Thermodynamic properties of the mixtures of some ionic liquids with alcohols using a simple equation of state

In the present work, we have used a simple equation of state called the GMA EoS to calculate the density of three ionic liquid mixtures including 1-butyl-3-methylimidazolum hexafluorophosphate, [BMIM] [PF₆] + methanol, 1-butyl-3-methylimidazolum tetrafluoroborate, [BMIM] [BF₄] + methanol, and [BMIM] [BF₄] + ethanol at different temperatures, pressures, and compositions. The isothermal compressibility, excess molar volumes, and excess Gibbs molar energy of these mixtures have been computed using this equation of state. The values of statistical parameters show that the GMA EoS can predict these thermodynamic properties very well within the experimental errors. The results show that isothermal compressibility of ionic liquids is lower than alcohols and the effect of temperature and pressure on the isothermal compressibility of ionic liquids is lower than alcohols. The excess molar volumes and excess molar Gibbs energy for these ionic liquid mixtures with alcohols are all negative at various temperatures and pressures over the whole composition range. The results have been interpreted in terms of intermolecular interactions and structural factors of the ionic liquids and alcohols.     

Origin of the Correlation of the Rate Constant of Substrate Hydroxylation by Nonheme Iron(IV)–oxo Complexes with the Bond‐Dissociation Energy of the C?H Bond of the Substrate

A series of hydrogen‐abstraction barriers of a nonheme iron(IV)–oxo oxidant mimicking the active species of taurine/α‐ketoglutarate dioxygenase (TauD) are rationalized by using a valence‐bond curve‐crossing diagram (see figure). It is shown that the barriers correlate with the strength of the C? H bond. Furthermore, electronic differences explain the differences between nonheme and heme iron(IV)–oxo hydrogen‐abstraction barriers.

     

Density and viscosity of 1-butyl-3-methylimidazolium nitrate with ethanol, 1-propanol, or 1-butanol at several temperatures

Densities and viscosities of 1-butyl-3-methylimidazolium nitrate [Bmim][NO₃], and its binaries with alcohol (ethanol, 1-propanol, or 1-butanol) were measured at different temperatures. The densities and viscosities of pure ionic liquid were correlated successfully by empirical equations. The Vogel–Fulcher–Tammann equations can fit the experimental data of viscosities for pure IL. Excess molar volume and viscosity deviations were calculated for the binaries. The excess molar volumes have negative deviations from the ideal solution.     

Maximal subgroups of <Emphasis Type="Italic">GL</Emphasis><Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>(<Emphasis Type="Italic">D</Emphasis>) with finite conjugacy classes

Let D be an infinite division ring. A famous result due to Herstein says that every non-central element of D has infinitely many conjugates and so, if D ^* is an FC-group, then D is a field. Let M be a maximal subgroup of GL _n (D), where n ≥ 1. In this paper, we prove that if M is an FC-group, then it is the multiplicative group of some maximal subfield of M _n (D). Moreover, if M is algebraic over Z(D), then [D : Z(D)] < ∞.     

An improved electrochemical method for the synthesis of some benzofuran derivatives

Electrochemical oxidation of catechol and some 3-substituted catechols (1a--c) has been studied in the presence of 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (3) in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols (1a--c) participate in a Michael addition reaction with 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (3) with consumption of only two electrons per molecule of (1a--c) to from the corresponding benzoforans (10a--c). The electrochemical synthesis of benzofurans has been successfully performed at a carbon rod electrode and in an undivided cell with high yields and purity.     

Entangled Three Qutrit Coherent States and Localizable Entanglement

Choosing I-concurrence as the measure of bipartite entanglement and using yon Neumann projective local measurements, localizable entanglement （LE） in a three-qutrit system is studied. A superposition of the qutrit-coherent- state of this system is considered ant its LE is obtained and analyzed as a function of the relevant parameters. It is observed that one may achieve the maximal entanglement or no entanglement at all, depending on the choice of the parameters involved.     

Advantages of using gold hollow nanoshells in cancer photothermal therapy

Lots of studies have been conducted on the optical properties of gold nanoparticles in the first region of near infrared(650 nm–950 nm), however new findings show that the second region of near-infrared(1000 nm–1350 nm) penetrates to the deeper tissues of the human body. Therefore, using the above-mentioned region in photo-thermal therapy(PTT) of cancer will be more appropriate. In this paper, absorption efficiency is calculated for gold spherical and rod-shaped nanoshells by the finite element method(FEM). The results show that the surface plasmon frequency of these nanostructures is highly dependent on the dimension and thickness of shell and it can be adjusted to the second region of near-infrared. Thus, due to their optical tunability and their high absorption efficiency the hollow nanoshells are the most appropriate options for eradicating cancer tissues.     

Simultaneous spectrophotometric determination of uranium and zirconium using cloud point extraction and multivariate methods

A cloud point extraction (CPE) process using the nonionic surfactant Triton X-114 to simultaneous extraction and spectrophotometric determination of uranium and zirconium from aqueous solution using partial least squares (PLS) regression is investigated. The method is based on the complexation reaction of these cations with Alizarin Red S (ARS) and subsequent micelle-mediated extraction of products. The chemical parameters affecting the separation phase and detection process were studied and optimized. Under the optimum experimental conditions (i.e. pH 5.2, Triton X-114?=?0.20%, equilibrium time 10?min and cloud point 45?°C), calibration graphs were linear in the range of 0.01?C3?mg?L^?1 with detection limits of 2.0 and 0.80???g L^?1 for U and Zr, respectively. The experimental calibration set was composed of 16 sample solutions using an orthogonal design for two component mixtures. The root mean square error of predictions (RMSEPs) for U and Zr were 0.0907 and 0.1117, respectively. The interference effect of some anions and cations was also tested. The method was applied to the simultaneous determination of U and Zr in water samples.     

Variation of electrochemical capacitor performance with Room Temperature Ionic Liquid electrolyte viscosity and ion size

The use of Room Temperature Ionic Liquid (RTIL) electrolytes promises to improve the energy density of Electrochemical Capacitors (ECs) by allowing for operation at higher voltages. RTIL electrolytes 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF(4)), 1-ethyl-3-methylimidazolium dicyanamide (EMImN(CN)(2)), 1,2-dimethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide (DMPImTFSI), and 1-butyl-3-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate (BMPyFAP) were studied. Tetraethylammonium tetrafluoroborate 1 molar solution in anhydrous propylene carbonate (Et(4)NBF(4)-PC 1M) was studied for comparison purposes. Carbon was produced from phenolic resin activated in CO(2). The porosity of the carbon samples were characterised by N(2) adsorption-desorption at 77 K and the relevant electrochemical behaviour was characterised by galvanostatic charge-discharge, electrochemical impedance spectroscopy and cyclic voltammetry. The highest operating voltage of 3.5 V was obtained for BMPyFAP, whilst the best capacitive performance was obtained for EMImBF(4). The maximum energy density increased to 70 Wh kg(-1) (carbon) for RTIL EMImBF(4) from 35 Wh kg(-1)(carbon) for the organic electrolyte Et(4)NBF(4)-PC 1M. It was found that the performance of the RTIL electrolytes could be related to the IL viscosity and ion size whilst the electrolyte equivalent series resistances produced a linear relationship with viscosity. It was found that the capacitance performance of the RTIL electrolytes followed the order EMImBF(4) > DMPImTFSI > BMPyFAP > EMImN(CN)(2). The electrolyte and equivalent series resistance were in the order EMImN(CN)(2) < EMImBF(4) < DMPImTFSI < BMPyFAP.