Manufacture of concentrated solutions, having a low salt content, of cobalt and chromium 1:2 complex dyes which are free from sulfonic acid groups
AssigneeBASF SE
InventorOtto Kaufmann
Life of this patent
Estimating the term…
Abstract
A process for the manufacture of concentrated solutions, having a low salt content, of o,o'-dihydroxy-or o,o'-dihydroxycarboxy-cobalt and -chrominum 1:2 complex dyes which are free from sulfonic acid groups, wherein the metallizing is carried out in water and a solvent of the formula I ##STR1## where X is hydrogen or methyl, m is 0 or 1, n is 1, 2 or 3 and R and R.sup.1 independently of one another are hydrogen or alkyl of 1 to 4 carbon atoms, in the presence or absence of additional solvents, and in the presence of water-soluble salts.
Claims9
A process for the manufacture of a solution, which has a low salt content, of a sulfonic acid group-free o,o'-dihydroxy- or o,o'-hydroxycarboxy-azo dye cobalt or chromium 1:2 complex, which process comprises:
- metallizing the azo dye with a metallizing agent to complex said dye with chromium or cobalt, the metallizing being carried out in water and a solvent consisting essentially of an organic compound of the formula:
- ##STR19## in which A is hydrogen or methyl, m is zero or 1, n is an integer of from 1 to 3 and R and R.sup.1 are, each independently, hydrogen or alkyl of 1 to 4 carbon atoms, and in the presence of at least one water-soluble salt selected from the group consisting of alkali metal and magnesium salts, and
- separating the resulting two-phase system whereby the aqueous phase takes up the salts while the organic phase results in a concentrated solution, of low salt content, of the metal complex dye.
Dependencies are inferred from the claim text.