Some Practical Hints on Application of UNIQUAC Solution Model

C = Combinatorial part of the activity coefficient Q = UNIQUAC equation R = Residual part of the activity coefficient 

A universal quasi-chemical model (UNIQUAC) (Abrartts and Prarrsnitz, 1975) has been successfully applied for the correlation of several LLE systerrrs. This model depends on optimized interaction parameters between each pair of components in the system, which can be obtained by experiments. The UNIQUAC eqrration can be fitted to the experimental composition by optimizing the interaction parameter (a. and a ). The optimized interaction parameters can also be correlated with temperature. 

In this work, LLE data for (water + ethanol + cyclohexane) at temperatures ranging from 298.2 to 313.2 K were measured, and UNIQUAC model were used to correlate these data. The values for the interaction parameters were obtained for this equilibrium model. The effect of ethanol addition on solubility of water in cyclohexane (organic phase) was also investigated at different temperatures (298.2, 303.2, 308.2, and 313.2) K. 

Ethanol and cyclohexane were obtained from Merck at a purity of 99.8% and were used without further purification. The purity of these materials was checked by gas chromatography. Water was distilled before being used. 

A 300 ml glass cell connected to a thermostat was made to measure the LLE data The temperature of the cell was controlled by a water jacket and maintained with an accuracy of within 0.1K. A magnetic stirrer provided sufficient agitation within the 

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O Some Practical Hints on Application of UNIQUAC Solution Model... 

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