Transfer hydrogenation

Transfer hydrogenation is the addition of hydrogen (H₂; dihydrogen in inorganic and organometallic chemistry) to a molecule from a source other than gaseous H₂. It is applied in industry and in organic synthesis, in part because of the inconvenience and expense of using gaseous H₂. One large scale application of transfer hydrogenation is coal liquefaction using "donor solvents" such as tetralin.