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Phase-Phase Partitioning

Abstract

What do we predict with SMx Solvation Models

Solvation free energy Vapour pressure Partition coefficient
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By combining these we can also calculate solubility, interference adsorption and membrane permeability.

Partition coefficients

Really straight forward, since we can use the difference between the two solvation energies

\[ \Delta G^\circ_{1\to2}=\Delta G^\circ_{sol\:2}-\Delta G^\circ_{sol\:1} \]

To calculate a \(K_{eq}\) from this we can use the equation

Where \(\Delta G^\circ=\Delta G^\circ_{1\to2}\)

\[ K_{eq}=\exp{\big(\frac{-\Delta G^\circ}{RT}\big)} \]

And we can simply take the log of \(K_{eq}\) to get \(\log K\)

Note

I didn’t bother to write notes on \(\log P\), \(\log S\), membrane/water partitioning or soil/water partitioning, since he skips over a lot of the equations. I’ll likely cover a lot of the methodology in Advanced Physical Chemistry.