Patent GB-443859-A (GB)
Title: Process for dyeing leather
IPC: B60L7/00
Filed: 1934-12-07
Abstract: Acid wool and mordant dyes, dyeing with; azo dyes.--Leather, especially chrome leather, is dyed with a salt of an aminoazobenzenesulphonic acid containing in the residue of the coupling component a mono- or poly-oxyalkyl-amino group and containing, if desired, other nuclear substitutents.  The neutralized hides are dyed in the rotary cask with 150--200 per cent of water at 65 DEG  C., a solution of 1--2 per cent of the dyestuff being introduced through the hollow axle, the fat liquor being added after 45 minutes, and the cask being then kept in motion for a further 45 minutes, or longer in the case of heavy hides.  Examples are given of the preparation of the dyestuffs: (1) 3-aminobenzenesulphonic acid --> di - (b  - oxyethyl) aminobenzene which dyes leather a powerful yellow throughout; (2) 2-chloraniline --> 3-di-(b -oxyethyl)aminobenzenesulphonic acid, which dyes chrome leather a powerful yellow throughout; (3) 4-nitraniline --> 3-N-ethyl-(b -oxyethyl)aminobenzenesulphonic acid, which dyes chrome leather brownish red throughout; (4) 5 - nitro - 2 - aminobenzenesulphonic acid --> 3 - chloro - 1 - di - (b  - oxyethyl)aminobenzene which dyes chrome leather deep bordeaux red on the surface and dark red violet in the interior. A table is also given showing the shades obtainable on the surface and in the interior of the leather with various combinations of dyestuff components, additional diazo components being 2 : 5- and 3 : 4-dichloranilines, 2- and 3-nitranilines, 4-chloro-2-nitraniline, 2 : 6-dichloro - 4 - nitraniline, 2 : 4 - dinitraniline, 3 - nitro - 4 - aminotoluene, 4 - nitro - 2 - amino - 1 - methoxybenzene, 4 - nitro - 2 - amino - 1 - (b  - oxyethyl) - oxybenzene, 3 - nitro - 4 - amino-1 - ethoxybenzene, 6 - nitro - 3 - amino - 4 - methoxytoluene, 4 - aminobenzenesulphonic acid, 4 - chloro - 2 - aminobenzenesulphonic acid, 6 - chloro - 3 - aminobenzenesulphonic acid, 2 : 5 - dichloro - 3 - and 4 - aminobenzenesulphonic acids, 3 - nitro - 4 - aminobenzenesulphonic acid and 4-nitro-2-aminobenzenesulphonic acid, and additional coupling components being di-(b  : g  - dioxypropyl)aminobenzene, b -oxyethylaminobenzene, 3 - (b  - oxyethyl)aminotoluene (cf. Specification 181,750, [Class 2 (iii)]), 3-di-(b -oxyethyl)aminotoluene, 4 - chloro - 2 - di - (b  - oxyethyl)amino - 1 - methoxybenzene, 3 - di - (b  - oxyethyl)aminophenol, 3 - di - (b : g  - dioxypropyl)aminotoluene, 3 - chloro - 1 - di - (b  : g  - dioxypropyl)amino benzene, 3 - (b  - oxyethyl)amino - 4 - methoxytoluene, 3 - di - (b  - oxyethyl)amino - 4 - methoxytoluene, 3 - di - (b  : g  - dioxypropyl) amino - 4 - methoxytoluene and 2 - di - (b  -oxyethyl)amino - 1 : 4 - dimethylbenzene.  Specification 438,398 also is referred to.  3 - Di - (b  - oxyethyl)aminobenzenesulphonic acid is obtained by heating glycol chlorhydrin (2 mols.) with metanilic acid (1 mol.) in presence of alkali.  3 - N - Ethyl - (b  - oxyethyl)aminobenzenesulphonic acid is obtained by heating glycol chlorhydrin (1 mol.) with ethylmetanilic acid (1 mol.) in presence of alkali. 3 - Chlor - 1 - di - (b  - oxyethyl)aminobenzene and 3 - chloro - 1 - di - (b  - g  - dioxypropyl) aminobenzene are obtained by reaction of glycol chlorhydrin and glycerol a -monochlorhydrin respectively with 3-chloraniline (cf. Specification 181,750).  4 - Chloro - 2 - di - (b - oxyethyl)amino-1-methoxybenzene is similarly obtained from glycol chlorhydrin and 4-chloro-2-amino-1-methoxybenzene.  4 - Nitro - 2 - amino - 1 - (b  - oxyethyl)oxybenzene is obtained by partial reduction of 2 : 4 - dinitro - 1 - (b  - oxyethyl)oxybenzene with sodium disulphide.  Di - (b  : g  - dioxypropyl)aminobenzene is obtained by boiling aniline (1 mol.) and glycerol-a -monochlorhydrin (2 mols.) with an aqueous suspension of calcium carbonate.  3 - Di - (b  : g  - dioxypropyl)aminotoluene is obtained by heating glycerol-a -monochlorhydrin with m-toluidine.  3 - Di - (b  : g  - dioxypropyl)amino - 4 - methoxytoluene is obtained by reaction of glycerol-a -monochlorhydrin with 3-amino-4-methoxy-1-methylbenzene.