Basf Aktiengesellschaft

J&ouml;rg Heilek

Bernd Eck

Volker Schliephake

Otto Machhammer

Dieter Baumann

Herbert Helfert

Joachim Thiel

Rudolf Erich Lorenz

Martin Schmidt-Radde

Melanie Brunner

Theo Proll

Bernhard Maltry

Klaus Br&ouml;llos

The invention describes a process for the isolation of pure N-vinylpyrrolidone from N-vinylpyrrolidone-containing crude products, comprising a single-stage or multistage crystallization process, which comprises passing the mother liquor from the first crystallization stage either to a distillative and/or extractive purification, or returning it to an N-vinylpyrrolidone-containing product stream of the preparation process.

Method for obtaining pure n-vinyl pyrrolidone

Acrylic acid or methacrylic acid is purified be crystallization to obtain crystals and a mother liquor, by a process in which the crystals are washed with a was liquid containing the acid and having a temperature from 15 to 40&deg; C. Furthermore, a process for the preparation of acrylic acid or methacrylic acid comprises the abovementioned purification process.

Method of purifying and producing acrylic acid or methacrylic acid

Method for producing a granulate from a melt

Method for producing acrylic acid

In a process for purifying acrylic acid by crystallization by means of vacuum evaporation, a solution which contains acrylic acid and water and may contain further components is crystallized by means of vacuum evaporation with formation of a liquid phase, consisting of a mother liquor containing more than 10% by weight of water and of the crystals, and a vapor phase, the vapor phase is introduced into a liquid material in a condensation zone with formation of a liquid condensation mixture, and the liquid condensation mixture is recycled at least partly to the condensation zone, the operating conditions in the condensation zone being established so that no solid is precipitated.

Purification of acrylic acid by crystallization by means of vacuum evaporation

Growing community of inventors

Bammental, Germany

Jörg Heilek

Growing community of inventors

Bammental, Germany

J&ouml;rg Heilek

Jörg Heilek