Process for the preparation of a dyestuff consisting substantially of only unsymmetrical 1:2-chromium complex azo dyestuffs
AssigneeHoechst Aktiengesellschaft
InventorsFritz Meininger, Hermann Fuchs
Life of this patent
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Abstract
Process for preparing a dyestuff consisting essentially of only unsymmetrical 1:2-chromium complex azo dyestuffs by heating a mixture of o,o'-dihydroxy azo dyestuffs and o-carboxy-o'-hydroxy azo dyestuffs, both being free from sulfonic acid groups, with chromium-III chloride in an organic solvent at a temperature of 105.degree. to 120.degree.C until the portion of o,o'-dihydroxy azo dyestuff is completely metallized and completing the 1:2-chromium complex formation by adjusting the pH-value to 5.0-6.5, and heating at a temperature of 70.degree. to 90.degree.C.
Claims15
A process for the preparation of a dyestuff consisting essentially of an unsymmetrical 1:2-chromium complex azo dyestuff of the formula ##SPC7##
- wherein A is phenylene unsubstituted by sulfonic acid or phenylene unsubstituted by sulfonic acid and substituted by chlorine, bromine, nitro, methyl, ethyl, methoxy, ethoxy, sulfamoyl or carbamoyl, B and X each is naphthalene, pyrazolone or acetoacetyl-phenylamide each of which is unsubstituted by sulfonic acid, and R is hydrogen, chlorine, bromine, methyl, .beta.-hydroxyethylsulfonyl, carboxyl, sulfamoyl, sulfo-N-monoalkylamino or sulfo-N-dialkylamino in which said alkyl is of one to four carbon atoms, which process comprises heating a mixture of an o,o'-dihydroxy azo compound of the formula ##EQU2## and an o-carboxy-o'-hydroxy azo compound of the formula ##SPC8##
- said compounds of the formulas (2) and (3) being unsubstituted by sulfonic acid, in a molar ratio of said compound of the formula (2) to said compound of the formula (3) in the range of about 1:0.75 to about 1:1 with about 1.0 to 1.1 molar amount of chromium-III compound, calculated on the compound of formula (2), in an organic solvent to a temperature of about 105.degree.C. to about 120.degree.C. to completely metallize said compound of the formula (2), and then heating said mixture at a pH of about 5.0 to about 6.5 at a temperature of about 70.degree.C. to about 90.degree.C. to form said unsymmetrical dyestuff of the formula (1).
A process for the preparation of a dyestuff consisting essentially of an unsymmetrical 1:2 chromium complex azo dyestuff of the formula ##SPC9##
- wherein A is phenyl substituted by a member selected from the group consisting of hydrogen, chlorine, nitro, chlorine and nitro, di-nitro, methyl, .beta.-hydroxyethylsulfonyl, N,N-diethylsulfonamide and sulfonamide;
- B and X each is naphthylene, acetoacetyl-phenylamide or pyrazolone containing a member selected from the group consisting of hydrogen, phenyl-methyl, di-chlorophenyl-methyl and phenyl-methyl-.beta.-hydroxyethylsulfonyl;
- and R is a member selected from the group consisting of hydrogen, chlorine, .beta.-hydroxyethylsulfonyl, carboxyl and sulfonamide, which process comprises:
- a. heating a mixture of an o,o'dihydroxy azo compound of the formula ##EQU3## and an o-carboxy-o'-hydroxy azo compound of the formula ##SPC10##
- in a molar ratio of said compound of the formula (2) to said compound of formula (3) in the range of about 1 :
- 0.75 to about 1 :
- 1 with about 1.0 to 1.1 molar amount of chromium-III- calculated on the compound of formula (2), said heating being carried out in an organic solvent selected from the group consisting of n-butanol, ethylene glycol and mixtures thereof at a temperature of about 105.degree.C. to about 120.degree.C. to substantially completely metallize said compound of the formula (2);
- b. then adjusting the pH of the mixture to about 5.0 to 6.5;
- and
- c. heating said mixture at a temperature of about 70.degree.C. to about 90.degree.C. to form said unsymmetrical dyestuff consisting essentially only of the dyestuff of the formula (1).
Dependencies are inferred from the claim text.