A process is proposed for distillatively working up an aqueous composition which comprises 1,1,2.2-tetramethoxyethane, glyoxal dimethyl acetal and methanol, wherein the workup of this composition is carried out in a dividing wall column to form low boiler, medium boiler and/or high boiler fractions, and a dividing wall is disposed in the longitudinal direction in the dividing wall column to form an upper common column region, a lower common column region, a feed section having rectifying section and stripping section and a withdrawal section having stripping section and rectifying section, and the aqueous composition is fed into the middle region of the feed section.