method for the extraction of maleinezuuran hydride from waste water from the production of ftaalzuuranhydride.

摘要

Maleic anhydride is recovered by evaporating the effluent from the production of phthalic anhydride at from 40 DEG to 150 DEG C and from 50 to 760 mm to a water content of less than 10% by weight, heating the concentrate in a thin-film or falling-film evaporator at from 100 to 600 mm at from 120 DEG to 180 DEG C and distilling it in a column. The pure maleic anhydride is withdrawn laterally and the aqueous condensate is recycled to the offgas scrubber.