# How do you separate e and z isomers?

Nov 25, 2016

You separate them on the basis of their physical properties.

#### Explanation:

$E / Z$ isomers are different compounds, so they have different physical properties.

If they are solids, two common techniques are

Fractional Crystallization

Their solubilities may be different enough in a given solvent that one isomer may crystallize as a hot solution cools while the other isomer stays in solution.

Liquid Chromatography

Their affinities for the stationary phase may be different enough that they can be separated by liquid chromatography.

If they are liquids, three common techniques are

Liquid Chromatography

Liquids can also be separated by liquid chromatography.

Fractional distillation

The boiling points of the isomers might be different enough that you can separate them by fractional distillation.

Gas Chromatography

The affinities for the stationary phase may be different enough that they can be separated by gas chromatography.

If all else fails, you might try

Derivatization

If the isomers contain another functional group, you may be able to prepare a derivative of the isomers and separate the derivatives.