Patent GB-667168-A (GB)
Title: Process for the preparation of chromium containing mono-azo dyestuffs
IPC: C09B45/16
Filed: 1948-09-11
Abstract: Methylsulphone substituted azo dyestuff components are manufactured by methylating appropriate sulphinic acids, e.g. with dimethyl sulphate, or by oxidizing methyl phenyl thioethers, e.g. with hydrogen peroxide.  Thus, methylsulphonyl-o-aminophenols and their alkyl ethers (e.g. 2-aminophenol-4-methylsulphone and its methyl and ethyl ethers) are obtainable from o-nitrochlorobenzenesulphonyl chlorides by mildly reducing the sulphochloride group with sodium sulphite, methylating the resulting sulphinic acid, replacing the chlorine atom by a hydroxy or alkoxy group by the action of caustic alkali or an alcoholate, and reducing the nitro group, e.g. with sodium sulphide.  4 - Chloro - 9 - aminophenol - 6 - methylsulphone and 6 - chloro p  - 2 - aminophenol - 4 - methylsulphone are prepared by treating 1 : 4-dichlorobenzene-2-methylsulphone or 1 : 2-dichlorobenzene-4-methylsulphone with caustic alkali to replace the chlorine atom in the 1-position by a hydroxy group, nitrating the product and reducing the nitro group.  6 - and -5 Nitro - 2 - aminophenol - 4 - methylsulphones are prepared by nitration of, respectively, 2-aminophenol-4-methylsulphone or the benzoxyazolone obtained therefrom by the action of phosgene in an alkaline medium, followed, in the latter case, by hydrolysis.  2 - Aminophenol - 4 : 6 - di - (methylsulphone) is prepared by nitrating 1-hydroxybenzene-4 : 6-di-(methylsulphone) and reducing the nitro group.  Methylsulphonyl - o - carboxyamines (e.g. 2-aminobenzoic acid-4-methylsulphone) are prepared by oxidizing the methyl group in o-nitro-methyl-methylsulphonylbenzenes (e.g. with permanganate) and reducing the nitro group.  Methylsulphone substituted acetoacetic anilides are prepared by condensing aminobenzene-methylsulphones with diketene or b -ketocarboxylic esters.  Methylsulphone substituted 1-aryl-5-pyrazolones are obtainable from the same starting materials by converting the amino group to a hydrazino group and condensing the product with a b -ketocarboxylic ester.  Methylsulphone substituted naphthols are prepared from O-acylnaphtholsulphonic acids by way of the sulphonyl chloride and sulphinic acid, with final saponification of the acyloxy group.  A list of the last two types of coupling components is given.  Specifications 186,635, [Class 2 (iii)], 467,549 and 561,548 are referred to.ALSO:Chromed monoazo dyestuffs are manufactured by chroming monoazo dyestuffs of the general formula <FORM:0667168/IV (c)/1> wherein A represents the radical of a diazo component and B the radical of a coupling component coupling in the position adjacent to the group represented by Y, X represents a hydrogen or carboxyl group or a substituent convertible thereto under the conditions of the chroming reaction (e.g. a chlorine or bromine atom or a methoxy, ethoxy, carbomethoxy, carbethoxy or p-toluenesulphonyloxy group), in o-position to the azo group, Y represents a hydroxy group (including the enol form of a carbonyl group), and n is 1 or 2, the methylsulphone group or groups being bound aromatically to A or B, which may contain further non-ionizing substituents (e.g. halogen atoms or alkyl, alkoxy, acylamino, nitro or carboxylic acid amide groups).  The starting materials are obtainable from appropriate diazo and coupling components, especially from diazotized di-(methylsulphonyl)-o-aminophenols and coupling components free from methylsulphonyl groups, or from diazotized mono-(methylsulphonyl)-o-aminophenols and compounds of the benzene, naphthalene and pyrazolone series coupling in the neighbouring position to the hydroxy group and containing no, or only one, methylsulphone group, coupling being effected in an alkaline medium (e.g. in the presence of sodium carbonate and hydroxide), in some cases with the addition of pyridine.  Chroming may be effected by known methods for chroming metallizable azo dyestuffs, e.g. by methods using an alkaline aqueous medium (such as those using glycerol-alkali chromite), by the action of complex chromium compounds of o-hydroxycarboxylic acids of the benzene series (such as ammonium chromo-salicylate) or ammonium oxalato - ammino - chromate, in a practically neutral medium, or by the action of trivalent chromium salts (preferably in organic solvents, e.g. lower alcohols, the reaction medium being subsequently made albaline or the reaction product digested with an alkaline lye or with substances with an alkaline reaction). The chromed dyestuffs are suitable for dyeing wool from a weakly acid bath (e.g. one containing 2 per cent acetic or up to 4 per cent formic acid, calculated on the weight of wool), and for dyeing silk, leather, and synthetic fibres analogous to wool (e.g. those from superpolyamides, superpolyurethanes or casein). They may be mixed with the usual additives such as sodium sulphate or pyrophosphate, ammonium sulphate, condensation products of fatty alcohols with ethylene oxide, or guanamine sulphonic acids with high molecular alkyl radicals.  Examples describe the chroming of dyestuffs from various combinations of the following components: 2 - aminophenol - 4-methylsulphone and its 6-chloro and 6- and 5-nitro derivatives, 2-amino-4-methylsulphonyl benzoic acid, 2-aminophenol-4 : 6-di-(methylsulphone), 4 - chloro - 2 - aminophenol - 6-methylsulphone, 2 - amino - 1 - methoxy - and 1 - ethoxy - benzene - 4 - methylsulphone, and 1 - chloro - 2 - aminobenzene - 4 - methylsulphone; acetoacetic anilide, 3-methyl-5-pyrazolone, 1 - phenyl - 3 - methyl - 5 - pyrazolone, 1 - phenyl - 5 - pyrazolone - 3 - carboxylic acid amide, 2 : 4-dihydroxyquinoline, 1 - hydroxy - 3 - acetylamino - 4 - methylbenzene, 3 - 4 - dimethylphenol, 1 - acetylamino-7-naphthol, b -naphthol, p-cresol, and 1 - (m - chlorophenyl) - and 1 - (p - tolyl) - 3-methyl-5-pyrazolone. Lists of additional components are given, including the following coupling components containing a methylsulphone group: 1 - naphthol - 5 - methylsulphone, 2 - naphthol - 6 - methylsulphone, 1 - (m - and p - methylsulphonylphenyl) - 3-methyl-5-pyrazolone, and methylsulphone-substituted acetoacetic anilides.  Specifications 186,635, [Class 2 (iii)], 467,549 and 561,548 are referred to.