It has been pointed out previously that the butane/water partition coefficient is a key parameter in the determination of extraction affinity. We have taken 43 such partition coefficients and have obtained a very satisfactory correlation with Abraham solvation parameters. Similarly, we have obtained a good correlation of 43 gas/butane partition coefficients. These correlations are general, and can be used to predict further values of the butane/water and gas/butane partition coefficient.