Crystalline azopyrazolone acid dye
AssigneeE. I. Du Pont de Nemours and Company
InventorFrank Ray Hunter
Life of this patent
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Abstract
Crystalline, azopyrazolone acid dye and the preparation thereof, which dye is useful for dyeing textile materials using conventional, aqueous acid-dyeing techniques and is of the formula ##STR1## WHEREIN R is H or CH.sub.3, x is 1 or 2, y and z are each 0 or 1, the sum of y and z is 1 and M is lithium, sodium or potassium cation, said crystalline dye being characterized by the absence of absorption in the 6.0 micron region of its infrared scan.
Claims12
Crystalline, azopyrazolone acid dye of the formula
- wherein R is H or CH.sub.3, x is 1 or 2, y and z are each 0 or 1, the sum of y and z is 1 and M is ammonium, lithium, sodium or potassium cation, said crystalline dye being characterized by the absence of absorption in the 6.0 micron region of its infrared scan.
Process for preparing the crystalline, azopyrazolone acid dye of the formula ##STR8## wherein R is H or CH.sub.3, x is 1 or 2, y and z are each 0 or 1, the sum of y and z is 1 and M is ammonium, lithium, sodium or potassium cation, said crystalline dye being characterized by the absence of absorption in the 6.0 micron region of its infrared scan, which process consists of heating the dye which, in enol form, is of the formula ##STR9## wherein R, x, y and z are as defined above and M' is a cation, said dye being characterized by absorption in the 6.0 micron region of its infrared scan (using a mineral oil dispersant), in an aqueous liquid medium, at a pH above 10.0, at a temperature of 35.degree. C. to the boiling point of the aqueous liquid medium, in the presence of at least two equivalents of the cation M per equivalent of dye, with 0-1 equivalent of M being provided by M'.
Dependencies are inferred from the claim text.