Liquid-liquid extraction is a separation technique based on the difference in solubility of a solute in two immiscible liquids.
Immiscibility means that two liquids do not form a homogenous solution when mixed and partition into different phases.
Non-polar solutes generally partition into the organic phase, while polar solutes partition into the aqueous phase.
The partition coefficient is the ratio of solute concentration in the organic layer to the solute concentration in the aqueous layer.
Acid-base extraction is used to extract organic compounds from an organic solvent to an aqueous phase by transforming the solute to its ionic salt phase. This makes the solute more soluble in the aqueous phase than in the organic phase.
Source: Lara Al Hariri at the University of Massachusetts Amherst, MA, USA
Here, we show the laboratory preparation for 10 students working in pairs, with some excess. Please adjust quantities as needed.
1 Lab stand with ring fixture |
1 Hotplate |
1 Vacuum pump (or house vacuum) |
1 Medium 3-prong clamp |
1 125-mL separatory funnel with a stopper |
1 125-mL Erlenmeyer flask |
3 10-mL glass graduated cylinders |
2 50-mL glass graduated cylinders |
2 50-mL beakers |
3 100-mL beakers |
1 600-mL beaker |
1 250-mL filter flask |
1 Büchner funnel |
2 60-mL glass funnels |
2 100-mm watch glasses |
2 Glass stirring rods |
2 24/40 rubber adapters |
2 Pasteur pipette bulbs |
2 Small spatulas |
1 Package of pH paper |
1 Roll of lab tape and pen |