DE964083C - Process for the preparation of an acidic wool dye of the anthraquinone series - Google Patents

Description

ISSUED MAY 16, 1957

F 138.04 IVb / 22 b

It has been found that a valuable acidic wool dye of the anthraquinone series is obtained, if p-nitrobenzyl chloride is condensed with benzene according to Friedel-Crafts, the resultant p-Nitrodiphenylmethane reduces the benzene nucleus substituted by the amino group catalytically hydrogenated, the amine thus obtained, the p-benzylhexahydroaniline, in a known manner with leucoquinizarin or quinizarin converts and then sulfonated. The reduction of the nitro group and the Hydrogenation of the pure benzene nucleus can optionally take place at the same time.

It is already known that by condensation of leucoquinizarin with the isomeric o-derivative (o-benzylhexahydroaniline) and then Sulphonation gives a dye with similar properties. That for the manufacture This dye required o-benzylhexahydroaniline is only technically difficult accessible (see Tiffenau, Bulletin de la societe chimique de France, 4th series 1922, vol. 31, p. 331). In addition, the reaction of leucoquinizarin takes place with this o-substituted amine significantly poorer yield than the implementation of the isomeric p-compound.

example

In 1000 parts by weight of benzene there are 210 parts by weight Aluminum chloride and then 255 parts by weight of p-nitrobenzyl chloride

703 514/252

Stirring entered in portions. The temperature rises to about 50 ^° . The mixture is left to stir overnight. The next morning, the reaction mass is poured into water and the benzene layer, which contains the p-nitrodiphenylmethane, is separated off. After the excess benzene has been distilled off, the p-nitrodiphenylmethane formed is then distilled under a pressure of 12 mm. It is obtained in a yield of over 80% of theory / The reduction is carried out in the usual way, e.g. B. with iron and mineral acids or by means of hydrogen with the addition of z. B. of nickel catalysts. The hydrogenation of the product in the benzene nucleus carrying the amino group is carried out in a known manner with hydrogen using a hydrogenation catalyst, e.g. B. cobalt oxide performed.

50 parts by weight of leucoquinizarin and 100 parts by weight p-Benzylhexahydroaniline is stirred for 5 hours at 100 °, then it is added

300 parts by weight of nitrobenzene and ι part by weight of piperidine are added to the viscous reaction mass, heated to the boil and kept at the boiling temperature for ^{1 to 2 hours.} On cooling, the condensation product separates out in crystalline form and is isolated in the customary manner in good yield (over 90% of theory).

The dye is absorbed on wool in a clear, blue shade and has a very good color Wet fastness.

The condensation can also be carried out in a suitable solvent or diluent, z. B. butyl alcohol or o-dichlorobenzene run.

Claims (1)

PATENT CLAIM: Process for the preparation of an acidic wool dye the anthraquinone series, characterized in that p-nitrobenzyl chloride condensed with benzene according to Friedel-Crafts, the resulting p-nitrodiphenylmethane is reduced, catalytically hydrogenated the benzene nucleus substituted by the amino group, the thus obtained Amine reacts in a known manner with leucoquinizarin or quinizarin and then sulfonated. Considered publications:
British Patent No. 585,730;
French Patent No. 943 286;
Belgian patent specification No. 494 144.