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US 8,026,387 B2Granted
Method for producing isocyanates
AssigneeBASF SE
InventorsMatthias Kloetzer, Eckhard Stroefer, Heinrich-Josef Blankertz
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Abstract
The present invention relates to a multiple-stage process for the continuous preparation of organic, distillable polyisocyanates, preferably diisocyanates, more preferably aliphatic or cycloaliphatic diisocyanates, by reaction of the corresponding organic poly-amines with ureas to form low-molecular monomeric polyureas, and the thermal decomposition thereof.
Claims11
A process for the preparation of a di- or polyisocyanate, comprising:
- reacting at least one di- or poly-amine with urea to form a di- or poly-urea and ammonia;
- removing the ammonia formed in the reaction of the at least one di- or polyamine with urea;
- separating off excess urea and minor components formed in the reaction from the formed di- or poly-urea;
- and
- thermally decomposing the di- or poly-urea from which ammonia, excess urea and minor components have been separated in a disintegrator to form a crude di- or polyisocyanate and ammonia to obtain vapors containing di- or poly-urea and ammonia;
- and
- cooling the obtained vapors to separate the di- or poly-urea from the ammonia;
- wherein a residence time in the thermal disintegrator for the thermal decomposition is from 0.01 to 20 seconds.
5 more elements
Dependencies are inferred from the claim text.