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US 4,395,264 AGranted
Azo coupling process
AssigneeBASF Wyandotte Corporation
InventorGeorge W. Fenwick
Life of this patent
Estimating the term…
Abstract
The present invention relates to a process for coupling beta-naphthol with a diazotized amine as follows: 1. (a) Dissolving a beta-naphthol in water with a strong base (b) Precipitating the beta-naphthol with a strong acid and (c) Cooling the slurry. 2. Adding a diazotized amine to the beta-naphthol solution and 3. Increasing the pH in two steps, first with a strong base and then with a weak base.
Claims8
A process for coupling a beta-naphthol with a diazotized amine comprising
- 1. (a) dissolving a beta-naphthol in water with a strong base
- (b) precipitating the beta-naphthol with a strong acid and
- (c) cooling the slurry to about 0.degree. C. to 15.degree. C.
- 2. (a) adding a diazotized amine and
- 3. (a) increasing the pH to about 1.0 to 4.0 with a strong base and
- (b) further increasing the pH to about 5.0 to 10.0 with a weak base.
3 more elements
A process for producing an azo coloring material comprising:
- 1. diazotizing a substituted a amine by
- (a) mixing said amine with water
- (b) adding a strong base in amount sufficient to dissolve said amine
- (c) adding a strong acid in an amount sufficient to obtain a pH of less than about 2
- (d) cooling to about -5.degree. to 15.degree. C. and
- (e) slowly adding a slight molar excess of sodium nitrite solution and
- 2. (a) dissolving a beta-naphthol in water with a strong base
- (b) precipitating the beta-naphthol with a strong acid and
- (c) cooling the slurry to about 0.degree. C. to 15.degree. C.
- 3. (a) mixing the diazotized amine and said precipitated beta-napthol
- 4. (a) increasing the pH to a value greater than the pH resulting from steps 1-3, said greater pH falling within the range of about 1.0 to 4.0 with a strong base and
- (b) further increasing the pH to about 5.0 to 10.0 with a weak base.
9 more elements
Dependencies are inferred from the claim text.