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US 4,795,807 AGranted
Preparation of azo dyestuffs by diazotization and coupling in the presence of an ester
AssigneeCassella Aktiengesellschaft
InventorsUlrich Buhler, Friedrich Schophoff, Wolf Weidemuller
Life of this patent
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Abstract
Azo disperse dyestuffs are prepared by diazotization and coupling in an aqueous phase, the coupling being carried out in the presence of an ester of a lower aliphatic carboxylic acid.
Claims8
Process for the preparation of azo disperse dyestuffs by diazotization and coupling in an aqueous phase, characterized in that the coupling is carried out in the presence of 0.03 to 15% by weight, relative to the total amount of water present in the reaction mixture when coupling is complete, of an ester of the formula
- R--CO--OR.sup.1
- wherein
- R denotes H;
- --(CH.sub.2).sub.n --CO--OR.sup.2 ;
- alkyl having 1 to 5 carbon atoms;
- or alkyl having 1 to 5 carbon atoms and substituted by OR.sup.3, --COOR.sup.2, O--CO--R.sup.3, --C.sub.6 H.sub.5, --OC.sub.6 H.sub.5 or --OH;
- R.sup.1 and R.sup.2 denote ##STR23## alkyl having 1 to 8 carbon atoms;
- or alkyl having 1 to 8 carbon atoms and substituted by --OR.sup.4 --COOR.sup.4, --O--CO--R.sup.4, --C.sub.6 H.sub.5, --OC.sub.6 H.sub.5, --O--(CH.sub.2).sub.m --OR.sup.4 or --OH;
- R.sup.3 and R.sup.4 denote alkyl which has 1 to 8 carbon atoms;
- n denotes 0 to 4, and
- m denotes 1 to 4.
8 more elements
Dependencies are inferred from the claim text.