Vapour Liquid Equilibrium (VLE) data for natural ingredients and essential oils has not studied at all yet. It is because of complexity of these mixtures. In this study, the equilibrium concentration of the mixture components was studied by using the UNIQUAC model at different pressure. This model is capable of determining temperature between 70°C to 170°C and the pressure limits 30 Kpa to 202 Kpa. The modeling's results showed thymol in the liquid phase were increased from 50% molar to 90%

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... r in constant pressure by increasing temperature from bubble point to dew point's temperature. Thymol concentration in the liquid phase was increased from 42% molar to 78% molar by increasing water concentration of the mixture at a constant pressure of 100 Kpa and constant temperature 177°C. Another obtaining result showed that thymol concentration in the triple mixture, which includes 30% molar water, 35% molar thymol and 35% molar Cymene in liquid phase, was increased from 60% molar to 82% molar at constant temperature of 177°C by decreasing pressure from 100 Kpa to 20 Kpa.