Physical Chemistry I (TKK-2246) 14/15 Semester 2 Physical Chemistry I (TKK-2246) Instructor: Rama Oktavian Email: rama.oktavian86@gmail.com Office Hr.: M – F.13-15

Outlines 1. Solid-liquid equilibrium 2. Liquid-solid phase diagram 3. Eutectic point 4. Salting out

Liquid-solid equilibria

Liquid-solid equilibria the manufacture of liquid crystal displays and semiconductors in the food industry, the phase behavior and crystalline habit influences the characteristics of consumer products (Costa, et al., 2009) crystallization process

Liquid-solid equilibria

Liquid-solid phase diagram a1→a2, The system enters the two-phase region labelled ‘Liquid +B’ a2→a3, More of the solid forms, The liquid phase is richer in A than before a3→a4, At the end of this step, there is less liquid than at a3, and its composition is given by e

Liquid-solid phase diagram the eutectic composition, the mixture with the lowest melting point the solution having the eutectic composition xe is in equilibrium with both pure solid A and pure solid B. Eutectics point F' = 3 - P = 3 - 3 = 0 the eutectic mixture solidifies at a single definite temperature

Liquid-solid phase diagram The Lead (Pb)-Antimony (Sb) System The eutectic temperature is 246 °C ; the eutectic composition is 87 mass percent lead

Liquid-solid phase diagram The Lead (Pb)-Antimony (Sb) System The point a represents pure solid antimony at 300 °C Point b lies in the region Sb + L Point c represents equilibrium composition between solid antimony and liquid solution Point g represents pure lead (Pb) solid Point d represents equilibrium composition between solid lead and liquid solution Point b and f represents two phase region

Liquid-solid phase diagram The Lead (Pb)-Antimony (Sb) System At h, the system is entirely liquid As the system cools, solid antimony appears at i as the antimony crystallizes out, the saturated liquid becomes richer in lead and the liquid composition moves along the curve At j the solution has the eutectic composition e and is saturated with respect to lead also, so lead begins to precipitate

Liquid-solid phase diagram Reacting system A + B  AB2 there are two eutectics: one of the A-AB2-liquid ; the other of AB2 -B -liquid

Liquid-solid phase diagram H2O-Fe2Cl6 system

Liquid-solid phase diagram Incongruent system the alloy Na2K

Liquid-solid phase diagram a1→a2 - Some solid Na is deposited, and the remaining liquid is richer in K a2→just below a3, The sample is now entirely solid, and consists of solid Na and solid Na2K

Liquid-solid phase diagram b1→b2, No obvious change occurs until the phase boundary is reached at b2 when solid Na begins to deposit b2→b3, Solid Na deposits, but at b3 a reaction occurs to form Na2K. At b3, three phases are in mutual equilibrium b3→b4, As cooling continues, the amount of solid compound increases until at b4 Peritectic line

Salting out A common procedure to separate a mixture of an organic liquid in water by adding salt Example: Potassium carbonate added to a solution of methanol in water produces 2 liquid phases Source: Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry

Salting out K2CO3-H2O-CH3OH

Salting out Example researches on salting out effect Salting-out effect of sodium, potassium, carbonate, sulfite, tartrate and thiosulfate ions on aqueous mixtures of acetonitrile or 1-methyl-2-pyrrolidone: A liquid–liquid equilibrium study (Fluid Phase Equilibria Volume 360, 25 December 2013, Pages 357–366) Recovery of Aniline from Wastewater by Nitrobenzene Extraction Enhanced with Salting-Out Effect (Biomedical and Environmental Sciences Volume 23, Issue 3, June 2010, Pages 208–212) Effect of salting out on the desorption-resistance of polycyclic aromatic hydrocarbons (PAHs) in coastal sediment (Chemical Engineering Journal Volume 225, 1 June 2013, Pages 84–92)

Buffering out Example researches on buffering out effect Mohamed Taha, Han-Lan Teng, Ming-Jer Lee, Buffering-out: Separation of tetrahydrofuran, 1,3-dioxolane, or 1,4-dioxane from their aqueous solutions using EPPS buffer at 298.15 K (Separation and Purification Technology Volume 105, 5 February 2013, Pages 33–40) Mohamed Taha, Han-Lan Teng, Ming-Jer Lee, The buffering-out effect and phase separation in aqueous solutions of EPPS buffer with 1-propanol, 2-propanol, or 2-methyl-2-propanol at T = 298.15 K (The Journal of Chemical Thermodynamics Volume 47, April 2012, Pages 154–161) Mohamed Taha, Ming-Jer Lee, Solubility and phase separation of 4-morpholinepropanesulfonic acid (MOPS), and 3-morpholino-2-hydroxypropanesulfonic acid (MOPSO) in aqueous 1,4-dioxane and ethanol solutions (The Journal of Chemical Thermodynamics Volume 43, Issue 11, November 2011, Pages 1723–1730)

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