Daniel Michelet

Selective access to hydroquinone: «Fuchsone route

Publisher Summary Hydroquinone (HQ, 4-hydroxyphenol) and catechol (PC, 2-hydroxyphenol or pyrocatechol) are industrially prepared by: (1) selective access to HQ by aniline oxidation using manganese dioxide in sulphuric medium. Yields are high, but the process suffers from the stoichiometric co-production of mineral salts which is the cause of serious environmental problems, (2) selective access of HQ through autoxidation of p. diisopropylbenzene in corresponding dihydroperoxide, which is then converted in HQ and acetone through a acid catalysis. This is a complex process involving a very high conversion of diisopropyl benzene and co-production of corresponding hydroxy hydroperoxide and dicarbinol which compels the acid scission to be performed in the presence of hydrogen peroxide in order to convert these products to HQ, and (3) Simultaneous access to HQ and PC through phenol hydroxylation by hydrogen peroxide in the presence of either a homogeneous or heterogeneous catalyst.