Process for Production of (Meth)Acrylic Acid with High Boiling Fraction Work-Up By Means of Crystallization

A device for production of (meth)acrylic acid, comprising, connected with each other in fluid-conducting fashion

• α a synthesis area;
• β downstream of the synthesis area, a distillative work-up area, comprising a bottom zone formed in the lower area of the work-up area;
• γ downstream of the bottom zone, a heatable pressure container comprising an upper region and a lower region;
• and
• δ downstream of the upper region a crystallization area comprising a first outlet and at least one further outlet.

A method of using a device for production of (meth)acrylic acid, the device comprising, connected with each other in fluid-conducting fashion

• α a synthesis area;
• β downstream of the synthesis area, a distillative work-up area, comprising a bottom zone formed in the lower area of the work-up area;
• γ downstream of the bottom zone, a heatable pressure container comprising an upper region and a lower region;
• and
• δ downstream of the upper region a crystallization area comprising a first outlet and at least one further outlet the method comprising the steps of:
• a) synthesizing a crude (meth)acrylic acid phase;
• b) distillatively working-up the crude (meth)acrylic acid phase to obtain:
• a (meth)acrylic acid phase, and
• a dimer phase 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 a low boiling phase, and
• a high boiling phase comprising less (meth)acrylic acid than the low boiling phase;
• 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.

A process for the production of a polymer, comprising the steps of:

• I. producing a pure (meth)acrylic acid comprising the steps of:
• a) synthesizing a crude (meth)acrylic acid phase;
• b) distillatively working-up the crude (meth)acrylic acid phase to obtain:
• a (meth)acrylic acid phase, and
• a dimer phase 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 a low boiling phase, and
• a high boiling phase comprising less (meth)acrylic acid than the low boiling phase;
• 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 a monomer phase comprising the pure (meth)acrylic acid to obtain a polymer phase;
• and
• III. working-up the polymer phase to obtain the polymer.