Caro's Acid–Silica Gel: An Efficient and Versatile Catalyst for the One-Pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives

An efficient one-pot synthesis of tetrahydrobenzo[b]pyran is described. This involved the three-component reaction of aromatic aldehydes, molononitrile, and dimedone in the presence of a catalytic amount of Caro's acid supported on silica gel in ethanol/water under reflux.     

π-Stacking effects on acid capacity of p-aminobenzoic acid

Structural Chemistry - Acidity changes of p-aminobenzoic acid (pABA) after π-stacking with substituted benzenes (SB) have been investigated using quantum mechanical calculations at the...     

Complexation of Ba2+, Pb2+, Cd2+, and UO22+ Ions with 18-Crown-6 and Dicyclohexyl-18-Crown-6 in Nitromethane and Acetonitrile Solutions by a Competitive NMR Technique Using the 7Li Nucleus as a Probe

[⁷Li] NMR measurements were used to determine the stoichiometry and stability of Li⁺ complexes with 18-crown-6 and dicyclohexyl-18-crown-6 in nitromethane and acetonitrile solutions. A competitive [⁷Li] NMR technique was also employed to probe the complexation of Ba²⁺, Pb²⁺, Cd²⁺, and UO₂²⁺ ions with the same crown ethers–solvent systems. All the resulting 1 : 1 complexes were more stable in nitromethane than acetonitrile solution. In all cases, the stability of both crown complexes in nitromethane and acetonitrile varied in the order Pb²⁺ > Ba²⁺ > Li⁺ > Cd²⁺ > UO₂²⁺.     

Substituted 5-Antipyrinylazo-4-phenyl-2-aminothiazoles as Disperse Dyes for Dyeing Polyester Fabrics

Summary. A series of some new substituted 5-antipyrinylazo-4-phenyl-2-aminothiazole disperse dyes was synthesized by diazocoupling of 4-antipyrinyldiazonium chloride with aminothiazole derivatives. The synthesized dyes were characterized by UV-Vis absorption, IR, ¹H NMR, and MS spectroscopy. The dyes gave orange to reddish-violet shades with very good depth and levelness when applied to polyester fabrics as disperse dyes and their fastness properties were evaluated on polyester fibers. Also the position of color in CIELAB coordinates (L^*, a^*, b^*, H^*, and C^*) was assessed.     

Optimizing adsorptive removal of malachite green and methyl orange dyes from simulated wastewater by Mn‐doped CuO‐Nanoparticles loaded on activated carbon using CCD‐RSM: Mechanism,regeneration, isotherm,kinetic, and thermodynamic studies

In the present work, Mn‐doped CuO‐NPs‐AC was prepared by a simple method, characterized using various techniques such as FESEM, EDX, XRD, PSD, and pH_pzc and finally used for the adsorption of malachite green (MG) and methyl orange (MO) in a number of single and binary solutions. A series of adsorption experiments were conducted to investigate and optimize the influence of various factors (such as different pH, concentration of MG and MO, adsorbent mass, and sonication time) on the simultaneous adsorption of MG and MO using response surface methodology. Under optimal conditions of pH 10, adsorbent dose of 0.02 g, MG concentration of 30 mg L^?1, MO concentration of 30 mg L^?1, and sonication time of 4.5 min at room temperature, the maximum predicted adsorption was observed to be 100.0%, for both MG and MO, showing that there is a favorable harmony between the experimental data and model predictions. The adsorption isotherm of MO and MG by Mn‐doped CuO‐NPs‐AC could be well clarified by the Langmuir model with maximum adsorption capacity of 320.69 mg g^?1 and 290.11 mg g^?1 in the single solution and 233.02 mg g^?1 and 205.53 mg g^?1 in the binary solution by 0.005 g of adsorbent mass for MG and MO, respectively. Kinetic studies also revealed that both MG and MO adsorption were better defined by the pseudo‐second order model for both solutions. In addition, the thermodynamic constant studies disclosed that the adsorption of MG and MO was likely to be influenced by a physisorption mechanism. Eventually, the reusability of the Mn‐doped CuO‐NPs‐AC after six times showed a reduction in the adsorption percentage of MG and MO.     

Numerical simulation of particle-laden flow in an industrial wastewater sedimentation tank

Meccanica - The wastewater of steel production factories consists of a large amount of very small metal particles. The metal particles in this wastewater enter a large sedimentation tank and are...     

Sintering of dental ceramic/sol–gel-derived bioactive glass mixtures for dental applications: the study of microstructural,biological, and thermal properties

Journal of Sol-Gel Science and Technology - Although dental ceramic restorations are biocompatible, they are not necessarily bioactive. They can be modified by bioactive glasses to exhibit...     

Preconcentration and determination of five antidepressants from human milk and urine samples by stir bar filled magnetic ionic liquids using liquid–liquid–liquid microextraction-high-performance liquid chromatography

A sensitive and straightforward liquid–liquid–liquid microextraction method was developed to preconcentrate and cleanup antidepressants, including mirtazapine, venlafaxine, escitalopram, fluoxetine, and fluvoxamine, from biological samples before analyzing with high-performance liquid chromatography. The essential novelty of this study is using magnetic ionic liquids as the extraction phase in the lumen of hollow fiber and preparing a liquid magnetic stir bar. In this method, polypropylene hollow fiber was utilized as the permeable membrane for the analyte extraction. Six magnetic ionic liquids consisting of the transition metal and rare earth compounds were synthesized and then hollow fiber lumen was injected as acceptor phase to extract the antidepressants. Besides, 3-pentanol as a water-immiscible solvent was impregnated in the hollow fiber wall pores. The effective factors in the method were optimized with the central composition design. The resultant calibration curves were linear over the concentration range of 0.8–400.0 ng mL⁻¹ (R² ≥ 0.996). The method displayed the proper detection limit (0.11–0.24 ng mL⁻¹), the reasonable limit of quantification (≤0.79 ng mL⁻¹), wide linear ranges, high preconcentration factors (≥294.3), and suitable relative standard deviation (2.31–5.47%) for measuring antidepressant medications. Analysis of human milk and urine samples showed acceptable recoveries of 96.5–103.8% with excellent relative standard deviations lower than 5.95%.