10.01.12
• US Patent No. 8,247,620 B2; Rhodia has been awarded a US patent covering a process for the preparation of hydroquinone starting from a crude hydroquinone HQ0.
It is comprised of a refining stage that entails cooling the crude hydroquinone in a liquid form, comprising at least resorcin and pyrogallol as impurities, to effect crystallization of the pure hydroquinone; separating the pure hydroquinone crystals from the mother liquors; reheating and partially melting the separated crystals; completely melting the purified hydroquinone; and recovering the purified hydroquinone.