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Abstract  

The authors have measured the vapour pressure of the binary systems, piperidine+n -butylamine, piperidine+dipropylamine, piperidine+N-methyl piperidine, piperidine+N,N-dimethyl amino butane and N-methyl piperidine+n -butylamine. The measurements were carried out using an isoteniscope built by Jose [1]. The vapour pressure, excess Gibbs free energies at 298,15, 303,15, 313,15, 323,15, 333,15, and 325,15 K, are reported for these mixtures. The excess Gibbs free energies have been fitted to Redlich-Kister equation.

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The authors have measured the vapour pressure of the four binary systems, piperidine +tert-butyl methyl ether, piperidine +1,4 dioxane, piperidine + tetrahydropyrane and N-methyl piperidine +tert-butyl methyl ether. 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.

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Abstract  

Monomethylhydrazine (MMH) (CH3)NHNH2 is currently used as fuel for spacecraft engine combustion chambers. The Aestus engine of the upper stage of Ariane 5 is fed with MMH under pressure of 16 bars. The propellant, initially at room temperature, is about 393 K when introduced into the combustion chamber, due to heating up through the regenerative circuit. As MMH is unstable above 373 K, it has been necessary to check its decomposition rate and vapor pressure under such conditions. The vapor pressure of this propellant has been measured in a pressure vessel and the thermal decomposition rate was determined with the same device up to 500 K.

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Journal of Thermal Analysis and Calorimetry
Authors: A. Bessonov, N. Morozova, P. Semyannikov, S. Trubin, N. Gelfond, and I. Igumenov

Abstract  

The thermal properties of dimethylgold(III) carboxylates of general formula [(CH3)2Au(OOCR)]2 (R=methyl (1), tert-buthyl (2), trifluoromethyl (3), or phenyl (4)) in solid state have been investigated by the thermogravimetric analysis. The temperature dependences of saturated vapour pressure of complexes have been studied by the Knudsen effusion method with mass spectrometric indication. The thermodynamic parameters Δsub H T 0 and Δsub S T 0 of the sublimation processes have been calculated. Thermal decomposition of the vapour of complexes 1 and 2 has been studied by means of high temperature mass spectrometry in vacuum, and by-products of decomposition have been determined.

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Abstract  

The authors have measured the vapour pressure of the binary four systems, piperidin +1,4-dioxan, piperidin+tetrahydropyran, piperidin+tert-butyl methyl ether and N-methyl piperidin+tert-butyl methyl ether. The measurements were carried out using an isoteniscope built by J. Jose [1]. The vapour pressure, excess Gibbs free energies at 298.15 K, 303.15 K, 313.15 K, 323.15 K, 333.15 K and 343.15 K, are reported for these mixtures. The excess Gibbs free energies have been fitted to the Redlich-Kister equation.

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By means of a tensimetric flow method and a static method with a silica-membrane zero gauge, the dependence of vapour pressure on temperature was obtained for tris(2,4-pentanedionato)ruthenium(III), Ru(aa)3, and tris(1,1,1-trifluoropentane-2,4-dionato)ruthenium(III), Ru(tfa)3. The thermodynamic characteristics of vaporization and sublimation of these complexes were determined. The processes of thermal decomposition of the vapour of the compounds in vacuum, hydrogen and oxygen were investigated by using mass spectrometry in the temperature range 170–550‡C for Ru(aa)3 and 150–620‡C for Ru(tfa)3. The threshold temperatures of the stability of the vapour of the complexes and the rate constants of the thermolysis processes were determined. The main gaseous products of the thermal decomposition and the dependences of their composition on the presence of hydrogen and oxygen were established.

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