Thermodynamic stability of CaThF6(cr) by transpiration and e.m.f. techniques

In the present paper, we report the standard molar Gibbs energy of formation for CaThF₆ measured by gas equilibration and e.m.f. methods. The HF(g) vapour pressure over the equilibrium reaction: \({\text{CaThF}}_{6} \left( {\text{cr}} \right) + 2 {\text{H}}_{ 2} {\text{O}}\left( {\text{g}} \right) = {\text{CaF}}_{2} \left( {\text{cr}} \right) + {\text{ThO}}_{2} \left( {\text{cr}} \right) + 4{\text{HF}}\left( {\text{g}} \right)\) has been measured using transpiration technique. The above reaction mechanism has been established employing TG and XRD techniques. A fluoride e.m.f. cell: (−)Pt, CaF₂(cr) + ThOF₂(cr) + CaThF₆(cr) |CaF₂(cr)| NiO(cr) + NiF₂(cr), Pt(+) has been constructed to measure Gibbs energy of formation of CaThF₆ (cr) using CaF₂ (cr) as a solid electrolyte. The isobaric heat capacity \({\text{Cp}}_{\text{m}}^{{\circ }} \left( T \right)\) of the compound has been measured using differential scanning calorimetric technique. Based on the experimental results, thermodynamic functions for CaThF₆ have been generated.

     

Nickel‐Catalyzed Cross‐Coupling of Alkyl Zinc Halides for the Formation of C(sp2)?C(sp3) Bonds: Scope and Mechanism

Optimal conditions for a general Ni‐catalysed Negishi cross‐coupling of alkyl zinc halides with aryl, heteroaryl and alkenyl halides have been determined. These conditions allow the reaction to take place smoothly, with low catalyst loading, and in the presence of a wide variety of functional groups to afford products in good yields at room temperature. DFT studies on the mechanism support the occurrence of a catalytic cycle involving transmetalation of the alkyl zinc halide to Ni^I followed by oxidative addition of the haloarene and C? C reductive elimination.     

An Improved UPLC Method for Rapid Analysis of Levofloxacin in Human Plasma

A rapid, specific, and sensitive ultra-performance liquid chromatographic method for analysis of levofloxacin in human plasma has been developed and validated. Plasma samples were spiked with the internal standard (enoxacin) and extracted with 10:1 (v/v) ethyl acetate–isopropanol. UPLC was performed on a 100 × 2.1 mm i.d., 1.7 µm particle, C₁₈ column with 88:12 (v/v) 0.4% triethylamine buffer (pH 3)–acetonitrile as mobile phase, pumped isocratically at a pressure of 11,000 psi (758 bar) and a flow-rate of 0.3 mL min^?1. Ultraviolet detection was performed at 300 nm. The retention times of levofloxacin and enoxacin were 3.4 and 2.8 min, respectively, and the run-time was 5 min. Calibration showed that response was a linear function of concentration over the range 0.05–10 µg mL^?1 (r ² ≥ 0.99) and the method was validated over this range for both precision and accuracy. The relative standard deviation was <15% for both intra-day and inter-day assay (n = 5). Levofloxacin and enoxacin were stable in plasma; there was no evidence of degradation during three freeze–thaw cycles, post-preparative stability at 20 °C was ≥24 h, short-term stability at room temperature was ≥6 h, and long-term stability at ?70 °C was ≥30 days. The method was successfully used in a study of the bioequivalence of two levofloxacin tablet formulations in healthy volunteers.     

Cu–Cl Thermochemical Water Splitting Cycle: Probing Temperature-Dependent CuCl2 Hydrolysis and Thermolysis Reaction Using In Situ XAS

Journal of Thermal Analysis and Calorimetry - Recently, we reported detailed investigations on a hydrolysis step of Cu–Cl thermochemical cycle (Singh et al. in Int J Energy Res...     

Polymerization of elemental sulfur with various divinyl and diallyl monomers and properties of the copolymers

Abstract

Polymeric sulfur generated from thermal ROP forms a semi crystalline, intractable solid with poor mechanical properties and is not easy to melt and resists solid processing. Stabilization of diradical polymeric sulfur form can be achieved by reaction with dienes which stabilizes the polymeric sulfur (depolymerization of polymeric sulfur by polymerization with diene co-monomer). The present work demonstrates how the physical properties of the sulfur based copolymer can be tuned by varying the vinylic and allylic modifier. These particular new structurally modified sulfur based copolymers could act as efficient polymer binders for making concrete materials.     

Synthesis and characterization of ammonium molybdophosphate–silica nano-composite (AMP–SiO2) as a prospective sorbent for the separation of 137Cs from nuclear waste

The ammonium molybdophosphate–silica (AMP–SiO₂) nano-composites were prepared by sol–gel method. The material synthesized was nanocrystalline, with average crystallite size of primary particles in the range of 10–25 nm. Small angle X-ray scattering showed presence of mass fractal aggregates made of small particles with rough pore boundaries. To realize the scope of using AMP–SiO₂ nano-composites sorbent for removal of ¹³⁷Cs from nuclear waste solutions, its adsorption characteristics for cesium were evaluated. It was found that the AMP–SiO₂ nanocomposites were amenable for column operation, have high affinity for Cs, and possess very high adsorption capacity for Cs. From the perspective of separation of ¹³⁷Cs from acidic radioactive waste solution, AMP–SiO₂ nanocomposite holds significant promise.     

Analysis of Pazufloxacin Mesilate in Human Plasma and Urine by LC with Fluorescence and UV Detection,and Its Application to Pharmacokinetic Study

A liquid chromatographic method for analysis of pazufloxacin mesilate in human plasma and urine has been developed and validated for selectivity, sensitivity, accuracy, precision, and stability in pharmacokinetic analysis. The sensitivity of the method was 0.02 μg mL^?1 in plasma and 0.5 μg mL^?1 in urine, with overall intra-day and inter-day precision (RSD < 10%) and accuracy (90–120%) acceptable for clinical pharmacokinetic analysis. Recovery from plasma and urine was 80–110% for both pazufloxacin mesilate and enoxacin, the internal standard. Pazufloxacin was stable in both plasma and urine, with no significant degradation under four different conditions. The method was successfully used in a preliminary study of the bioavailability of pazufloxacin mesilate in healthy human volunteers after intravenous administration of 300 and 500 mg.