Process for the isolation of pyrocatechol and hydroquinone

Details Process for the isolation of pyrocatechol and hydroquinone Process for the isolation of pyrocatechol and hydroquinone

1980-07-02

1981-12-29

Sever, Frank

Distillation: processes, separatory

Plural distillations performed on same material

One a distillation under positive pressure or vacuum

203 91, 568752, 568753, B01D 310

Patent

active

043081126

ABSTRACT:
A process is described for the isolation of pyrocatechol and hydroquinone from mixtures containing the same, and phenol and higher boiling accompanying substances. The mixture can be one obtained by reacting phenol with a peroxidic hydroxylating agent and removing some of the phenol and the substances which have a lower boiling point than phenol. The mixture is subjected to a first rectification in which phenol and substances which have a boiling point between phenol and pyrocatechol are obtained overhead to leave behind a bottom product containing pyrocatechol and hydroquinone. The bottom product is subjected to a second rectification in which the pyrocatechol is obtained overhead to leave behind a bottom product containing hydroquinone and higher boiling accompanying substances. This bottom product is fed to a concentrating unit in which hydroquinone is evaporated overhead to leave behind high boiling accompanying substances as residue.

REFERENCES:
"Catalytic Hydroxylation of Phenol by Hydrogen Peroxide"; P. Maggioni et al; La Chimica E L'Industria; v 59, n 4; (Apr. 1977); pp. 239-242.
"Phenol"; Ind. Eng. Chem.; Prod. Res. Dev.; vol. 15; No. 3; (1956); pp. 212-215.

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