Differential Extraction

Define differential extraction

A method used to separate compounds based on their different solubilities in two immiscible liquids, usually water and an organic solvent.

Structures for benzoic acid

Structures for biphenyl

Know what compound will be in the aqueous layer and ether layer

Benzoic acid goes into the aqueous layer after it reacts with base and becomes water soluble.
Biphenyl stays in the ether layer because it is nonpolar

Know which solvent is best for polar compounds and used for wide range of compounds

Water is best for polar compounds.
Ether is a common organic solvent used for many nonpolar compounds.

Purpose of acids like HCl in a reaction

HCl is used to protonate a compound, often to turn a water soluble salt back into its neutral form so it precipitates.

What is sodium sulfate used for in this experiment

It is a drying agent. It removes water from the organic layer.

Melting points, what happens when impurities are present

Impurities lower the melting point and make the melting range wider.

Define recrystallization

A purification method where a solid is dissolved in hot solvent and then slowly cooled so pure crystals form.

Why cool crystals to room temp before using an ice bath

This allows slow crystal formation first. If cooled too fast, impurities can get trapped in the crystals.