Dosages en analyse minérale par extraction à l'aide de cations colorés : Dosages par extraction à l'aide de colorants basiques c. dosage de traces de phosphate par la safranine

An extraction method is described for the determination of traces of phosphate in the form of phosphomolybdate, in which safranine is used as complexing agent.     

Dosages en analyse minérale par extraction à l'aide de cations colorés: Dosages par extraction a l'aide de colorants basiques b. dosage de traces d'étain par le violet cristallisé

An extraction method is described for the determination of traces of tin in which crystal violet is used as complexing agent.     

Dosages en analyse minérale par extraction à l'aide de cations colorés : Dosages par extraction a l'aide de colorants basiques d. dosage de traces de sulfate par le bleu de méthylène

A method is described for the determination of traces of sulphate. By means of an exchange resin the sulphate ions are exchanged with an equivalent amount of thiocyanate ions and these are determined by the extraction method using methylene blue as complexing agent.     

Utilisation de l'acide phénylarsonique en turbidimétrie: Dosage du tantale

A turbidimetric method is described for the determination of tantalum with phenylarsonic acid. The method is fast and rarely requires preliminary separation. The only interfering elements are zirconium and niobium when present in molar ratios greater than Nb : Ta = 1 and Zr : Ta = 5.     

Contribution a l'étude de la standardisation des solutions acides normales: Utilisation de l'hydrogénocarbonate de sodium comme substance de référence

Experiments have shown that it is not advisable to use the crude product of the calcination of sodium bicarbonate as a standardization substance in acidimetry.     

Introduction á l'étude des sels basiques insolubles: Généralités sur la définition et l'étude des sels basiques. Détermination de l'indice de basicité d'un sel basique insoluble

In the course of this study, it has been attempted to give a precise definition of basic salts. These salts must be difterentiated from the adsorption compounds and even from the neutral salts correspondmg to an acid of which all the acidic functions have not been demonstrated.After havmg reviewed the principal techniques used up to now a potentiometric method is proposed, permitting the rapid determination of the basicity index of an insoluble basic salt. It consists, in principle, in precipitating the salt with an alkali hydroxide and deteminining the pH in the course of precipitation,Two measurements suffice theoretically to obtain the constitution of the salt studied.     

Propriétés des oxinates d'aluminium,de gallium et d'Indium.: Séparation du gallium par extraction par le chloroforme

A study has been made of the solubility in water as a function of pH of oxine and of the oxinatus of aluminium, gallium and indium, as well as their solubility in chloroform.The curves showing the partition between chloroform and water as a function of pu have been established.Gallium can be separated, from aluminium by extraction of the oxinate al pH₂O. It is possible by this means to separate one part of gallium from 10¹ parts of aluminium. The formation of the oxinates serves as a basis of an acidimetric determination of the ions Al⁺³, Ga⁺³ and In⁺³.     

Dosages coulométriques à courant constant et en solution non agitée

Accurate evalution of “transition times” occurring during constant current electrolysis in non-stirred media may be used analytically. An apparatus has been devised for such a purpose.The method has been applied to various practical problems and stress is laid on its potentialities and main features.Under favourable conditions, determinations are performed in less than one minute, with an accuracy of about 0.2%.     

Spectres d'absorption détectés par effet photoacoustique en infrarouge par transformée de Fourier—applications à quelques médicaments

Photoacoustic detection in Fourier transform i.r. spectrometry has led to spectra obtained without sample preparation. This fact may be a very important advantage in biological applications, but these spectra are not directly in good agreement with transmission spectra. In the present work a simple mathematical correction treatment is presented which is in accord with the theory of the photoacoustic effect. This correction routine is applied to some drugs in view of a possible application to direct identification in pharmaceutical preparations.     

Sur la thermogravimétrie des précipités analytiques : Dosage de l'yttrium

The thermolysis curves of yttrium hydroxide and oxalate are described.     

Sur la thermogravimétrie des précipités analytiques: Dosage de l'uranium

A study has been made of the gravimetric methods for the determination of 4- and 6-valent uranium and two new forms of weighing are suggested, as oxalate and anhydrous oxmate. The following table summarizes the temperature limits, determined by means of the Chevenard thermobalance, for various precipitates:

     

13.

Sur la thermogravimétrie des précipités analytiques: Dosage de l'lridium     

Clément Duval  Pierre Champ  Pierre Fauconnier 《Analytica chimica acta》1959

Thermolysis curves have been recorded of precipitates containing iridium, obtained with formic acid, 2-mercapto-benzothiazole and sodium sulphide respectively.     

14.

Séparation des traces de bore par extraction du fluoborate de tétraphénylarsonium     

J. Coursier  J. Huré  R. Platzer 《Analytica chimica acta》1955

     

15.

Hydrogénation du dioxyde de carbone en méthanol en présence de catalyseurs à base de molybdène     

《Comptes Rendus de l''Academie des Sciences Series IIB Mechanics Physics Astronomy》1999,2(3):167-174

     

16.

Séparation des isoméres de l'hexachlorocyclohexane par chromatographie en phase gaz     

C.L. Guillemin 《Analytica chimica acta》1962

Hexachlorocyclohexane isomers can be separated by a glass bead technique with polypropylene glycol Niax 1025 as the stationary phase. The principal isomers separated are the γ-hexachloro-cyclohexane (Lindane isomer), the α, β, ε, and δ isomers and γ-heptachlorocyclohexane. The life of the glass bead column is short — about 20 days in constant use. A longer column life can be obtained by pretreatment of the glass beads.     

17.

Amélioration de la tenue à la corrosion atmosphérique de matériaux utilisés en connectique (nickel doré). Traitements de surface par implantations d'ions     

《Comptes Rendus de l''Academie des Sciences Series IIB Mechanics Physics Astronomy》2000,3(5):365-371

Improvement of the atmospheric corrosion resistance of materials used in connectics. Surface treatments by ion implantation. Tests of corrosion of a material, constituted of brass covered with an electrochemical nickel coating (thickness ≈ 5 μm) and with a gold coating (thickness ≈ 0.4 μm or ≈ 1 μm), used in electrical contact applications, have been carried out in humid synthetic air with low contents of NO₂ (0.2 vpm), SO₂ (0.2 vpm) and Cl₂ (0.01 vpm). The results obtained show that the corrosion products are well localised on the surface. The aggregates formed are principally constituted of basic nitrate, sulphate and chloride of nickel and zinc. These studies showed that the corrosion of the material is due to the presence of porosities in the gold and nickel layers. X-ray analysis (SEM/EDS) revealed the presence of carbon in these porosities, probably related to the presence of organic compounds in the electrolytic coating baths. During the galvanic corrosion of nickel and zinc, the carbon is rejected to the periphery of the aggregates. The amount of carbon was determined by Van De Graaff analysis, by (d,p) nuclear reaction. Some treatments of the material by ion implantation (titanium or titanium and nitrogen or helium) have been realised in order to suppress the porosities of the gold layer. These treatments lead to a remarkable improvement of the corrosion resistance of the material. © 2000 Académie des sciences / Éditions scientifiques et médicales Elsevier SASatmospheric corrosion / nickel / brass / gold coating / ion implantation     

18.

Développement par déplacement sur échangeurs d'ions : Cas de la séparation de deux ions     

J. Coursier  J. Hure 《Analytica chimica acta》1958

In the case of ion exchange Chromatography it is possible to forecast, from the equilibrium constants, the phenomena that occur in frontal analysis of two ions.With the results obtained the separation of two compounds by displacement development can be predicted. In particular it is possible to calculate the minimum distance that a band must travel to obtain a separation of the solutes in zones.The method has been applied to the separation of sodium and potassium ions with the resin Dowex-50, using calcium ions as the developer.     

19.

Étude par chromatographie en phase gazeuse de nouveaux composés cristaux liquides nématiques à chaîne latérale     

《Comptes Rendus Chimie》2002,5(8-9):591-598

The analytic performances of three stationary phases ‘liquid crystal’ to side chain have been presented. Mesogenic compounds studied in this work are:– 3-CH₃: 2-(3-methylbenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene;– 4-CH₃: 2-(4-methylbenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene;– 3-Cl : 2-(3-chlorobenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene.The originality of these three compounds is essentially due to the presence of a substituted benzyloxy group, more voluminous, which is close to the n-hexyloxy flexible chain. Retention properties of these new liquid crystals have been characterised by the capillary column treated and impregnated according to the dynamic method. The position, ortho or para, of the methyl group on benzyloxy does not interfere significantly on the retention mechanism. In the case of the replacement of the methyl group by a halogen atom (chlorine), we noticed a radical change of the retention properties.     

20.

Séparation et dosage de traces de bore dans le silicium: Application de la méthode d'extraction chloroformique sous forme de fluoborate de tétraphénylarsonium     

L. Ducret  P. Seguin 《Analytica chimica acta》1957

     

Precipitating reagent	Form in which weighed	Temperature limits
Ammonium hydroxide	UO3	480–610°
Ammonium hydroxide	U3O8	745–946°
Ammoniac (gas)	U3O8	675–946°
Pyridine	U3O8	745–946°
Ammonium benzoate	U3O8	691–946°
Hexamethylenetetramine	U3O8	745–946°
Tannin	U3O8	570–878°
Hydrogen peroxide	U3O8	811–946°
Hydrofluoric acid	U3O8	811–946°
Ammonium sulphate	U3O8	850–946°
Disodium phosphate	U2P2O11	673–946°
Oxalic acid	U(C2O4)2	100–180°
Oxalic acid	U3O8	700–946°
Cupferron	U3O8	800–946°
β-Isatoxime	U3O8	408–946°
8-Hydroxyquinoline	HUO2(C9H6ON)3	< I57°
8-Hydroxyquinoline	UO2(C9H6ON)2	252–346°
Quinaldinic acid	U3O8	610–946°

Sur la thermogravimétrie des précipités analytiques: Dosage de l'lridium

Thermolysis curves have been recorded of precipitates containing iridium, obtained with formic acid, 2-mercapto-benzothiazole and sodium sulphide respectively.     

Séparation des isoméres de l'hexachlorocyclohexane par chromatographie en phase gaz

Hexachlorocyclohexane isomers can be separated by a glass bead technique with polypropylene glycol Niax 1025 as the stationary phase. The principal isomers separated are the γ-hexachloro-cyclohexane (Lindane isomer), the α, β, ε, and δ isomers and γ-heptachlorocyclohexane. The life of the glass bead column is short — about 20 days in constant use. A longer column life can be obtained by pretreatment of the glass beads.     

Amélioration de la tenue à la corrosion atmosphérique de matériaux utilisés en connectique (nickel doré). Traitements de surface par implantations d'ions

Improvement of the atmospheric corrosion resistance of materials used in connectics. Surface treatments by ion implantation. Tests of corrosion of a material, constituted of brass covered with an electrochemical nickel coating (thickness ≈ 5 μm) and with a gold coating (thickness ≈ 0.4 μm or ≈ 1 μm), used in electrical contact applications, have been carried out in humid synthetic air with low contents of NO₂ (0.2 vpm), SO₂ (0.2 vpm) and Cl₂ (0.01 vpm). The results obtained show that the corrosion products are well localised on the surface. The aggregates formed are principally constituted of basic nitrate, sulphate and chloride of nickel and zinc. These studies showed that the corrosion of the material is due to the presence of porosities in the gold and nickel layers. X-ray analysis (SEM/EDS) revealed the presence of carbon in these porosities, probably related to the presence of organic compounds in the electrolytic coating baths. During the galvanic corrosion of nickel and zinc, the carbon is rejected to the periphery of the aggregates. The amount of carbon was determined by Van De Graaff analysis, by (d,p) nuclear reaction. Some treatments of the material by ion implantation (titanium or titanium and nitrogen or helium) have been realised in order to suppress the porosities of the gold layer. These treatments lead to a remarkable improvement of the corrosion resistance of the material. © 2000 Académie des sciences / Éditions scientifiques et médicales Elsevier SASatmospheric corrosion / nickel / brass / gold coating / ion implantation     

Développement par déplacement sur échangeurs d'ions : Cas de la séparation de deux ions

In the case of ion exchange Chromatography it is possible to forecast, from the equilibrium constants, the phenomena that occur in frontal analysis of two ions.With the results obtained the separation of two compounds by displacement development can be predicted. In particular it is possible to calculate the minimum distance that a band must travel to obtain a separation of the solutes in zones.The method has been applied to the separation of sodium and potassium ions with the resin Dowex-50, using calcium ions as the developer.     

Étude par chromatographie en phase gazeuse de nouveaux composés cristaux liquides nématiques à chaîne latérale

The analytic performances of three stationary phases ‘liquid crystal’ to side chain have been presented. Mesogenic compounds studied in this work are:– 3-CH₃: 2-(3-methylbenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene;– 4-CH₃: 2-(4-methylbenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene;– 3-Cl : 2-(3-chlorobenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene.The originality of these three compounds is essentially due to the presence of a substituted benzyloxy group, more voluminous, which is close to the n-hexyloxy flexible chain. Retention properties of these new liquid crystals have been characterised by the capillary column treated and impregnated according to the dynamic method. The position, ortho or para, of the methyl group on benzyloxy does not interfere significantly on the retention mechanism. In the case of the replacement of the methyl group by a halogen atom (chlorine), we noticed a radical change of the retention properties.