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.     

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:

     

4.

Sur la thermogravimétrie des précipités analytiques : Dosage de L'ammonium     

Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

The temperature of 110° C is quite suitable for drying ammonium chloride, prior to weighing. If the residual platinum from the pyrolysis of ammonium chloroplatinate is weighed it. is necessary to ignite, either between 407° and 538° C, or above 811° C.     

5.

Sur la thermogravimétrie des précipites analytiques : Dosage du strontium     

Clément Duval 《Analytica chimica acta》1947

By means of the CHEVENARD thermobalance, the authors have traced the curve of pyrolysis of the following strontium compounds; sulphate, fluoride, iodate, arsenate, carbonate, chromate, oxalate and tartrate. They have determined the temperatures at which the dissociation of the sulphate and chromate begins to occur. They recommend as excellent the weighing of strontium in the form of the iodate and para periodate.     

6.

Sur la thermogravimétrie des précipités analytiques: Dosage du thallium     

Simonne Peltier  Clément Duval 《Analytica chimica acta》1948

With the help of the chevenard thermobalance the authors have established the following limits for drying or ashing, of thallium derivatives before weighing. Trioxide prepared chemically: 126° to 230°; trioxide prepared electrolytically: 156° to 283°; chloride: 56° to 425°; iodide. 70° to473°; sulphate : 92° to 355°; luteocobaltic thalliumchloride :50° to 210°; chromate : 97° to 745°; hexachloroplatinate: 65° to 155°; thionalide complex: 69° to 156°; mercaptobenzothiazole complex: 52° to 217°.The two trioxides which have been prepared show signs of a transitory formation of 3Tl₂O₃.Tl₂O on heating, but above 600° they behave differently. The chemically prepared trioxide shows two ranges of thermal stability.     

7.

Sur la thermogravimétrie des précipités analytiques : Dosage du zirconium     

Clément Duval 《Analytica chimica acta》1951

With the help of the chevenard thermobalance, the authors have traced and examined the thermolysis curves of the precipitates proposed for the determination of zirconium. The methods in which picric acid, potassium iodate, ammonium arsenate and oxine are used, have been rejected; those in which ammonia, aniline, diethylaniline and in particular mandelic acid are used, are recommended for the automatic determination of zirconium. Zirconium hydroxide can be prepared in a pure state by means of aniline, while various other reagents smoothly afford zirconyl hydroxide. The problem of reduction of zirconium by pyrolysis of its arsenic(V) derivatives has been posed but not solved.     

8.

Sur la thermogravimétrie des précipités analytiques: Dosage du chrome     

Clément Duval 《Analytica chimica acta》1949

By means of the CHEVENARD thermobalance, the precipitates used for the determination of chromium have been investigated and the following limits of temperature established:

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°

     

9.

Sur la thermogravimétrie des précipités analytiques : Dosage du sodium     

Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

This thermogravimetric study has enabled the authors to specify a large number of points of detail in connection with the correct determination of sodium. Their attention has been particularly directed to the triple acetates, which they recommend should be weighed only in the form of pyro-uranates. The method of ball, less classical than the others, would merit greater attention on the part of analysts.     

10.

Sur la thermogravimétrie des précipités analytiques : Dosage du Potassium     

Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

The authors have studied the pyrolysis of 10 compounds of potassium and defined the limits of temperature between which they must dried in order to be determined accurately by weighing. Apart from the hexanitritocobaltate, the use of which is restricted to volumetric and coloimetric analysis, it can be said that the 9 other salts examined are well suited to the determination of potassium, the hydrontertrate, used within the limits prescribed by the authors, merits special attention.     

11.

Sur la thermogravimétrie des précipités analytiques : Dosage du bismuth     

Clément Duval 《Analytica chimica acta》1951

With the help of the CHEVENARD thermobalance, the authors have traced the 36 pyrolysis curves of the precipitates used for the gravimetric determination of bismuth. They have retained 15 methods suitable for the automatic determination. In particular, they recommend the methods using thionalide, phenyldithiobiazolonethiol, and phenylaisonic acid. A critical examination of the methods selected for the gravimetric determination of bismuth seems to show that MAJUMDAR's phenyldithiobiazolonethiol is the best available at present. The authors suggest the rejection (because constant weight is not reached, or because quantitative precipitation does not occur, or because the formula of the compounds formed does not tally with the one presumed) of the precipitation methods using glucose, hypophosphorous acid, iodic acid, hydrogen sulphide, sodium thiosulphate, potassium bichromate, ammonium molybdate, potassium chromic thiocyanate, hexamethylenetetramine, pyrogallol, gallic acid, oxine, antipyrine-methyleneamine, and α-naphthoquinoline.     

12.

Sur la thermogravimétrie des précipités analytiques : Dosage du zinc     

Monique De Clerq  Clément Duval 《Analytica chimica acta》1951

With the help of the CHEVENARD thermobalance, the authors have traced the pyrolysis curves of the precipitates which serve for the gravimetric determination of zinc. In the table, the temperature limits and the forms in which the precipitates are weighed, are listed. Eight new reagents for the automatic determination of zinc are included in the table.     

13.

Sur la thermogravimétrie des précipités analytiques: Dosage du platine     

Pierre Champ  Pierre Fauconnier  Clément Duval 《Analytica chimica acta》1954

The authors have studied the thermogravimetric curves of precipitates proposed for the determination of platinum. This precipitated metal is, like gold, sometimes oxidisable, sometimes deposited at constant weight. Bivalent platinum thiophenolate, isolated by the authors, is excellently suitable for gravimetry, after which comes the weighing as platinum (II) chlorides.     

14.

Sur la thermogravimétrie des précipités analytiques : Dosage du mercure     

Clément Duval  Nguyen Dat Xuong 《Analytica chimica acta》1951

With the help of the CHEVENARD thermobalance, the authors have traced the pyrolysis curves of the precipitates which are used for the gravimetric determination of mercury. The methods in which a period?ate, a molybdate, a vanadate, cupferron, and 2-chloro-7-methoxy-5-thiolacridine are used, have been rejected. Only four methods out of the 21 proposed for the precipitation of metallic mercury have been considered. The dissociation of mercuric nitrate has no interest from the analytical

Precipitating reagent	Form in which weighed	Temperature limits
Ammonium hydroxide (to a chromic salt)	Cr2O3	> 812°
Ammonium hydroxide (to chromic acid)	Cr2O3	> 188°
Ammoniac (gas)	Cr(OH)3	440–475°
Ammoniac (gas)	Cr2O3	> 845°
Aniline	Cr2O3	> 830°
Hydroxylamine	Cr2O3	> 850°
Thiosemicarbazide	Cr2Oa3.H2O	380–410°
Thiosemicarbazide	Cr2O3	> 475°
Potassium cyanate	Cr2O3.H2O	320–370°
Potassium cyanate	Cr2O3	> 473°
Ammonium nitrite	Cr2O3	> 880°
Potassium iodo-iodate	Cr2O3	> 850°
Disodium phosphate	CrPO4	> 946°
Silver nitrate	Ag2CrO4	92–812°
Mercurous nitrate	Hg2CrO4	82–256°
Mercurous nitrate	Cr2O3	> 671°
Barium nitrate	BaCrO4	< 60°
Lead nitrate	PbCrO4	91–904°
8-Hydroxyquinoline	Cr(C9H6ON)3	70–156°
8-Hydroxyquinoline	Cr2O3	> 500°

     

15.

Sur la thermogravimétrie des précipités analytiques : Dosage du Lithium     

Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

The four salts normally used for the gravimetric determination of lithium have been submitted to pyrolysis with the aid of the chevenard thermobalance. To obtain correct results it is necessary to heat the chloride between 175° C, and 606° C, the sulphate above 160°, the phosphate above 450° C, and the aluminate above 471°.     

16.

Sur la thermogravimétrie des précipités analytiques: Dosage du lanthane     

Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

The three gravimetric methods so far proposed for the determination of lanthanum have been tried out experimentally. The oxide prepared from the hydroxide must be heated to at least 944° and that obtained from the oxalate at not less than 876°. The basic carbonate reaches almost constant weight between 700° and 800°. Finally the oxinate should be kept at 130°.     

17.

Sur la thermogravimétrie des précipités analytiques: Dosage du hafnium     

Annie Dautel  Clément Duval 《Analytica chimica acta》1959

A zirconium-free oxychloride of hafnium was prepared. The hafnium can be determined gravimetrically from the thermolysis curves of the precipitate. In particular, the neutral selenate, the p-hydroxyphenylarsinate and the mandelate were studied, and the curves obtained were compared to those plotted of the homologous zirconium derivatives.     

18.

Sur la thermogravimétrie des précipités analytiques : Dosage du samarium     

Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

In the gravimetric determination of samarium, it is necessary to ignite the hydroxide above 813° and the oxalate above 800° in order to ensure complete transformation to the oxide Sm₂O₃ .     

19.

Sur la thermogravimétrie des précipités analytiques : Dosage du rhodium     

Clément Du Val  Pierre Champ  Pierre Fauconnier 《Analytica chimica acta》1955

The authors show that rhodium is not so easily oxidized, as one has up to now supposed. It is possible to weigh the metal up to 550°. They propose 2 new forms of weighing with the help of the internal complexes which can be formed with thionalide and mercapto-2-benzoxazole.     

20.

Sur la thermogravimétrie des précipités analytiques: Dosage du calcium     

Clément Duval 《Analytica chimica acta》1947

With the object of determining the best conditions of temperature to be used by the analyst for weighing to constant weight precipitates containing calcium, the authors made a detailed study of the curves of pyrolysis which they have recorded by means of the Chevenard thermobalance. The following were studied : oxalate, carbonate, oxide, precipitated sulphate and gypsum, fluoride, iodate, arsenate, molybdate, tungstate, nickel-hexanitrite, tartrate, 8-hydroxyquinolate, and picrolonate. They suggest a rapid method for the analysis of the sulphate and carbonate of calcium in gypsum, a. new gravimetric determination by electrolysis of nickel-hexanitrite of calcium-potassium, of which the structural formula has been established. Finally, they recommend, in the case of precipitation of calcium as the tartrate, weighing as carbonate rather than oxide.     

Réactif précipitant	Forme de pesée	Limites de température
Electrolyse	Hg	<70°
Zinc + Iodure de potassium	Hg	<72°
Hydrazine	Hg	<55°
Acide hypophosphoreux	Hg	<71°
Acide nitrique	HgO	100°–200°
Acide chlorhydrique	Cl2Hg2	<130°
*Iodure de potassium	I2Hg	45°–88°
*Iodate de potassium	(IO3)2Hg2	<175°
Periodate de potassium	(IO3)2Hg2	<175°
Sulfure d'ammonium	SHg	<109°
*Thiosulfate de sodium	SHg	75–220°
Arséniate disodique	(AsO4)2Hg3	45–418°
*Thiocyanate de cobalt	[Hg(SCN)4]Co	50–200°
Thiocyanate de zinc	[Hg(SCN)4]Zn	<270°
*Chromate de potassium	CrO4Hg2	52–256°
Chromate de potassium ammoniacal	CrO4Hg2	52–256°
*Bichromate d 'ammonium + Pyridine	Cr2O7[Hg(C5H5N)2]	56–66°
*Sel de Reinecke	[Cr(CNS)4(NH3)2]2Hg	77–158°
Molybdate alcalin	[Cr(CNS)4(NH3)2]2Hg	77–158°
Tungstate alcalin	WO3	>880°
Vanadate alcalin	WO3	>880°
Iodure de cadmium ammoniacal	(HgI3)2[Cd(NH3)4]	<69°
Iodure de potassium + Sulfate de cuivre + Ethylène diamine	[HgI4][Cu En2]	à 20°
*Iodure de potassium + Sulfate de cuivre + Propylène diamine	[HgI4][Cu Pn2]	<157°
Acide oxalique	C2O4Hg2	<100°
Anthranilate de sodium	(C6H6O2N)2Hg	<113°
Pyridine	Cl2Hg(C5H5N)	<113°
Dithiane	Cl2Hg.C4H8S2	<97°
*Chlorure de cuivre-biguanide + iodure de potassium	[HgI4][Cu(C2N5H7)2]	60–175°
Cupferron	[HgI4][Cu(C2N5H7)2]	60–175°
*Thionalide	(C12H10ONS)2Hg	90–169°
Chloro-2 méthoxy-7 thiol-5 acridine	(C12H10ONS)2Hg	90–169°

Sur la thermogravimétrie des précipités analytiques : Dosage de L'ammonium

The temperature of 110° C is quite suitable for drying ammonium chloride, prior to weighing. If the residual platinum from the pyrolysis of ammonium chloroplatinate is weighed it. is necessary to ignite, either between 407° and 538° C, or above 811° C.     

Sur la thermogravimétrie des précipites analytiques : Dosage du strontium

By means of the CHEVENARD thermobalance, the authors have traced the curve of pyrolysis of the following strontium compounds; sulphate, fluoride, iodate, arsenate, carbonate, chromate, oxalate and tartrate. They have determined the temperatures at which the dissociation of the sulphate and chromate begins to occur. They recommend as excellent the weighing of strontium in the form of the iodate and para periodate.     

Sur la thermogravimétrie des précipités analytiques: Dosage du thallium

With the help of the chevenard thermobalance the authors have established the following limits for drying or ashing, of thallium derivatives before weighing. Trioxide prepared chemically: 126° to 230°; trioxide prepared electrolytically: 156° to 283°; chloride: 56° to 425°; iodide. 70° to473°; sulphate : 92° to 355°; luteocobaltic thalliumchloride :50° to 210°; chromate : 97° to 745°; hexachloroplatinate: 65° to 155°; thionalide complex: 69° to 156°; mercaptobenzothiazole complex: 52° to 217°.The two trioxides which have been prepared show signs of a transitory formation of 3Tl₂O₃.Tl₂O on heating, but above 600° they behave differently. The chemically prepared trioxide shows two ranges of thermal stability.     

Sur la thermogravimétrie des précipités analytiques : Dosage du zirconium

With the help of the chevenard thermobalance, the authors have traced and examined the thermolysis curves of the precipitates proposed for the determination of zirconium. The methods in which picric acid, potassium iodate, ammonium arsenate and oxine are used, have been rejected; those in which ammonia, aniline, diethylaniline and in particular mandelic acid are used, are recommended for the automatic determination of zirconium. Zirconium hydroxide can be prepared in a pure state by means of aniline, while various other reagents smoothly afford zirconyl hydroxide. The problem of reduction of zirconium by pyrolysis of its arsenic(V) derivatives has been posed but not solved.     

Sur la thermogravimétrie des précipités analytiques: Dosage du chrome

By means of the CHEVENARD thermobalance, the precipitates used for the determination of chromium have been investigated and the following limits of temperature established:

Sur la thermogravimétrie des précipités analytiques : Dosage du sodium

This thermogravimetric study has enabled the authors to specify a large number of points of detail in connection with the correct determination of sodium. Their attention has been particularly directed to the triple acetates, which they recommend should be weighed only in the form of pyro-uranates. The method of ball, less classical than the others, would merit greater attention on the part of analysts.     

Sur la thermogravimétrie des précipités analytiques : Dosage du Potassium

The authors have studied the pyrolysis of 10 compounds of potassium and defined the limits of temperature between which they must dried in order to be determined accurately by weighing. Apart from the hexanitritocobaltate, the use of which is restricted to volumetric and coloimetric analysis, it can be said that the 9 other salts examined are well suited to the determination of potassium, the hydrontertrate, used within the limits prescribed by the authors, merits special attention.     

Sur la thermogravimétrie des précipités analytiques : Dosage du bismuth

With the help of the CHEVENARD thermobalance, the authors have traced the 36 pyrolysis curves of the precipitates used for the gravimetric determination of bismuth. They have retained 15 methods suitable for the automatic determination. In particular, they recommend the methods using thionalide, phenyldithiobiazolonethiol, and phenylaisonic acid. A critical examination of the methods selected for the gravimetric determination of bismuth seems to show that MAJUMDAR's phenyldithiobiazolonethiol is the best available at present. The authors suggest the rejection (because constant weight is not reached, or because quantitative precipitation does not occur, or because the formula of the compounds formed does not tally with the one presumed) of the precipitation methods using glucose, hypophosphorous acid, iodic acid, hydrogen sulphide, sodium thiosulphate, potassium bichromate, ammonium molybdate, potassium chromic thiocyanate, hexamethylenetetramine, pyrogallol, gallic acid, oxine, antipyrine-methyleneamine, and α-naphthoquinoline.     

Sur la thermogravimétrie des précipités analytiques : Dosage du zinc

With the help of the CHEVENARD thermobalance, the authors have traced the pyrolysis curves of the precipitates which serve for the gravimetric determination of zinc. In the table, the temperature limits and the forms in which the precipitates are weighed, are listed. Eight new reagents for the automatic determination of zinc are included in the table.     

Sur la thermogravimétrie des précipités analytiques: Dosage du platine

The authors have studied the thermogravimetric curves of precipitates proposed for the determination of platinum. This precipitated metal is, like gold, sometimes oxidisable, sometimes deposited at constant weight. Bivalent platinum thiophenolate, isolated by the authors, is excellently suitable for gravimetry, after which comes the weighing as platinum (II) chlorides.     

Sur la thermogravimétrie des précipités analytiques : Dosage du mercure

With the help of the CHEVENARD thermobalance, the authors have traced the pyrolysis curves of the precipitates which are used for the gravimetric determination of mercury. The methods in which a period?ate, a molybdate, a vanadate, cupferron, and 2-chloro-7-methoxy-5-thiolacridine are used, have been rejected. Only four methods out of the 21 proposed for the precipitation of metallic mercury have been considered. The dissociation of mercuric nitrate has no interest from the analytical

Sur la thermogravimétrie des précipités analytiques : Dosage du Lithium

The four salts normally used for the gravimetric determination of lithium have been submitted to pyrolysis with the aid of the chevenard thermobalance. To obtain correct results it is necessary to heat the chloride between 175° C, and 606° C, the sulphate above 160°, the phosphate above 450° C, and the aluminate above 471°.     

Sur la thermogravimétrie des précipités analytiques: Dosage du lanthane

The three gravimetric methods so far proposed for the determination of lanthanum have been tried out experimentally. The oxide prepared from the hydroxide must be heated to at least 944° and that obtained from the oxalate at not less than 876°. The basic carbonate reaches almost constant weight between 700° and 800°. Finally the oxinate should be kept at 130°.     

Sur la thermogravimétrie des précipités analytiques: Dosage du hafnium

A zirconium-free oxychloride of hafnium was prepared. The hafnium can be determined gravimetrically from the thermolysis curves of the precipitate. In particular, the neutral selenate, the p-hydroxyphenylarsinate and the mandelate were studied, and the curves obtained were compared to those plotted of the homologous zirconium derivatives.     

Sur la thermogravimétrie des précipités analytiques : Dosage du samarium

In the gravimetric determination of samarium, it is necessary to ignite the hydroxide above 813° and the oxalate above 800° in order to ensure complete transformation to the oxide Sm₂O₃ .     

Sur la thermogravimétrie des précipités analytiques : Dosage du rhodium

The authors show that rhodium is not so easily oxidized, as one has up to now supposed. It is possible to weigh the metal up to 550°. They propose 2 new forms of weighing with the help of the internal complexes which can be formed with thionalide and mercapto-2-benzoxazole.     

Sur la thermogravimétrie des précipités analytiques: Dosage du calcium

With the object of determining the best conditions of temperature to be used by the analyst for weighing to constant weight precipitates containing calcium, the authors made a detailed study of the curves of pyrolysis which they have recorded by means of the Chevenard thermobalance. The following were studied : oxalate, carbonate, oxide, precipitated sulphate and gypsum, fluoride, iodate, arsenate, molybdate, tungstate, nickel-hexanitrite, tartrate, 8-hydroxyquinolate, and picrolonate. They suggest a rapid method for the analysis of the sulphate and carbonate of calcium in gypsum, a. new gravimetric determination by electrolysis of nickel-hexanitrite of calcium-potassium, of which the structural formula has been established. Finally, they recommend, in the case of precipitation of calcium as the tartrate, weighing as carbonate rather than oxide.