Isolation of acrylic acid by means of a distillation column having a side offtake

A process for separating acrylic acid from a composition that comprises acrylic acid and an accompanying product, the process comprising:

• first, contacting the composition with an aqueous liquid stream, thereby obtaining a liquid solution comprising acrylic acid, accompanying product, and water,
• adding an entrainer to the liquid solution, thereby obtaining a heterogeneous minimum azeotrope with the water of the liquid solution,
• separating the liquid solution by distillation into an overhead product comprising the minimum azeotrope and a bottom product comprising acrylic acid and the accompanying product,
• separating the overhead product into water and a recirculatable entrainer, and
• separating the bottom product by distillation into acrylic acid and the accompanying product,
• wherein separating the bottom product comprises:
• introducing and separating the bottom product in a distillation column that comprises a side offtake,
• taking off high-boiling constituents of the accompanying product from a bottom of the distillation column,
• taking off low-boiling constituents of the accompanying product from a top of the distillation column, and
• taking off the acrylic acid from the side offtake,
• wherein taking off the acrylic acid from the side offtake comprises taking off the acrylic acid from the side offtake in a liquid form,
• wherein the distillation column is a dividing wall column comprising a dividing wall extending essentially vertically through the column,
• wherein the dividing wall extends from a dividing wall-free top region to a dividing wall-free bottom region or to a floor of a bottom, and
• wherein the distillation column further comprises a barrier wall that is constructed to close off a part of the distillation column located on a side of the side offtake from the dividing wall-free top region.