Patent ID: 6458989
Filing Date: 2002-10-01
Classification: B01D,C07C

Abstract:
A process for preparing pure (meth)acrylic acid starting from a crude (meth)acrylic acid, which comprises the following stages:A: treating the crude (meth)acrylic acid with at least one compound which is able to remove aldehydes, to give an aldehyde-free crude (meth)acrylic acid which contains acetic acid and high boilers; B: subjecting the aldehyde-free crude (meth)acrylic acid to imprecise distillation, to give a low-boiling fraction comprising at least 70% by weight of (meth)acrylic acid and also acetic acid and a high-boiling fraction comprising (meth)acrylic acid and high boilers; C: isolating a pure (meth)acrylic acid from the high-boiling fraction, and D: esterifying the low-boiling fraction comprising (meth)acrylic acid and acetic acid that is obtained in stage B by means of one or more alkanols, to give an esterification mixture comprising one or more (meth)acrylates, one or more acetic esters, and one or more alkanols.