Process for the preparation of metallizable azo dyes carrying out coupling in an inert gas atmosphere in the presence of an ammonium salt
AssigneeCiba-Geigy Corporation
InventorsHans P. Joswig, Werner Huber
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Abstract
A process for the preparation of an azo dye of formula ##STR1## wherein K is the .beta.-naphthol radical, X is hydrogen or nitro and M is an alkali metal ion or an ammonium ion, which process comprises coupling an aqueous solution containing 15 to 30 percent by weight of a diazo component of formula ##STR2## and 6 to 20 mol % of an ammonium salt, based on the molar amount of the diazo component, at a pH in the range from 10.5 to 11.5 and in an inert gas atmosphere, to a coupling component of formula ##STR3## in which formulae (2) and (3) above K and X are as defined for formula (1). The present invention makes it possible to obtain the claimed azo dyes in high yield.
Claims13
A process for the preparation of an azo dye of formula ##STR6## wherein K is the .beta.-naphthol radical, X is hydrogen or nitro and M is an alkali metal ion or an ammonium ion, which process comprises coupling an aqueous solution containing 15 to 30 percent by weight of a diazo component of formula ##STR7## and 6 to 20 mol % of an ammonium salt, based on the molar amount of the diazo component, at a pH in the range from 10.5 to 11.5, a temperature from 32.degree. to 34.degree. C. and in an inert gas atmosphere, to a coupling component of formula ##STR8## in which formulae (2) and (3) above K and X are as defined for formula (1).
Dependencies are inferred from the claim text.