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US 4,359,577 AGranted
Non-pyrophoric nigrosine base
AssigneeAmerican Cyanamid Company
InventorsAlbrecht H. Granzow, Erwin Klingsberg
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Abstract
Nigrosine base (Color Index 50,415:1) which is pyrophoric is made non-pyrophoric by sparging a solution thereof in aniline with air.
Claims5
A method of preparing non-pyrophoric nigrosine base comprising aerating pyrophoric nigrosine base in aniline with an oxygen-containing gas at a temperature of about 20.degree.-150.degree. C. for a period of about 4 to 30 hours with agitation.
Dependencies are inferred from the claim text.