Patent GB-820444-A (GB)
Title: Process for the manufacture of organic acid chlorides
IPC: C07B45/00
Filed: 1956-01-30
Abstract: Acid chlorides of azo dyestuffs containing sulphonic or carboxylic acid groups are prepared by reacting the acid dyestuff with thionyl chloride in the presence of a formic acid amide in which the amide nitrogen atom is derived from a secondary amine. Specified formamides are dimethyl- and diethyl-formamides, formic acid morpholide or piperidide and N-methyl-formanilide.  The formamide may be used in amounts varying from an excess or equivalent quantity calculated on the dyestuff acid, to catalytic (e.g. 0.05 to 0.1 equivalents) quantities.  Inert solvents such as benzene, toluene, xylene, chlorobenzene, nitrobenzene and dioxane may be used in the reaction mixture.  Components that may be used in the preparation of suitable acid azo dyestuffs are specified.  In examples, acid chlorides of the following azo dyestuffs are prepared: p-toluidine or 4-aminobenzoic acid or 1 - amino - 2 - methyl - 5 - chlorobenzene --> 1 - phenyl - 3 - methyl - 5 - pyrazolone - 41 - sulphonic acid, 4 - amino - 3 - nitrobenzoic acid or sulphanilic acid --> 1-acetoacetylamino-2-chlorobenzene, 1-amino-4-methylbenzene - 5 - sulphonic acid --> 2 : 3 - oxynaphthanilide, 4 - chloro - 3 - aminobenzoic acid --> 2 : 3 - oxynaphthoic acid, 1 - amino - 2-methyl - 5 - chlorobenzene --> 2 - oxynaphthalene - 6 - sulphonic acid, 1 - amino - 2 - methyl - 4 - chlorobenzene or 3 - chloroaniline or sulphanilic acid or 2-amino-1 : 11-diphenylsulphone-4-sulphonic acid --> 2-oxynaphthalene - 3 : 6 - disulphonic acid, 6-chloro-3-aminobenzoic acid --> 1-amino-5-methyl-2-methoxybenzene --> 2 : 3-oxynaphthoic acid, 1-methoxy - 4 - methyl - 3 - (21 - nitro - 41 - carboxyphenylazo or 41-nitro-51-carboxyphenylazo)-6-(211 - hydroxy - 311 - carboxynaphthylazo) - benzene, 1 : 4 - dimethoxy - 3 - (21 - chloro - 51 - carboxyphenylazo) - 6 - (211 - hydroxy - 311 - carboxynaphthylazo) - benzene and 1 - (21 - chloro - 51 - carboxyphenylazo) - 4 - (211 - hydroxy-311-carboxynaphthylazo)-naphthalene.ALSO:Acid chlorides of organic sulphonic or carboxylic acids are prepared by reacting the acid with thionyl chloride in the presence of a formic acid amide in which the amide nitrogen atom is derived from a secondary amine. Specified formamides are dimethyl- and diethyl-formamides, formic acid morpholide or piperidide and N-methyl-formanilide.  The formamide may be used in amounts varying from an excess or equivalent quantity calculated on the acid, to catalytic (e.g. 0.05 to 0.1 equivalent) quantities.  Inert solvents such as benzene, toluene, chlorobenzene, nitrobenzene, xylene and dioxane may be used in the reaction mixture.  The acid chlorides may be used to form esters or amides in known manner, and also oxythionaphthenes by treatment of benzene- or naphthalene-thioglycollic acid chlorides with Friedel-Crafts catalysts, such as iron or aluminium halides, to effect ring-closure.  In Examples: (1) the following acids are converted into their acid chlorides by the process described: 2-naphthalene-sulphonic, p-toluene sulphonic, stearic, pyridine-3-carboxylic, 4-chloro- or -bromo- or -nitro-benzoic, 1-nitroanthraquinone - 2 - carboxylic, 2 : 3 - oxynaphthoic acid, naphthalene-2-thioglycollic 8-chloronaphthalene - 1 - thioglycollic, 2 - chloro - 1 - methylbenzene - 4 - thioglycollic, 2 : 4 - dichloro - 1 - methylbenzene - 5 - thioglycollic, 2 - chloro - 1 : 4-dimethylbenzene - 5 - thioglycollic, 4 - chloro-2-methylbenzene - 1 - thioglycollic, 3 - chlorobenzene-1-thioglycollic, iso- and tere-phthalic, adipic, methane sulphonic, oleic, 8-chloronaphthalene - 1 - sulphonic, 4 - methoxy- or -ethoxy-1 - cyanobenzene - 2 - sulphonic and 4 - chloro-6 - methyl - 1 - cyanobenzene - 2 - sulphonic acids; (2) p-toluene sulphochloride is reacted with ammonia to give p-toluene sulphonamide; (3) the chlorides of 2-naphthalene-sulphonic, 4-chloro- or -nitro-benzoic and 2 : 3-oxynaphthoic acids are reacted with aniline to give the corresponding anilides; (4) the chlorides of the thioglycollic acids specified above are reacted with aluminium chloride to give the corresponding oxy-thionaphthenes.