Iodine monochloride as volumetric reagent

Summary Iodine monochloride is used as volumetric reagent for the determination of arsenious oxide, tartar-emetic, hydrazine sulphate, hydroquinone, sodium sulphite, stannous chloride and potassium ferrocyanide at pH 6.5 to 7.5 in sodium acetate buffered solutions. Chloroform is employed as indicator. It becomes faintly violet at the end-point due to the liberation of iodine. In case of hydroquinone the chloroform layer changes its colour from yellow to orange at the end-point.Part I: See Z. analyt. Chem. 162, 357 (1958).     

Bromine cyanide as titrimetric oxidant in non-aqueous media

Bromine cyanide has been used for the potentiometric determination of sulphide, sulphite, thiocyanate, iodide, tin(II), arsenic(III),hydrazine hydrate, phenylhydrazine, 1,1-methylphenyldrazine and chloralhydrazine in glacial acetic acid and 1 : 1 acetic acid-acetic anhydride mixture, of thiourea, ethylthiourea, isopropylthiourea, benzylthiourea, alpha-phenylthiourea and o-tolythiourea in methanol, and of sodium methyl-, ethyl-,dimethyl-, diehtyl- and isopropyldithiocarbamates in ehtanol and acetonitrile media. The behaviour of bromine cyanide in these non- aqueous solvents has been compared with its behaviour in aqueous medium and with that of iodine cyanide in these non-aqueous solvents.     

Sodium meta-vanadate as volumetric reagent: Iodine monochloride method

In hydrochloric acid medium sodium meta-vanadate was used as a volumetric reagent for the determination of copper, zinc, cobalt, mercury, and lead. Cu⁺², Zn⁺² and Co⁺²were precipitated as complex mercurythiocyanates, Hg⁺² as mercuric zinc thiocyanate and Pb⁺² as Iodide. The thiocyanates were dissolved in concentrated hydrochloric acid and titrated against standard sodium meta-vanadate solution in the presence of iodine monochloride as a pie.oxidizer and catalyst. In titration of the iodide against the meta-vanadate. it was not necessary to add iodine monochloride to the titrant because it is formed during the titration. Chloroform was used as an indicator. It was pink owing to the liberation of iodine during the titration and became pale yellow at the end-point because of the formation of iodine monochlonde.     

Diethylenetetra-ammonium sulphatocerate as volumetric reagent: Iodine monochloride method

The method of preparation of diethylenetetra-ammoniuin sulphatocerate is described. This substance has been used as an oxidant to determine potassium iodide, ferrous ammonium sulphate, arsenious oxide, stannous chloride, hydrazinc sulphate, thallous chloride. hydroquinone and potassium ferrocyanide by a volumetric method, using iodine inonochloride as catalyst and preoxidizer. During these titrations, normality of the solution with respect to hydrochloric acid has been kept at about 6N. 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.     

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.     

Potassium meta-periodate as volumetric reagent : Iodine bromide method

Potassium meta-periodate has been used as an oxidising agent in acid medium for the volumetric estimationss of potassium iodide, arsenious oxide, antimonous oxide, stannous chloride, mercurous chloride, sodium sulphite, sodium thiosulphate, sodium tetrathionate, ferrous sulphate, potassium thiocyanate, hydrazine sulphate, phenylhydrazine hydrochloride and hydroquinone by the iodine bromide method. Carbon tetrachloride is used as an indicator. It is coloured pink during the titration. and becomes colourless at the end-point due to the formation of stable iodine bromide complex IBr2-, which does not dissociate, in the presence of a large excess of bromide ion.     

Diethylenetetra-ammonium sulphatocerate as volumetric reagent: Iodine monochloride method. Indirect determinations

In presence of 4N to N hydrochloric acid, diethylenetetra-ammnonium sulphatocerate was used as a volumetric reagent to determine indirectly potassium iodate, potassium metaperiodate, potassium dichromate, potassium bromate, ceric sulphate, hydrogen peroxide, lead dioxide and chloramine-B by the iodine monochloride method. An excess of potassium iodide added to each of the substances in the acid medium was, titrated back with a standard solution of diethylene-tetra-ammonium suphatocerate. Chloroform was used as an indicator. It was coloured violet owing to the liberation of iodine during the titralion and became very pale yellow at the end-point because of the formation of iodine monochloride.     

Sodium meta-vanadate as volumetric reagent : Iodine monochloride method (Indirect determinatios)

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

N-chlorobenzamide as volumetric reagent

Summary N-Chlorobenzamide has been used as a volumetric reagent for the visual and potentiometrie determination of some common reducing agents, hydrazines, and thioureas.

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Zusammenfassung N-Chlorbenzamid wurde als volumetrisches Reagens für die visuelle und potentiometrische Bestimmung von einigen gebräuchlichen Reduktionsmitteln sowie von Hydrazin- und Thioharnstoffderivaten benutzt.

     

Sodium hypochlorite as volumetric reagent

Summary Sodium hypochlorite solution has been used as an oxidising agent for the volumetric determination of semicarbazide hydrochloride, phenylhydrazine hydrochloride, benzalazine, benzalsemicarbazone, o-chlorobenzalsemicarbazone, acetonesemicarbazone, aminoguanidine hydrochloride, thiosemicarbazide, o-hydroxy benzalsemicarbazone, 3,4-methylenedioxy benzalsemicarbazone and p-methoxy benzalsemicarbazone, using iodine monochloride as catalyst and preoxidizer. During these titrations normality of the solution with respect to hydrochloric acid has been kept between 2.0 N and 3.5 N. Chloroform is used as an indicator. It is coloured pink due to the liberation of iodine during the titration and becomes very pale yellow at the end-point owing to the formation of iodine monochloride. Each hydrazino group in these compounds is oxidised quantitatively with a four-electron change to nitrogen with sodium hypochlorite as an oxidant in hydrochloric acid solution.     

Potassium persulphate as volumetric reagent

Summary Potassium persulphate has been used as volumetric reagent for the direct determination of hydrazine sulphate, phenyl hydrazine hydrochloride, semicarbazide hydrochloride, thiosemicarbazide, acetone semicarbazone, benzal semicarbazone, benzalazine, aminoguanidine hydrochloride, 4-phenyl semicarbazide hydrochloride, ethylmethyl ketone semicarbazone and 4-hydroxy-3-methoxy benzal semicarbazone in hydrochlorid acid medium at room temperature, using iodine monochloride as a catalyst and preoxidiser. Chloroform was used as an indicator. It was coloured violet owing to the liberation of iodine during the titration and became very pale yellow at the end-point due to the formation of iodine monochloride. Normality of the solution with respect to hydrochloric acid was kept between 6.0 and 7.5 N in these redox titrations.     

Perbenzoic acid as volumetric reagent

Summary Perbenzoic acid (0.05 M) chloroform solution is used as volumetric reagent for the determination of potassium ferrocyanide, arsenious oxide, tartar emetic, sodium sulphite, stannous chloride, hydrazine sulphate and sodium thiosulphate atph 4.0 to 4.5 in sodium acetate and acetic acid buffer solutions, using iodine as catalyst and preoxidiser. Appearance of faint violet colour in chloroform layer indicates the end point in visual titrations. In potentiometric titrations bright platinum foil is used as an oxidation-reduction electrode and it is coupled with saturated calomel electrode. At the equivalence point there is a sharp jump in potential in each titration.     

Sodium hypochlorite as volumetric reagent

Summary In presence of 5 N to 6 N hydrochloric acid, ferrous ethylenediamine sulphate was used as a reducing agent to determine indirectly potassium chlorate, potassium bromate, potassium metaperiodate, potassium dichromate, potassium ferricyanide, potassium permanganate, potassium persulphate, hydrogen peroxide, ceric sulphate and chloramine-T. An excess of ferrous ethylenediamine sulphate added to each of the substances in the acid medium was titrated with a standard solution of sodium hypochlorite. Iodine monochloride was used as catalyst and preoxidizer and chloroform was used as an indicator. Chloroform was coloured violet owing to the liberation of iodine during the titration and became very pale yellow at the end-point because of the formation of iodine monochloride.Part I: See Z. analyt. Chem. 160, 429 (1958).     

Pressurometric titrations with xenon trioxide as oxidant

The reaction of XeO(3) with thirteen reducing agents was studied qualitatively. From these, Fe(II) and Ti(III) were chosen for direct titration with XeO(3) with pressurometric end-point detection. The precision was a few parts per thousand. Evidence was found for the production of oxygen during both titrations, and of hydrogen peroxide formation during the Ti(III) reaction. The Ti(III)/Xe reacting ratio was independent of the amount of Ti(III) from 35.5 to 87.7 micromole and was 5.93 +/- 0.03 instead of the expected 6.00. The ratio for the Fe(II) reaction varied from 5.85 to 5.95 over the Fe(II) range from 10.05 to 78.7 micromole. The stoichiometric ratio for the iodometric standardization of XeO(3) solutions was confirmed as 6.00.     

Trivalent molybdenum as volumetric reducing agent

Summary The purpose of the present investigation is to introduce trivalent molybdenum as a new analytical reducing agent, in hydrochloric as well as sulphuric acid media.The solution is prepared in 9N acid by electrolytic or mercuryreduction of the hexavalent form. It is preferentially stocked and used in high acid concentrations, whereby its stability in air is optimal, falling to half its titer after nearly two months. It has been tested with success as reductant for ceric, dichromate, ferric and vanadate. It has the advantage of being used in ordinary opened burettes. Titrations were followed potentiometrically in general, and alternately visually in decinormal media, whereby molybdenum blue appears at the end-point. The percentage error in fifteen discussed experiments never surpassed ±1%. Some oxidation titrations were also undertaken using iodate and bromate, with the same degree of accuracy, provided they were conducted in 6N acid. In weaker acid concentrations, equilibria were more slowly attained, with a more or less pronounced deviation, due to some oxidisability that necessitates controlled inert atmosphere.     

Iodine as a New Deoximating Agent

Iodine is found to he an effective and mild reagent for conversion of aldoximes and ketoximes to their parent carbonyl compounds.     

DMSO作为氧化剂在有机合成中的应用

简要综述了二甲亚砜作为氧化剂的合成应用在最近十几年来的研究进展。