A New Reagent for the Reduction of N-Arylsulfonylimines

Potassiumselenatedborohydride(KBHZSe3),sodiumselenatedborohydride(NaBHZSe3)werepreparedfirstbyLalancetteetall.However,sincethen,therehavebeenlittlereportabouttheirapplication.Wehaveusedpotassiumselenatedborohydrideinformamidetoreducearomaticnitrocompounds,andsuccessfullyobtainedthecorrespondinganilines2.Inaddition,wehavealsoreportedthereductionofarylsulfonylchloridestothecorrespondingdisulfidesbysodiumselenatedborohydriderefluxinginCH,CN'.Fromourresearchwork,KBHZSe3andNaBHZSe3werefou…     

Absolute potassium cation affinities (PCAs) in the gas phase

The potassium cation affinities (PCAs) of 136 ligands (20 classes) in the gas phase were established by hybrid density functional theory calculations (B3-LYP with the 6-311+G(3df,2p) basis set). For these 136 ligands, 70 experimental values are available for comparison. Except for five specific PCA values-those of phenylalanine, cytosine, guanine, adenine (kinetic-method measurement), and Me(2)SO (by high-pressure mass spectrometric equilibrium measurement)-our theoretical estimates and the experimental affinities are in excellent agreement (mean absolute deviation (MAD) of 4.5 kJ mol(-1)). Comparisons with previously reported theoretical PCAs are also made. The effect of substituents on the modes of binding and the PCAs of unsubstituted parent ligands are discussed. Linear relations between Li+/Na+ and K+ affinities suggest that for the wide range of ligands studied here, the nature of binding between the cations and a given ligand is similar, and this allows the estimation of PCAs from known Li+ and/or Na+ affinities. Furthermore, empirical equations relating the PCAs of ligands with their dipole moments, polarizabilities (or molecular weights), and the number of binding sites were established. Such equations offer a simple method for estimating the PCAs of ligands not included in the present study.     

A new procedure to enols of 2-acylmethyl-4,4-dimethyl-2-oxazolines underultrasonically dispersed potassium system

Various enols of 2-acylmethyl-4,4-dimethyl-2-oxazolines were prepared in moderate yields via ultrasonically catalyzed reactions of 2,4,4-trimethyl-2-oxazoline with arenecarboxylic esters in the presence of UDP-t-BuCl-i-Pr2NH system.     

Activity Coefficients of Potassium Chloride in Water–Ethanol Mixtures

Activity coefficients of KCl were determined in water–ethanol solvents in the range 5–20% (w/w) ethanol, from experimental electromotive force (emf) data. The molalities varied from 0.1 mol-kg^–1 to near saturation and measurements were taken in the temperature range 25 to 45°C. The Pitzer model was used to describe the nonideal behavior of the electrolyte and the corresponding coefficients were determined for each solvent. The Pitzer–Simonson equations were also applied and found superior in the study of KCl in those nonaqueous solutions.     

Solubility of copper (I) bromide in aqueous solutions of potassium bromide

The solubilities of cuprous bromide were measured at 24.8°C in aqueous KBr and in aqueous KBr-KNO₃ mixtures. The results have been analyzed to give equilibrium constanns from formation of neutral and negatively charged complexes of CuBr, and sets of virial parameters suitable for calculation of activity coefficients for the complexes.     

靛蓝胭脂红-高碘酸钾-草酸钠催化光度法测定钢中微量钒

研究了在1 mol/L磷酸介质中，钒(V)对KIO4氧化靛蓝胭脂红褪色反应的催化作用及草酸钠的活化作用，建立了一种测定钒的方法。无草酸钠时该体系为准零级反应，表观活化能为76.7 kJ/mol，在22℃时钒量在0～5mg/L范围内与?A呈线性，检出限为0.1　mg/L。在草酸钠存在下则为准一级反应，表观活化能为60.1 kJ/mol，钒量在0～mg/L范围内与1g(A0/A)呈线性，检出限为0.02mg/L。提高介质酸度，可显著降低反应温度。在NaF及尿素存在下，大多数常见离子无干扰。本法简便快速，选择性和灵敏度较高，用于钢中微量钒的直接测定，结果满意。     

Hydrophilic Carotenoids: Surface Properties and Aggregation Behavior of the Potassium Salt of the Highly Unsaturated Diacid Norbixin

The oft‐claimed ‘good’ water solubility of the food color norbixin ( 3 ) could not be confirmed. In contrast, the potassium salt 5 of norbixin formed suitable dispersions. The surface and aggregation properties of salt 5 were investigated and compared with other naturally occurring and synthetic hydrophilic carotenoids (Table).