Trimethylphenylammonium Tribromide as a New and Efficient Oxidizing Agent for the Oxidative Coupling of Thiols into Disulfides and Chemoselective Oxidation of Sulfides into Sulfoxides

Abstract

Trimethylphenylammonium tribromide has been introduced as a versatile and new oxidizing agent for the preparation of disulfides and sulfoxides from thiols and sulfides, respectively. The reaction progress is simple, and proceeds under mild and homogenous conditions in ambient temperature.

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GRAPHICAL ABSTRACT      

Synthesis of high-modulus thermoset PUs of PCL-PTMG/CNW biomaterials with different soft domain architecture and composition for high shape memory performance

Cellulose - In this research work, a series of thermoset polyurethane (tPU) nanocomposites and a thermoplastic PU (TPPU) were synthesized using semi-crystalline polyols. Poly(ε-caprolactone)...     

Supramolecular-based solvent microextraction of carbaryl in water samples followed by high performance liquid chromatography determination

In this study, a simple, rapid, low cost, sensitive and environmentally friendly technique, supramolecular solvent microextraction (SM-SME) followed by high performance liquid chromatography-ultraviolet has been proposed to extract carbaryl from water samples. Parameters, affecting the SM-SME performance such as the weight of decanoic acid (DeA), volume of tetrahydrofuran (THF), pH and salt concentration, were studied and optimised. The effect of the pH on the extraction efficiency was evaluated by one–factor-at-a-time methodology, but the other variables were optimised by a face-centred cube central composite design methodology. Optimum extraction conditions were obtained: DeA: 70 mg; THF: 650 µL; salt concentration: 10% (w/v) NaCl and pH = 2–4), and the performance of the proposed method was evaluated. Under the optimum conditions, good linearity (1.0–500 µg L^?1, r² = 0.9994) was obtained. Limit of detection and limit of quantification were 0.3–1.0 µg L^?1, respectively. Also, the recoveries of the carbaryl were obtained in the ranged from 96% to 105%. Finally, proposed method was successfully applied for the determination of the carbaryl in the water samples of farms run-off and rivers and satisfactory results were obtained.     

Stimuli‐responsive polyurethane bionanocomposites of poly(ethylene glycol)/poly(ε‐caprolactone) and [poly(ε‐caprolactone)‐grafted‐] cellulose nanocrystals

In this study, in situ polyurethane (PU) bionanocomposites of poly(ethylene glycol) (PEG)/poly(ε‐caprolactone) (PCL) polyols, bare cellulose nanocrystals (CNCs) and PCL‐grafted CNCs (G‐CNC) were synthesized with different contents of CNCs as cross‐linking agent to control the extent of phase separation. The effect of confining the chains between CNCs through urethane linkages and presence of PCL grafts on phase and crystallization behavior was evaluated. Crystallization and chemical networking were controlled to tune the shape fixity (SF) and recovery (SR) of the specimens, resulting in a SF of 100% for linear and PU nanocomposites of G‐CNC (0.5% and 1%) samples. The PU nanocomposite of G‐CNC (0.5%) was selected as the optimum sample with the highest SR of 100%. The effect of surface hydrophobicity on cellular behavior of Human Foreskin Fibroblast (as a normal cell) and HepG2 (as a cancerous cell) cells was evaluated. Cell adhesion analysis of the prepared samples indicated two different behaviors possibly due to the difference in the epigenetic nature of the cells and cellular integrin‐ based bonds showing a great potential for a variety of tissue engineering applications.