FIELD: chemistry.
SUBSTANCE: invention relates to a method of producing purified hydroquinone and moulding said hydroquinone into flakes from crude hydroquinone essentially containing hydroquinone and small amounts of impurities, including at least resorcinol, pyrogallol and trace amounts of pyrocatechol. The method is characterised by that it involves the following steps: a step for purifying crude hydroquinone by distillation, involving (A) distillation with removal of low-boiling substances from the top part of the column, wherein crude hydroquinone HQ° is fed into the distillation column and wherein resorcinol is removed from the top part of the distillation column, optionally together with all or some of the other light impurities, as a result of which a crude mixture M is extracted from the bottom part of the column, containing hydroquinone and heavy impurities; and (B) distillation with removal of high-boiling substances from the bottom part of the column, wherein the crude mixture M, obtained at step (A), is fed into the distillation column and wherein pyrogallol is removed from the bottom part of the column, optionally together with all or some of the other heavy impurities, as a result of which hydroquinone in purified form (HQ) is extracted from the top part of the column. Further, the method involves a step for moulding the purified hydroquinone obtained from distillation, via deposition thereof in form of a film onto a substrate made from heat-conducting material or coated with heat-conducting material, followed by solidification thereof by bringing the substrate to a suitable temperature, and then extracting the solidified hydroquinone in form of flakes using any suitable means. The time for holding the hydroquinone in the distillation column at step (A) and step (B) is less than one hour. The invention also relates to hydroquinone flakes obtained using the described method and apparatus for realising said method.
EFFECT: use of the present invention enables to avoid problems associated with use of hydroquinone powder.
39 cl, 6 dwg
