Salicylic Acid: Sodium Phenolate and Carbon Dioxide

Salicylic acid is the acid in aspirin. Kolbe's method, as Gattermann (1914) teaches it: make sodium phenolate, dry it to a dust, heat it slowly from 110 to 200 °C in a stream of carbon dioxide, then free the acid with hydrochloric acid and purify it with superheated steam. Everything depends on the phenolate being perfectly dry. Phenol burns skin and poisons through it: gloves and goggles throughout. The picture: salicylic acid needles (Wikimedia Commons).