Calculate partition behavior, extraction recovery, repeated stages, solvent demand, pH effects, and separation performance with clear mathematical steps and exports.
Select the calculation mode that matches your extraction problem. Enter the requested coefficient, concentration, volume, recovery, or pH values. Keep phase volumes positive and use consistent physical assumptions. The calculator converts supported units before applying each equation. For repeated extraction, the listed organic volume means fresh solvent used during every stage. Select Calculate to see the main result, supporting quantities, and substitution steps. Use the CSV or PDF buttons to save the current calculation.
Liquid-liquid extraction separates a solute between two immiscible phases. The distribution coefficient describes the equilibrium concentration ratio for a defined chemical species. A larger coefficient toward the organic phase usually means stronger transfer into that phase. The actual fraction extracted also depends on the two phase volumes, so a large coefficient does not alone guarantee high recovery.
For one extraction, the recovery fraction follows a simple phase-balance expression. Increasing organic volume or the distribution ratio raises recovery. However, using the same total solvent in several smaller portions can often recover more solute than using that solvent once. This happens because every fresh portion establishes a new equilibrium with the solute remaining in the aqueous phase.
The distribution ratio can differ from a true neutral-species partition coefficient. Ionizable compounds may change chemical form with pH. For a weak acid that partitions mainly in its neutral form, increasing pH generally lowers the effective distribution ratio. For a weak base, the trend reverses under the simplified neutral-only partition model. These calculations assume rapid equilibrium and negligible mutual solubility.
Separation factor compares distribution behavior for two solutes. A value near one indicates similar partitioning, while a larger ratio indicates stronger selectivity under the chosen conditions. Real extraction design can also involve activity coefficients, solvent loading, complex formation, temperature, emulsions, and nonideal phase behavior.
Use the inverse modes when planning an experiment. The solvent-volume mode estimates one-stage solvent demand for a target recovery. The stages mode calculates the minimum whole number of equal extractions required. Results should be interpreted with experimental data when precision matters. Always define whether your reported coefficient represents a specific species or the total analytical concentration. For laboratory planning, compare calculated recoveries with measured equilibrium values, document temperature and solvent composition, and verify that both phases remain chemically stable throughout testing.
| D | Vaq (mL) | Vorg (mL) | Single extraction recovery | Three-stage recovery |
|---|---|---|---|---|
| 1 | 100 | 25 | 20.00% | 48.80% |
| 2 | 100 | 25 | 33.33% | 70.37% |
| 4 | 100 | 25 | 50.00% | 87.50% |
| 10 | 100 | 25 | 71.43% | 97.67% |
It is the equilibrium concentration ratio of a solute between two phases under specified conditions.
Not always. A partition coefficient usually refers to one chemical form, while a distribution ratio can include all forms present in each phase.
Fresh solvent repeatedly contacts the remaining solute, creating a new equilibrium at each stage.
pH changes ionization. If only the neutral form partitions strongly, ionization lowers its effective distribution into the organic phase.
It means solute A has a larger distribution ratio than solute B under the entered conditions.
No. The equations use ideal equilibrium relationships unless your entered distribution ratios already include nonideal effects.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.