Jacek Gregorowicz

Vapour pressures and excess Gibbs energies of (butan-1-ol + n-octane or n-decane) at 373.15 and 383.15 K☆

Abstract The vapour pressures of (butan-1-ol + n -octane or n -decane) have been measured at 373.15 and 383.15 K using the ebulliometric method. Correlation of the experimental results by means of the NRTL and UNIQUAC equations leads to pressure residuals significantly exceeding experimental errors. The excess molar Gibbs energies G m E were calculated. Using these values the excess molar enthalpy H m E was calculated and compared with literature calorimetric values.

Development of a vapour-liquid equilibrium apparatus to work at pressures up to 3 MPa

Abstract An apparatus for vapour - liquid equilibrium measurement at elevated pressures was built. Construction was based on the Rogalski - Malanowski glass ebulliometer designed for precise measurements up to normal pressure. Experimental procedure was also developed. For the performance test of the proposed apparatus the vapour pressure was measured for four pure substances (benzene, heptane, cyclohexane and water) and the vapour - liquid equilibrium (VLE) was determined for two binary mixtures (benzene + heptane and benzene + cyclohexane). The results obtained were satisfactory.

Vapour pressure data for 1-butanol, cumene, n-octane and n-decane and their statistically consistent reduction with the antoine equation

Abstract Vapour pressures of pure substances: 1-butanol, cumene, n-octane and n-decane have been measured. A statistical consistent algorithm, based on the maximum likelihood principle, has been applied to data reduction and estimation of the Antoine equation parameters. The nonlinear correlating procedure, including estimation of true values of measured variables and error analysis, is proposed. A computational algorithm suitable for a personal computer is also presented.

Solubilities of lactic acid and 2-hydroxyhexanoic acid in supercritical CO2

Abstract Solubilities of lactic acid and 2-hydroxyhexanoic acid in supercritical CO2 have been measured at T=(311 or 313, 318, 328 K) in the pressure range from 50 to 200 bar. The measurements have been performed using a flow-type apparatus. The solute solubility in compressed carbon dioxide increased with pressure at all investigated temperatures. At pressures below 130 bar, a solubility decrease on temperature increase was observed. An accurate correlation method for the solubility of low volatile substances in supercritical CO2 has been applied for the interpolation of the experimental results.

Vapour-liquid equilibrium and solid-solid equilibrium in the system formed by octan-1-ol and n-decane: measurement and calculation

Abstract The total vapour pressures of the binary system containing octan-1-ol and n -decane were measured at 373.15 K and 383.15 K using the ebulliometric method. The solid-liquid equilibrium (SLE) data were determined by the Rossini method. The experimental data were correlated using the Redlich-Kister, NRTL and modified NRTL equations. The prediction of SLE data from vapour-liquid equilibrium (VLE) and excess enthalpy H E data is proposed and discussed.

Modelling of the three phase LLV region for ternary hydrocarbon mixtures with the Soave-Redlich-Kwong equation of state

Abstract The prediction of the three phase liquid-liquid-vapour (L2L1V) region for the ternary mixtures ethane + propane + eicosane (C2 + C3 + C20) and methane + ethane + eicosane (C1 + C2 + C20) was performed using the Soave-Redlich-Kwong equation of state. A procedure for finding K- and L-points is presented. It is based on the solution of thermodynamic conditions for the K- and L-point using the Newton iteration technique with carefully chosen starting points. The calculations were performed with all binary interaction parameters set to zero and with binary interaction parameters fitted to vapour-liquid equilibrium data of the binary subsystems. In the latter case for all binary subsystems two adjustable parameters with classical mixing rules were used. The results obtained show only qualitative agreement with experimental data for both sets of interaction parameters.

Liquid-phase PVT data of alkylbenzenes

Abstract Liquid-phase PVT data are presented at 318.15 and 33.15 K for pressures up to 5 MPa for toluene, ethylbenzene, propylbenzene, isopropylbenzene and butylbenzene and for equimolar mixtures of the others with isopropylbenzene. The constants of an equation describing the observed P-V behaviour and calculated isothermal compressibilities at zero pressure for each liquid are also reported. Results for pure liquids as well as small values of excess volumes and compressibilities for the mixtures studied suggest that alkyl group length and structure influence the differences in the observed properties.

Solubility of tetracosane in supercritical ethane and ethylene

Abstract Results of measurements of solubility of eicosane in ethane and ethylene are presented. Measurements were performed in wide temperature and pressure intervals using a flow method. Investigations of the system ethane+eicosane were performed in the vapour–liquid equilibrium region. The system ethylene+eicosane was investigated both in the vapour–liquid equilibrium and solid–fluid equilibrium regions. The results obtained for this system show that the crystalline structure of solid eicosane has significant influence on its concentration in the gas phase. On the basis of the results obtained, influence of the proximity of the critical end point on the solubility enhancement is discussed. Results of calculations for the investigated systems with equation of state models are presented and discussed.

Correlation and prediction of vapour-liquid equilibria in ternary systems formed by hydrocarbons

Abstract The problem of prediction and correlation of vapour-liquid equilibria (VLE) in ternary systems has been discussed and the limitation of the applicability of the known methods for this purpose has been pointed out. The investigations on the comparison of the efficiency of the various methods for the correlation and prediction of VLE in ternary systems belonging to different classes of mixtures have been undertaken. As a part of this work, the total pressure data for 4 ternary mixtures ( n -hexane-cyclohex-ane-benzene, n -hexane-methylcyclopentane-benzene, 1-heptene- n -heptane- n -octane and cyclohexane- n -heptane-toluene) and 12 appropriate binary mixtures ( n -hexane-cyclohexane, n -hexane-benzene, cyclohexane-benzene, n -hexane-methylcyclopentane, n -hexane-benzene, methylcyclopentane-benzene, 1-heptene- n -heptane, 1-heptene- n -octane, n -heptane- n -octane, cyclohexane- n -heptane, cyclohexane-toluene and n -heptane-toluene) have been selected and correlated by means of the NRTL, the UNIQUAC and the Wilson equations. Subsequently, the ternary VLE data have been predicted using the binary parameters of the equations calculated from appropriate binary VLE data. The correlation and the prediction results have been fully discussed from the point of view of intermolecular interactions and some recommendations for the use of the investigated equations for such calculations are made.

Correlation and prediction of vle in ternary systems formed by hydrocarbons and alcohols

Abstract The problem of the prediction and correlation of vapour-liquid equilibria (VLE) in ternary systems has been discussed and the limited applicability of the known methods for this purpose pointed out. A comparison of the efficiency of the various methods for ternary systems of different classes of mixtures has been undertaken. As a part of this work, total pressure data for 6 ternary mixtures (cyclohexane-ethanol-toluene, cyclohexane-ethanol-benzene, n -hexane-ethanol-benzene, cyclohexane-2-propanol-benzene, n -hexane-1-propanol-benzene, cyclohexane-methanol-benzene) and 18 appropriate binary mixtures (cyclohexane-ethanol, cyclohexane-toluene, ethanol-toluene, cyclohexane-ethanol, benzene-cyclohexane, benzene-ethanol, ethanol-benzene, n -hexane-benzene, n -hexane-ethanol, benzene-2-propanol, benzene-cyclohexane, cyclohexane-2-propanol, benzene-1-propanol, benzene- n -hexane, n -hexane-1-propanol, cyclohexane-methanol, benzene-cyclohexane, benzene-methanol) were selected and correlated by means of the NRTL, UNIQUAC, Wilson and NRTLMK equations. The ternary VLE data were then predicted using the binary parameters of the equations calculated from appropriate binary VLE data. The correlation and prediction results are fully discussed from the point of view of intermolecular interactions, and a number of recommendations on the use of the equations investigated for such calculations are made.