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 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 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

     

4.

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°.     

5.

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°.     

6.

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.     

7.

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.     

8.

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.     

9.

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.     

10.

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.     

11.

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:

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°

     

12.

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 .     

13.

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.     

14.

Sur la thermogravimétrie des précipités analytiques : Dosage du gallium     

Thérése Dupuis  Clḿent Duval 《Analytica chimica acta》1949

With the help of the Chcvcnard thcrmobalancc the authors have determined the minimum temperatures necessary for quantitatively converting the derivatives of gallium into oxide Ga₂0₃.

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 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.     

16.

Sur la thermogravimétrie des précipités analytiques : Dosage du césium     

Mlle Tihérése Duval  Clément Duval 《Analytica chimica acta》1948

A new method of gravimetric determination. of cesium is described, based on weighing the residue [CoO + 3NO₃Cs] from the destruction, between 219o and 194o, of the hexanitritocobaltate. Study has also been made of the pyrolysis of the chloride, perchlorate, sulphate, hexachlorostannate and hexachloroplatinate. In each case there is specified the temperature range in which the salts should be heated in order that they may be determined correctly by weighing.     

17.

Sur la thermogravimétrie des précipités analytiques: Dosage du cérium     

Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

In order to obtain correct results in. the gravimetric determination of cerium, analysis with the help of the chevenard thermobalance has shown that it is necessary to ignite the hydroxide above 450°, the iodate at 40–45°, the sulphate between 277 and 845°, the hexacyanoferrate at 20°, the oxalate above 450° and the oxinate between 128 and 233°.     

18.

Sur la thermogravimétrie des précipités analytiques : Dosage du néodyme     

Mlle Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

In the gravimetric determination of neodymium, the hydroxide should be heated to above 608° and the oxalate decahydrate to above 813°, in order to ensure a correct weight. The anhydrous oxalate can be weighed after heating between 290° and 350°.     

19.

Sur la thermogravimétrie des précipités analytiques : Dosage du Magnésium     

Thérèse Duval  Clément Duval 《Analytica chimica acta》1948

With the aid of the thermobalance of chevenard the authors have studied the pyrolysis of the following compounds of magnesium, which have been proposed for the gravimetric determination of this element: hydroxide, fluoride, sulphate, magnesium ammonium phosphate magnesium ammonium arsenate, magnesium ammonium carbonate, oxalate and 8-hydroxy-quinolate. Brucite is compared with the artificial product. The gelatinous nature of the precipitated fluoride prevents a definite formula being assigned to it. The series of hydrates of the sulphate is compared with that produced by the aqueous route. Precipitated ammonium magnesium, carbonate has not a definite composition. The heating curve of the oxinate differs appreciably from the literature data.     

20.

Sur la thermogravimétrie des précipités analytiques: Dosage du manganèse     

Thérèse Dupuis  Jean Besson  Clément Duval 《Analytica chimica acta》1949

The pyrolysis curves given by the precipitates used in the determination of manganese have been studied. The peroxide MnO₂, rnanganous acid H₂MnO₃ and manganic oxide Mn₂O₃, have not been considered. Manganous oxide, MnO, is stable at relatively high temperatures. For the automatie determination, only the steps shown at low temperatures by the sulphate, the oxalate, tlio oxinate and the anthranilate are reeommended. According to the determination in question, the basic salt begins to form at various temperatures between 456° and 1000°.     

Hydroxide by ammonium hydroxide	408°
Hydroxide by ammonia	400°
Hydroxide by urea	475°
Hydroxide by aniline	546°
Hydroxide by sulpliitc	813°
Hydroxide by tannin	520°
Cupfcrron	745°
Camphoratc	478°
Dibromo-oxinate	817°

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 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 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 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 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 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 gallium

With the help of the Chcvcnard thcrmobalancc the authors have determined the minimum temperatures necessary for quantitatively converting the derivatives of gallium into oxide Ga₂0₃.

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.     

Sur la thermogravimétrie des précipités analytiques : Dosage du césium

A new method of gravimetric determination. of cesium is described, based on weighing the residue [CoO + 3NO₃Cs] from the destruction, between 219o and 194o, of the hexanitritocobaltate. Study has also been made of the pyrolysis of the chloride, perchlorate, sulphate, hexachlorostannate and hexachloroplatinate. In each case there is specified the temperature range in which the salts should be heated in order that they may be determined correctly by weighing.     

Sur la thermogravimétrie des précipités analytiques: Dosage du cérium

In order to obtain correct results in. the gravimetric determination of cerium, analysis with the help of the chevenard thermobalance has shown that it is necessary to ignite the hydroxide above 450°, the iodate at 40–45°, the sulphate between 277 and 845°, the hexacyanoferrate at 20°, the oxalate above 450° and the oxinate between 128 and 233°.     

Sur la thermogravimétrie des précipités analytiques : Dosage du néodyme

In the gravimetric determination of neodymium, the hydroxide should be heated to above 608° and the oxalate decahydrate to above 813°, in order to ensure a correct weight. The anhydrous oxalate can be weighed after heating between 290° and 350°.     

Sur la thermogravimétrie des précipités analytiques : Dosage du Magnésium

With the aid of the thermobalance of chevenard the authors have studied the pyrolysis of the following compounds of magnesium, which have been proposed for the gravimetric determination of this element: hydroxide, fluoride, sulphate, magnesium ammonium phosphate magnesium ammonium arsenate, magnesium ammonium carbonate, oxalate and 8-hydroxy-quinolate. Brucite is compared with the artificial product. The gelatinous nature of the precipitated fluoride prevents a definite formula being assigned to it. The series of hydrates of the sulphate is compared with that produced by the aqueous route. Precipitated ammonium magnesium, carbonate has not a definite composition. The heating curve of the oxinate differs appreciably from the literature data.     

Sur la thermogravimétrie des précipités analytiques: Dosage du manganèse

The pyrolysis curves given by the precipitates used in the determination of manganese have been studied. The peroxide MnO₂, rnanganous acid H₂MnO₃ and manganic oxide Mn₂O₃, have not been considered. Manganous oxide, MnO, is stable at relatively high temperatures. For the automatie determination, only the steps shown at low temperatures by the sulphate, the oxalate, tlio oxinate and the anthranilate are reeommended. According to the determination in question, the basic salt begins to form at various temperatures between 456° and 1000°.