Green route for selective gram‐scale oxidation of sulfides using tungstate/triazine‐based ionic liquid immobilized on magnetic nanoparticles as a phase‐transfer heterogeneous catalyst

Tungstate ions were successfully loaded onto triazine‐based ionic liquid‐functionalized magnetic nanoparticles through an anion exchange process. The use of triazine core for creating ionic liquid led to the immobilization of high amounts of WO₄^2?. The resulting catalyst showed high activity and selectivity in the oxidation of sulfides to sulfoxides with H₂O₂ as a green oxidant at room temperature. In addition, due to the presence of ammonium groups in the catalyst structure, water dispersibility of the catalyst was increased. More important, the catalyst was magnetically recovered and reused for up to six runs without any marked decrease of activity and selectivity. Finally, easy gram‐scale oxidation of methylphenyl sulfide as well as fast separation of catalyst and product makes the protocol economical and industrially applicable.     

Homogeneous Liquid–Liquid Microextraction Via Flotation Assistance (HLLME-FA) Method for the Pretreatment of Organochlorine Pesticides in Aqueous Samples and Determination by GC–MS

This work proposes a new, rapid and simple homogeneous liquid–liquid microextraction via flotation assistance technique for the analysis of six organochlorine pesticides in water samples. A special extraction cell was used to facilitate collection of the low-density solvent extract. No centrifugation was required in this procedure. Determination was carried using gas chromatography–mass spectrometry. The water sample solution was then added into the extraction cell containing appropriate mixture of extract and homogeneous solvents. In the first step, a homogeneous solution and then with the continuation of water sample injection, a cloudy solution was formed. Using air flotation, the organic solution was collected at the conical part of the designed cell. The optimized levels of effective parameters were found based on response surface methodology approach. Applying the optimized conditions to the system understudy, the limits of detection of all target analytes were obtained in the range of 1.4–7 ng mL^?1, while the precisions were found to be in the range of 11.08–14.87 (RSD, n = 3). The linearity of the method lay in the range of 10–150 ng mL^?1 with the coefficients of correlation (r ² ) ranging from 0.998 to 0.999.     

Mild and Efficient Procedure for Michael Addition of N-Heterocycles to α,β-Unsaturated Compounds Using Anhydrous K3PO4 as Catalyst

Imidazole, 1,2,4-triazole, indole, and benzotriazole undergo conjugate additions with α, β-unsaturated carbonyl compounds in the presence of anhydrous potassium phosphate at ambient temperature to afford the corresponding Michael adducts in excellent yields.     

Introducing Organic Gas Steam-Liquid Extraction as a New Preconcentration Method for Benzene,Toluene, Ethylbenzene and Xylene Determination in Water Samples by Gas Chromatography-Flame Ionization Detection

Journal of Analytical Chemistry - In this study, for the first time, the organic gas steam-liquid extraction by a special hand-made cell was used as a simple and inexpensive preconcentration...     

Towards insight into properties and stabilities of complexes of ozone with CO2, CS2 and SCO species

The MP2 method in combination with the aug-cc-pVXZ (X = D and T) basis set has been carried out to examine the complexes between O₃ and isostructure species of CO₂, CS₂ and SCO. Two, two and four minima have been located on the potential energy surfaces of O₃–CO₂, O₃–CS₂ and O₃–SCO complexes, respectively. The results reveal that the stabilization of complexes should be in the order O₃–CS₂ > O₃–SCO > O₃–CO₂.