Patent GB-684527-A (GB)
Title: New disazo-dyestuffs and process for their manufacture
IPC: C09B43/14
Filed: 1950-12-01
Abstract: Amino-salicylic acids which may contain a sulphonic acid group are condensed with m- or p-nitrobenzoyl chloride to form nitrobenzoyl-amino-salicylic acids, and the nitro group then reduced to amino.  The nuclei may contain further substituents other than carboxylic acid or sulphonic acid groups.  Specified starting materials are 3-amino-5-sulphosalicylic acid, 5-amino-4-sulphosalicylic acid and 5-amino-3-sulphosalicyclic acid. Specifications 555,791, 583,849 and 619,969 are referred to.ALSO:The invention comprises disazo dyestuffs of the formula R1-N = N-R2-NH-CO-R3-NH-CO-NH-R4-N = N-R5 or R1-NH-CO-R3-N = N-R2-NH-CO-NH-R4-N = N-R5, in which R1-R5 are benzene nuclei; R1 and R5 are salicylic acid residues; the linkages to R2 and R4 are para and to R3 are meta or para; R4 contains a chlorine atom ortho to the azo group; one sulphonic acid group is present on R1 or R2 in the first formula and on R1 in th second formula; there are no carboxylic acid or sulphonic acid groups other than those stated above.  The dyestuffs are made by reacting phosgene with one mol. of NH2-R4-N = N-R5 and one mol. of the other appropriate monoazo dyestuff.  They are used for dyeing and printing cellulosic fibres such as cotton, linen or regenerated cellulose.  They may be metallized on the fibre and/or in the dyebath, e.g. as in Specification 455,274 or 619,969. The starting materials of the formula R1-N = N-R2-NH -CO-R3-NH2 are made as follows: (1) Amino-sulpho-salicylic acids are diazotized and coupled with H-R2-NH2, the product condensed with m- or p-nitrobenzoyl chloride and the nitro group reduced to amino; (2) sulphonated amines NH2-R2-X are diazotized and coupled with unsulphonated salicylic acids, X then converted into amino, the product condensed with m- or p-nitrobenzoyl chloride and the nitro group reduced to amino; (3) in certain cases the method of (2) may be carried out where X is amino, e.g. with p-phenylene diamine sulphonic acid, only one amino group of which is diazotized.  In method (1) H-R2-NH2 may be coupled in the form of its methanesulphonic acid derivative and then hydrolysed.  The starting materials of the formula R1 - NH - CO - R3 - N = N - R2 - NH2 are made by diazotizing an aminobenzoylamino-sulpho-salicylic acid (see Group IV (b) and coupling with H-R2-NH2 which may be in the form of its methane-sulphonic acid as above.  The starting materials of the formula NH2-R4-N = N-R5 are made by diazotizing an o-chloraniline containing a para-substituent Y, coupling with a salicylic acid and converting Y to amino.  In the examples: (1) diazotized 2-chloro-4-nitroaniline is coupled with salicylic acid and the nitro group reduced to amino; also diazotized 5-amino-3-sulphosalicylic acid is coupled with cresidine, the product condensed with m- or p-nitrobenzoyl chloride and the nitro group reduced to amino; the two monoazo dyestuffs are then reacted with phosgene; (2) as in (1) using as second component the monoazo dyestuff from diazotized 5-(m- or p-amino-benzoylamino)-3-sulphosalicylic acid and cresidine; (3) as in (1) using as second component the dyestuff from diazotized 4-nitroaniline-2-sulphonic acid and salicylic acid, reduced, coupled with m- or p-nitrobenzoyl chloride and the nitro group again reduced to amino; an alternative second component is obtained by condensing the monoazo dyestuff p-phenylene diamine monosulphonic acid --> salicylic acid with m- or p-nitrobenzoyl chloride and reducing the nitro group to amino; (4) cotton is dyed with the product of (1). Other suitable components are mentioned.  Specifications 555,791 and 583,849 also are referred to.