Hydroquinone - Uses

Uses

Hydroquinone has a variety of uses principally associated with its action as a reducing agent that is soluble in water. It is a major component in most photographic developers for film and paper where, with the compound Metol, it reduces silver halides to elemental silver.

There are a variety of other uses associated with its reducing power. As a polymerization inhibitor, hydroquinone prevents polymerization of acrylic acid, methyl methacrylate, cyanoacrylate, and other monomers that are susceptible to radical-initiated polymerization. This application exploits the antioxidant properties of hydroquinone.

Hydroquinone can undergo mild oxidation to convert to the compound parabenzoquinone, C₆H₄O₂, often called p-quinone or simply quinone. Reduction of quinone reverses this reaction back to hydroquinone. Some biochemical compounds in nature have this sort of hydroquinone or quinone section in their structures, such as Coenzyme Q, and can undergo similar redox interconversions.

Hydroquinone can lose an H+ from both to form a diphenolate ion. The disodium diphenolate salt of hydroquinone is used as an alternating comonomer unit in the production of the polymer PEEK.