Process for redissociating Michael adducts which are present in a liquid F and have been formed in the preparation of acrylic acid or esters thereof

A process for redissociating Michael adducts which have been formed in the preparation of acrylic acid or esters thereof, comprising:

• feeding a liquid F having a temperature TZ to a separating column K at a Feed Point I in a separating space of the column above a lowest separating internal;
• separating the liquid F into at least a gas stream G comprising at least one of acrylic acid and an ester thereof as Michael addition redissociation products and a reflux liquid;
• removing the gas stream G from a top space of the column K;
• collecting the reflux liquid having a temperature TSU in a bottom space of the column K having a gas pressure GD to form a bottom liquid having a liquid level S;
• removing a stream {dot over (M)} from the bottom space of the column K;
• pumping the stream {dot over (M)} at TSU via a radial centrifugal pump P having a semiopen radial impeller through a secondary space of an indirect heat exchanger UW;
• heating the stream {dot over (M)} in the heat exchanger UW to form a stream {dot over (M)}* having a temperature TRS;
• feeding the stream {dot over (M)}* to a Feed Point II in the bottom space of the column K;
• wherein
• a proportion of Michael addition product in the liquid F, is at least 10% by weight based on the weight of the liquid F,
• a pressure of the gas phase in the column K decreases from the bottom upward,
• the temperature TRS is greater than TSU and is such that at least a portion of the Michael adducts present in stream {dot over (M)}* is redissociated to form the at least one of acrylic acid and an ester thereof as Michael addition redissociation products;
• the Feed Point II is located below the lowermost separating internal of the separating column K and above the level S of the bottoms liquid,
• the level S is less than half a distance A measured from a lowest point of the column K to an underside of the lowermost separating internal,
• stream {dot over (M)}* is fed at Feed Point II in such a way that the feed stream is not directed toward the bottoms liquid;
• and
• the stream {dot over (M)}* boils at the gas pressure GD.