GB354281A - Manufacture of vat-dyestuffs containing sulphur - Google Patents

Abstract

Vat dyestuffs of the thiazine series are manufactured by the action of an oxidizing agent on a 2 : 5-diarylamino-3-mercapto-1 : 4-benzoquinone, the two arylamino groups being the same or different and derived from primary or secondary amines of the benzene, naphthalene, anthracene, or anthraquinone series, or substition products thereof. The 6-position in the quinone nucleus may be substituted, e.g. by an alkyl group. The starting materials may be obtained by treating a 3-halogen-2 : 5-diarylamino-1 : 4-benzoquinone with sodium sulphide in the presence of a diluent, and need not be isolated. As oxidizing agents are specified air, nitrobenzene, and sulphur. In examples: (1) 2 : 5 - dianilido - 3 - mercapto - 1 : 4 - benzoquinone (obtained by the action of an aqueous-alcoholic solution of sodium sulphide on 3 : 6-dianilido-2-chloro-1 : 4-benzoquinone) is oxidized with nitrobenzene; the product dyes wool brown shades; (2) 2 : 5-di-b -naphthylamino-3-chloro-1 : 4-benzoquinone (prepared from 2 : 6-dichloroquinone and b -naphthylamine) is treated with sodium sulphide in aqueous alcoholic solution and the mercapto-compound oxidized without isolation by boiling with sulphur; the product dyes wool violet-brown shades; (3) 2 : 5-di-41-chloranilido-3-chloro-6-methyl-1 : 4-benzoquinone (obtained from 2 : 3 : 5-trichloro-6-methyl-1 : 4-benzoquinone and p-chloraniline) is treated with sodium sulphide in aqueous alcoholic solution and the mercapto-compound is isolated and oxidized by means of air in boiling alcoholic solution; the product dyes wool olive brown shades.