• Set up a distillation assembly / carry out an assembly with the backward flow.
• In a 250 mL dicol, pour 20 ml of pure glacial ethanol acid, 15 mL of isoamyl alcohol (or 3 - methylbutan - 1- ol), then 1 mL of concentrated sulfuric acid.
• Add a few grains of pumice, then heat the whole with the backward flow for 30 minutes.
• Cool the dicol, then pour its content into a 250 mL separatory funnel.
• Add 25 mL of sodium bicarbonate solution.(CAUTION : A strong bubbling occurs. As soon as the gas evolution has almost ceased, seal the funnel, then shake / stir it with its valve open to eliminate the gas which is produced, and let it decant.)
• Throw away the aqueous phase into the sink, and pour the organic phase into a dry Erlenmeyer flak.
• Dry the organic phase with some anhydrous magnesium sulfate. Filtrate it on a paper folded filter, then collect the fitrate into a 100 mL ground-in monocol fat flask / a ground-in boiling flask.
• Distil the dry organic phase, and collect the portion over 137° temperature into a ground-in 50 mL Erlenmeyer flask (isoamyl acetate or ethanoate of 3 - methylbutyl).

CAUTION : It is important to work under a hood and to wear gloves and safety goggles while manipulating glacial ethanol acid and concentrated sulfuric acid.

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