Numerical study of two-phase flow in a square cavity under magnetic field of parallel wires

Meccanica - In this paper, a two-phase model is administered to investigate natural convection of Fe3O4–water ferrofluid in a square cavity and under turbulent regime. Ferrofluid flow is...     

Synthesis of 1,2,3 triazole-linked pyrimidines catalyzed by mg-Al-LDH-immobilized-CuI as a heterogeneous catalyst

A useful and efficient procedure was obtained for the synthesis of 1,2,3-triazole-linked pyrimidines via click reaction of propynylated pyrimidine and aromatic azides in the presence of Mg-Al-LDH-immobilized-CuI with high-to-excellent yields. Moreover, the prepared catalyst was characterized by the FT-IR spectroscopy, XRD, BET, SEM, and ICP techniques. The developed synthetic technique offers numerous advantages such as a clean reaction, easy workup, high reaction yields, and short reaction time.     

Efficient Reduction of Dioxygen with Ferrocene Catalyzed by Thiocarbohydrazone Tetranuclear Cobalt(III) Coordination Compound

The synthesis, characterization and crystal structure of a tetranuclear cobalt(III) coordination compound, [Co₄(L)₄](HSO₄)₂(SO₄)·4.1(CH₃OH)·H₂O ( 1 ), with thiocarbohydrazone based ligand is reported. This compound can efficiently catalyze the reduction of oxygen (O₂) by a weak electron donor ferrocene, (Fc), at the polarized water/dichloroethane interface which was investigated by voltammetry and biphasic shake-flask experiments. Compound 1 contains four cobalt cores which are connected together by sulphur atoms. By having four cobalt cores this coordination compound provides a multi-electron transfer system for oxygen reduction reactions. The results also suggest that compound 1 catalyzes decomposition of H₂O₂ at the interface.     

One-pot synthesis of coumarine derivatives using butylenebispyridinium hydrogen sulfate as novel ionic liquid catalyst

Pechmann condensation reaction of 3-hydroxyphenol and ethyl acetoacetate in the presence of 1,1′‐butylenebispyridinium hydrogen sulfate as an efficient, green, and recyclable catalyst produces 7-hydroxy-4-methylcoumarin in good yield under solvent-free conditions at room temperature. This catalyst has advantages such as the following: good to excellent yields, short reaction times, simplicity in operation, and easy workup procedure.     

Volumetric,Acoustic, Viscometric Properties,and Solute–Solvent Interactions of Metformin Hydrochloride in Aqueous Solution of Polyethylene Glycol (PEG 4000) at Different Temperatures (T = 288.15—318.15 K)

Journal of Solution Chemistry - An attempt to understand the interactions between metformin, a drug, and a water-soluble polymer, polyethylene glycol (PEG 4000) in aqueous solutions through...     

Glassy carbon electrode modified by new Copper(I) oxide nanocomposite for glucose detection: An electroanalysis study

The Glucose amount of human blood is very vital because in higher levels than allowed value the corporal biological system was hampered. Therefore, in this study, the Cu₂O was deposited on the reduced Graphene oxide (RGO) by polydopamin (PDA) as linker. The new RGO‐PDA‐Cu₂O nanocomposite was deposited on the glassy carbon electrode (GCE) surface after its characterization by UV–Visible, fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), Energy‐dispersive X‐ray (EDX), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) techniques. The electroanalysis of the new electrode was investigated by the cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) methods. The obtained detection limit of glucose (Glu) showed that the deposited GCE by RGO‐PDA‐Cu₂O nanocomposite has a high potential for its diagnosis. In addition, this electrode was applied to the Glu detection as biosensor in real samples in order to utilize in commercial applications.     

Synthesis of propyl aminopyridine modified magnetite nanoparticles for cadmium (II) adsorption in aqueous solutions

In this study, 2‐aminopyridine functionalized magnetite nanoparticles were chemically synthesized and used for removing Cd²⁺ ions from aqueous solutions. The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis of X‐rays (EDX), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM). The SEM results showed the synthesized magnetite nanoparticles have particle size around 26 nm. The effects of several variables including solution pH and volume, adsorbent mass, ionic strength and contact time on the Cd²⁺ adsorption were studied in batch experiments and finally the optimum conditions for adsorption were obtained. The kinetic data were investigated by pseudo‐ first‐order, pseudo‐ second‐order, intraparticle diffusion and Elovich kinetic models and data were described reasonably by pseudo‐ second‐order model (R² = 0.9996) with q_e = 2.31 mg g^?1. Adsorption data were analyzed using Langmuir, Freundlich and Temkin isotherm models. The results indicated that the data were well fitted to the Freundlich isotherm model (R² = 0.9907). After study the possible interference effect of foreign ions on Cd²⁺ removal, the applicability of the proposed nanoparticles for adsorption from real samples confirmed the successfully removal of Cd²⁺ ions with removal efficiency higher than 92%. The obtained results showed that the synthesized nanoparticles as a reusable adsorbent can act as a good choice for Cd²⁺ removal with an easy procedure.     

Salep as a biological source for the synthesis of biochar with utility for the catalysis

Hydrothermal carbonization of salep as a domestic biosource was carried out to afford a biochar, BC, with exceptional catalytic activity. BC can be further magnetized by incorporation of magnetic nanoparticles to furnish a magnetic catalyst, BC‐Fe, with improved recovery and recyclability for the hydrogenation of nitroarenes in the absence of any precious metal. BC‐Fe was also applied as a catalyst support for the immobilization of Pd nanoparticles and development of an efficient, biocompatible and cost‐effective catalyst, Pd@BC‐Fe, with utility for the oxidation of benzyl alcohols under mild reaction condition in a selective manner to afford corresponding acids in high yields. The study of the recyclability of the catalyst confirmed high recyclability of Pd@BC‐Fe.     

Synthesis of spiro[pyrazoloquinoline-oxindoles] and spiro[chromenopyrazolo-oxindoles] promoted by guanidine-functionalized magnetic Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles

Magnetic nanoparticles (MNPs) Fe₃O₄-immobilized guanidine (Fe₃O₄ MNPs-guanidine) have been used as an efficient catalyst for the preparation of spiro[pyrazoloquinoline-oxindoles] and spiro[chromenopyrazolo-oxindoles] by four-component reactions of phenylhydrazine or hydrazine hydrate, isatins, ketoesters and naphthylamine or 2-naphthol under reflux condition in ethanol. This method provides several advantages including mild reaction conditions, the applicability to a wide range of substrates, the reusability of the catalyst and low catalyst loading.