Acetic anhydride (CH
3
CO)
2
O, is a mobile, colorless liquid that has an acrid odor. It is the largest commercially produced carboxylic acid anhydride. Its chief industrial application is for acetylation reactions, and it is also used in many other applications in organic synthesis. Manufacturing processes include the acetic acid process, the acetaldehyde oxidation process, and methyl acetate carbonylation. Acetic anhydride penetrates the skin, forming burns and blisters.