Volume 233, Issue 11

Introducing1-(2-aminoethyl)-1-dodecyl-2-undecyl-4,5-dihydro-1 H -imidazol-1-ium chloride (LQI), 1-(2-aminoethyl)-1-dodecyl-2-tridecyl-4,5-dihydro-1 H -imidazol-1-ium chloride (MQI) as two organic structures quaternary ammonium salts, which have been made and analyzed by FTIR, 1 H NMR spectroscopic methods. (X-65) carbon steel’s corrosion in naturally formed rocks’ oil wells formation water in the nonappearance (Blank) and using a wide range of concentrations (50, 100, 200, 300, 400, 500 ppm) of these cationic surfactants, as inhibition blockers using direct current (DC), alternative current (AC) electrochemical ways. To sum up, the inhibition efficiency grew with up the gradual rise in the inhibitor content till having peaked at (500 ppm) registered (94.83%) for (MQI). Specifically, carbon steel’s morphology was closely inspected with the aid of highly automated scanning electron microscopy, and energy dispersive X-ray facilities. As a matter of fact, quantum chemical calculations enriched the theoretical study of the (LQI, MQI) compounds depend on energy levels’, energy maps, and 3D structures consideration.

The ligands 1,10-phenanthroline, (P) and para-aminobenzoate, (B); as well as their corresponding MnPB complex [bis-(dimanganese di-μ-paraaminobenzoate dichloro diphenanthroline)] have been investigated as inhibitors of mild steel corrosion in H 2 SO 4 (0.5 M) solutions via potentiodynamic and electrochemical impedance spectroscopy techniques. Stability of the prepared complex was examined by UV-visible spectroscopy. The corrosion inhibition, thermodynamics, and adsorptive properties obtained have shown that MnPB complex has remarkable effects in the acidic solutions. Theoretical fitting of different adsorption isotherms such as Langmuir, Flory–Huggins, and the kinetic-thermodynamic models were tested and the thermodynamic activation parameters were calculated. The data revealed that the corrosion inhibition mechanism of mild steel in acidic solutions by the MnPB complex goes via physicochemical adsorption.

A new star shape tetra-cationic surfactant was synthesized to evaluate as corrosion inhibitors for carbon steel in different acid media. This surfactant prepared by the reaction of tris(2-(dimethylamino)ethyl) O,O′,O′′-(nitrilotris(ethane-2,1-diyl)) trimaleate with 1-bromododecane and abbreviated as STCS. The chemical structure of the prepared surfactant was confirmed by FT-IR, 13 C and 1 HNMR and elemental analysis. Their aggregation behavior in watery solution was explored by surface tension measurements. The surface tension of water was decreased nearly to 35 mN m −1 when adding the surfactant. This result demonstrates that the surfactant shows remarkable surface activity, due to the effect of the head groups. Corrosion inhibition efficiency of the surfactant on the carbon steel surface in 1 M hydrochloride acid and 1 M H 2 SO 4 was evaluated using the electrochemical measurements. These measurements revealed that the synthesized surfactant act as effective mixed-type corrosion inhibitors. Their adsorption on a carbon steel surface was well described by the Langmuir adsorption isotherm. Corrosion inhibition efficiency was enhanced with increasing the concentration of inhibitor and increasing the temperatures. The results of the quantum chemical calculations and the electrochemical measurements were in good agreement.

The potential of an economically cheap raw material (rice husk) was evaluated in the present study to remove dyes including reactive yellow 15 (RY15) and reactive red 241 (RR241) in single and multi-component systems. The adsorbent was modified and functionalized chemically using glycidoxypropyltrimethoxysilane, sulfur and silane to enhance the removal efficiency of pollutants. The modified rice husk was evaluated by scanning electron microscope (SEM) and Fourier transform Infrared Spectroscopy (FTIR). Batch adsorption study showed that the modified rice husk with silane graft (RHSi) had highest removal efficiency of both dyes with 20% more removal compared to raw rice husk. The sorption correlated well with Langmuir, Freundlich, SIPS and Redlich-Peterson models for adsorption. Highest sorption was obtained at 10 mg L −1 of dye, 50 °C, 200 mg g −1 of adsorbent dose and pH 4. The mixture of two dyes poorly fit to the original Langmuir but fit best to the Langmuir-like model. This indicates that competitive Langmuir-like model considers that the capacities of adsorbents are equal. Results showed that the components compete for the available binding sites on adsorbent surface. It was also indicated that silane grafting can offer comparatively more binding sites compared to the raw rice husk and single-solute isotherm parameters cannot used for multi-component solute system.

Multifunctional pyrazole derivative, i.e. 3-amino-1-(5-hydroxy-3-methyl-1H-pyrazol-4-yl)-1H-benzo[f]chromene-2-carbonitrile ( PBCC ) has been synthesized and characterized. To shed light on various properties of interests, the ground state geometry was optimized by adopting Density Functional Theory (PBE/TZ2P). The effect of different functionals on the absorption wavelengths was studied by using Time-Domain DFT (TDDFT), e.g. GGA functional PBE, hybrid functionals B3LYP and PBE0, rang separated functionals CAM-B3LYP, LCY-PBE and CAMY-B3LYP, Dispersion Corrections PBE-D3 and B3LYP-D3. Among all these functionals PBE and PBE-D3 were found to be good choices which reproduced the absorption spectra of the PBCC . With the aim to enhance the electro-optical, charge transfer and photovoltaic properties, five new derivatives were designed by di-substituting the –F, –Cl, –Br, –COOH and –CN at benzochromene moiety. The electron injection barrier, band gap alignment and related calculated photovoltaic parameters revealed that PBCC and its newly designed derivatives would be proficient to be used in photovoltaic devices. These compounds can be used as donor materials in dye-sensitized solar cells (DSSCs) with favorable type-II band alignment. Moreover, PBCC and most of its derivatives might also be good choice as efficient acceptors with poly(dithieno[3,2-b:2,3-d]pyrrole thiophene) (PDTPr-T) and donor materials with Phenyl-C61-butyric acid methyl ester (PC61BM) in organic solar cells.

Present study was conducted to appraise the interaction mechanism of 4-acetamidophenol (4-AP) with DNA based on UV-Vis and FTIR techniques based on binding energy, isolated atomic energy, LUMO and HOMO orbitals gap and geometry of molecule. Analysis revealed the groove binding and intercalation mode of interaction between 4-AP and DNA since hyperchromic and bathochromic shifts were observed in response of interaction of DNA. The planar part of interacting molecule intercalated with DNA and non-planar part of 4-acetamidophenol bounded with DNA (groove binding). The constants for binding between 4-AP and DNA were calculated and 20.12 × 10 3 mol −1 dm 3 binding constant was recorded at pH 4.7, whereas this value was 5.32 × 10 3 mol −1 dm 3 for the pH 7.4. The binding constant value for interaction of 4-AP with DNA revealed the possibility of oral administration of 4-AP. The 4-AP binding with DNA is spontaneous process, which was confirmed from negative value of free energy at room temperature. FTIR study revealed that C–H and C=C (aromatic) functional groups were involved in binding at pH 4.7 and C=O (amide) was involved in groove binding, whereas C–H (aromatic) was responsible for intercalation at pH 7.4 and C–H (alkaline) and C=O (amide) were responsible for groove binding at pH 4.7.

In this work, combined experimental and computational studies of an organic nonlinear optical material, phenylurea (PU), are reported. Optical quality single crystal of PU, was successfully grown by the slow evaporation method. The unit cell parameters of the grown PU crystal belong to the monoclinic system and these belong to the non-centrosymmetric (NCS), P2 1 , space group. Morphology of the crystal was indexed and it reveals its 14 distinct faces. Vibrational modes of PU functional groups were assigned successfully using FTIR and Raman spectrum. The grown crystal exhibits low cutoff wavelength at UV region with good optical transparency and blue wavelength emission. The preliminary measurements confirmed that second harmonic generation (SHG) activity (∼7.6 KDP and ∼2.2 urea) with excellent laser induced threshold damage (LDT) having a value of 2.92 GW/cm 2 (∼1.95 urea). TG/DTA analysis shows that endothermic nature of grown crystal with thermal stability up to 154 °C. The Vickers micro hardness test confirms soft material behavior of PU crystal and it was further explored by crystal void percentage calculation. Electrical properties such as dielectric and photoconductivity measurements were carried out for grown crystal. Furthermore, density functional theory (DFT) studies such as Mulliken charge distribution, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) map and first order hyperpolarizability (β) were determined to probe the structure-property relationship. These results suggest that PU single crystal can be a better alternate for urea in NLO applications.