Investigation of photocatalytic chlorpyrifos degradation by a new silica mesoporous material immobilized by WS2 and Fe3O4 nanoparticles: Application of response surface methodology

In the present research, Fe₃O₄ and WS₂ nanoparticles immobilized on or in KIT-6 (KIT: Korea Institute of Science and Technology) pores (KIT-6/WS₂-Fe₃O₄) were synthesized and studied as a photocatalyst for degradation of representative chlorpyrifos as an organophosphorus pesticide. In addition, the KIT-6/WS₂-Fe₃O₄ photocatalyst was characterized by different methods such as TEM, FESEM-EDS-Mapping, XRD, and N₂ adsorption/desorption surface area, in order to understand their morphology, structural, and physical properties. The photocatalytic performance of this photocatalyst was investigated for degradation of chlorpyrifos by visible light irritation. The effects of variables such as chlorpyrifos concentration, KIT-6/WS₂-Fe₃O₄ nanocatalyst amount, pH, and irradiation time on chlorpyrifos degradation efficiency was studied by central composite design with response surface methodology. The optimum conditions for CP degradation were obtained by 50 mg KIT-6/WS₂-Fe₃O₄ nanocatalyst, and 7.2 ppm chlorpyrifos solution with pH = 6, at 52 min. The pseudo-first-order model with rate constants equal to 0.069 min⁻¹ as best choice efficiency described the chlorpyrifos degradation process according to Langmuir-Hinshelwood kinetic.     

Na<Subscript>2</Subscript>EDTA: an efficient,green and reusable catalyst for the synthesis of biologically important spirooxindoles,spiroacenaphthylenes and spiro-2-amino-4<Emphasis Type="Italic">H</Emphasis>-pyrans under solvent-free conditions

For the first time, the organic salt Na₂EDTA was used as a catalyst for an effective and facile preparation of spiro-4H-pyrans via single-pot three-component condensation of isatin/acenaphthoquinone/ninhydrin, malononitrile, and CH-acids through Knoevenagel–Michael–annulation sequence. This new protocol employing Na₂EDTA, which is a green, recyclable, and inexpensive catalyst, offers advantages such as solvent-free and highly efficient reaction conditions, short reaction times (10–15 min), easy work-up and high yields which make it more economic than other environmentally synthetic methods.     

Synthesis and properties of novel reusable nano-ordered KIT-5-<Emphasis Type="Italic">N</Emphasis>-sulfamic acid as a heterogeneous catalyst for solvent-free synthesis of 2,4,5-triaryl-1 <Emphasis Type="Italic">H</Emphasis>-imidazoles

A novel silica-bonded propyl-N-sulfamic acid nanocatalyst (NHSO₃H-KIT-5) supported on modified silica mesopore KIT-5 as an organic-inorganic hybrid with high specific surface area was successfully prepared. The 3-aminopropyltriethoxysilane (APTES) on KIT-5 was reacted with chlorosulfonic acid and accurately characterized by the FT-IR, XRD, SEM, EDAXS, and TGA techniques. This heterogeneous and recyclable catalyst catalyzed one pot, multicomponent condensation of benzil, aromatic aldehydes, and ammonium acetate in the presences of 0.05 g of nanocatalyst under solvent-free conditions to afford triaryl-imidazoles in excellent yields. This catalyst showed high catalytic activity under green conditions. This reaction was performed under open air conditions and required no special reaction conditions or chromatographic separation for purification.     

Octic Anharmonic Oscillators: Perturbed Coherent States and the Classical Limit

We use the Poincaré-Linstedt method to find a classical perturbation solution to the octic anharmonic oscillator. Next, we derive perturbed coherent states for this system, calculate the expectation value of the -operator in them and enforce a limiting process to retrieve the classical result from the corresponding quantum one. We have observed a frequency shift proportional to the sixth power of the amplitude for this system. Our results are in agreement with those obtained from Taylor-series method.     

A Sensitive Electrochemical Sensor Based on Graphene Oxide Nanosheets Decorated by Fe3O4@Au Nanostructure Stabilized on Polypyrrole for Efficient Triclosan Sensing

Triclosan is broadly utilized as preservative or antiseptic in various cosmetic and personal care products. It becomes hazardous for environmental safety and human health more than a certain concentration. In this research, graphene oxide (GO) nanosheets were prepared by composing Fe₃O₄@Au nanostructure decorated GO together with polypyrrole (PPy) (Fe₃O₄@Au‐PPy/GO nanocomposite) in a facile way. The composite excellent increased the electrochemical response, presenting a high sensitive electrochemical method for triclosan detection. The synthesized Fe₃O₄@Au‐PPy/GO nanocomposite was characterized for its morphological, magnetically and structural properties by FESEM‐mapping, TEM, and XRD. The Fe₃O₄@Au‐PPy/GO nanocomposites modified glassy carbon electrodes (GCE), Fe₃O₄@Au‐PPy/GO GCE, showed a higher sensitivity good stability, reproducibility, lower LOD (2.5×10^?9 M) and potential practical application in electrochemical detection of triclosan under optimized experimental conditions.     

A solvent-free synthesis of 1,2,3,5-tetrasubstituted pyrroles from enaminones and α-haloketones

A simple synthesis of 1,2,3,5-tetrasubstituted pyrrole derivatives from the reaction of enaminone withα-haloketones,under solvent-free conditions,is described.     

Systematic Analysis of Polymer Molecular Weight Influence on the Organic Photovoltaic Performance

The molecular weight of an electron donor‐conjugated polymer is as essential as other well‐known parameters in the chemical structure of the polymer, such as length and the nature of any side groups (alkyl chains) positioned on the polymeric backbone, as well as their placement, relative strength, the ratio of the donor and acceptor moieties in the backbone of donor–acceptor (D–A)‐conjugated polymers, and the arrangement of their energy levels for organic photovoltaic performance. Finding the “optimal” molecular weight for a specific conjugated polymer is an important aspect for the development of novel photovoltaic polymers. Therefore, it is evident that the chemistry of functional conjugated polymers faces major challenges and materials have to adopt a broad range of specifications in order to be established for high photovoltaic performance. In this review, the approaches followed for enhancing the molecular weight of electron‐donor polymers are presented in detail, as well as how this influences the optoelectronic properties, charge transport properties, structural conformation, morphology, and the photovoltaic performance of the active layer.