摘要 |
<p>Hydroquinone devoid of impurities is prepared from a crude hydroquinone essentially containing hydroquinone and small amounts of impurities including at least resorcinol, pyrogallol and traces of pyrocatechol and comprises at least the following steps: dissolving the crude hydroquinone in water, crystallizing the hydroquinone, separating the purified hydroquinone, and, optionally, drying the purified hydroquinone.</p> |