Synthesis of selenoxides by oxidation of selenides with superoxide radical anions and 2-nitrobenzenesulfonyl chloride

Alkyl phenyl selenoxides were produced in excellent yields by oxidation of the corresponding selenides with 2-nitrobenzenesulfonyl chloride and potassium superoxide in dry acetonitrile at −15 °C.     

Novel Synthesis of Benzotriazol-1-yl Methyl Selenides and Tellurides

Benzotriazole has played an important role as a synthetic auxiliary for preparative chemists1. It is also well known that organic selenides or tellurides are versatile intermediates in organic synthesis2. However, there are only few reports on the synthesis of the difunctionalized compounds containing both benzotriazolyl group and organoselenium or tellurium group3. Herein we wish to report a new and convenient synthesis of benzotriazol-1-yl methyl selenides and tellurides 4a-h.Selenium or tel…     

十一烯酸钠与十一酸钠水溶液的表面化学

决定表面活性剂性能的首要因素是其分子结构．关于表面活性剂性能随极性头类型、疏水基化学组成、疏水链数目、长度及分支等因素的影响已有许多研究[1]．相比之下，疏水基中含有双键的影响研究较少．实际上，在由两亲分子组成的生物膜中，不饱和脂肪酸酯的存在有重要意义，它使     

Spectrophotometric Studies On Determination of Some Cephalosporins and Amoxycillin With Chlorobenzotriazole and Sodium Hypochlorite

Abstract

Two simple colorimetric methods for the determination of certain cephalosporins (cefaclor and cefadroxil) and amoxycillin sodium are described. The suggested methods depend upon the oxidation of these compounds using sodium hypochlorite (SHC) and 1-chlorobenzotriazole (1-CBT) in alkaline medium and colorimetric measurment of the chromophore formed. The different experimental parameters are studied and incorporated into the procedures. The mean percentages found range from 100.0 ± 0.4 to 100.5 ± 0.9. The proposed methods have been successfully applied to the analysis of some pharmaceutical formulations and the results obtained have been statistically compared with those obtaind using the official methods. The proposed methods are convenient, rapid within the concentration range 15-123 μg. ml^?1.     

A Novel Synthesis of Selenides and Selenol Esters Using Liquid-Liquid Phase-Transfer Catalysis

This article describes the first attempt to synthesize selenides and selenol esters prepared from the reaction of 1-benzyl or 1-acylselenophenylmethaniminium halides and organic halides under liquid-liquid phase-transfer conditions. This method also can be applied to the synthesis of diseleno tweezers-like molecules as metalloreceptors.     

过硼酸钠选择氧化苯硫基乙酸酯的研究

近年来,亚砜的研究十分活跃,苯亚磺酰基乙酸酯是有用的合成中间体,它可以起烷基化反应、Michael反应和缩合反应.我们在含硫碳负离子的研究工作中需要一系列的苯亚磺酰基乙酸酯(3_(a—j))作为合成中间体.合成这类化合物最方便的方法是用合适的硫酚制成硫醚后进行选择性氧化,常用的氧化剂是过氧化氢、过碘酸钠和间氯过苯甲酸.但是,各种方法均有不足之处.例如,用过氧化氢容易发生过度氧化,导致产品不纯;间氯过苯甲酸价高;按文献用过碘酸钠氧化硝基苯硫乙酸酯(2_(a—j)),反应难以进行.不久前,Mckillop等报道用过硼酸钠(NaBO_3·4H_2O)可使硫醚氧化生成亚砜.但是,他们的研究对象仅局限于结构简单的二烃基硫醚,而在分子内若有其它官能团时能否进行选择性氧化,则未见报道.我们进行了过硼酸钠选择氧化苯硫基乙酸酯的研究,取得了很好的结果.     

Salting-Out of Some Alkyl Acetates in Aqueous Sodium Chloride Solutions

Summary.  Solubilities of methyl acetate (MeOAc), ethyl acetate (EtOAc), 1-propyl acetate (1-PrOAc), 1-butyl acetate (1-BuOAc), 2-methyl-1-propyl acetate (iso-BuOAc), 2-butyl acetate (sec-BuOAc), 2-methyl-2-propyl acetate (ter-BuOAc), 1-pentyl acetate (1-PeOAc) and 1-hexyl acetate (1-HeOAc) in water and in aqueous sodium chloride solutions at concentrations ranging up to 1.0 molċdm⁻³ were determined at 25.0°C by analyzing the saturated aqueous or salt solutions. Solubility ratios of alkyl acetates in pure water and in aqueous sodium chloride solution were calculated and found to be linearly dependent on the concentration of sodium chloride. The solubility ratios were also calculated by the approach of the scaled particle theory and according to the theories of McDevit and Long, Cross, Conway et al., and Aveyard. All these theories, except that of Conway, correctly predict the order of magnitude of the experimental results, but do not discriminate between isomeric butyl acetates. The theoretical values obtained from the scaled particle and Aveyard theories coincide well with the experimental values, especially for the higher alkyl acetates. The purely electrostatic theory of Conway et al. not even predicts the salting-out effect for the alkyl acetates investigated. Received July 12, 1999. Accepted September 23, 1999     

十一烯酸钠与十一酸钠水溶液的表面化学

The CMCs, γcmcS and micropolarities of aqueous solutions of sodium undecenoate(UNDE) and sodium undecanoate (UNDA) have been studied by surface tension measurement and fluorescence method. It is revealed that double bond at the en of hydrophobic chain weakens its hydrophobicity, hence lowering the effectiveness of micelle formation and that of surface tension reduction. The limited adsorption amount is less, while micropolarity higher, in UNDE solution than those in UNDA's. Therefore, conformation of the hydrophobic chain in aggregates is infered to be more bending for UNDE. Changes of thermodynamic parameters in micellization and adsorption show smaller free energy reduction and larger increases in entropy and enthalpy for UNDE than those for UNDA.     

Microwave Assisted Selective Oxidation of Benzylic Alcohols with Calcium Hypochlorite under Solvent-Free Conditions

Summary.  A remarkably fast microwave assisted selective oxidation of benzylic alcohols with calcium hypochlorite under solvent-free conditions is described. Received August 28, 2000. Accepted September 21, 2000     

Volumetric,Viscometric, and Refractive Index Behaviour of Glycine in Aqueous Diols at Different Temperatures

Densities, ρ, viscosities, η, and refractive indices, n_D, of glycine (Gly) (0.1 — 0.5 M) in aqueous 1,2‐ethanediol (1,2‐EtD), 1,2‐propanediol (1,2‐PrD), and 1,3‐butanediol (1,3‐BuD) (30% v/v) were measured at 298, 303, 308, and 313 K. Experimental values of ρ and η were used to calculate partial molar volumes, ?⁰_v, partial molar volumes of transfer of Gly from water to aqueous diol solutions, ?⁰_v(tr), Falkenhagen and Jones ‐Dole coefficients, A and B, respectively, free energies of activation of viscous flow, Δμ⁰*₁ and Δμ⁰*₂, per mole of solvent and solute, respectively, enthalpies, ΔH* and entropies, ΔS* of activation of viscous flow. Large positive values of ?⁰_v, and an increasing value of S_v*, for all the three mixtures at each temperature suggest the presence of strong solute‐solvent interaction, and this interaction decreases as the size of alkyl moiety increases from 1,2‐EtD to 1,3‐BuD. Positive ?⁰_v(tr) values tend to decrease with increasing the number of CH₂ group, thereby indicating that the electrostriction effect in diols follows the sequence; 1,2‐EtD > 1,2‐PrD > 1,3‐BuD. Small A values, with large values of B, are indicative of weak solute‐solute and strong solute‐solvent interactions that operate in the present systems, and that the magnitudes of B are in the sequence: 1,2‐EtD > 1,2‐PrD > 1,3‐BuD and, thus, the sequence represents the strength of interaction between Gly and diol molecules. Moreover, positive SB/ST values suggest the structure‐breaking nature of Gly in diol + water mixtures. The observed values of Δμ⁰*₂ fall in the sequence: 1,2‐EtD > 1,2‐PrD > 1,3‐BuD which, like ?⁰_v and S_v*, reinforce that Gly‐diol interaction decreases with subsequent addition of CH₂ group in diols. The trends in the variation of ΔH* and ΔS* with Gly concentration also reveal the presence of significant solute‐solvent interaction in all three systems. An almost linear increase in RD with an increasing amount of Gly reveals that Gly tends to increase the polarizability of the aqueous‐diol molecules under study. The variation of all these parameters with concentration of Gly and with temperature suggests the presence of strong solute‐solvent interaction, which decreases as the size of alkyl moiety in diols increases from 1,2‐EtD to 1,3‐BuD.     

Oxidation of Hydrazides Using Sodium Perborate: Formation of N,N-Diacylhydrazines

Substituted aromatic hydrazides react very smoothly with sodium perborate in glacial acetic acid at room temperature to give N, N′-diacylhydrazines in excellent yields and purity.     

二苯胺重氮盐与十二烷基硫酸钠在水溶液中的相互作用

报道了二苯胺-4-重氮盐(DDS)与十二烷基硫酸钠(SDS)在水溶液中的相互作用.实验结果表明,体系粘度随SDS/DDS物质的量比(ξ)的变化而急增急降.当ξ=0～0.9时,二者形成沉淀,体系的粘度基本不变;当ξ=1.9～2.3时,沉淀溶解并伴随着体系粘度急增,最高粘度达初始值的2520倍;之后,随ξ的增大,体系粘度迅速下降至初始值.对DDS-SDS聚集体的微观结构与体系粘度的关系进行了初步讨论.同时发现体系粘度是光敏性的,紫外光照可使其迅速下降.     

Kinetic Spectrophotometric Determination of Chromium (VI) by Oxidation of Sodium Pyrogallol-5-sulphonate by Hydrogen Peroxide

Summary. A new selective, sensitive, and simple kinetic method is developed for the determination of trace amounts of chromium (VI). The method is based on the catalytic effect of Cr(VI) on the reaction of sodium pyrogallol-5-sulphonate (PS) with hydrogen peroxide. The reaction is followed spectrophotometrically by tracing the oxidation product at 437nm within 1min after addition of H₂O₂. The optimum reaction conditions are PS (1.32·10^–3mol·dm^–3), H₂O₂ (0.32mol·dm^–3), HClO₄ (2.6·10^–3mol·dm^–3) at 25°C. Following this procedure, chromium (VI) can be determined with a linear calibration graph up to 0.25ng·cm^–3 and a detection limit of 0.024ng·cm^–3, based on the 3 criterion. The interference effect of several species was also investigated and it was found that the most common cations and anions do not interfere with the determination. The developed procedure was successfully applied to the determination of Cr(VI) and total Cr in river waters and total Cr in herbal samples.     

D-甘露醇与D-山梨醇在氯化钠水溶液中的稀释焓

应用等温流动微量热法测定了298.15 K时互为旋光异构体的D-甘露醇与D-山梨醇在不同浓度的氯化钠水溶液中的稀释焓, 利用 McMillan-Mayer 理论计算了D-甘露醇与D-山梨醇在不同浓度的氯化钠水溶液中的焓对相互作用系数. 结果表明, D-甘露醇和D-山梨醇在氯化钠水溶液中的焓对相互作用系数h2均为正值, h2的值随着氯化钠浓度的增加皆逐渐增大, 但D-山梨醇的焓对相互作用系数h2增大的速率[dh2 /dm(NaCl)]比 D-甘露醇的要大. 根据两多元醇分子构象结构的差异， 溶质-溶质相互作用和溶质-溶剂相互作用对结果进行了解释.     

钨酸钠与酸性离子液体催化醇的环境友好氧化反应

钨酸钠与酸性离子液体组成的催化体系可以催化双氧水进行醇的清洁氧化,反应在有机底物/水两相中进行.本体系在催化氧化仲醇为相应的酮时具有很好的活性;催化伯醇氧化时可以得到相应的醛、羧酸或两者的混合物.整个催化体系具有很好的重复利用性.     

敌敌畏催化过硼酸钠氧化联苯胺反应体系的研究及应用

利用敌敌畏(DDV)可以催化过硼酸钠(SPB)氧化联苯胺反应的特性,建立了测定DDV的单扫描极谱分析方法,此方法的灵敏度高,其对应的线性范围是3.0×10-9～7.5×10-6g/mL(R2=0.9992),检出限为1.0×10-9g/mL。方法用于测定植物样品中DDV的残留量,结果令人满意。另外,实验指出了DDV的催化作用,并研究了SPB联苯胺氧化产物的电极还原机理。     

Electrical Conductance Studies in Aqueous Solutions of Glutaric Acid,Disodium Glutarate and Sodium Hydrogen Glutarate

Conductivity measurements of glutaric acid and disodium glutarate in dilute aqueous solutions were performed in the 288.15 to 323.15 K temperature range. The limiting equivalent conductances of glutarate anions, λ ^o(HGlut⁻,T) and λ ^o(1/2Glut²⁻,T), and the dissociation constants of glutaric acid, K ₁(T) and K ₂(T), were derived by the use of the Onsager and the Quint and Viallard conductivity equations. The applied molecular model was successfully confirmed by analyzing the conductivities of sodium hydrogen glutarate at 298.15 K.     

无溶剂微波预处理-NaOH溶液搅拌法提取干红辣椒中的辣椒素

将无溶剂微波预处理与NaOH搅拌提取相结合提取辣椒素类物质(Capsaicinoids)。在干辣椒样品中加入微波吸收介质羰基铁粉(CIP),对干辣椒样品进行微波预处理。根据辣椒素与NaOH之间可发生特异性反应,利用NaOH溶液从辣椒中提取两种主要的辣椒素类化合物---辣椒素(Capsaicin,C)和二氢辣椒素(Dihydrocapsaicin,DHC)。实验表明,本方法提取时间短(10min),提取率高,并可有效避免有机溶剂对实验室的污染。     

碲氢化钠存在下3－氧代硫代羧酸酯的一步合成法

３－氧代硫代羧酸酯可由α－溴代酮与碲氢化钠作用形成的烯醇盐与二硫代碳酸二乙酯进行乙氧硫代羰基化反应制得。３－氧代硫代羧酸酯的烯醇含量可由核磁共振谱测得     

Interaction of Sodium Dodecylbenezen Sulfonate with Polymer as Studied by Surface Tension,ESR and UV-vis spectroscopy

The interaction between sodium dodecylbenezen sulfonate(SDBS) and Poly(ethylene oxide) (PEO) has been studied,' using surface tension and dye solubilization to determine the critical micelle concentration(CMC) without PEO, the critical aggregate concentration(cac) and polymer saturation concentration(c₂) in the presence of PEO. The structure of surfactant-polymer complexes is analyzed by ESR and UV-vis spectra. For SDBS-PEO system, the result indicates that ptoymer-surfactant complexes have a more “ open” structure than the ordinary micelles. The polymer molecules may penetrate into the palisade of the micelles. Polyacrylamide(PAm) molecules remain in bulk solution as free molecules, and do not interact with SDBS.