorption isotherm. Temperature influence studies of CPQ and MPQ adsorption behavior, as well as estimated thermodynamic magnitudes, are consistent with a physisorption process. The computational correlations (DFT, Monte Carlo, and Molecular Dynamic simulations) justify the experimental observations

Protecting group free, stereocontrolled synthesis of β-Halo-enamides

Enamides, dienamides, and enynamides are important building blocks in synthetic, biological, and medicinal chemistry as well as materials science. Despite the extensive breath of their potential utility in synthetic chemistry, there is a lack of simple, high-yielding methods to deliver them efficiently and as single isomers. In this paper, we present a novel, protecting group free, efficient, and stereoselective approach to the generation of β-halo-enamides. The methodology presented provides a robust synthetic platform from which E- or Z-enamides can be generated in good yields and with complete stereocontrol

Study of 5-azidomethyl-8-hydroxyquinoline structure by X-ray diffraction and HF-DFT computational methods

5-Azidomethyl-8-hydroxyquinoline has been synthesized and characterized using IR, 1 H and 13 C NMR spectroscopic methods. Thermal analysis revealed no solid-solid phase transitions. The crystal structure of this compound was refined by Rietveld method from powder X-ray diffraction data at 295 K. The single crystal structure of the compound at 260 K was solved and refined using SHELX 97 program. According to the data obtained by both methods, the structure of the compound is monoclinic, space group P2 1 /c, with Z = 4 and Z ' = 1. For the single crystal at 260 K, a = 12.2879 (9) Å, b = 4.8782 (3) Å, c = 15.7423 (12) Å, β=100.807(14)°. Mechanisms of deformation resulting from intra-and intermolecular interactions, such as hydrogen bonding, induced slight torsions in the crystal structure. The optimized molecular geometry of 5-azidomethyl-8-hydroxyquinoline in the ground state is calculated using density functional theory (B3LYP) and Hartree-Fock (HF) methods with the 6-311G(d,p) basis set. The calculated results show good agreement with experimental values. Energy gap of the molecule was found using HOMO and LUMO calculation which reveals that charge transfer occurs within the molecule