Mechanochemical Synthesis of High Crystalline Cerium Hexaboride Nanoparticles from CeO2‐B2O3‐Mg Ternary System

High crystalline cerium hexaboride (CeB₆) nanoparticles (NPs) were synthesized using mixture of mag‐ nesium (Mg), cerium oxide (CeO₂) and boron oxide (B₂O₃) via the mechanochemical process at room tem‐ perature. Based on the results, magnesiothermic reduction of B₂O₃ occurred after about 2 h of milling in a mechanically induced self‐sustaining reaction (MSR). The significant amount of heat produced by the reduction reaction resulted in CeO₂ reduction to elemental Ce which finally reacted with elemental B and formed CeB₆ compound. According to XRD analyses, the degree of crystallinity and lattice parameter of the product was calculated about 93 % and 4.1458 Å, respectively. The morphology observations revealed that the synthesized CeB₆ had semi‐cubic shape with the range of size 25–60 nm. The synthesis of CeB₆ during the thermal treatment was studied by simultaneous thermal analysis (STA) technique. It was found that the reduction of B₂O₃ took place after melting of Mg meanwhile, no CeB₆ phase achieved even up to 1100 °C.     

Supramolecular-based dispersive liquid-liquid microextraction: a novel sample preparation technique utilizes coacervates and reverse micelles

The present study reports a novel sample enrichment method termed supramolecular-based dispersive liquid-liquid microextraction (SM-DLLME). The SM solvent selected was made up of reversed micelles of decanoic acid dispersed in tetrahydrofuran (THF)-water. THF plays double role, not only acts as a disperser solvent but also causes self-assembly of decanoic acid. The contaminant used as a model was Malachite Green (MG). It was a cationic dye and was preconcentrated without any derivatization or ion-pair formation reaction. In SM-DLLME, the most important advantages of DLLME technique and preconcentration strategy based on the coacervation and reverse micelles have come together. Moreover, in this method, disadvantages of DLLME such as extraction capability of only hydrophobic analytes and hiring toxic and hazardous organic solvents as the extraction solvent and disadvantages of coacervation-based extraction method such as tedious, labor-intensive and time-consuming stirring procedure have been avoided. Several variables affecting the microextraction efficiency were investigated and optimized. Under the optimized conditions and preconcentration of only 5.00 mL of sample, the enhancement factor was 52, limit of detection (LOD) was 4 μg/L and relative standard deviations (RSDs) for 145 and 36 μg/L of MG in textile industry wastewater were 1.8 and 3.2%, respectively (n = 6).     

Speciation of chromium in water samples using dispersive liquid–liquid microextraction and flame atomic absorption spectrometry

A novel method for preconcentration is described for chromium speciation at microgram per liter to sub-microgram per liter levels. It is based on selective complex formation of both Cr(VI) and Cr(III) followed by dispersive liquid–liquid microextraction and determination by microsample introduction-flame atomic absorption spectrometry. Effects influencing complex formation and extraction (such as pH, temperature, time, solvent, salinity and the amount of chelating agent) have been optimized. Enrichment factors up to 275 and 262 were obtained for Cr(VI) and total Cr, respectively. The calibration graph is linear from 0.3 to 20 µg L^?1, and detection limits are 0.07 and 0.08 µg L^?1 for Cr(VI) and total Cr, respectively. Relative standard deviations (RSDs) were obtained to be 2.0% for Cr(VI) and 2.6% for total Cr (n?=?7).     

A one-pot synthesis of N-alkylthiazoline-2-thiones from CS2, primary amines, and 2-chloro-1,3-dicarbonyl compounds in water

Abstract  

A simple synthesis of N-alkylthiazoline-2-thiones by reaction of primary amines, carbon disulfide, and 2-chloro-1,3-dicarbonyl compounds in water is described. Proceeding without catalyst under one-pot conditions in high yields and with broad scope, this method high synthetic utility.     

Potassium Thiocyanate‐Promoted One‐Pot Synthesis of (1,3‐Diaryl‐2,5‐dioxoimidazolidin‐4‐ylidene)acetates from Aryl Isocyanates and Alkyl Propiolates. Short Communication

The reaction of aryl isocyanates and alkyl propiolates (=alkyl prop‐2‐ynoates) in the presence of potassium thiocyanate (KSCN) led to geometric isomers of alkyl 2‐(1,3‐diaryl‐2,5‐dioxoimidazolidin‐4‐ylidene)acetates in moderate‐to‐good yields.     

A Novel One‐Pot Synthesis of Substituted Quinolines

A synthesis of quinoline derivatives is described via reaction between ethyl bromopyruvate (=ethyl 3‐bromo‐2‐oxopropanoate), acetylenedicarboxylate, and isatin (=1H‐indole‐2,3‐dione) in the presence of NaH as a base. Also, these reactions were performed without ethyl bromopyruvate. The reaction in the presence of ethyl bromopyruvate provides regioselectively a quinoline with the ethyl ester group in 4‐position. In the absence of ethyl bromopyruvate, the reaction leads to functionalized quinolines with the same ester groups in 2‐, 3‐, and 4‐positions.     

Biodegradable Cell-Seeded Collagen Based Polymer Scaffolds for Wound Healing and Skin Reconstruction

In the present study a collagen-glycosaminoglycans scaffold, following chemical modifications, was prepared as an analog of the extracellular matrix (ECM) by a freeze drying method. Appropriate tests related to its use for wound healing (evaluation of the structure by scanning electron microscopy, swelling properties, biodegradability properties, Fourier transform infrared spectroscopy and cell culture) were done on the scaffolds. Amniotic fluid-derived stem (AFS) cell seeded scaffolds were shown to be potentially useful for wound healing.     

Solvent-Free,Microwave-Assisted,One-Pot Synthesis of 2-Acetyl-N,3-diaryl-4-nitro-butanamides

A combination of benzyltriethylammonium borohydride and chlorotrimethylsilane (1:1) in dichloromethane (0–25°C) has been found to be a convenient reagent system for the selective reduction of carboxylic acids to alcohols.