Hoechst Aktiengesellschaft

Eberhard Mundlos

Reinhard Mohr

Kurt Hohmann

Theodor Papenfuhs

Rudolf Lowenfeld

Wilfried Bachmann

Christian Gnabs

Norbert Kollodzeiski

Kurt Janecka

Gerhard Waese

Luis Herz

A dyeing process has been found which enables to dye uniformly polyacrylonitrile fiber materials, by using as dyestuffs basic azo dyestuffs being non-quarternized and containing neither cationic quaternary ammonium groups nor cationic N-substituted or N-unsubstituted iminium groups, said azo dyestuffs containing on the other hand at least one unsubstituted or substituted amino group, hydrazino group, amidino group or guanidino group capable of forming salts. The very dyeing process as such is carried out according to usual processing data for dyeing polyacrylonitriles in a slightly acid medium. Especially with the use of several of these dyestuffs for polychromic dyeing, such as trichromic dyeing, special advantages are obtained, insofar that even at cut-rate dyeing periods and for preparing light color shades, there are obtained even dyes with constant color shades, when using these dyestuffs having good migrating properties.

Process for dyeing uniformly polyacrylonitrile fiber materials

New basic azo dyestuffs of the formula ##STR1## where D.sup.(+) is the radical of an aromatic or heterocyclic diazo component containing a quaternary nitrogen atom,

Quaternary basic azodyestuffs containing a propenyl amino radical

An improved process for isolating 2-hydroxynaphthalenecarboxylic acids from reaction mixtures of the alkali metal salts of the 2-hydroxynaphthalene with carbon dioxide had been found which comprises diluting with water the reaction mixture which contains the di-alkali metal salt of 2-hydroxynaphthalenecarboxylic acid and 2-hydroxynaphthalene, while keeping the mixture at a temperature of at least 80.degree. C, then adjusting the pH-value to about 6 to 7 by means of aqueous mineral acid, separating the lower phase at at least 80.degree. C, cooling the upper phase to about 15.degree. to 25.degree. C, separating the 2-hydroxynaphthalene, then adjusting the pH-value to about 1 to 2 by means of aqueous mineral acid and isolating the separated 2-hydroxynaphthalenecarboxylic acid. By this novel process, work intensive operations, expensive technical apparatuses which are suspectible to repairs, solvents which do not participate directly in the reaction and therewith complicated regenerations, as known from the present art, are completely avoided. It permits clear and very easy separation of the reaction products at only one and the same stage in the process and allows in advantageous manner continuous operation.

Process for isolating 2-hydroxynaphthalene carboxylic acids from

New valuable basic oxazine dyestuffs of the formula ##STR1## in which R is hydrogen or lower alkyl, R.sub.1 is hydrogen or lower alkyl substituted by halogen, lower alkoxy, cyano or hydroxy, R.sub.2 and R.sub.3 each is hydrogen or lower alkyl or lower alkyl substituted by halogen, lower alkoxy, cyano or hydroxy, or R.sub.1 and R.sub.2 form together with the nitrogen atom the pyrrolidino, piperazino, piperidino or morpholino ring, and the phenyl nucleus a is substituted by lower alkyl, lower alkoxy, acetyl, cyano, halogen, phenoxy or trifluoromethyl, and X.sup.(.sup.-) is an anion has been found which are well suitable for the dyeing or printing of tanned cellulose fibers, silk, leather, or acetate rayon, synthetic polyamide fibers or acid-modified polyester and polyamide fibers and fibers containing polyacrylonitrile or polyvinylidene cyanide. The dyeings and prints obtained are bright and color-intensive and have good fastnesses to light and to wet processing.

Basic oxazine dyestuffs

Growing community of inventors

Heusenstamm, Germany

Eberhard Mundlos