Color reduction of polymethylene polyphenyl polyisocyanates

The present invention is directed to a process for the production of polymethylene polyphenyl polyisocyanates by phosgenating the corresponding polyamines in solution in an inert organic solvent, removing excess phosgene, and stripping the solvent. The improvement resides in adding at least 0.02 par...

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Bibliographische Detailangaben
Hauptverfasser:	ADKINS, RICK L, BLUE, CLARENCE D
Format:	Patent
Sprache:	eng ; fre ; ger
Schlagworte:	ACYCLIC OR CARBOCYCLIC COMPOUNDS CHEMISTRY COMPOSITIONS BASED THEREON MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS METALLURGY ORGANIC CHEMISTRY ORGANIC MACROMOLECULAR COMPOUNDS THEIR PREPARATION OR CHEMICAL WORKING-UP
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Beschreibung
Zusammenfassung:	The present invention is directed to a process for the production of polymethylene polyphenyl polyisocyanates by phosgenating the corresponding polyamines in solution in an inert organic solvent, removing excess phosgene, and stripping the solvent. The improvement resides in adding at least 0.02 parts by weight of reducing agent per 150 parts by weight of polyamine to the polyamines at any time prior to the stripping step.