The determination of copper by complexometric titration with ethylenediaminetetraacetic acid

A method has been developed for the determination of cupric copper by complexometric titration with ethylen.ediaminetctraacetic acid. The titrations were followed potentiometrically, and were effected at pH 5–6 in the presence of an ammonium acetate buffer. Interfering metals such as ferric iron, aluminium, cadmium, zinc, manganese, nickel, cobalt and lead must be removed by a preliminary separation.     

On the detection of aluminium by means of aluminon

The well-known reaction of aluminium with aluminon has been modified in such a way as to make it specific for this element. This has been accomplished by adding sulphurous acid beforehand and ethanol and hydrochloric acid afterwards. Thc first reagent prevents the interference of chromium, indium, gallium, and titranium; the second those of beryllium, scandium, zirconium and small amounts of ferric iron.     

Analytical applications of the photochemical action of light: Determination of oxalic acid by photo-oxidation in the presence of ferric salts

A new method has been developed for the determination of oxalic acid. This depends upon the photochemical oxidation of oxalic acid in. the presence of ferric sulphate. The method involves exposing a measured volume of oxalic acid solution, with an excess of ferric alum and some sulphuric acid,tosunlight in quartz or pyrex beaker for 15 to 30 minutes. The progress of the reaction is indicated by the disappearance of the yellow colour of the ferricoxalate complex from the solution. After completion of the reaction, the ferrous salt formed is determined using standard sodium vanadate and either diphenylbenXXXdine or diphenylamme-sulphonate as internal indicator in the presence of sufficient phosphoric acid. Formic acid does not interfere in the photochemical method of deteminination.     

分光光度法测定水溶液中的有机酸含量

利用水溶液中的有机酸在高氯酸羟胺(HAP)和N,N′-二环己基碳酰亚胺(DCC)存在的条件下生成的羟肟酸,以及羟肟酸在酸性高氯酸铁溶液中显色的性质,建立了一种分光光度测定水中有机酸含量的方法。对显色剂的酸度、浓度、加入体积、HAP和DCC的浓度、加入体积以及显色反应的温度、反应时间对吸光度的影响进行了考察。结果表明,该显色反应在反应条件:0.0687mol/LHAP1.0mL、0.6mol/LDCC0.5mL、震荡均匀后室温下放置反应15min、0.02mol/L酸性高氯酸铁溶液(高氯酸浓度0.3mol/L)显色条件下具有最大的吸光度;并对正丁酸、正戊酸、苯甲酸进行了线性关系考察。结果表明,该检测方法具有仪器简单、操作方便、线性范围较宽、准确度高等优点,可用于那些不易从水溶液中萃取的有机酸的测定,也可用于液相色谱洗脱液中有机酸的测定。     

Determination of Aluminium with 8-Hydroxyquinoline-5-Sulfonic Acid in Presence of A Cationic Surfactant by First and Second Derivative Synchronous Fluorimetry

Abstract

An analytical method has been developed for the fluorimetric determination of nanogram amounts of aluminium in solution. The method is based on the reaction of aluminium with B-hydroxyquinoli-ne-5-sulfonic acid in presence of hexadeciltrimethylammonium bromide as a surfactant agent. Synchronous scanned first and second derivative fluorimetry has been employed to increase the sensitivity of the method. The influence of reaction variables as well as instrumental parameters is discussed. The interference of various foreign ions has also been examined and in some cases eliminated or reduced by addition of 1, 10-phenanthroline.     

Application of α-benzoinoxime for substoichiometric extractive separation of copper in activation analysis

A method has been developed for the substoichiometric extraction of copper with a solution of α-benzoinoxime in chloroform. The separation can be carried out in the absence or in the presence of tartaric acid at pH 6.8–7.0 and 9.5, respectively. In the presence of tartaric acid no interference has been observed. The method has been applied to the determination of copper in biological material, silicon, aluminium and kaolin by the neutron activation method.     

Analytical applications of the photochemical action of light: Determination of ferric iron by photochemical reduction in the presence of citric and mandelic acids

A new method has been developed for the determination of ferric sulphate through its photochemical reduction with citric and mandelic acids in sunlight. The method consists in irradiating with sunlight a measured volume of the ferric sulphate solution together with an excess of citric or mandelic acid in a quartz or pyrex glass beaker until reduction is complete. The ferrous salt formed is determined by titration with a standard solution of sodium vanadate in the presence of the proper concentration of sulphuric and phosphoric acids, employing diphenylbenzidine or diphenylamine sulphonate as internal indicators. The photoreduction is greatly retarded by sulphuric acid.     

Enhancement of the reducing properties of metallic mercury in presence of complex forming ions

The reducing properties of metallic mercury in solutions containing ions forming precipitates or complexes with mercuric or mercurous ions have been studied.The reducing power of mercury in the presence of thiocyanate is greatly enhanced, and it is similar to that in the presence of hydrochloric acid. The effects of the thiocyanate and ferric concentrations have been examined. To reduce a 0.01 M solution of ferric ion without forming a precipitate of mercurous thiocyanate, a concentration of thiocyanate of at least 0.05 M is required. The action of mercurythiocyanate system on some oxidising substances has been studied. The most important reaction is the reduction of ferric ions. The method has been applied to the determination of iron on macro and semimicroscale and good results have been obtained.The reducing power of metallic mercury in the presence of cyanide has also been examined. In general it acts as a strong reducer in alkaline medium. Atmospheric oxygen is reduced partially to water and hydrogen peroxide. Ferricyanide is reduced quantitatively to ferrocyanide. The action of metallic mercury in the presence of cyanide on other oxidising substances has also been examined.     

Titrimetric determination of aluminium in steel

A titrinetric method has been worked out for the determination of aluminium in plain steels using dicniorodiethyl ether to separate off the iron and titrating with hydrochloric acid first in the absence and then in the presence of fluoride.     

Quantitative Separation of Citric Acid From Trichloroacetic Acid on Plates Coated with Calcium Sulphate Containing Zinc Oxide

Abstract

Thin-layer chromatographic behaviour of ten acids on coating of calcium sulphate containing ammonium molybdate, aluminium oxide, calcium carbonate, copper sulphate, ferric chloride, magnesium sulphate, phthalic anhydride, titanium oxide, zinc oxide etc. has been studied. Quantitative separation of citric acid from trichloroacetic acids has been achieved on calcium sulphate containirig zinc oxide in ethyl acetate. Herbicide, trichloroacetic acid can be separated from plant growth regulators such as indole-3-acetic, β-naphthaleneacetic and β-naphthoxy acetic acids and from other organic acids.     

Sur la transformation du β-nitrostyrène sous l'action du chlorure d'acétyle en présence d'un chlorure métallique

While β-nitrostyrene yields only hydroxymic or hydroxamic acid derivatives by treatment with acetyl chloride in the presence of zinc, tin, titanium or aluminium chloride, it also gives 3-chloro 2-indolinone and a 5-acetyl derivative of the latter, when the reaction is carried out with ferric chloride. The procedures of this reaction are examined, and a mechanism is suggested.     

Extraction chromatographic study of aluminium(III) and mutual separation of aluminium(III), gallium(III), indium(III) and thallium(III) with N-n-octylaniline

A selective method has been developed for extraction chromatographic studies of aluminium(III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium(III) was quantitatively extracted with the 0.065 mol/L N-n-octylaninine from 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (KdAl(III)) versus N-n-octylaniline concentrationin 0.005 and 0.007 mol/L sodium succinate gave theslopes 0.5 and 0.7 respectively and showed theprobable composition of theextracted species was 1:1 (metal to amine ratio) and the nature of extracted species is [RR''NH2+ Al succinate2-] org. .The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium(III), indium(III), gallium(III) and thallium(III) has been developed by using suitable masking agents. The method is fast, accurate and precise.     

A radioactive tracer and radiation study of the stability of ferric and ferrous ions and ascorbic acid

A preliminary liquid-liquid extraction study of ferric and ferrous ions has been undertaken using the radioactive tracer technique with⁵⁹Fe as an indicator of iron. Various solvents were studied and suitable media and solvents were selected for the separation of the two oxidation states of iron. Such separation was used to study the effect of ascorbic acid and other reducing agents on the reduction of ferric ions. The oxidation of ferrous ions to the ferric state under the effect of gamma radiation from⁶⁰Co has also been investigated in the absence and presence of ascorbic acid, using spectrophotometry. In addition, a calculation of the amount of iron oxidized by gamma radiation is given with a discussion of its mechanism and possible effects on the metabolism of iron in the human body.     

Homogeneous precipitation of basic aluminium benzoate with a buffer solution

Addition of an ammonium benzoate-benzoic acid buffer solution to a solution of aluminium ions gives a homogeneous precipitation of basic aluminium benzoate. This has advantages over the urea method for the gravimetric determination of aluminium in the presence of large quantities of manganese, calcium, cadmium, nickel, cobalt, copper, and zinc ions.     

Interaction of radium with freshwater sediments and their mineral components. I.

The radiotracer method has been used for investigation of the adsorption and desorption of traces of radium on ferric hydroxide and quartz under conditions similar to those prevailing in waste and surface waters. The effects of pH, liquid to solid ratio, ionic strength and presence of Ca²⁺ or SO ₄ ^2- ions have been studied. It has been concluded that at pH less than 7 and at concentration of suspended sediments (of common composition) less than 100 mg·1^–1 ferric hydroxide and quartz have negligible effect on the state and migration of radium in surface waters. Radium adsorbed on quartz can be easily desorbed with dilute solutions of hydrochloric acid or sodium chloride.     

Simultaneous determination of aluminium and iron in glasses,phosphate rocks and cement using first- and second-derivative spectrophotometry

First- and second-derivative spectrophoto-metric methods for the simultaneous determination of aluminium and iron in their mixtures are described. The methods are based on the colored complexes formed by aluminium and iron with hematoxylin in the presence of cetyltrimethylammonium bromide as a surfactant. The zero-crossing method has been utilized to measure the first- and second-derivative value of the derivative spectrum. Aluminium (0.05-1 microg ml(-1)) could be determined in the presence of iron (0.09-1.6 microg ml(-1)) and vice versa. The detection limits of aluminium and iron are 0.01 and 0.09 microg ml(-1), respectively in the first-derivative mode and 0.014 and 0.1 microg ml(-1) in the second-derivative mode. The proposed method has been applied to the simultaneous determination of aluminium and iron in glasses, phosphate rocks, cement and magnesite alloy.     

Quantitative estimations of ferric iron by phosphoric acid in aqueous-alcoholic medium

Summary The only method recommended for the direct estimation of ferric iron in presence of HCl is to reduce the ferric iron to ferrous iron and then to titrate against KMnO₄ solution by adding Reinhardt-Zimmermann reagent (MnSO₄ + H₂SO₄ + H₃PO₄). The solubility of the phosphato complexes of ferric chloride and phosphoric acid is much reduced by adding a nonaqueous solvent, ethyl alcohol or acetone. This property has been availed of to find out a method of estimating ferric iron directly against standard solution of phosphoric acid in aqueous-nonaqueous medium using K₄Fe(CN)₆ or cupferron as external indicators. A slight discrepancy at the end point, however, exists in the direct titration but it can be removed by applying a correction factor determined from the estimated results.     

一种具有快速响应特性的光导纤维铁传感器

将邻氨基苯甲酸共价偶联到聚乙烯醇基质上,制得一个基于荧光碰撞猝灭机理的测定Fe^3^+的光导纤维化学传感器。此传感器响应速度仅为90ms,且可逆性好。用它测定铝合金中的铁含量,取得满意的结果。     

Polystyrene and Silica Gel–Supported,AlCl3-Catalyzed Preparation of Diaryl Sulfoxides from Arenes and Thionyl Chloride

A simple, chemoselective, and efficient method has been developed for direct conversion of arenes to symmetrical diaryl sulfoxides using thionyl chloride in the presence of a catalytic amount of cross-linked polystyrene-supported aluminium chloride (Ps-AlCl₃) and silica gel–supported aluminium chloride (SiO₂-AlCl₃). These solid acid catalysts are stable and can be easily recovered and reused without appreciable change in their efficiency.     

溴化十六烷基吡啶自盐酸溶液中在铝表面上的吸附及其缓蚀作用

用失重法研究了溴化十六烷基呲啶对铝在盐酸溶液中的缓蚀作用, 应用吸附理论和Sekine方法处理实验数据~[4], 发现溴化十六烷基吡啶自盐酸溶液中在铝表面上产生了吸附, 且基本服从Langmuir吸附等温式。求得吸附热为35.4 kJ mol~(-1), 认为这种吸附是产生缓蚀作用的重要原因。实验还表明, 缓蚀率随温度升高而增大, 根据这些结果讨论了吸附与缓蚀作用之间的关系。