3-(5-tert-Butyl-2-hydroxybenzoyl)propanoic acid

The title compound, C12H18O4, was synthesized as a part of an investigation into corrosion inhibitors, as it is structurally related to the commercial reagent Ircagor 419. The molecules form centrosymmetric dimers due to hydrogen bonding involving the carboxyl groups, typical for the crystal structures of carboxylic acids. There is also an intramolecular hydrogen bond between the phenol hydroxyl group and the ortho keto O atom. pi - pi interactions between benzene rings link the molecules into stacks running along the a axis (distances between the planes of adjacent molecules are 3.305 and 3.389 angstrom). Intermolecular hydrogen bonds, together with the stacking interactions, give rise to infinite sheets parallel to the ac plane of the crystal structure.