Iodine trichloride in glacial acetic acid as an oxidizing titrant

A systematic study of the redox reactions of iodine trichloride with various inorganic ions in glacial acetic acid medium is described. Sodium sulphite, arsenic trichloride, antimony trichloride, iron(II) perchlorate and mecury(I) perchlorate were examined. Potentiometric and amperometric methods were used to follow the reduction of iodine trichloride, which yields different products according to the type of reductant.     

Iodine trichloride as an analytical reagent for determination of some organic compounds

Procedures are described for the determination of organic compounds with iodine trichloride under Andrews's titration conditions. Samples are directly titrated with iodine trichloride or first reacted with an excess of iodine monochloride, with subsequent titration of the iodine formed. The direct titration is done initially in feebly acid medium, then the acidity is raised (biotin, methionine, cystine and thiomersal). Pre-oxidation with iodine monochloride is used if the organic compound reacts slowly [tryptophan and arsenic(III) compounds] or is determined in bicarbonate medium (hydroxylamine and thiosemicarbazide). The ferrocyanide formed by the reduction of ferricyanide (by thiourea and allylthiourea) can also be titrated. Arsenic(V) compounds are determined after reduction to arsenic(III), and iodine in organic compounds is converted into iodide by alkaline fusion into iodide and the iodide titrated.     

Determination of isoniazid in drugs

A titrimetric method is described for the determination of isoniazid in pharmaceutical preparations. Samples are treated with an excess of iodine monochloride, and the iodine produced is titrated with iodine trichloride to an Andrews end-point. p-Aminosalicylic acid undergoes only nuclear iodination and does not interfere. Mixtures of isoniazid with vitamin C or methionine are analysed by first titrating both compounds by the Andrews method and then determining either vitamin C alone by titration with iodine monochloride or methionine by a second Andrews titration after destruction of isoniazid with nitrous acid. In both cases, isoniazid is obtained by difference. A mixture of isoniazid, methionine and vitamin C can also be analysed.     

Non-aqueous redox titrations with iodine and iodine halides. Determination of xanthates and dithiocarbamates

Summary Iodine and iodine halides (monobromide, monochloride and trichloride) solutions in acetonitrile have been used as oxidimetric reagents for the visual and potentiometric determination of alkali metal salts of xanthic and dithiocarbamic acids also dissolved in acetonitrile. The methods are simple, accurate, rapid and widely applicable.

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Zusammenfassung Jod und dessen Halogenverbindungen (Monobromid, Monochlorid und Trichlorid) in Acetonitril gelöst wurden als oxydimetrische Reagenzien zur visuellen und potentiometrischen Titration von Alkali-Xanthogenaten und-dithiocarbamidaten in dem genannten Lösungsmittel verwendet. Das Verfahren ist einfach, genau und vielseitig anwendbar.

     

Simple spectrophotometric and titrimetric methods for the determination of sulfur dioxide.

The proposed work describes a simple spectrophotmetric as well as a titrimetric method to determine sulfur dioxide. The spectrophotometric method is based on a redox reaction between sulfur dioxide and iodine monochloride obtained from iodine with chloramine-T in acetic acid. The reagent iodine monochloride oxidizes sulfur dioxide to sulfate, thereby reducing itself to iodine. Thus liberated iodine will also oxidize sulfur dioxide and reduce itself to iodide. The obtained iodide is expected to combine with iodine to form a brown-colored homoatomictriiodide anion (460 nm), which forms an ion-pair with the sulfonamide cation, providing exceptional color stability to the system under an acidic condition, and is quantitatively relatd to sulfur dioxide. The system obeys Beer's law in the range 5 - 100 microg of sulfur dioxide in a final volume of 10 ml. The molar absorptivity is 5.03 x 10(3) l mol(-1)cm(-1), with a relative standard deviation of 3.2% for 50 microg of sulfur dioxide (n = 10). In the titrimetric method, the reagent iodine monochloride was reduced with potassium iodide (10%) to iodine, which oxidized sulfur dioxide to sulfate, and excess iodine was determined with a thiosulfate solution. The volume difference of thiosulfate with the reagent and with the sulfur dioxide determined the sulfur dioxide. Reproducible and accurate results were obtained in the range of 0.1 - 1.5 mg of sulfur dioxide with a relative standard deviation of 1.2% for 0.8 mg of sulfur dioxide (n = 10).     

An investigation of the potential uses of iodine monochloride as a titrant in thermometric titrimetry

An investigation has been made of the potential uses of iodine monochloride as a titrant in thermometric titrimetry. A series of substances, inorganic and organic, has been selected so that a range of stoichiometries and of various types of reaction products result from the oxidation. It has been found to be necessary to prevent the formation of iodine formed by oxidation of the iodide produced by the reduction of iodine monochloride. This is successfully accomplished by using mercury(II) to mask the iodide in a mercury(II)-iodide complex. However, the evolution of gaseous products tends to give curvature of the enthalpogram near the equivalence point and the method is not recommended for the determination of compounds such as thiosemicarbazide. For many other systems, iodine monochloride used in the presence of mercury(II) has analytical potential as a thermometric titrant.     

ICl3电离能的实验和理论研究

结合紫外光电子能谱实验和量子化学计算方法研究了三氯化碘的电离能．实验得到的ICl3的紫外光电子能谱是一氯化碘和氯气的混合能谱,这表明ICl3分解为ICl和Cl2．采用B3LYlP方法在6-311 G(df)基组水平上得到了ICl3分解的过渡态．计算表明ICl3分解吸收少量热量,反应的活化能为168．4kJ／mol．采用HF方法和外壳层格林函数方法(OVGF)预测了ICl3不同轨道的电离能,OVGF方法得到的ICl3第一垂直电离能为10．372eV．     

Discovery and crystal structure of a novel chlorocarbon host: perchlorofluorene-9-spirocyclohexa-2′,5′-diene

Chlorination of triphenylene (1a) employing a mixture of aluminium trichloride and sulphur monochloride in sulphuryl chloride leads to rearrangement with formation of the title chlorocarbon (2), a new host, as main product. X-ray crystal structure analyses of the unsolvated spirocycle (2) as well as of its inclusion compounds with guests benzene and cyclohexa-1,4-diene are described.     

Volumetric studies in oxidation-reduction reactions: Oxidation with chloramine-t. indirect determinations

Chloramine-T has been used as an oxidizing agent in hydrochloric acid medium for the indirect volumetric determination of hydrogen peroxide, lead dioxide, selenium dioxide, sodium formate, potassium meta-periodate, potassium permanganate and potassium dichromate using iodine monochloride as a catalyst, prcoxidizer and an indicator. Chloroform is coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride.     

Sodium meta-vanadate as volumetric reagent : Iodine monochloride method

Sodium meta-vanadate has been used as an oxidising agent in hydrochloric acid medium for the volumetric estimations of potassium iodide, sodium arsenite, mercurous chloride, potassium thiocyanate, sodium sulphite, sodium bisulphite, sodium thiosulphate, ferrous sulphate and hydrazine sulphate, using iodine monochloride as a catalyst and preoxidiser. Chloroform is used as an indicator. It is coloured pink due to the liberation, of iodine during the titration and becomes light pale yellow at the end-point due to the formation of iodine monochloride.     

Studies in oxidation-reduction reactions: Oxidation with chloramine-b,iodine monochloride method

Chloramine-B has been used as an oxidizing agent in hydrochloric acid medium for the volumetric estimations of potassium iodide, arsenious oxide, tartar-emetic, mercurous chloride, stannous chloride, potassium thiocyanate, ferrous ammonium sulphate, hydrazine sulphate and hydroquinone, using iodine monochloride as a catalyst and pre-oxidizer. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes light pale yellow at the end-point because of the formation of iodine monochloride.     

Studies in oxidation-reduction reactions: Oxidation with chloramine-b indirect determinations

Chloramine-B has been used as an oxidizing agent in hydrochloric acid medium for the indirect volumetric estimations of hydrogen peroxide, lead dioxide, manganese dioxide, selenium dioxide, sodium formate, sodium sulphide, sodium metavanadate, potassium iodate and copper sulphate using iodine monochloride as a catalyst and pre-oxidiser. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes light pale yellow at the end-point because of the formation of iodine monochloride.     

Volumetric studies in oxidation-reduction reactions: Oxidation with chloramine-t. iodine monochloride method

Chloramine-T has been used as an oxidizing agent in hydrochloric acid medium' for the volumetric estimations of potassium iodide, hydrazine sulphate, arscnious oxide, stannous chloride, mercurous chloride, tartar-emetic, potassium thiocyanate and ferrous ammonium sulphate, using iodine monochloride as a catalyst and pre-oxidizer. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride.     

Theoretical analysis of reactions of electrophilic iodination and chlorination of benzene and polycyclic arenes in density functional theory approximation

Quantum-chemical method DFT B3LYP/6-311G* was applied to stage by stage thermodynamic calculation of reactions of electrophilic iodination of benzene, naphthalene, phenanthrene, and anthracene with iodine and iodine monochloride, and comparison with chlorination reactions was performed. The main distinction of iodination process from chlorination was an enhanced reversibility owing to protodeiodination. The reversibility of iodination grows with the electron-donor properties of aromatic substrates. The calculations permit an assumption that the chlorination of anthracene and phenanthrene with iodine monochloride occurs most probably through stages of electrophilic iodination-dehydroiodination.     

Iodination and Chlorination of Aromatic Polycyclic Hydrocarbons with Iodine Monochloride in Aqueous Sulfuric Acid

Polycyclic aromatic hydrocarbons when treated with iodine monochloride in water solutions of sulfuric acid afford iodo- and chloroderivatives. Biphenyl, fluorene, acenaphthene, 1-nitronaphthalene undergo iodination. Naphthalene furnishes a mixture of iodo- and chloroderivatives, prevailing the latter. Anthracene and phenanthrene provide only chlorinated products. The iodine monochloride in the sulfuric acid is a stronger iodinating agent than in acetonitrile.     

Dependence of the electronic absorption spectra of aqueous solutions of iodine monochloride on the conditions of dilution and storage time

The electronic absorption spectra of aqueous solutions of iodine monochloride ICl are studied. The spectra of as-prepared solutions display the absorption band associated with hydrated ICl molecules. An additional band indicating that molecular iodine was formed in the solution emerges in the spectrum as dissolution takes place. Only the band belonging to iodine monochloride remains in the absorption spectra, and no additional bands appear after chloride anions Cl^? are added to the solution. The absorption spectrum becomes more complex when ICl is dissolved in an alkaline medium. The band belonging to molecular iodine emerges in the spectra at low alkali concentrations, while being transformed to other shorter-wavelength bands at high alkali concentrations (рН ≥ 12).     

The reaction of iodine monochloride and monobromide with tetraorganotins

The reactions of iodine monochloride and iodine monobromide with a tetraalkyltin (butyl) and a tetraaryltin (phenyl) have been studied with a view to establishing their utility as routes to organotin chlorides and bromides respectively. Rapid high yield syntheses of the triorganotin bromides, diorganotin dichlorides and trialkyltin chloride were achieved. Some further suggestions are made on the mechanism of interhalogen fission of tincarbon bonds.     

Charge transfer complexes of N-substituted 2-pyrrolidinones

The complex formation of 1-ethyl-2-pyrrolidinone, 1-benzyl-2-pyrrolidinone and 1-phenyl-2-pyrrolidinone with iodine, iodine monobromide and iodine monochloride has been studied by u.v. and visible spectroscopic methods in carbon tetrachloride, dichloromethane, 1,2-dichloroethane, n-heptane and cyclohexane. The results show the equilibrium constants (K), complexation enthalpies (ΔH) and the wavelengths of maximum absorption bands (λ_max) of the complexes to vary markedly with the solvent. The decrease in the K values with increasing acceptor number (AN) of the solvent may be due to the competition of the solvent and the halogen molecule for the amide; for halogenated hydrocarbon solvents can act as weak electron acceptors. The complex formation ability of the electron donors decreases in the order 1-ethyl-2-pyrrolidinone ⪢ 1-benzyl-2-pyrrolidinone ⪢ 1-phenyl-2-pyrrolidinone, and the electron acceptor properties decrease in the order iodine monochloride ⪢ iodine monobromide ⪢ iodine.     

Volumetric studies in oxidation-reduction reactions : Oxidation with sodium hypochlorite iodine monochloride method

Alkaline sodium hypochlorite was used as an oxidant to determine arsenious oxide, hydrazine sulphate, ferrous ammonium sulphate, stannous chloride, sodium sulphite, potassium iodide, mercurous chloride, thallous chloride and tartar emetic, by a volumetric method, using iodine monochloride as catalyst and preoxidizer. During these titrations, the normality of the solution with respect to hydrochloric acid was kept between 5N and 7N, Chloroform was used as an indicator. Its pink colour due to the liberation of iodine during the titration turns very pale yellow at the end-point because of the formation of iodine monochloride     

Synthesis of some 3,6-disubstituted pyridazines

Some novel 3-halo-6-(4-substituted-phenoxy)pyridazines and 3,6-di-(4-substituted-phenoxy)pyridazines were synthesized from 3,6-dichloropyridazine or 3,6-diiodopyridazine. 3,6-Diiodopyridazine was prepared from 3,6-dichloropyridazine using hydriodic acid/iodine monochloride.