Abstract: A process for the preparation of concentrated solutions or suspensions of anionic organic compounds is described, which process comprises a) acidifying an aqueous solution or dispersion of an anionic organic compound that comprises salts and/or impurities to a pH of 4.5 or less, if the pH is above that value, so that the anionic organic compound becomes insoluble in water and precipitates out in the form of the free acid, b) bringing the suspension obtained from the previous step to a salt content below 2% by weight, based on the total weight of retentate, by means of ultra-filtration with a ceramic membrane or an acid-resistant organic membrane having a pore size of from 1 to 20 nm, and c) optionally washing out of the salts with water at a pH of less than 4.

Abstract: The dyes of formula (1) according to claim 1 and the copper complexes of dyes of formula (2) according to claim 9 or the mixtures of mono-copper complex with the bis-copper complex are excellently suitable for dyeing paper with good light-fastness properties.

Abstract: Use of the mono-copper complex of a dye of formula (1) wherein Z1, Z2, R1, R2, R3, R4, X, n and m are as defined in the claims, and mixtures thereof with the bis-copper complex of such a dye, for dyeing natural and synthetic material.

Abstract: Disclosed are dye mixtures for shading white paper which may contain fluorescent brightener. The dye mixtures comprise a violet dye according to the formula (1) or (2) indicated in claim 1 and sufficient of a red, blue or further violet anionic azo dye that this dye mixture is capable of producing in the Cielab color co-ordinates system a relative hue angle of 270 to 295° when the dyeing contains 0.00005 to 0.005% by weight of dye, based on the weight of the paper, with the proviso that the value 0.005% is excluded.

Abstract: Described is a process for preparing concentrated solutions or suspensions of anionic organic compounds which comprises a) acidifying an aqueous solution or suspension of an anionic organic compound containing salts and/or impurities to a pH of 4.5 or less, if the pH is above this value, so that b) the anionic organic compound is water-insoluble and precipitates in the form of the free acid, c) bringing the suspension to a salt content below 2% by weight, based on the total weight of the retentate, by means of ultrafiltration with a membrane having pore diameters of from 0.001 to 0.02 &mgr;m, and d) optionally washing out the salts with water having a pH below 4,5, e) optionally carrying out acid-free washing with water thereafter, and then f) concentrating, so that the amount of anionic organic compound is 5-50% by weight, and g) if desired, bringing the anionic organic compound into solution by adding an appropriate base.

Abstract: Disclosed are dye mixtures for shading white paper which may contain fluorescent brightener. The dye mixtures comprise a violet dye according to the formula (1) or (2) indicated in claim 1 and sufficient of a red, blue or further violet anionic azo dye that this dye mixture is capable of producing in the Cielab colour co-ordinates system a relative hue angle of 270 to 295° when the dyeing contains 0.00005 to 0.005% by weight of dye, based on the weight of the paper, with the proviso that the value 0.005% is excluded.

Abstract: The cationic or basic dyes of formulae (1) and (2) cited in claim 1 are particularly suitable for dyeing paper.These dyes dye paper in a yellow, orange or brown shade having good fastness properties.

Abstract: The cationic or basic aminobenzothiazole dyes disclosed herein are particularly suitable for dyeing paper.Paper is dyed with these dyes in blue or violet shades of good fastness properties.

Abstract: The dyestuffs of the formula ##STR1## in which A, R.sub.1, M and n are as defined in claim 1, are suitable for dyeing paper with good light-fastness.

Abstract: The dyes of formula ##STR1## wherein X, Y and M are as defined in claim 1, are suitable for dyeing paper with good lightfastness.

Abstract: Concentrated aqueous solutions are described comprising specific anionic disazo dyes and polyglycol amines, which are highly suitable as commercial forms.

Abstract: The dyes of formula ##STR1## wherein R, M and n are as defined in claim 1, are preeminently suitable for dyeing paper in blue shades.

Abstract: A method of dyeing paper utilizing dyes suitable for dyeing paper in blue shades having the formula ##STR1## wherein R is hydrogen, --OH, --OR.sup.1 , --NH.sub.2, NHR.sup.1, --NHCOR.sup.1, --NHSO.sub.2 R.sup.1, --NHCONH.sub.2 or --NHCONHR.sup.1, in which R.sup.1 is unsubstituted alkyl or alkyl substituted by C.sub.1 -C.sub.4 -alkoxy, hydroxy-substituted C.sub.1 -C.sub.4 -alkoxy, phenyl, phenoxy or phenylcarbamoyl, in each instance the phenyl moiety being unsubstituted or substituted by C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkoxy or phenoxy, R.sup.1 is also unsubstituted phenyl or naphthyl or phenyl or naphthyl which is substituted by sulfo, carboxy, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, halogen, nitro, C.sub.1 -C.sub.4 -alkylcarbonylamino or C.sub.1 -C.sub.4 -alkoxycarbonylamino;X, each independently of the other, is hydrogen, unsubstituted alkyl or alkoxy or alkyl or alkoxy which is substituted by C.sub.1 -C.sub.4 -alkoxy, hydroxy-substituted C.sub.1 -C.sub.

Abstract: Reactive dyes of the formula ##STR1## in which D is the radical of a diazo component of the benzene, naphthalene, azobenzene, naphthylazobenzene, azonaphthalene or phenylazonaphthalene series, K is the radical of a coupling component of the benzene or naphthalene series or of the heterocyclic series, except a pyrazolone radical, R.sub.1 and R.sub.2, independently of each other, are each hydrogen or an unsubstituted or substituted C.sub.1-4 -alkyl radical, and X.sub.1 and X.sub.2, independently of each other, are each unsubstituted or substituted aminofluoro-s-triazinyl, are particularly suitable for dyeing and printing cellulose-containing fibre materials and produce, in high dyeing yield, dyeings and prints having good fastness properties.

Abstract: Dyes of formula (1) as claimed in claim 1 can conveniently be prepared by reacting an anthraquinone compound of formula (2) with a haloformate of formula (3) in an inert organic solvent and in the presence of 1 to 2 moles of a heterocyclic tertiary nitrogen base per mole of compound of formula (2).

Abstract: A process for dyeing paper which comprises the use of dyes of the formula ##STR1## wherein R is hydrogen, hydroxyl or amino, X is the azoxy or azo group, and n is 1 or 2, and the bonds of the complexing oxygen atom in the .alpha.-position and of the azo group in the .beta.-position at the naphthalene nuclei are mutually interchangeable. Dyeings of good wetfastness and lightfastness are obtained.