Jacques Jose

A static apparatus for measurement of low vapor pressures. Experimental results on high molecular-weight hydrocarbons

Abstract Equipment is described for measurement of low vapor pressures (p sat ) in the range : 10 −3 ⩽ p sat /Torr ⩽ 10 and −70 ⩽ t°C ⩽ 190. The apparatus consists basically of a cell connected directly to a pressure gage using high vacuum technology. The gage is calibrated with vapor pressure data of water. Naphtalene and n-dodecan were chosen as test substances. Measurements were made on high molecular weight hydrocarbons : n-eicosan, n-docosan, n-tetracosan, 1-methyl naphtalene, 2-ethylnaphtalene, fluorene and pyrene. Small amounts (2–5 cm 3 ) are enough for such measurements.

Recommended vapour and sublimation pressures and related thermal data for chlorobenzenes

Abstract Recommended data on vapour pressures are presented for all dichlorobenzenes, all trichlorobenzenes, and pentachlorobenzene in the temperature range from the triple point up to the normal boiling point. For some chlorobenzenes where reliable sublimation pressures and solid heat capacities are available (1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,3,5-trichlorobenzene, and pentachlorobenzene), recommended sublimation pressures are also given that cover the range from about −40°C (with the exception of 1,4-dichlorobenzene where there are no experimental sublimation pressures below the phase transition at −1.38°C) up to the triple point temperature. The data were developed by a simultaneous multi-property correlation of vapour or sublimation pressures and the related thermal data (heat capacities in the liquid or the solid phase, heat capacities of the ideal gas, enthalpies of vaporisation or sublimation). The data are presented as parameters of the Cox correlation equation which has an identical form for description of vapour–solid (v–s) and vapour–liquid (v–l) equilibria and are consistent at the triple point. Recommendations are based mostly on new experimental vapour and sublimation pressures obtained recently by the authors. Solid and liquid heat capacities required for the simultaneous correlation were provided by merging new experimental data measured using a C80 Setaram heat conduction calorimeter over approximate temperature range from 30 to 160°C (depending on the compound) with the data critically selected from the literature.

Mesure des pressions de vapeur d'hydrocarbures C10 A C18n-alcanes etn-alkylbenzenes dans le domaine 3-1000 pascal

Vapour pressure measurements of high boiling point hydrocarbons (C10-C18n-alkanes and n-alkylbenzenes) were carried out in the range: 10−1 < P0 < 10 mm Hg, 50 < t0 < 250°C. n nThe gas-saturation method for measuring low vapour pressures was used. n nTrial was made of several equations for the representation of the vapour pressure-temperature relationship. The best extrapolation is given by the Scott and Osborn equation. The experimental data are well correlated by this equation.

Water vapour pressure above saturated salt solutions at low temperatures

Abstract The properties of water–salt systems in relation to their vapour pressure are studied especially at low temperature. The water vapour pressure of saturated salt solutions of strontium chloride, zinc chloride, nickel chloride, nickel nitrate, magnesium chloride, magnesium bromide, magnesium nitrate, calcium chloride, potassium nitrite, lithium chloride, lithium bromide, lithium iodide and sodium bromide are measured in a temperature range −40 to +10°C. The apparatus used in this study, is well adapted to measure very low pressure with an uncertainty of pressure measurement of 2% for a range between 10−3 and 10 mm Hg. The experimental values are fitted by Antoine equation with mean percent deviation lower than 1%. Comparison of these values with literature data shows a good agreement.

Tension de vapeur d'hydrocarbures polyaromatiques dans le domaine 10-3–10 Torr

Abstract Vapour pressure measurements of polyaromatic hydrocarbons were carried out in the range 10 −3 Torr P T s

Excess volumes of mixtures of hexamethylphosphorotriamide (HMPT) with hydrocarbons and halogenated hydrocarbons

190°C, in the solid and liquid state. The results were obtained using a static method employing a Datametrix Barocel electronic manometer equiped with a wide-range pressure sensor. A regulating system maintains the gage at constant temperature (320°C) to avoid cold spots. The gage was calibrated using vapor pressure data for water. The apparatus was tested using data for naphthalene. Measurements were made on six polyaromatic hydrocarbons: diphenyl, diphenylmethane, 1,2-diphenyl-ethane, o -terphenyl, triphenylmethane and triphenylethylene. Small amounts (2 cm 3 ) are enough for such measurements. Only a few experimental vapor-pressure values are reported in the literature in the range of the present investigation. Enthalpies of sublimation and vaporization were derived by application of the Clapeyron relation.

Pressions de vapeur et enthalpies libres d'exces de systemes binaires: Hexamethylphosphorotriamide (HMPT) + n-hexane; n-heptane; n-octane: A 298,15 K; 303,15 K; 313,15 K; 323,15 K; 333,15 K

Excess volumes of hexamethylphosphorotriamide ( hmpt )+ n -hexane, n -pentane, 1-hexane, 1-hexyne, cyclohexane, cyclohexene, benzene, toluene, o -and p -xylene, chlorobenzene, 2-and 4-chlorotoluene, 1-chlorobutane, and 1-chloropentane have been measured at 298.15 K as function of composition by a dilatometric method. The results are discussed in terms of molecular interactions.

Equilibres liquide-vapeur isothermes de mélanges binaires formés de composés hétérocycliques tels que : morpholine, tetrahydropyranne, piperidine et 1,4-dioxane

Abstract The vapor pressures of the binary systems hexamethylphosphorotriamide (HMPT) + n -hexane, + n -heptane, + n -octane, have been measured with an isoteniscope of our design over the temperature range 298.15–333.15 K. The vapor pressures, excess Gibbs free energies at 298.15, 303.15, 313.15, 323.15 and 333.15 K are reported for the three mixtures. The excess Gibbs free energies for the three systems have been calculated and fitted to the Redlich—Kister equation. The excess enthalpies at 298.15 K for the three systems have been calculated from the Gibbs—Helmholtz equation. For the systems HMPT— n -hexane and HMPT— n -heptane, these excess enthalpies have been compared with the direct values measured with an isothermal calorimeter built by us. For the system HMPT— n -octane, the excess enthalpies have been compared with those calculated by Kehiaians Theory of molecular surface interaction.

Realisation d'un ensemble destine a la mesure de faibles pressions de vapeur (Domaine: 3–1000 Pa)

The authors have measured the vapour pressure of four binary systems, morpholine+piperidine, morpholine+1,4-dioxane, morpholine+tetrahydropyrane and 1,4-dioxane+tetrahydropyrane. The measurements were carried out using an isoteniscope built by J. Jose [1]. The vapour pressure, excess Gibbs free energies at 298.15, 303.15, 313.15, 323.15, 333.15 and 343.15 K are reported for these mixtures. The excess Gibbs free energies have been fitted to the Redlich-Kister equation.ZusammenfassungVon den Autoren wurde der Gasdruck der vier binären Systeme Morpholin+Piperidin, Morpholin+1,4-Dioxan, Morpholin+Tetrahydropyran und 1,4-Dioxan+Tetrahydropyran vermessen. Die Messungen wurden mit Hilfe eines von J. Jose [1] gebauten Isoteniskopes durchgeführt. Für diese Gemische werden Gasdruck und überschüssige Gibbs’che freie Energie für 298.15K, 303.15 K, 313.15 K, 323.15 K, 333.15 K und 343.15 K angegeben. Die überschüssige Gibbs’sche freie Energie wurde nach der Redlich-Kister-Gleichung bemessen.

EQUILIBRES LIQUIDE-VAPEUR ISOTHERMES DE MELANGES BINAIRES, AMINE+AMINE

Equipment is described for measurement of low vapor pressure, P0, in the range: 3 Pa < P0 <1000 Pa; 50°C < t < 250°C. A possible error of 1% in P and ± 0.02°C in T were estimated. n nThe inert gas-saturation method was used. The vapor pressure was determined by measuring the saturated vapor concentration in the inert gas using a gas chromatograph. The detector chromatograph was calibrated for the material studied. External calibration was chosen and a special syringe was designed and built for this purpose. n nThe apparatus was designed with the following features: (1) by adapting a sample injection valve the gas phase analysis is simple and very accurate; (2) the use of a differential pressure transducer permits accurate measurement of inert gas pressure. n nThe partial vapor pressure, Pi, was measured for several total pressures, P. The extrapolation to P = 0 of the plot log Pi, vs. P gave the partial vapor pressure of pure substance. This method was derived from thermodynamic considerations (Poynting effect and non-ideality of gas phase).