Kiyofumi Kurihara

Determination and correlation of LLE and SLE data for the system aniline+cyclohexane

A newly developed laser light scattering technique was used for the determination of mutual solubilities in the aniline+cydohexane system at moderate pressures. The liquid-liquid equilibria (LLE) were measured from the region of solid-liquid equilibria (SLE) to the upper critical solution temperature. Freezing points in this system were determined by a cooling curve method. The solubility data were correlated with the NRTL equation.

Measurement and correlation of excess molar enthalpies for the 2-butanol + water and methanol + cyclohexane systems with limited miscibility at 283.15, 288.15 and 298.15 K

Abstract The excess molar enthalpies for the 2-butanol+water and methanol+cyclohexane systems with limited miscibility were measured at 283.15, 288.15 and 298.15 K using a flow microcalorimeter. The experimental data were correlated by the modified Redlich–Kister equation and the three local-composition (LC) models (NRTL, modified Wilson and EBLCM). These LC models were also examined for predicting the liquid–liquid solubility for both systems using the parameters obtained from the excess enthalpy data.

Prediction of ternary vapor-liquid equilibria by mixing rule containing regular solution and residual excess free energy terms

Based on a mixing rule, for the energy parameter > lda” in SRK equation, containing the geometrical mean of pure energy parameters and the residual part of the excess free energy at infinite pressure, vapor-liquid equilibria are predicted with good accuracy for 6 ternary systems consisting of polar and non-polar substances. The Wilson equation is applied to express the residual part of the excess free energy at infinite pressure. In addition, the significance of interaction coefficient kij of the conventional mixing rule is considered thermodynamically using the proposed mixing rule as the basis.

PREDICTION OF PHASE EQUILIBRIA FOR THE SYSTEMS CONTAINING AMMONIA USING PRASOG

Abstract In order to extend the applicability of a Peng–Robinson group contribution method called PRASOG to ammonia-containing systems, the group pair parameters were determined using binary vapor–liquid and vapor–liquid–liquid equilibrium data. The vapor–liquid and vapor–liquid–liquid equilibria were predicted using the determined parameters for the binary and ternary systems containing ammonia, paraffins, olefins, water, alcohols, and nitriles. The predictive accuracy of liquid–liquid equilibria using group pair parameters from liquid–liquid equilibrium data is compared with those using the parameters from vapor–liquid equilibrium data.

The calculation of excess molar enthalpies of liquid mixtures at high pressures and temperatures from measurements at ambient conditions

Abstract In this paper, a new approach for calculating the excess molar enthalpies of liquid mixtures at high pressures and temperatures based on the experimental excess molar enthalpy ( H E ) data at low pressure is proposed. This model (we call it the G E –EOS( H E ) model) is an equation of state (EOS) (original Peng–Robinson (PR) EOS with a conventional mixing rule) combined with an excess Gibbs energy model (NRTL equation). This approach has been tested by calculating excess molar enthalpies of seven binary systems. The binary parameters in the NRTL equation were determined only from the low-pressure excess molar enthalpy data. The calculated results show that the G E –EOS( H E ) model can calculate excess molar enthalpies over a wide range of temperatures and pressures on the basis of low-pressure data.

An implicit type EOS-GE(VP) model employing vapor pressure standard state I. Prediction of high-pressure vapor-liquid equilibria based on low temperature data

Abstract The implicit type EOS- G E0 model at zero pressure has been successfully used for prediction of thermodynamic properties with available excess free energy model parameters. It has been pointed out however that this model needs an extrapolation procedure at reduced temperatures above about 0.85 and the extrapolation procedure is rather cumbersome. In this paper, an implicit type EOS- G E model which requires no extrapolation method is proposed. This proposed model (EOS- G E(VP) ) employs a standard state for the mixing process which is the vapor pressure of the most volatile component at the temperature of the mixture. Using this EOS- G E(VP) model with the Soave-Redlich-Kwong equation of state and the Wilson and NRTL equations, vapor-liquid equilibria including near-critical and super-critical components have been predicted for 8 binary systems consisting of 50 data sets.

An implicit type EOS-GE(VP) model employing vapor pressure standard state. II. Prediction of excess enthalpy using the EOS-GE model

Abstract In this paper, the EOS-GE models, combining the Soave-Redlich-Kwong equation of state with the NRTL equation, are examined for the prediction of liquid excess enthalpy. The implicit type EOS-GE(VP) model employing a new standard state which is the vapor pressure of the most volatile component at the temperature of the mixture gives satisfactory reproduction of the excess enthalpy of 11 binary systems at 101.3 kPa. These results are compared with those with the MHV2 and PSRK models which are of the explicit type. The implicit type EOS-GE(VP) is also applied to predict high-pressure liquid excess enthalpy from the liquid excess enthalpy data at 101.3 kPa.