Tetrachloro-p-hydroquinone

Xun L, E Topp, CS Orser (1992c) Purification and characterization of a tetrachloro-p-hydroquinone reductive dehalogenase from a Flavobacterium sp. J Bacterial 174 8003-8007. 

One of the primary starting materials for all members of this group is chloranil (tetrachloro-p-benzoquinone). Today, it is customarily prepared by oxidative chlorination of hydroquinone. 

A system has been proposed which involves quinone/hydroquinone interconversions. A number of such couples are insoluble in acid solution and can therefore be used as active solid masses when made conductive by the addition of graphite. A system which has been studied experimentally is based on anthraquinone, Q, and tetrachloro-p-benzoquinone (chloranil), Qr, and their reduced or hydroforms. The overall cell reactions are then... 

Pentachlorophenol and three of its biodegradation products (pentachloroanisole, tetrachloro-jo-hydroquinone, tetrachloio-p-benzoquinone), were baseline resolved in 18 min on a Cjg column (2 = 254 nm) using an isocratic 60/40 acetonitrile/water (0.1% acetic acid) mobile phase [970], This was considerably more efficient than a methanol/water gradient, not because of better resolution or shorter elution times but because there was no re-equilibration time needed between injections for the acetonitrile/water system. 

HjCat represents catechol or hydroquinone, Q quinone, SQ semiquinone anion, HCat- catechol monoanion, and Cat2 catechol dianion DTBQ represents 3,5-di-rerr-butyl-o-quinone, o-Q o-benzoquinone, p-Q p-benzoquinone, TCQ tetrachloro-o-benzoquinone, and TFQ tetrafluoro-o-benzoquinone. 

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