Determination of chloride ion by electrochemiluminescence and investigation of the mechanism

The electrochemiluminescence (ECL) of luminol in aqueous alkaline solution was studied.Trace amounts of chloride showed significant effect on the efficiency of light emission of luminol as a posi-tive trigonometrical wave pulse was exerted on the solution. The detection limit for the chloride is5.0 ×10~(-6) mol/L and the linear calibration range extends up to 1.0 ×10~(-2) mol/L; the relative standarddeviation for 1.0 ×10~(-5) mol / L chloride is 5%. The influencing factors for chloride determination arealso discussed. The possible mechanism for the electrochemiluminescence reaction may be due to theoxidation of chloride ion in the solution to ClO~-, and the latter acts on luminol and then gives outluminescence. The method has been applied to determine the total chloride in tap water with satisfactoryresults.     

Solubilities, Densities and Refractive Indices of Rubidium Chloride or Cesium Chloride in Ethanol Aqueous Solutions at Different Temperatures

The data of solubilities, densities and refractive indices of rubidium chloride or cesium chloride in the system CEHsOH-H2O were measured by using a simple accurate analytical method at different temperatures, with mass fractions of ethanol in the range of 0 to 1.0. In all cases, the presence of ethanol significantly reduced the solubility of rubidium chloride and cesium chloride in aqueous solution. The solubilities of the saturated solutions were fitted via polynomial equations as a function of the mass fraction of ethanol. The CsC1-C2H5OH-H2O ternary system appeared in two liquid phases： alcoholic phase and water phase, when the mass fractions of ethanol were in the range of 10.37% to 49.59% at 35 ℃. Density and refractive index were also determined for the same ternary systems with varied unsaturated salt concentrations. Values for both experiment and theory were correlated with the salt concentrations and proportions of alcohol in the solutions. The equations proposed could also account for the saturated solutions.     

Heterogeneous reaction of NO_2 on the surface of NaCl particles

Sodium chloride is the major constituent of sea salt particles in atmospheric environment, with an esti- mated annual contribution of 1012 kg of sea salt parti- cles to the atmosphere[1]. Many studies have shown a significant chloride deficit in these particles when compared to bulk seawater[2,3]. This deficit has been attributed to reactions with NOx and SO2[4]. Simulta- neously, NO2 is one of the main pollutants of mobile vehicles. Reaction (1) may be particularly important to the atmosph…     

Influence of counteranions on catalytic ability of immobilized laccase in Cu-alginate matrices： Inhibition of chloride and activation of acetate

Laccase is a promising oxidase with environmental applications, such as lignin degradation and chlorophenol detoxification. Laccase immobilization can significantly improve physiochemical stability and reusability compared to the free enzymes. In this work, anion effect was investigated in entrapment of Cu-alginate matrix with five types of anions, including perchlorate(ClO4à), nitrate(NO3à), sulfate(SO42à), chloride(Clà), and acetate(CH3CO2à). Accordingly, chloride inhibition and acetate activation were detected in the o-tolidine kinetic experiments, while effects of the other three anions were much smaller. Such counteranion effects were also observed in the laccase-catalyzed biodegradation of 2,4-dichlorophenol. The results indicated that counteranions in the enzyme immobilization process are crucial for catalytic capacity, probably due to the competition with the carboxylate groups in alginate.Our results also imply that these anions might coordinate the copper cations in laccase.     

Clean Synthesis in Water：Darzens Condensation Reaction of Aromatic Aldehydes with Phenacyl Chloride

The Darzens condensation reaction of aromatic aldehydes with phenacyl chloride proceeded very efficiently in a water suspension medium in the presence of triethylbenzylammonium chloride and only trans-2,3-epoxy-1,3-diaryl-1-propanones were formed which can be isolated simply by filtration.The structures of these compounds were confirmed by elemental analysis,IR and ^1H NMR spectra.Therir configurations are in agreement with that of the same compounds reported in the literature.Compared to the classical Darzens condensation,this new method has the advantages of good yields,high stereoselectivity,low running cost inexpensive and environmentally benign procedure.     

Tin(II) Chloride Dihydrate Catalyzed Groebke Condensation: An Efficient Protocol for the Synthesis of 3-Aminoimidazo[1,2-a]pyridines

The ability of tin(II) chloride dihydrate as a catalyst to promote the three-component condensation reaction from a diversity of aromatic aldehydes, 2-aminopyridines and isonitriles at room temperature is described. This methodology affords a number of 3-aminoimidazo[1,2-a]pyridines in the presence of tin(II) chloride dihydrate as a new and mild Lewis acid catalyst in the multi-component reaction in reasonable yields and short reaction time without any significant optimization of the reaction conditions.     

Study on the Synthesis of Phenylacetic Acid by Carbonylation of Benzyl Chloride under Normal Pressure

The influences of some factors on the yield of phenylacetic acid in the carbonylation of benzyl chloride were studied in this paper. These factors included the variety and content of catalyst, and that of solvent, way of material feeding, reaction temperature, sodium hydrate concentration, triphenylphosphine content, presence of surfactant, the ratio of organic phase volume to aqueous phase volume etc. The optimum reaction conditions were found to be: with a one-time pour of 0.15g Pd(PPh3)2Cl2, 0.24g PPh3, 75ml NaOH of 3.5mol/L, 20ml benzyl chloride and 55ml n-butyl alcohol, and the reaction was carried out at 50℃ for about 3 hours. The as-obtained yield of phenylacetic acid was as high as 97.6%. In addition, the influences of the presence of phenylacetic acid and air in the reaction system were also studied. The results showed that the presence of air in the system and the entrainment of phenylacetic acid in the circulating organic phase had great influence on the reaction rate, the stability and performance of catalyst and the yield of phenylacetic acid.     

An Efficient One-pot Synthesis of β-Amino/β-Acetamido Carbonyl Compounds via ZrCl4-catalyzed Mannich-type Reaction

Zirconium(IV) chloride catalyzed efficient one-pot synthesis of β-amino/β-acetamido carbonyl compounds at room temperature is described. In the presence of ZrCl4, the three-component Mannich-type reaction via a variety of in situ generated aldimines, with various ketones, aromatic aldehydes and aromatic amines in ethanol, led to the formation of β-amino carbonyl compounds and the four-component Mannich-type reaction of aromatic aldehydes with various ketones, acetonitrile and acetyl chloride resulted in the corresponding β-acetamido carbonyl compounds in high to excellent yields. This methodology has also been applied towards the synthesis of dimeric β-amino/β-acetamido carbonyl compounds.     

Unusual Reaction of Diazo Compounds with Enamines

Transition metal catalyzed decomposition of diazo compounds and consequent transformations constitute various synthetic useful reactions in the past decades. The catalytic addition of diazo compounds to olefins generally provides cyclopropanes in high yield. However the reaction of electron-rich enamines with diazo compounds gave variable results. Wenkert et al. reported the reaction of enamines with ethyl diazoacetae (EDA) in the presence of cuprous chloride or silver oxide unexpectedly gave…     

New Approach to Synthesis of 6,7—Dimethoxyisatin

A new approach to synthesis of 6,7-dimethoxyisatin is reported.2-nitro-3,4-dimethoxy mandelonitrile in glacial acetic acid was treated with the solution of stannous chloride in hydrochloric acid to give 6,7-dimethoxyisatin in a high yield.     

Benzylation of Aromatic Compounds with Benzyl Chloride Catalyzed by Nafion／Si02 Nanocomposite Catalyst

In the presence of Nafion/SiO2compounds with benzyl chloride proceedednanocomposite catalyst, the benzylation of aromatic to afford diphenylmethane derivatives in high yields,The catalyst showed high catalytic activity not only for electron-rich aromatic compounds, but also for electron-poor aromatic compounds. Under identical conditions, the self-benzylation of benzyl chloride, and dibenzylation and/or multi-benzylation of aromatic compounds were negligible     

Ferric Chloride Catalyzed Isomerization and Cyclization of Geraniol,Linalood and Nerol

Ferric chloride catalyzes the isomerization and cyclization of geraniol,linalood and nerol in acctonitrile giving α-terpincol in good to high yields.     

Specific features of the detection of hydrogen chloride in air with semiconductor sensors

The donor and acceptor character of the change in the resistance of semiconductor sensors in the presence of hydrogen chloride in air was elucidated. Conditions controlling the character of the sensor signal were revealed. The donor signal of the sensor increases with increasing temperature of the sensor, increasing air humidity, and decreasing concentration of hydrogen chloride. On the contrary, a decrease in the temperature of the sensor, a decrease in humidity, and an increase in the concentration of hydrogen chloride enhance the acceptor signal of the sensor. Air humidity has the decisive effect on the character of the sensor signal. It was demonstrated that semiconductor sensors allow the determination of hydrogen chloride in air at a level of the maximum permissible concentration (MPC) in the sanitary zone (0.2 mg/m³). Original Russian Text ￠ L.A. Obvintseva, E.A. Oksengoit-Gruzman, V.L. Kuchaev, A.K. Avetisov, F.Kh. Chibirova, M.P. Dmitrieva, 2008, published in Zhurnal Analiticheskoi Khimii, 2008, Vol. 63, No. 3, pp. 308–313.     

Determination of the apparent standard potential of the Dy/Dy(Ⅲ) system in the LiCl-KCl eutectic

The apparent standard potential of Dy/Dy(III) system in the LiCl-KCl eutectic has been determined by the logarithmic analysis of the semi-integrals of voltammograms, logarithmic analysis of chronopotentiograms and the open circuit potentiometry. The dysprosium equilibrium potentiab for various concentration of dysprosium chloride in the LiCl-KCl eutectic melt between 400-500℃ were first determined experimentally, and the apparent standard potential of this system and its temperature dependance have been calculated.     

Syntheses of α-Hydroxyarylacetic Acidsin the Presence of DifferentPhase Transfer Catalysts Under Sonication

IntroductionA one-step preparation of a--hydroxyarylacetic acids from arylaldehydes, bromoform andpotassium hydroxide in the presence of catalyst lithium chloride in a mixed solvent of waterand 1,4-dioxane has been de.cribed[1]. There are a number of articles wherein authors havereported the preparation of a-aminoarylacetic acidsL2.3J and a-hydroxyl c ycloh exaneca r box yl icacid with a similar procedure[']. On the other hand, it was reported that some reactions underultrasonic wave often ta…     

A simple and convenient method for direct α-chlorination of ketones with ammonium chloride and Oxone~

When ketones were treated with ammonium chloride and Oxone~ in MeOH at room temperature,a directα-chlorination of ketones was occurred and a series of the corresponding a-chloroketones were obtained in moderate to good yields after 24 h.In this reaction,ammonium chloride was used as the source of chlorine and Oxone~ was used as an oxidant.This method was simple, convenient and providing a novel procedure for preparation of a-chloroketones.     

Factors Influencing Sulfinatodehalogenation Reactions of Perhalocarbons

The study on the factors influencing sulfinatodehalogenation of perfluorohexyl chloride plus octene-1 by using Na2S2O4/NaHCO3 discovered that among the various solvents tested (e.g. Me2SO, NMP, DMAc, CH3CN,CH3CN/H2O) at different temperatures, Me2SO was found to be the most suitable solvent and the conversion of the chloride was very dependent on the reaction temperature. When Me2SO was used in the reaction of perfluoroalkyl iodides, the reaction temperature could be decreased by 20℃ as compared with that carried out in CH3CN/H2O to reach the comparable yields.     

Synthesis of N-benzoyl-N''''-aryl selenoureas under PTC

Recently many syntheses of selenium-containing compounds have been reported and studied, in which compounds selenoureas are used as the precursors for the syntheses of selenium-nitrogen heterocyclic compounds and their activities have received increasing attentions. Herein, we report the facile preparation of N-benzoyl-N'-aryl selenourea derivatives using potassium selenocyanate. In this typical procedure, Benzoyl chloride 1 was treated with potassium selenocyanate in CH2Cl2 under the condit…     

An Efficient Synthesis of Tertiaryaminomethylphosphonates,A Versatile Precursor for Synthesis of Glyphosate and α—Aminomethylphosphonates

Reaction of simple dialkyl phosphites with symmetrical 1,3,5-trisubstituted hexahydrotriazines (HHTs) in the presence of benzyl chloride,afforded tertiaryaminomethylphosphonates in excellent yields. Glyphosate,α-aminomethylphosphonates and their derivatives can therefore be synthesized by this procedure conveniently.     

A Facile Approach to Regioselective 1-O-Deacylation of Peracylated Glycopyranoses

The regioselective 1-O-deacylation of peracylated glycopyranoses 1a-d with zinc chloride and zinc oxide in THE/MeOH gave the corresponding tetra-O-acylglycopyranoses 2a-d in good yields.