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In this article, new Gibbs free energy of mixing is derived when there are specific interactions between sol- vent-solute molecules and between solute-solute molecules in binary solutions. It is asssumed that a probability of specific interactions satisfies a binomial distribution. Using this Gibbs free energy of mixing, we investigate possible types of partial miscibilities and show that Ω-shaped temperature-composition phase diagrams can exist. We calculate Ω-shaped temperature- composition phase diagram of water-2-butanol system and compare that with result calculated by the method of Hino 5 et al.

In some binary solution, closed miscibility loop of temperature-composition phase diagram occurs where both an upper critical solution temperature and a lower critical solution temperature exist. It is known that this phenomena occurs if specific interaction between molecules exists. There are several ways describing the specific interaction. In this work it is assumed that the total number of specific interactions is distributed according to binomial distribution. In this case, exact mathematical conditions for closed miscibility loop phase behavior are derived when the specific interaction is applied to reg- ular solution theory, quasichemical theory and Flory-Huggins lattice theory. And we investigated the effect of parameters on the phase diagram. The phase diagram of water-nicotine is calculated and compared with experimental data.

Using the free volume of van der Waals equation, Carnahan-Starling equation for hard spheres, Wilson equa- tion for nonrandom mixing of solution, NRTL equation and our equation, several new equations of states for pure gases are derived. Using these equations, compressibility factors for pure gases are calculated and compared with Nelson-Obert gen- eralized compressibility factor charts. The equation of states using the concept of molecular nonrandom distribution gave better results than those of molecular random distribution. This shows that the molecular nonrandom distribution makes considerable effect on the equation of states.

Performing random number simulations, we obtained an approximate distribution of the number of ways arranging molecules in a binary lattice solution of nonrandom mixing with a specific interaction. From the distribution an approximate equation of excess Gibbs energy for a binary lattice solution was derived. Using the equation, liquid-vapor equilibrium at constant pressure for 15 binary solutions were calculated and compared with the result from Wilson equation, Van Laar equation and Redlich-Kister equation.

의 일차결합에 대한 정규분포로 가정하였다. 난수모의실험을 수행하여 이 가정이 타당하다는 것을 입증하였고, 이 분포로부터 3 성분 논랜덤 혼합 격자용액의 과잉깁스에너지 에 대한 근사식을 유도하였다. 이를 이용하여 여러 3성분용액의 액체-증기 상평형 계산을 하였고 다른 식들의 계산 결과와비교하여 보았다.주제어: 논랜덤 혼합, 삼성분계, 과잉깁스에너지, 격자ABSRTACT. It is assumed for three components lattice solution that the number of ways of arranging particles ran-domly on the lattice follows a normal distribution of a linear combination of N

Performing random number simulations, we approximated that the distribution of the number of ways for arranging molecules randomly on a lattice is a normal distributon for N12, the number of interactions between the nearest neighbors of different molecules. From this distribution, an approximate equation of the excess Gibbs energy GE for a lattice solution of nonrandom mixing was derived. Using the equation, liquid-vapor equilibria of several binary solutions were calculated and compared with the calculated result of other equations.

Department of Chemistry, Duk Sung W omens University Seoul 132- 714, Korea (Received November 10, 2004) . , hole, free v olum e !" # $% . & van der Waals '() * Lennard-Jones 6-12 '() " + ,- '(). /0 123 $% . Flory 4-567 , Sanchez 8 Lacom be 9 , Dee 8 Walsch :; ?@A $% . B CD E Dee 8 Walsch , Mie(p,6) '(). 123 + , 9 , Lennard-Jones 6-12 '(). 123 + CF 9 . 23 LCST G4. / PS+PVME[(poly sty rene)+poly (viny l methyl ether)] HIJ K LM. NO3 PQR S3 /T% . U V +W XY Z V" /[\% . : , K LMABSTRACT. Many theories f or poly m eric liquids are based on the concepts of cell, hole, free volume or lattice etc.In the theories, van der Waals potential, L ennard-Jones 6-12 potential and their m odif ied potentials are comm only used.A n eqaution of satet theory of Flory & his coworkers, a cell theory of Dee a E = i HIJ. `a3 j XY :; 1k chain flexiblity 8 free volum e . lm Flory

The concept of a continuous lattice from the viewpoint of classical mechanics was introduced and a Lennard Jones 6 12 potential was used to modify the lattice fluid theory of Sanchez and Lacombe. Thus, a new equation of state for pure polymeric liquids was obtained. With this equation, PVT data, thermal expansivities and isothermal compressibilities of several polymeric liquids were calculated and compared with experimental values and with those of the lattice fluid theory and other theories. The new equation gave similar precision to Hole theory in the calculation of volumes thermal expansivity and isothermal compressibility and gave better agreement with the experimental data than the other theories used in the comparison.

It has been shown, using the significant structure theory of liquids, that a lower critical solution temperature behavior as well as a upper critical solution temperature behavior can be expected for polymer–polymer systems and that a phase diagram of closed-loop-type in a polymer–polymer–solvent system can be possible. In this article the sublimation energy of a mixture was expressed as a quadratic form of segment surface fractions on pure components rather than that of mole fractions, and the effect of the segment surface fractions on critical compositions was explained. The calculated partial miscibilities were in good agreement with the experiment.

The significant structure theory of liquids has been applied to the partially miscible systems, of which the temperature-composition phase diagrams are of closed loop type. In this paper, the sublimation energy of a mixture is expressed as a quadratic form of surface area fractions of components, and the energy correction parameter between one component and the other is assumed to be a second order function of temperature for simplicity, although it is a higher order function of temperatures and compositions. The calculated partial miscibilities are in good agreement with the experiment. Considered mixture systems are water-nicotine and waterβ picoline systems.