Enthalpies of combustion of 1,2-dihydroxybenzene and of six alkylsubstituted 1,2-dihydroxybenzenes

The standard (p^o = 101.325 kPa) molar enthalpies of combustion in oxygen at 298.15 K were measured by static-bomb calorimetry and the standard molar enthalpies of sublimation at 298.15 K were measured by microcalorimetry for 1,2-dihydroxybenzene (catechol) and six alkylsubstituted catechols:

     

2.

Thermochemical properties of benzoic acid derivatives VIII. Enthalpies of combustion and formation of o-, m-, and p- t-butylbenzoic acids     

M. Colomina  P. Jiménez  R. Pérez-Ossorio  C. Turrión 《The Journal of chemical thermodynamics》1979,11(12):1179-1184

The enthalpies of formation in the crystalline state at 298.15 K of o-, m-, and p-t-butyl-benzoic acids have been determined by static-bomb calorimetry. Vapour-pressure determinations were made by the Knudsen-effusion technique and the sublimation enthalpies at the mean temperatures of the measurement ranges have been derived for the three acids. The values obtained are:

	$\text{?Δ}{}_{\mathrm{<mtext>c</mtext>}}\text{H}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{(cr)/(kJ·mol}{}^{\mathrm{?1}}\text{)}$	$\text{Δ}{}_{\mathrm{<mtext>sub</mtext>}}\text{H}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{/(kJ·mol}{}^{\mathrm{?1}}\text{)}$
Catechol	2864.5 ± 0.8	86.6 ± 1.6
3-Methylcatechol	3505.4 ± 0.5	93.2 ± 1.0
4-Methylcatechol	3504.6 ± 0.6	94.9 ± 1.0
3-isoPropylcatechol	4808.8 ± 1.1	97.8 ± 1.7
4-terButylcatechol	5461.9 ± 0.9	99.3 ± 1.4
3-Methyl-6-isopropylcatechol	5460.2 ± 0.9	96.6 ± 0.9
3,5-diterButylcatechol	8082.7 ± 1.8	100.1 ± 0.6

     

3.

Thermochemical properties of benzoic acid derivatives XI. Vapour pressures and enthalpies of sublimation and formation of the six dimethylbenzoic acids     

M. Colomina  P. Jimenez  M.V. Roux  C. Turrion 《The Journal of chemical thermodynamics》1984,16(12):1121-1127

The energies of combustion of 3,4- and 3,5-dimethylbenzoic acids have been revised by combustion calorimetry. Vapour pressures of very pure samples of the six dimethylbenzoic acids have been determined over a range of temperatures near 298 K by the Knudsen-effusion technique. From the experimental results and our previously published thermochemical quantities the following results for the six C₆H₃(CH₃)₂CO₂H isomers at 298.15 K have been derived.

	$\text{ΔH}{}_{\mathrm{f}}{}^{\mathrm{o}}\text{(c, 298.15 K)/kJ mol}{}^{\mathrm{?1}}$	$\text{ΔH}{}_{\mathrm{s}}\text{/kJ mol}{}^{\mathrm{?1}}$
o-t-butylbenzoic acid	476.2 ± 1.9	99.8 ± 0.4	(at 314.6 K)
m-t-butylbenzoic acid	504.3 ± 1.6	103.0 ± 0.5	(at 326.5 K)
p-t-butylbenzoic acid	502.9 ± 1.7	103.8 ± 0.4	(at 334.1 K)

     

4.

Spectrophotometric studies of neomycin-copper complex and determination of neomycin sulfate using an auxiliary ligand     

J.K. Agrawal  S.G. Harmalkar  R. Vijayavargiya 《Microchemical Journal》1976,21(2):202-208

Spectrophotometric investigation of the deep blue colored, water-soluble complex of

1. Stability constant and free energy of formation of Cu-NMS complex at 30 ± 1 °C

Isomer		$\text{Δ}{}_{\mathrm{<mtext>f</mtext>}}\text{H}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{(cr)}$	$\text{Δ}{}_{\mathrm{<mtext>sub</mtext>}}\text{H}{}_{\mathrm{m}}{}^{\mathrm{o}}$	$\text{Δ}{}_{\mathrm{<mtext>f</mtext>}}\text{H}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{(g)}$
	kJ·mol?1	kJ·mol?1	kJ·mol?1
2,6-	?440.7 ± 1.7	99.1 ± 0.2	?341.6 ± 1.7
2,3-	?450.4 ± 1.7	104.6 ± 0.4	?345.8 ± 1.7
2,5-	?456.1 ± 1.6	105.0 ± 0.6	?351.1 ± 1.7
2,4-	?458.5 ± 1.7	103.5 ± 0.3	?355.0 ± 1.7
3,4-	?468.8 ± 1.9	106.4 ± 0.3	?362.4 ± 1.9
3,5-	?466.8 ± 1.7	102.3 ± 0.3	?364.5 ± 1.7

     

5.

Non-bonded sulphur-sulphur interactions in 3,5-dithiaheptane and 3,6-dithiaoctane     

Margret Månsson 《The Journal of chemical thermodynamics》1974,6(12):1153-1159

Enthalpies of combustion and vaporization at 298.15 K have been measured for 3,5-dithiaheptane and 3,6-dithiaoctane. Enthalpies of formation at 298.15 K have been derived for the compounds in the liquid and gaseous states. The results are:

Method	$\text{log}\text{K}{}_{\mathrm{s}}$	ΔF (Kcal/mole)
Mukherji and Dey (4)	4.11	?5.70
Subhrana and Raghavrao (6)	4.80	?6.66

     

6.

Thermochemistry of uranium compounds V. Standard enthalpies of formation of the monouranates of lithium,potassium, and rubidium     

P.A.G O&#x;Hare  H.R Hoekstra 《The Journal of chemical thermodynamics》1974,6(12):1161-1169

Enthalpies of reaction, ΔH_r, of the monouranates of lithium, potassium, and rubidium with 1 mol dm^?3 HCl have been measured calorimetrically. From these measurements, and auxiliary determinations of the enthalpies of solution in acid of the chlorides of lithium, potassium, and rubidium and of uranyl chloride, the standard enthalpies of formation of the uranates, ΔH_f^o, have been derived. The results obtained are as follows:

	$\text{ΔH}{}_{\mathrm{f}}{}^{\mathrm{o}}\text{(l)/kJ mol}{}^{\mathrm{?1}}$	$\text{ΔH}{}_{\mathrm{f}}{}^{\mathrm{o}}\text{(g)/kJ mol}{}^{\mathrm{?1}}$
3,5-Dithiaheptane	?116.0 ± 1.5	?65.2 ± 1.5
3,6-Dithiaoctane	?142.5 ± 1.5	?83.0 ± 1.5

     

7.

Thermochemical properties of benzoic acid derivatives X. Enthalpies of combustion and formation of 2,3-, 2,4-, 2,6-, 3,4-, and 3,5-dimethoxybenzoic acids     

M. Colomina  M.V. Roux  C. Turrion 《The Journal of chemical thermodynamics》1981,13(12):1169-1173

The energies of combustion of 2,3-, 2,4-, 2,6-, 3,4-, and 3,5-dimethoxybenzoic acids have been determined by static-bomb calorimetry. The enthalpies of formation in the crystalline state at 298.15 K have been derived for these five acids. The values obtained are:

	$\text{ΔH}{}_{\mathrm{r}}\text{/kcal}{}_{\mathrm{th}}\text{mol}{}^{\mathrm{?1}}$	$\text{ΔH}{}_{\mathrm{f}}{}^{\mathrm{o}}\text{(c, 298.15 K)/kcal}{}_{\mathrm{th}}\text{mol}{}^{\mathrm{?1}}$
α-Li2UO4	?(41.77±0.02)	?(463.31±0.84)
K2UO4	?(42.07±0.05)	?(451.39±0.83)
Rb2UO4	?(41.30±0.05)	?(452.00±0.85)

     

8.

Heat capacity and thermodynamic functions of CsCrCl₃ and RbCrCl₃. Structural phase transitions     

Joaquín García  Juan Bartolomé  Domingo González  Rafael Navarro  Willem Jacobus Crama 《The Journal of chemical thermodynamics》1983,15(12):1109-1126

We present the heat capacities measured by adiabatic calorimetry from 6 to 350 K, and by differential scanning calorimetry from 300 to 500 K, of CsCrCl₃ and RbCrCl₃. A first-order transition at T_c = (171.1±0.1) K was detected for CsCrCl₃. The RbCrCl₃ showed at T_c = (193.3±0.1) K a transition with thermal hysteresis at temperatures just below the maximum. At T₁ = (440±10) K a continuous transition was also detected. Furthermore, at T_N ≈ 16 K, and for both compounds, a small bump due to magnetic long-range ordering was observed. The thermodynamic functions at 298.15 K are

	$\text{?ΔH}{}_{\mathrm{f}}{}^{\mathrm{o}}\text{(c)/kJ mol}{}^{\mathrm{?1}}$
2,3-dimethoxybenzoic acid	687.0 ± 1.4
2,4-dimethoxybenzoic acid	712.2 ± 1.4
2,6-dimethoxybenzoic acid	693.8 ± 1.4
3,4-dimethoxybenzoic acid	714.0 ± 1.4
3,5-dimethoxybenzoic acid	724.0 ± 1.5

     

9.

Thermochemical studies of three bis(O-alkyl-N-benzoylthiocarbamato)nickel(II) complexes     

《The Journal of chemical thermodynamics》2004,36(8):627-631

     

10.

Standard enthalpy of solution and formation of cesium chromate. Derived thermodynamic properties of the aqueous chromate,bichromate, and dichromate ions,alkali metal and alkaline earth chromates,and lead chromate     

P.A.G. O&#x;Hare  Juliana Boerio 《The Journal of chemical thermodynamics》1975,7(12):1195-1204

Calorimetric measurements of the enthalpy of solution of cesium chromate gave ΔH_soln = (7622 ± 24) cal_th mol^?1 for a dilution of Cs₂CrO₄·21128H₂O. This result, along with the enthalpy of dilution gave the standard enthalpy of solution, ΔH_soln^o = (7512 ± 31) cal_th mol^?1, whence the standard enthalpy of formation, ΔH_f⁰(Cs₂CrO₄, c, 298.15 K), was calculated to be ?(341.78 ± 0.46) kcal_th mol^?1. Recomputed thermodynamic data for the formation of the other alkali metal chromates have been tabulated. From their solubilities and enthalpies of solution, the standard entropies, S⁰(298 K), of BaCrO₄ and PbCrO₄ were estimated to be (38.9 ± 0.9) and (43.7 ± 1.2) cal_th K^?1 mol^?1, respectively. There is evidence that ΔH_f⁰(SrCrO₄, c, 298.15 K) may be in error. Thermochemical, solubility, and equilibrium data, have been combined to update the thermodynamic properties of the aqueous chromate (CrO₄^2?), bichromate (HCrO₄^?), and dichromate (Cr₂O₇^2?) ions. The new values at 298.15 K are as follows:

	$\text{C}{}_{\mathrm{<mtext>p,</mtext><mtext>m</mtext>}}\text{R}$	$\text{S}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{R}$	$\text{{H}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{(T)?H}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{(0)}}\text{R}\text{K}$	$\text{?{G}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{(T)?H}{}_{\mathrm{m}}{}^{\mathrm{o}}\text{(0}}\text{RT}$
CsCrCl3	15.38	26.49	3503.2	14.735
RbCrCl3	15.76	25.99	3556.8	14.384

     

11.

Standard molar enthalpies of formation of two crystalline bis[N-(diethylaminothiocarbonyl)benzamidinato]nickel(II) complexes     

《The Journal of chemical thermodynamics》2004,36(9):753-757

     

12.

Determination of acidic dissociation constants of several vic-dioximes     

Charles V. Banks  Anton B. Carlson 《Analytica chimica acta》1952

The acidic dissociation constants of three vic-dioximes have been determined from spectrophotometric data. The results may be summarized as follows:

	$\text{S}{}^0\text{/}\text{cal}{}_{\mathrm{th}}\text{K}{}^{\mathrm{?1}}\text{mol}{}^{\mathrm{?1}}$	$\text{ΔH}{}_{\mathrm{f}}{}^0\text{/kcal}{}_{\mathrm{th}}\text{mol}{}^{\mathrm{?1}}$	$\text{ΔG}{}_{\mathrm{f}}{}^0\text{/kcal}{}_{\mathrm{th}}\text{mol}{}^{\mathrm{?1}}$
CrO42?(aq)	(13.8 ± 0.5)	?(210.93 ± 0.45)	?(174.8 ± 0.5)
HCrO4?(aq)	(46.6 ± 1.8)	?(210.0 ± 0.7)	?(183.7 ± 0.5)
Cr2O72?(aq)	(67.4 ± 3.9)	?(356.5 ± 1.5)	?(312.8 ± 1.0)

     

13.

Standard molar enthalpies of formation,vapour pressures,and enthalpies of sublimation of 2-chloro-4-nitroaniline and 2-chloro-5-nitroaniline     

《The Journal of chemical thermodynamics》2003,35(8):1343-1359

     

14.

Solvent extraction studies of cobalt in aqueous thiocyanate solutions using Aliquat-336     

Curtis McDonald  Carina M. Alfaro-Franco 《Microchemical Journal》1984,30(2):194-200

Cobalt ions in aqueous thiocyanate solution react with Aliquat-336-xylene solution to form anion-association complex which is easily extracted into the organic phase. A typical extraction procedure involves extracting a solution which is 10 ppm in cobalt and 0.06 M,

5. Stripping of Cobalt from 2% Aliquat-336-Xylene Solutions

pK1	pK2
2,3-butanedionedioxime	10.6 ± 0.1	11.9 ± 0.3
1,2-cyclohexanedionedioxime	10.6 ± 0.2	12.4 ± 0.5
1,2-cycloheptanedionedioxime	10.7 ± 0.2	12.3 ± 0.5

     

15.

Electrical conduction and diffusion studies in NH₄H₂PO₄ and KH₂PO₄ single crystals     

M. Sharon  Anjan K. Kalia 《Journal of solid state chemistry》1977,21(3):171-183

Electrical conduction (dc) studies are made with pure and cobalt(II)-doped single crystals of NH₄H₂PO₄ and KH₂PO₄. The effect of the dopant concentration on the enthalpy for the migration of protons and the enthalpy for the rotation of the H₂PO₄ group have been studied. It is suggested that proton migration occurs through a synchronous phosphate rotation mechanism. Tritium diffusion studies in KDP and ³²PO₄ diffusion in ADP crystals have been made. The mechanisms for the conduction and diffusion processes are found to be different in nature. The distribution coefficients of Co(II) dopant in ADP (2.92 × 10^?3) and KDP (1.14 × 10^?3) are calculated. The following enthalpy values are obtained.

Strippant	Cobalt stripped (%)
Na2S (M) 1.0	18.3
2.0	10.7
Na2SO3 (M) 0.1	10.7
0.5	49.6
1.0	52.9
EDA (%) 2.5	76.6
NaOH (M) 0.1	4.1
0.5	74.1
1.0	90.8
2.0	76.8
NH4OH (M) 0.1	24.1
0.5	91.8
1.0	97.5
2.0	99.9
EDTA (M) 0.02	>99.9
0.05	>99.9
0.1	>99.9
EDTA (%) 0.1	>99.9
0.5	>99.9
1.0	>99.9

     

16.

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.

	KDP (eV)	ADP (eV)
Enthalpy for the migration of protons	0.01 ± 0.01	0.15 ± 0.02
Enthalpy for the rotation of phosphate group	0.71 ± 0.01	0.66 ± 0.01
Enthalpy for T-diffusion	0.14 ± 0.01	—
Enthalpy for 32PO4 diffusion	—	0.24 ± 0.01

     

17.

Polarographic determination of antimony in leadantimony alloys     

H.F. Hourigan  J.W. Robinson 《Analytica chimica acta》1954

A polarographic method for the determination of antimony in lead-antimony alloys has been developed. It was found that the interference due to the presence of varying concentrations of lead and hydrochloric acid would be eliminated by the addition of potassium chloride.

t001. The method gave satisfactory results within the range:

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°

     

18.

Thermochemical studies of three N-thiocarbamoylbenzamidines     

《The Journal of chemical thermodynamics》2004,36(7):555-559

     

19.

Triene electrocyclizations: Some structure reactivity relations     

E.N. Marvell  G. Caple  C. Delphey  J. Platt  N. Polston  J. Tashiro 《Tetrahedron》1973,29(23):3797-3806

Two stereoselective routes for the synthesis of trienes having a central cis double bond have been devised. These were employed for the synthesis of (Z)-1-(cyclohexen-1-yl)-1,3-butadiene (1), (Z,E)-1-(cyclohexen-1-yl)-1,3-pentadiene (2), (Z,Z)-1-(cyclohexen-1-yl)-1,3-pentadiene (3), 1,2-divinyleyclohexene (4), (E,Z)-1-phenyl-1,3,5-hexatriene (5), (Z,Z)-1-phenyl-1,3,5-hexatriene (6) and (E,Z)-1-(p-chlorophenyl)-1,3,5-hexatriene (7). Rates of the thermal electrocyclization and activation parameters were measured for these in inert solvents. The results are tabulated below.

Hydrochloric acid	4 — 8M
Lead	0 — 0.03M
Antimony	0 — 0.002M

     

20.

Sur la thermogravimt́rie des prćipitś analytiques: Dosage de l'indium     

Thérése Dupuis  Clément Duval 《Analytica chimica acta》1949

The authors discuss several aspects of the chemistry of indium, giving evidence for a hydrate 2ln₂O₃.H₂O and studying in detail the behaviour of indium sulphide heated in air. Compared with that of gallium, the oxinate is particularly stable.Compounds used for the gravimetric determination of indium should be heated to the following temperatures in order to give correct results:

Compound	k1 x 105	(sec?1)	Temp (°C)	ΔH3	ΔS3
1	12·8	132	29	?6
2	12·5	132	29	?1
3	2·6	173	34	?5
4	3·86	125	25	?15
5	16·0	145	28	?8
6	3·0	195
7	15·0	145	25	?18(?)

     

Hydroxide by ammonia	345°
Hydroxide by hexamethylene tetramine	546°
Hydroxide by cyanate	475°
Sulphide	94–221°, 320–544°, 690°
Phosphate	477°
Luteocobaltic indichloride	100–105°
Oxinate	100–285°
Diethyldithiocarbamate	100–210°

Thermochemical properties of benzoic acid derivatives VIII. Enthalpies of combustion and formation of o-, m-, and p- t-butylbenzoic acids

The enthalpies of formation in the crystalline state at 298.15 K of o-, m-, and p-t-butyl-benzoic acids have been determined by static-bomb calorimetry. Vapour-pressure determinations were made by the Knudsen-effusion technique and the sublimation enthalpies at the mean temperatures of the measurement ranges have been derived for the three acids. The values obtained are:

Thermochemical properties of benzoic acid derivatives XI. Vapour pressures and enthalpies of sublimation and formation of the six dimethylbenzoic acids

The energies of combustion of 3,4- and 3,5-dimethylbenzoic acids have been revised by combustion calorimetry. Vapour pressures of very pure samples of the six dimethylbenzoic acids have been determined over a range of temperatures near 298 K by the Knudsen-effusion technique. From the experimental results and our previously published thermochemical quantities the following results for the six C₆H₃(CH₃)₂CO₂H isomers at 298.15 K have been derived.

Spectrophotometric studies of neomycin-copper complex and determination of neomycin sulfate using an auxiliary ligand

Spectrophotometric investigation of the deep blue colored, water-soluble complex of

1. Stability constant and free energy of formation of Cu-NMS complex at 30 ± 1 °C

Non-bonded sulphur-sulphur interactions in 3,5-dithiaheptane and 3,6-dithiaoctane

Enthalpies of combustion and vaporization at 298.15 K have been measured for 3,5-dithiaheptane and 3,6-dithiaoctane. Enthalpies of formation at 298.15 K have been derived for the compounds in the liquid and gaseous states. The results are:

Thermochemistry of uranium compounds V. Standard enthalpies of formation of the monouranates of lithium,potassium, and rubidium

Enthalpies of reaction, ΔH_r, of the monouranates of lithium, potassium, and rubidium with 1 mol dm^?3 HCl have been measured calorimetrically. From these measurements, and auxiliary determinations of the enthalpies of solution in acid of the chlorides of lithium, potassium, and rubidium and of uranyl chloride, the standard enthalpies of formation of the uranates, ΔH_f^o, have been derived. The results obtained are as follows:

Thermochemical properties of benzoic acid derivatives X. Enthalpies of combustion and formation of 2,3-, 2,4-, 2,6-, 3,4-, and 3,5-dimethoxybenzoic acids

The energies of combustion of 2,3-, 2,4-, 2,6-, 3,4-, and 3,5-dimethoxybenzoic acids have been determined by static-bomb calorimetry. The enthalpies of formation in the crystalline state at 298.15 K have been derived for these five acids. The values obtained are:

Heat capacity and thermodynamic functions of CsCrCl3 and RbCrCl3. Structural phase transitions

We present the heat capacities measured by adiabatic calorimetry from 6 to 350 K, and by differential scanning calorimetry from 300 to 500 K, of CsCrCl₃ and RbCrCl₃. A first-order transition at T_c = (171.1±0.1) K was detected for CsCrCl₃. The RbCrCl₃ showed at T_c = (193.3±0.1) K a transition with thermal hysteresis at temperatures just below the maximum. At T₁ = (440±10) K a continuous transition was also detected. Furthermore, at T_N ≈ 16 K, and for both compounds, a small bump due to magnetic long-range ordering was observed. The thermodynamic functions at 298.15 K are

Standard enthalpy of solution and formation of cesium chromate. Derived thermodynamic properties of the aqueous chromate,bichromate, and dichromate ions,alkali metal and alkaline earth chromates,and lead chromate

Calorimetric measurements of the enthalpy of solution of cesium chromate gave ΔH_soln = (7622 ± 24) cal_th mol^?1 for a dilution of Cs₂CrO₄·21128H₂O. This result, along with the enthalpy of dilution gave the standard enthalpy of solution, ΔH_soln^o = (7512 ± 31) cal_th mol^?1, whence the standard enthalpy of formation, ΔH_f⁰(Cs₂CrO₄, c, 298.15 K), was calculated to be ?(341.78 ± 0.46) kcal_th mol^?1. Recomputed thermodynamic data for the formation of the other alkali metal chromates have been tabulated. From their solubilities and enthalpies of solution, the standard entropies, S⁰(298 K), of BaCrO₄ and PbCrO₄ were estimated to be (38.9 ± 0.9) and (43.7 ± 1.2) cal_th K^?1 mol^?1, respectively. There is evidence that ΔH_f⁰(SrCrO₄, c, 298.15 K) may be in error. Thermochemical, solubility, and equilibrium data, have been combined to update the thermodynamic properties of the aqueous chromate (CrO₄^2?), bichromate (HCrO₄^?), and dichromate (Cr₂O₇^2?) ions. The new values at 298.15 K are as follows:

Determination of acidic dissociation constants of several vic-dioximes

The acidic dissociation constants of three vic-dioximes have been determined from spectrophotometric data. The results may be summarized as follows:

Solvent extraction studies of cobalt in aqueous thiocyanate solutions using Aliquat-336

Cobalt ions in aqueous thiocyanate solution react with Aliquat-336-xylene solution to form anion-association complex which is easily extracted into the organic phase. A typical extraction procedure involves extracting a solution which is 10 ppm in cobalt and 0.06 M,

5. Stripping of Cobalt from 2% Aliquat-336-Xylene Solutions

Electrical conduction and diffusion studies in NH4H2PO4 and KH2PO4 single crystals

Electrical conduction (dc) studies are made with pure and cobalt(II)-doped single crystals of NH₄H₂PO₄ and KH₂PO₄. The effect of the dopant concentration on the enthalpy for the migration of protons and the enthalpy for the rotation of the H₂PO₄ group have been studied. It is suggested that proton migration occurs through a synchronous phosphate rotation mechanism. Tritium diffusion studies in KDP and ³²PO₄ diffusion in ADP crystals have been made. The mechanisms for the conduction and diffusion processes are found to be different in nature. The distribution coefficients of Co(II) dopant in ADP (2.92 × 10^?3) and KDP (1.14 × 10^?3) are calculated. The following enthalpy values are obtained.

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.

Polarographic determination of antimony in leadantimony alloys

A polarographic method for the determination of antimony in lead-antimony alloys has been developed. It was found that the interference due to the presence of varying concentrations of lead and hydrochloric acid would be eliminated by the addition of potassium chloride.

t001. The method gave satisfactory results within the range:

Triene electrocyclizations: Some structure reactivity relations

Two stereoselective routes for the synthesis of trienes having a central cis double bond have been devised. These were employed for the synthesis of (Z)-1-(cyclohexen-1-yl)-1,3-butadiene (1), (Z,E)-1-(cyclohexen-1-yl)-1,3-pentadiene (2), (Z,Z)-1-(cyclohexen-1-yl)-1,3-pentadiene (3), 1,2-divinyleyclohexene (4), (E,Z)-1-phenyl-1,3,5-hexatriene (5), (Z,Z)-1-phenyl-1,3,5-hexatriene (6) and (E,Z)-1-(p-chlorophenyl)-1,3,5-hexatriene (7). Rates of the thermal electrocyclization and activation parameters were measured for these in inert solvents. The results are tabulated below.

Sur la thermogravimt́rie des prćipitś analytiques: Dosage de l'indium

The authors discuss several aspects of the chemistry of indium, giving evidence for a hydrate 2ln₂O₃.H₂O and studying in detail the behaviour of indium sulphide heated in air. Compared with that of gallium, the oxinate is particularly stable.Compounds used for the gravimetric determination of indium should be heated to the following temperatures in order to give correct results: