Citric acid is both an alpha and beta-hydroxy acid, and exhibits the characteristic reactions of each. When heated to 175°C, it is partially
converted to aconitic acid by elimination of water, and to acetonedicarboxylic acid by the loss of carbon dioxide and water. At temperature above
175°C, citric acid yields an oily distillate, which crystallizes as itaconic acid. Further heating yields a non-crystallizable oil which is
citraconic anhydride. The hydrogenation of citric acid yields tricarballylic acid. |