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  • Author or Editor: A. Bougrine x
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Abstract

Three isothermal sections of the isobaric ternary system H2O–NaOH–C5H10NH were determined by Isoplethic Thermal Analysis at 293, 313, and 323 K. Miscibility gaps were completely delimited and each critical point was calculated. This system is then characterized by a prevalent miscibility gap, three crystallization domains and two triphasic invariant domains. The relevant exploitation of this diagram so permits us to deduce the demixing temperature leading to the optimal transfer of the organic compounds in the light phase and also the composition of the organic phase recovered after this second step of extraction. Moreover, the addition of calculated quantities of sodium hydroxide aqueous solution allows to be in optimized conditions for the next distillation operations.

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Abstract  

Two isothermal sections of the isobaric ternary system H2O–Na2SO4–C5H10NH were determined by isoplethic thermal analysis at 293 and 323 K. The compositions of the aqueous and organic invariant liquids, respectively L1 and L2, as well as that of the critical point, were characterized for each isotherm. The temperature of the invariant reaction was obtained by controlled flow thermal analysis and the temperature of the demixing ending, by interpolation of the monovariant lines. All these informations allowed us to establish the isobaric polythermal diagram of the H2O–Na2SO4–C5H10NH system, for the temperature range 293–323 K, as well as a qualitative representation of the monovariant curves. This system is then characterized by a wide miscibility gap, three crystallization domains, and four-three-phase invariant domains. The relevant exploitation of this diagram so permits us to deduce the demixing temperature leading to the optimal transfer of the organic compounds in the light phase and also the composition of the organic phase recovered after this first step of extraction.

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Abstract  

Isoplethic thermal analysis was used to determine the solid-liquid-liquid equilibria in the ternary system water-sodium sulfate-piperidine. The changes in state observed on the thermogram recorded during the displacement in a quasi-binary section permit the identification of the different phases and the delimitation of the corresponding equilibrium domains. Two isotherms were established at 25°C and 40°C because these temperatures frame the peritectic decomposition of the sodium sulfate decahydrate. Miscibility gaps were completely delimited and each critical point was calculated. This study permitted to determine the optimal conditions for separating the organic phase by liquid-liquid extraction.

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