Patent GB-776268-A (GB)
Title: Improvements in or relating to disazo dyestuffs
IPC: C09B31/06
Filed: 1953-10-28
Abstract: The invention comprises disazo dyestuffs, free from carboxylic or sulphonic acid groups and sulphonamide groups, of formula:- <FORM:0776268/IV(b)/1> wherein R1 and R2 are radicals of the benzene series, R3 is a radical of the benzene or naphthalene series coupled in the 1-and 4-positions to -N=N- and -azorespectively and containing a lower alkoxy group in the orthoposition to -azo-, wherein R1 and R2 possess together at least one methoxy group in ortho-position to -N=N- and -azorespectively and -OH is in para-position to -azo-, the dyestuffs being free from acylamino groups when the radical R2 possesses no methoxy group in ortho-position to -azo-.  The dyes are prepared by coupling 1 mol of the diazo compound of an aminobenzene which may have a methoxy group ortho to the amino group, with 1 mol of an amine of the benzene or naphthalene series having a lower alkoxy group ortho to the amino group and coupling para to the amino group, the resultant aminomonoazo dyestuff being diazotized and coupled with 1 mol of a hydroxybenzene coupling para to the hydroxy group and which may have a methoxy group meta to the hydroxy group.  The dyestuffs may be prepared in admixture with other diazo dyestuffs.  Thus a mixture of two or more aminobenzenes one of which may be devoid of methoxy groups may be used as starting component, or a mixture of two or more phenols one of which may be devoid of methoxy groups may be used as end components.  The aminobenzene or aminonaphthalene middle components may be coupled in the form of their #j-methane sulphonic acids, the #j-methane sulphonic acid group being subsequently split off from the monoazo dyestuff.  Lower alkoxy groups are defined as groups containing not more than four carbon atoms.  The dyestuffs dye cellulose ester fibres and synthetic polyamide or polyester fibres in yellow, orange, scarlet, ruby and red-brown shades.  In examples the following disazo dyestuffs are prepared: o-aminoanisole --> 1-amino-2-methoxy-5-methylbenzene --> phenol or 2- or 3-methylphenol or 2- or -3-methoxyphenol o-aminoanisole --> 1-amino-2 : 5-dimethoxybenzene --> phenol or 3-methoxy- or -ethoxy-phenol or o-chlorophenol or 2- or 3-methylphenol or a mixture of phenol and 3-methoxyphenol, o-aminoanisole --> 1-amino-2-ethoxynaphthalene --> 3-methoxyphenol (in the preparation of this dyestuff aqueous ammonia may be added to accelerate the second coupling); o-aminoanisole --> 1-amino -2- methoxynaphthalene --> phenol; aniline --> 1-amino-2:5-dimethoxybenzene or 1-amino-2-methoxy-5-methylbenzene --> 3-methoxyphenol; 1-amino-2:5-dimethoxybenzene --> 1-amino-2-methoxy-5-methylbenzene or 1-amino-2:5-dimethoxybenzene or 1-amino-2-methoxynaphthalene --> phenol; 1-amino-2-methoxy-5-methylbenzene --> 1-amino-2-methoxy-5-methylbenzene --> phenol; 1-amino-2:5-dimethoxy-4-acetylaminobenzene or 1-amino-4-methoxy- or -acetylamino-benzene --> 1-amino -2:5- dimethoxybenzene --> 3-methoxyphenol; 1-amino-3- or -4-acetyl- or -4-propionylbenzene --> 1-amino-2:5-dimethoxybenzene --> 3-methoxyphenol; 1-amino-4-acetylaminobenzene --> 1-amino-2-methoxy-5-methylbenzene or 1-amino-2:5-diethoxybenzene --> 3-methoxyphenol; aniline or 1-amino-4-acetylaminobenzene or a mixture of 1-amino-4-acetylaminobenzene and o-aminoanisole --> 1-amino-2:5-dimethoxybenzene --> mixture of phenol and 3-methoxyphenol.  Specification 398,842 [Group IV] is referred to.