Acetylsalicylic acid from aspirin tablets

Acetylsalicylic acid (ASA), or aspirin, is a common painkiller with anti-inflammatory properties. It's a useful precursor in the home lab. It can be hydrolysed to salicylic acid, which in turn can be decarboxylated to phenol, or used to prepare oil of wintergreen. There are many other uses as well. Before the ASA can be used however, it must be extracted from its off-the-counter tablet form.

To extract the ASA, I pour the tablets (usually 40 tablets containing 300mg each) into a beaker and crush them. Next I add 100ml ethanol to the crushed tablets. Acetone and isopropanol can also be used but the quantities must be changed accordingly. Anyway, I stir the ethanol and crushed tablets for about 2 minutes to dissolve the ASA, then filter the mixture. The filtrate is an ASA solution in ethanol and the residue consists of binders and additives from the tablets.

The ASA-ethanol solution can be evaporated down to yield crystals of acetylsalicylic acid (ASA).

left = starting product and right = extracted acetylsalicylic acid