Liquid—liquid equilibrium data: Their retrieval, correlation and prediction Part II: Correlation

Application of a flow microcalorimeter to determine the excess enthalpies of binary mixtures of non-electrolytes

Ebulliometers modified for the accurate determination of vapour—liquid equilibrium

Thermodynamics of liquid mixtures containing a very strongly polar compound: Part 6. DISQUAC characterization of N,N-dialkylamides

Measurement and correlation of liquidliquid equilibria of binary and ternary systems containing methanol and hydrocarbons

The heat produced by mixing two continuous liquid flows is measured in a mixing cell consisting of a T tubing where the two incoming streams merge and a long narrow channel where the mixture exchanges heat with an isothermal air bath through an electric heat-flux meter. The liquid flow rates are set to allow the liquid to reach the bath temperature before leaving the mixing cell. The incoming liquids are brought to the bath temperature through a heat exchanger. Viscous flow heat evolution is reproduced by circulating the liquid in a reference cell. The corresponding heat effect is subtracted from the heat effect in the mixing cell. Both cells are provided with calibration heaters. The heat flux detector consists of a thermocouple assembly soldered to the cell and a heat sink kept at the bath temperature. The electric power is linearly related to the heat flux transmitted to the heat sink. The electric signal is amplified by a Keithley 150 B amplifier and recorded. The measurement is obtained by comparing the base line shift of the recorder on mixing to the deviation produced by a known current applied in one calibration heater while the liquids are pumped. The calibration cell is chosen to reduce the base line shift on mixing, and the current is set to produce a heat effect close to that of mixing. Tacussel “electroburap” BC/VRE Syringe pumps, equipped with lO-cm3 syringes were set at flow rates ranging from 0.01 to 0.4 cm3/min. Flow rates were obtained with a precision of 0.2% and calibrated by weighing. The use of a step-by-step electric motor did not produce any fluctuation of the recorder response. Degassing of pure liquids was found necessary because the solubility of air is lower in mixtures than in pure-liquids. Bubble growth in the mixing cell caused instability of the recorder response. Air concentration

Heats of mixing of binary mixtures of N-methylpyrrolidinone, ethanolamine, n-heptane, cyclohexane, and benzene by differential flow calorimetry

The separation of aromatic and saturated hydrocarbons is performed on a large scale in industry for the recovery of pure aromatic hydrocarbons from petroleum fractions. These separations are achieved by various techniques, which often require the addition of a solvent (extractive distillation, liquid-liquid extraction). The design of separation processes requires experimental information on phase equilibria and related thermodynamic properties. The determination of many thermodynamic data describing a quaternary system of two solvents and two hydrocarbons is also of theoretical interest for testing the qualities of the representation of these experimental quantities by a model of solution. Excess enthalpies (9, liquid-liquid equilibrium data (3, vapor-liquid equilibrium data ( 7, 6, 78) of mixtures of n-heptane, benzene, and two solvents, N-methylpyrrolidone (NMP) and monoethanolamine (MEA), were measured to complement the data already available in the literature cited. NMP is one of the industrially accepted solvents for aromatic hydrocarbon separation, it is sometimes used in a mixture with another solvent.

Experimental measurements of phase equilibrium properties for systems containing n-heptane, benzene, N-methylpyrrolidone, and monoethanolamine. Representation by the NRTL equation

Jean Louis Gustin

Papers

Heats of mixing of binary mixtures of N-methylpyrrolidinone, ethanolamine, n-heptane, cyclohexane, and benzene by differential flow calorimetry

Experimental measurements of phase equilibrium properties for systems containing n-heptane, benzene, N-methylpyrrolidone, and monoethanolamine. Representation by the NRTL equation