# Phase-Phase Partitioning¶

Abstract

## What do we predict with SMx Solvation Models¶

Solvation free energy Vapour pressure Partition coefficient

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.