GB643054A - Process for the preparation of dis- and polyazo dyestuffs - Google Patents

Abstract

A compound which is probably 1 : 2 : 7-triamino-8-naphthol-6-sulphonic acid is produced by reduction, with stannous chloride and hydrochloric acid, of the disazo dyestuff obtained by coupling diazotized 2-amino-5-nitrobenzene-1-sulphonic acid with 2 : 8 : 6-aminonaphtholsulphonic acid in an acid medium, acetylating the resulting monoazo dyestuff and coupling the product with diazotized a -naphthylamine in an alkaline medium.ALSO:Dis- and poly-azo dyestuffs are manufactured by coupling diazo compounds with azo dyestuffs of the general formula <FORM:0643054/IV (c)/1> wherein R represents the residue of a diazo compound and X hydrogen or SO3H, and wherein Y1 represents <FORM:0643054/IV (c)/2> (R1 being hydrogen, alkyl, cycloalkyl, aralkyl or aryl) and Y2 hydrogen, or vice versa when X is hydrogen, and, if desired, treating the product with a saponifying agent (e.g. sodium carbonate, ammonia, barium hydroxide, caustic soda solution, acetic acid or mineral acids), at ordinary or increased temperatures, in order to convert the <FORM:0643054/IV (c)/3> group into NHR1. The coupling, which takes place in the 7-position, and in positions capable of coupling in R when such are present, may be effected in the presence of acid binding agents, e.g. sodium acetate, sodium bicarbonate, potassium carbonate, caustic soda solution, calcium hydroxide, ammonia or tertiary organic bases such as pyridine. The starting materials are obtainable by the process of Specification 643,046, and the acyl groups specified correspond to the acylating agents therein enumerated, with the exception of thiophosgene chlorsulphonic acid and thioacetic acid, but with the addition of succinic acid. Examples and a table illustrate the use of a variety of diazo compounds, including diazotized aminoazo and aminodisazo dyestuffs, tetrazotized diamines, and the diazoazo compounds obtained from the latter by coupling with an equimolecular proportion of a coupling component. The products dye animal, vegetable or synthetic fibres or leather, and, if they contain groups capable of forming complexes, may be treated in substance or on the fibre with metal-yielding agents. Reference is also made to the diazotization and coupling on the fibre of the aminotrisazo dyestuff obtained by saponification of the dyestuff 2 - naphthylamine - 5 - sulphonic acid-->(acid) 1 : 5 : 7 - aminonaphtholsulphonic acid (acetylated) (alkaline)\sMbenzidine-->salicylic acid. Specification 281,410, [Class 15 (ii)], also is referred to. The Specification as open to inspection under Sect. 91 comprises also the use of coupling components in which R1 in the grouping <FORM:0643054/IV (c)/4> represents a second acyl group. This subject-matter does not appear in the Specification as accepted.