By repeating this procedure for other binary mixtures with compositions of E, F, G, we obtain the points E, F, G. When the amount of A is just to make the mixture from two phases to one single homogeneous phase, the composition is represented by the point D. The ratio of B/S is constant while the amount of A is changing. Experimental solubilityģ Under constant temperature, if we add component A into this binary mixture drop by drop, the composition of the ternary mixture will change along line DA. This mixture is separated into two equilibrium liquid phases, P and Q. If components B and S are partially miscible, we can choose any binary mixture liquid of B and S, say point D in Fig. The equilibrium solubility curve is obtained through experiments. Liquid-liquid phase diagram wheree components A and B are partially miscible. Outside the envelope is one phase region. The two phases are identical at point P, whichh is called the Plait point. An original mixture of composition M will separate into two conjugate phases a and b which are on equilibrium tie line through point M. The two phase region is included inside below the curved envelope. A common phase diagram is Type I system and shown in Fig 2, wheree a pair of components A and B are partially miscible, and liquid C dissolves completely in A or B. For example, the distance from M to base AB is the mass fraction of C (x C 0.40). The perpendicular distance from the point M to any base line is the mass fraction of the component at the corner opposite to that base line. Coordinates for a triangular diagramĢ The three corners represent three pure components, A, B and C. Since we have three components, the equilibrium data are often expressed in equilateral triangular coordinates. Triangular coordinates and equilibrium data. The other three concentrations must be calculated from the phase equilibrium. If the pressure and temperature are specified, then setting one concentration will fix the system. We have six variables: temperature, pressure, and four concentrations. For a ternary system, the number of degrees of freedom is three, as calculated by the phase rule (F C - P ). In a liquid-liquid system, the minimum number of components is three and we have two phases in equilibrium. This is different from distillation, in which the liquid is partially vaporized to create another (vapor) phase, but the two phases are similar chemically. The two phases are chemically quite different, which leads to a separation of the components according to their distribution or partition between the two phases, normally one organic and one water. It is a process of transferring a solute from one liquid phase to another immiscible or partially miscible liquid in contact with the first. 1 Liquid-Liquid Extraction (LLX) Extraction is a liquid-liquid operation.
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