2-[(2-Acetoxybenzoyl)oxy]benzoic acid

Abstract

The title compound, C16H12O6, is a common impurity of ortho-acetylsalicylic acid (aspirin). The benzene rings form a dihedral angle of 81.9 (1)° while the acetyl and carboxyl groups form dihedral angles of 74.0 (1) and 26.4 (2)°, respectively, with the benzene rings to which they are bound. In the crystal, molecules are linked by pairs of O—H...O hydrogen bonds between the carboxyl groups, forming inversion dimers.