Iodine/potassium iodide catalyst for the synthesis of trifluoromethylated quinazolines via intramolecular cyclization of 2,2,2-trifluoro-N-benzyl-N′-arylacetimidamides

Molecular Diversity - An efficient and simple protocol for the synthesis of trifluoromethylated quinazolines has been described by I2-/KI-promoted oxidative C(sp3)–C(sp2) bond under the...     

Analytical Approximate Solution of SchrSdinger Equation in D Dimensions with Quadratic Exponential-Type Potential for Arbitrary/-State

We present the bound state solution of Schr6dinger equation in D dimensions for quadratic exponential-type potential for arbitrary l-state. We use generalized parametric Nikiforov-Uvarov method to obtain the energy levels and the corresponding eigenfunction in dosed form. We also compute the energy eigenvalues numerically.     

All optical self signal processing using chalcogenide nonlinear fiber Bragg grating

In this study, we simulate numerically quasi pulse propagation in a uniform nonlinear fiber Bragg grating (FBG) made of chalcogenide glasses. Because of bistability and nonlinearity behavior of FBG, the shapes of output pulse vary abruptly and strongly according to the input peak intensity. We take Gaussian pulse as input and produce saw-tooth wave and square wave in the output by suitable input amplitude and FBG length also we could reach pulse chopping and pulse compression. These all optical signal processing achieved for a few length, i.e. 6.6 mm and few intensity, i.e. 35 W/m² because of high nonlinearity of chalcogenide glasses.     

Ab‐Initio calculations of the CO adsorption and dissociation on substitutional Fe–Cu surface alloys relevant to Fischer–Tropsch Synthesis: bcc‐(Cu)Fe(100) and fcc‐(Fe)Cu(100)

Direct CO dissociation is seen the main path of the first step in the Fischer–Tropsch Synthesis (FTS) on the reactive iron surfaces. Cu/Fe alloy film is addressed with various applications over face‐centered‐cubic (fcc)‐Cu and body‐centered‐cubic (bcc)‐Fe in the FTS, i.e. preventing iron carbide formation (through direct CO dissociation) by moderating the surface reactivity and facilitating the reduction of iron surfaces, respectively. In this study by density functional theory, the stable configurations of CO molecule on various Cu/Fe alloys over fcc‐Cu(100) and bcc‐Fe(100) surfaces with different CO coverage (25% and 50%) have been evaluated. Our results showed that the ensemble effect plays a fundamental role to CO adsorption energy on the surface alloys over bcc‐Fe(100); on the other hand, the ligand effect determines the CO stability on the fcc‐Cu(100) surface alloys. CO dissociation barrier was also calculated on the surface alloys that showed although the CO dissociation process is thermodynamically possible on the more reactive surface alloys, but according to their high barrier, CO dissociation does not occur directly on these surfaces. Copyright © 2013 John Wiley & Sons, Ltd.     

Thermal and structural studies of zinc zirconate nanoscale composite derived from sol–gel process

In the present investigation, a novel synthetic zinc zirconate nanocomposites were prepared by a sol–gel technique using a very stable sol containing zirconium acetylacetonate, zinc acetate, monoethanolamine, and 1,3-propanediol as chelating agent. Thermal analysis results indicated that the decomposition of zinc zirconate precursors occurred at 225 and 234 °C. The influence of thermal annealing (temperatures and duration) on their structural properties has been studied by means of X-ray diffraction and Fourier transform-infrared spectroscopy techniques. The results indicated that a higher percent of zinc zirconate is formed at 800 °C and reached maximum at 1,000 °C in 120 min. The morphology, composition, and bandgap properties of zinc zirconate nanoparticles were characterized by transmission electron microscope, scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy, and ultraviolet diffiuse reflectance. The SEM observation showed that average grain size of zinc zirconate nanopowders was 58 nm. The optical results revealed maximum absorbances at 394, 413, and 438 nm for ZnZrO₃ sample annealed at 400, 800, and 900 °C for 30 min, respectively. This is an indication that the nanopowder can absorb lights in the higher wavelength.     

Second law analysis for nanofluid flow in mini-channel heat sink with finned surface: a study on fin geometries

Journal of Thermal Analysis and Calorimetry - In this numerical work, a second law analysis is carried out for the nanofluid flow and heat transfer in the mini-channel with finned surface. The...     

Electrochemically Induced Diels‐Alder Reaction: An Overview

One of the most important name reactions in organic chemistry, is the Diels‐Alder cycloaddition reaction. It is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile to construct a substituted cyclohexene derivative. It is the stereotypical example of a pericyclic reaction with a concerted mechanism. In synthesis, the use of electricity instead of stoichiometric amounts of oxidant or reducing agents is definitely appealing for economic, ecological and selective, reasons. In this review, we try to underscore the combination of the electrosynthesis with Diels‐Alder cycloaddition reaction to establish of a powerful synthetic tool which may encourage synthetic organic chemists to use it in the future.     

Selective extraction of clonazepam from human plasma and urine samples by molecularly imprinted polymeric beads

A molecularly imprinted polymer (MIP) based on free‐radical polymerization was prepared with 1‐(N,N‐biscarboxymethyl)amino‐3‐allylglycerol and N,N‐dimethylacrylamide as functional monomers, N,N‐methylene diacrylamide as the cross‐linker, copper ion‐clonazepam as the template and 2,2‐azobis(2‐methylbutyronitrile) as the initiator. The imprinted polymer was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, and SEM. The MIP of agglomerated microparticles with multipores was used for SPE. The imprinted polymer sorbent was selective for clonazepam. The optimum pH and sorption capacity were 5 and 0.18 mg/g at 20°C, respectively. The profile of the drug uptake by the sorbent reflects good accessibility of the active sites in the imprinted polymer sorbent. The MIP‐SPE was the most feasible technique for the extraction of clonazepam with a high recovery from human plasma and urine samples.     

Isocyanide‐Based Multicomponent Synthesis of Functionalized 2,6‐Dioxohexahydropyrimidines in 1 M Aqueous Glucose

An effective route to novel 2,6‐dioxohexahydropyrimidines is described. This involves reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates in the presence of N,N′‐dimethylurea in 1M aq. glucose.     

A fast numerical algorithm based on the Taylor wavelets for solving the fractional integro‐differential equations with weakly singular kernels

In this paper, a fast numerical algorithm based on the Taylor wavelets is proposed for finding the numerical solutions of the fractional integro‐differential equations with weakly singular kernels. The properties of Taylor wavelets are given, and the operational matrix of fractional integration is constructed. These wavelets are utilized to reduce the solution of the given fractional integro‐differential equation to the solution of a linear system of algebraic equations. Also, convergence of the proposed method is studied. Illustrative examples are included to demonstrate the validity and applicability of the technique.