Chitosan hydrogel-based electrolyte for clean and biodegradable batteries: energetic and conductometric studies

Measurements of voltages generated in clean and biodegradable batteries using lithium-chitosan as electrolyte, carbon and nickel as electrodes, were reported. They produced small amounts of energy providing environment was preserved. The energy smallness was argued by conductivity measurements. The concentration and temperature dependences were undertaken. These measurements were carried out from 0.0005 to 1.0 mol dm^?3 in the temperature range 258–323 K, and were compared to glycerol, being clean viscous solvent. The purpose was to substitute toxic solvents currently used, by clean and biodegradable solvents having good performances. The results were analysed with Debye–Huckel–Onsager law at low concentrations and Quasi–Lattice Model at moderate and higher concentrations. The temperature dependence of conductivity was also described using Vogel–Tamman–Fulcher equation. By comparing it to Arrhenius theory, very interesting parameters, such as electrical conductivity infinite dilution, activation energy and Vogel temperature, corresponding to glass transition temperature were extracted from the fit of experimental data.     

Synthesis of a new quaternary phosphonium salt: NMR study of the conformational structure and dynamics

A novel phosphonium salt based on pyridoxine was synthesized. Conformational analysis of the compound in solution was performed using dynamic NMR experiments and calculations. The obtained results revealed some differences in the conformational transitions and the energy parameters of the conformational exchange of the studied compound in comparison to previously reported data for other phosphorus‐containing pyridoxine derivatives. It was shown that increasing the substituent at the C‐11 carbon leads to greater differences in the populations of stable states and the corresponding equilibrium energies. Copyright © 2015 John Wiley & Sons, Ltd.     

Predicting human intestinal absorption in the presence of bile salt with micellar liquid chromatography

Understanding intestinal absorption for pharmaceutical compounds is vital to estimate the bioavailability and therefore the in vivo potential of a drug. This study considers the application of micellar liquid chromatography (MLC) to predict passive intestinal absorption with a selection of model compounds. MLC is already known to aid prediction of absorption using simple surfactant systems; however, with this study the focus was on the presence of a more complex, bile salt surfactant, as would be encountered in the in vivo environment. As a result, MLC using a specific bile salt has been confirmed as an ideal in vitro system to predict the intestinal permeability for a wide range of drugs, through the development of a quantitative partition–absorption relationship. MLC offers many benefits including environmental, economic, time‐saving and ethical advantages compared with the traditional techniques employed to obtain passive intestinal absorption values. Copyright © 2016 John Wiley & Sons, Ltd.     

Heterogeneous palladium multi-task catalyst for sequential Heck-reduction-cyclization (HRC) reactions: influence of the support

An evaluation study of various palladium supports led to the selection of charcoal as the most efficient system for the preparation of oxindoles by sequential Heck-reduction-cyclization (HRC) reactions. The in situ prepared Pd0/C was not recyclable for further cross-coupling reactions but remains still highly active for reduction processes. The sustainable chemistry described herein allows extremely simple experimental protocol under mild conditions, free of any base, ligand and additive.     

EPR Study of the Kinetics of the Formation of Radicals from Dibenzoyl Peroxide on Porous Glass

The kinetics of the formation of radicals from dibenzoyl peroxide supported on porous glass have been determined with EPR techniques over the temperature range of 25-100°C. Values of the activation energy of 18.5 and 25 kcal/mole have been observed for two differently prepared porous glass support materials.     

Syntheses of terminally functionalized polyisobutylene derivatives using diazonium salts

A new strategy for the synthesis of end‐functionalized polyisobutylene (PIB) oligomers is detailed. Commercially available vinyl‐terminated PIB oligomers were modified to form aniline‐terminated PIB via an aromatic electrophilic substitution reaction. The PIB‐bound aryl amines so formed were then converted into diazonium salts using isopentyl nitrite and an acid in methylene chloride. These salts served as versatile intermediates in synthetic reactions affording azo dye‐containing PIB derivatives and other terminally‐functionalized PIB derivatives not readily available by other reactions. The advantages and limitations of various name reactions including diazo couplings, Sandmeyer reactions, dediazoniations, and Heck reactions are discussed. The kinetics of polar substitution reactions at the termini of these nonpolar oligomers and the effects of solvent on these reactions were also examined. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

葫[n]环联脲(n=5,6,7,8)与两种重氮氟硼酸盐的包合作用研究

用核磁共振氢谱和紫外-可见光谱滴定法考察了葫[n]环联脲(Cucurbit[n]uril,n=5,6,7,8)与对甲苯重氮氟硼酸盐和4,4′-联苯二重氮氟硼酸盐的配位情况,并用曲线拟合求得形成的包结配合物的稳定常数.结果表明,不同空腔的葫[n]环联脲对不同尺寸的重氮氟硼酸盐具有很显著的选择性包结作用.在相同条件下,与葫[6]环联脲相比,葫[7]环联脲更易于容纳苯环.同时,随着酸性的增强,葫[n]环联脲上的脲羰基质子化程度加大,使得其配位能力有所减弱.     

无水钾镁矾类复盐(A~ )_2Cd_2(SO_4)_3的热化学

The standard molar formation enthalpies of (A＋ )2Cd2(SO4)3[A＋ is NH＋ 4 or K＋ ] are determined from the enthalpies of dissolution (Δ SHm) of [(A＋ )2SO4(s)＋ 2CdSO4(s)] and (A＋ )2Cd2(SO4)3(s) in twice distilled water or 3 mol· L－ 1 HNO3 solvent respectively,at 298.2 K,as: Δ fH m[(NH4)2Cd2(SO4)3,s,298.2K]=－ 3031.74± 0.08 kJ· mol－ 1 Δ fH m[K2Cd2(SO4)3,s,298.2K]=－ 3305.52± 0.17 kJ· mol－ 1