High caustic coupling process for preparing substituted 2-nitro-2'-hydroxyazobenzenes
First Claim
1. A process for the production of a compound of the formula ##STR7## wherein T7 is hydrogen or chlorine,T8 is hydrogen, chlorine, lower alkyl of 1 to 4 carbon atoms, lower alkoxy of 1 to 4 carbon atoms, carboalkoxy of 2 to 9 carbon atoms, carboxy or --SO3 H,T9 is alkyl of 1 to 12 carbon atoms, alkoxy of 1 to 4 carbon atoms, phenyl, phenyl substituted with alkyl groups, said alkyl groups having 1 to 8 carbon atoms, cycloalkyl of 5 to 6 carbon atoms, carboalkoxy of 2 to 9 carbon atoms, chlorine, carboxyethyl or arylalkyl of 7 to 9 carbon atoms,T10 is hydrogen, alkyl of 1 to 12 carbon atoms, lower alkoxy of 1 to 4 carbon atoms, aralalkyl of 7 to 9 carbon atoms, chlorine or hydroxyl, andT11 is hydrogen, which comprisesadding an essentially stoichiometric to a small excess amount, relevant to the phenol to be coupled, of an aqueous mineral acid solution of a diazonium salt of an amine of the formula ##STR8## where T7 and T8 are defined as above, to a strongly alkaline lower alkanol or aqueous lower alkanol solution of a phenol of the formula ##STR9## where T9, T10 and T11 are defined as above, containing alkali metal hydroxide in sufficient amount to neutralize completely the acid diazonium salt solution as added and to still provide an excess of hydroxyl ion concentration and to provide a pH value substantially over 11 throughout the coupling reaction in the reaction mixture, wherein the reaction solvent mixture is at least 50% by weight of lower alkanol, while maintaining the reaction temperature between -15°
- C. and +30°
C., andacidifying the reaction mixture to isolate the product.
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Abstract
Substituted 2-nitro-2'"'"'-hydroxyazobenzenes are prepared by adding an aqueous mineral acid solution of a diazotized o-nitroaniline to a strongly alkaline lower alkanol or aqueous lower alkanol solution of a substituted phenol, containing sufficient alkali metal hydroxide to assure a pH value substantially over 11 and an excess of hydroxyl ion in the reaction mixture even after all the acidic diazonium salt solution is added, wherein the reaction solvent mixture is at least 50% by weight of lower alkanol, at a reaction temperature between -15° C. and +30° C.
The o-nitroazobenzenes obtained are intermediate products useful in the manufacture of benzotriazole UV absorbers.
49 Citations
11 Claims
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1. A process for the production of a compound of the formula ##STR7## wherein T7 is hydrogen or chlorine,
T8 is hydrogen, chlorine, lower alkyl of 1 to 4 carbon atoms, lower alkoxy of 1 to 4 carbon atoms, carboalkoxy of 2 to 9 carbon atoms, carboxy or --SO3 H, T9 is alkyl of 1 to 12 carbon atoms, alkoxy of 1 to 4 carbon atoms, phenyl, phenyl substituted with alkyl groups, said alkyl groups having 1 to 8 carbon atoms, cycloalkyl of 5 to 6 carbon atoms, carboalkoxy of 2 to 9 carbon atoms, chlorine, carboxyethyl or arylalkyl of 7 to 9 carbon atoms, T10 is hydrogen, alkyl of 1 to 12 carbon atoms, lower alkoxy of 1 to 4 carbon atoms, aralalkyl of 7 to 9 carbon atoms, chlorine or hydroxyl, and T11 is hydrogen, which comprises adding an essentially stoichiometric to a small excess amount, relevant to the phenol to be coupled, of an aqueous mineral acid solution of a diazonium salt of an amine of the formula ##STR8## where T7 and T8 are defined as above, to a strongly alkaline lower alkanol or aqueous lower alkanol solution of a phenol of the formula ##STR9## where T9, T10 and T11 are defined as above, containing alkali metal hydroxide in sufficient amount to neutralize completely the acid diazonium salt solution as added and to still provide an excess of hydroxyl ion concentration and to provide a pH value substantially over 11 throughout the coupling reaction in the reaction mixture, wherein the reaction solvent mixture is at least 50% by weight of lower alkanol, while maintaining the reaction temperature between -15° - C. and +30°
C., andacidifying the reaction mixture to isolate the product. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- C. and +30°
Specification
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- Resources
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Current AssigneeCIBA Specialty Chemicals
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Original AssigneeCiba-Geigy Corporation (Novartis Ag)
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InventorsWinter, Roland A. E., Dexter, Martin
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Primary Examiner(s)Higel, Floyd D.
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Application NumberUS06/222,808Time in Patent Office603 DaysField of Search260/206, 260/207, 260/144US Class Current534/582CPC Class CodesC07C 37/14 by addition reactions, i.e....C07C 39/15 with all hydroxy groups on ...C07D 249/20 with aryl radicals directly...C08K 5/23 Azo-compoundsC08K 5/3475 condensed with carbocyclic ...C09B 29/10 from coupling components co...C09D 7/48 Stabilisers against degrada...
