Production of Succinic Acid Directly from Tartaric Acid by Iodine-Mediated Transfer Hydrogenation

Herein, a new method to selectively convert tartaric acid to succinic acid was developed by catalytic transfer hydrogenation using iodine as the catalyst and methyl isobutyl ketone (MIBK) as both the hydrogen donor and the solvent. Under optimized reaction conditions, 85% succinic acid can be obtained directly from tartaric acid with a catalytic amount of iodine in MIBK at 160 °C for 4 h. Moreover, succinic acid can automatically precipitate out from the reaction solvent after cooling due to its much lower solubility in MIBK at room temperature, which provides an easy way for product separation. The detailed mechanism has been studied extensively by control experiments. The cheap catalyst, mild reaction condition, and easy separation of the product make this process a green path for succinic acid production.