Process for the preparation of pyrocatechol and hydroquinone

摘要

A process for the isolation of hydroquinone, pyrocatechol, phenol and carboxylic acid from the reaction mixture containing the same such as one obtained by reaction of phenol with percarboxylic acid is disclosed. The reaction mixture is fed to a first rectification column and subjected to distillation whereby there is obtained a bottoms product containing pyrocatechol, hydroquinone and phenol. The top product is largely condensed and recycled, there being withdrawn from the top of the rectification column a mixture comprising phenol and carboxylic acid. The phenol and carboxylic acid mixture are continuously fed to a second rectification column where carboxylic acid is separated from phenol and substantially pure phenol is withdrawn from the stripping section and/or bottom of the second rectification column.