engleski

Measurements of vapour–liquid equilibria in systems consinsting of compounds with isopropyl group

Recent new results of a continuing project dealing with phase equilibria in mixtures belonging to distinct families of organic compounds are reported in this presentation. Vapour–liquid equilibria were determined isothermally for binary subsystems and ternary systems containing alcohol, hydrocarbon, ether or ketone, namely in the systems 2, 3-dimethylbutane + diisopropyl ether + methylisopropylketone (at 313.15, 323.15, 333.15 K), and in the isopropylalcohol + 2, 2, 4-trimethylpentane + 2, 4-dimethyl-3-pentanone (at 330, 340 K). All components involved have a common alkyl group [isopropyl (CH3)2CH–], hydroxyl group OH–, ether group –O–, and carbonyl group =C=O. The complete thermodynamic data (x–y–P–T) were determined at several isotherms. No azeotropic behaviour has been found except for isopropanol + 2, 2, 4-trimethylpentane system. The data reduction has been carried by the programme based on the maximum likelihood procedure1 which was modified by Pavlíček2. This new robust algorithm makes it possible to correlate vapour–liquid equilibrium isotherms or isobars together resulting in one set of universal parameters valid in the experimental pressure and temperature range. It can be applied to any correlation equation with temperature independent parameters such as e. g. the Wilson or NRTL equation. Averaged standard deviations for all systems are 0.015, 0.010, 0.03 kPA, and 0.11 K for liquid phase composition (mole fraction), vapour phase composition (mole fraction), pressure and temperature, respectively. The experimental ternary data were compared with the data predicted using binary parameters with very good results. It should be pointed out that predictions need not necessarily reflect the quality of data, because the imperfections of models also contribute to a certain worsening of calculated values. References 1. E. Hála, K. Aim, T. Boublík, J. Linek and I. Wichterle, Vapor–Liquid Equilibrium at Normal and Reduced Pressures (in Czech). Academia, Prague, 1982. 2. J. Pavlíček and I. Wichterle, Fluid Phase Equilibr. 2007, 260, 70–73.

vapour–liquid equilibria; ternary systems; 2; 3-dimethylbutane + diisopropyl ether + methylisopropylketone; isopropylalcohol + 2; 2; 4-trimethylpentane + 2; 4-dimethyl-3-pentanone

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