Convenient synthesis of alkyl thioacetate from alkyl halide using a polymer-supported sodium thioacetate

Alkyl halides are efficiently converted to their corresponding S-alkyl thioacetates under mild and nonaqueous conditions, using polymer-supported sodium thioacetate as a new polymeric reagent at room temperature in high yields and purity. The spent polymeric reagent can be removed quantitatively by filtration and pure products can be obtained by evaporation of the solvent. The spent polymeric reagent can be regenerated and reused several times without its activity changing appreciably.     

Synthesis of Novel Chiral Ionic Liquid and Its Application in Reduction of Prochiral Ketones to the Corresponding Chiral Alcohols Using NaBH4

A novel chiral ionic liquid (CIL) based on nicotinium salt has been synthesized and used as an efficient asymmetric chiral catalyst for reduction of acetophenone derivatives with NaBH₄ in methanol at room temperature. The optically active alcohols were obtained in low to moderate enantiomeric excess in a short reaction time.     

Aluminum Chloride (Alcl3) Promotes Selective Oxidative Deprotection of Benzylic Trimethylsilyl and Tert- Butyldimethylsilyl Ethers to the Corresponding Carbonyl Compounds with Manganese Dioxide (Mno2)

Various types of trimethylsilyl and tert-butyldimethylsilyl ethers of primary and secondary benzylic alcohols could be selectively converted to their corresponding carbonyl compounds with MnO₂ in the presence of AlCl₃ in good to excellent yields.     

Study of Tangle on the Three Qubit Werner States by Using of Twirl Operation

International Journal of Theoretical Physics - In this paper we study the Tangle of three qubit Werner state using Twirl operation and association scheme. To do this, we introduce the invariants of...     

Simulation of conjugate radiation–forced convection heat transfer in a porous medium using the lattice Boltzmann method

In this paper, a lattice Boltzmann method is employed to simulate the conjugate radiation–forced convection heat transfer in a porous medium. The absorbing, emitting, and scattering phenomena are fully included in the model. The effects of different parameters of a silicon carbide porous medium including porosity, pore size, conduction–radiation ratio, extinction coefficient and kinematic viscosity ratio on the temperature and velocity distributions are investigated. The convergence times of modified and regular LBMs for this problem are 15 s and 94 s, respectively, indicating a considerable reduction in the solution time through using the modified LBM. Further, the thermal plume formed behind the porous cylinder elongates as the porosity and pore size increase. This result reveals that the thermal penetration of the porous cylinder increases with increasing the porosity and pore size. Finally, the mean temperature at the channel output increases by about 22% as the extinction coefficient of fluid increases in the range of 0–0.03.

     

Ultrasound and Sonochemistry for Radical Polymerization: Sound Synthesis

The use of ultrasound as an external stimulus for promoting polymerization reactions has received increasing attention in recent years. In this Review article, the fundamental processes that can lead to either the homolytic cleavage of polymer chains, or the sonolysis of solvent (or other) small molecules, under the application of ultrasound are described. These reactions promote the production of reactive radicals, which can be utilized in chain-growth radical polymerizations under the right conditions. A full historical overview of the development of ultrasound-assisted radical polymerization is provided, with special attention given to the recently described systems that are “controlled” by methods of reversible (radical) deactivation. Perspectives are shared on what challenges still remain in polymer sonochemistry, as well as new areas that are yet to be explored.     

Syntheses,Characterizations and Crystal Structures of Two New Racemic Amidophosphoesters: rac-(C6H5O)(cyclo-C6H11NH)P(O)N(C4H8)NP(O)(NH-cyclo-C6H11)(OC6H5) and rac-(p-CH3-C6H4NH)P(O)(OC6H4-p-CH3)(OC6H5)

Crystallography Reports - The new racemic compounds, rac-diphenyl bis(cyclo-hexylamido)(piperazine)-1,4-diyldiphosphinate, C28H42N4O4P2 (I), and...     

Effects of self-fields on electron trajectory and gain in planar wiggler free-electron lasers with two-stream and ion-channel guiding

The effects of self-fields on electron trajectories and gain in planar wiggler free-electron lasers with two-stream and ion-channel guiding are investigated. An analysis of the two-stream quasi-steady-state electron trajectories is given by solving the equation of motion in the presence of ion-channel guiding and the planar wiggler. The electron trajectories and the gain are derived. The stability of the trajectories, the characteristics of the linear gain, and the normalized maximum gain are studied numerically. The numerical calculations show that there are eight group trajectories rather than the two groups reported in the absence of the self-fields. It is also shown that the normalized gain group seven （G7） decreases while the rest increases with the increase in normalized ion-channel frequency. The two-stream instability and the self-field lead to a decrease in the maximum gain, except for G7.     

Robust synchronization of a class of uncertain chaotic systems based on quadratic optimal theory and adaptive strategy

This paper presents a chaos synchronization method for a class of uncertain chaotic systems using the combination of an optimal control theory and an adaptive strategy. A quadratic optimal regulator and an adaptive control are used to represent the controller's structure. The asymptotic stability of the corresponding error dynamical system is guaranteed through Lyapunov stability analysis. The proposed controller is employed in two uncertain chaotic Lu systems, and their promising performances are illustrated.     

Sorptive thin film microextraction followed by direct solid state spectrofluorimetry: A simple,rapid and sensitive method for determination of carvedilol in human plasma

A poly acrylate-ethylene glycol (PA-EG) thin film is introduced for the first time as a novel polar sorbent for sorptive extraction method coupled directly to solid-state spectrofluorimetry without the necessity of a desorption step. The structure, polarity, fluorescence property and extraction performance of the developed thin film were investigated systematically. Carvedilol was used as the model analyte to evaluate the proposed method. The entire procedure involved one-step extraction of carvedilol from plasma using PA-EG thin film sorptive phase without protein precipitation. Extraction variables were studied in order to establish the best experimental conditions. Optimum extraction conditions were the followings: stirring speed of 1000 rpm, pH of 6.8, extraction temperature of 60 °C, and extraction time of 60 min. Under optimal conditions, extraction of carvedilol was carried out in spiked human plasma; and the linear range of calibration curve was 15–300 ng mL⁻¹ with regression coefficient of 0.998. Limit of detection (LOD) for the method was 4.5 ng mL⁻¹. The intra- and inter-day accuracy and precision of the proposed method were evaluated in plasma sample spiked with three concentration levels of carvedilol; yielding a recovery of 91–112% and relative standard deviation of less than 8%, respectively. The established procedure was successfully applied for quantification of carvedilol in plasma sample of a volunteer patient. The developed PA-EG thin film sorptive phase followed by solid-state spectrofluorimetric method provides a simple, rapid and sensitive approach for the analysis of carvedilol in human plasma.