Patent ID: 8309668

Claim:
A process for producing a superabsorbent polymer comprising the steps of: I a) producing crude (meth)acrylic acid phase wherein crude (meth)acrylic acid comprises from about 1 to about 80 wt % of (meth)acrylic acid; wherein said producing crude (meth)acrylic acid phase is selected from the group consisting of gas phase oxidation, dehydration of an organic molecule having at least one OH-group wherein the organic molecule is selected from the group consisting of glycerine, lactic acid and β-hydroxypropionic acid, optionally followed by an oxidation, and liquid phase oxidation; b) distilling the (meth)acrylic acid phase of a) to obtain a (meth)acrylic acid phase, and a dimer base comprising (meth)acrylic acid dimers or (meth)acrylic acid oligomers or both; c) splitting at least a part of the (meth)acrylic acid dimers or of the (meth)acrylic acid oligomers or both from the dimer phase to obtain a (meth)acrylic acid-comprising low boiling phase, and a high boiling phase comprising less (meth)acrylic acid than the low boiling phase, wherein said high boiling phase is discarded; d) separating at least a part of the (meth)acrylic acid from the low boiling phase by forming one or more crystals to obtain a pure (meth)acrylic acid and a residue; II. polymerizing the (meth)acrylic acid in the presence of a cross linker to obtain a superabsorber polymer phase; and III. working-up the polymer phase to obtain the superabsorbent polymer.