Extraction Partition Coefficient Calculator

Work out extraction partition coefficient instantly with clear inputs, formula shown and shareable results.

About Extraction Partition Coefficient Calculator

The partition coefficient is the ratio of equilibrium concentrations in the two phases and is a property of the solute and solvent pair. How much actually transfers also depends on the volumes: the fraction extracted is KdVo/(KdVo + Va). With Kd = 4 and equal volumes, 80% moves across in one contact, which is why two small washes beat one large one.

Formulas

Partition coefficient

Kd = [solute in organic] / [solute in aqueous]

Fraction extracted

fraction = Kd.Vo / (Kd.Vo + Va)

Worked example

With the default values below, Extraction Partition Coefficient Calculator returns Partition Coefficient Kd of 4.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Solute concentration in the organic phaseminimum 0 g/L: 8 g/L
Solute concentration in the aqueous phaseminimum 0 g/L: 2 g/L
Organic phase volumeminimum 0 mL: 50 mL
Aqueous phase volumeminimum 0 mL: 50 mL

Results

Partition Coefficient Kd: 4.000
Extracted Into The Organic Phase: 80.00%
Left In The Aqueous Phase: 20.00%
log P: 0.6021

Step by step

1Values used
2Partition coefficient
3Fraction extracted
4Partition Coefficient Kd= 4.000
5Extracted Into The Organic Phase= 80.00
6Left In The Aqueous Phase= 20.00
7log P= 0.6021

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why are several small extractions better than one big one?

Each contact removes the same fraction of what remains, so repeating compounds the recovery. Three 20 mL washes beat one 60 mL wash at the same Kd.

What is log P?

The base-ten log of the partition coefficient, usually for octanol-water. It is the standard lipophilicity measure in drug design.