Lumière–Barbier method

The Lumière–Barbier method is a method of acetylating aromatic amines in aqueous solutions.{{cite book |title=Organic chemistry |last1=Clayden |last2=Greeves |last3=Warren |year=2001 |publisher=Oxford university press |isbn=978-0-19-850346-0 |page=[https://archive.org/details/organicchemistry00clay_0/page/188 188] |url-access=registration |url=https://archive.org/details/organicchemistry00clay_0/page/188 }} Illustrative is the acetylation of aniline. First aniline is dissolved in water using one equivalent of hydrochloric acid. This solution is subsequently treated, sequentially, with acetic anhydride and aqueous sodium acetate. Aniline attacks acetic anhydride followed by deprotonation of the ammonium ion:

Image:Lumière–Barbier method step 2.svg

Acetate then acts as a leaving group:

Image:Lumière–Barbier method step 3.svg

The acetanilide product is insoluble in water and can therefore be filtered off as crystals.