GB321703A - Improvements in the manufacture and production of vat dyestuffs - Google Patents

Abstract

321,703. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). Aug. 9, 1928. Anthraquinone vat dyes, dyeing in reddish shades, are obtained by treating 4<1>- naphthalimido-N-pyrazolanthrone or an N-alkyl derivative thereof with alkaline condensing agents. The products from the unalkylated parent materials may be subsequently alkylated, and the products with or without alkyl groups may be halogenated if desired. The parent materials are made bv condensing 4-chlornaphthalimide or its N-alkyl derivatives with pyrazolanthrone. In examples (1) The product from 4- chlornaphthalimide and pyrazolanthrone is fused with alcoholic potash; (2) the product from 4- chlor-N-methylnaphthalimide is similarly treated; the resulting dyestuff dyes cotton from the vat in violet red shades, somewhat clearer than those obtained from the unalkylated dyestuff; (3) the dyestuff obtained in example 1 is alkylated by treating with toluenesulphonic acid methyl ester and sodium carbonate in trichlorbenzene; (4) the product obtained in example 3 is chlorinated by means of sulphuryl chloride in nitrobenzene in the presence of iodine; the resulting dyestuff dyes in clear blue red shades: and (5) the product of example 3 is brominated in sulphuric acid monohydrate: the product dyes cotton in strong blue red shades. The Provisional Specification is not limited to the use, as parent materials of 4'-naphthalimido-N- pyrazolanthrone and its N-alkyl derivatives, but includes also the use of substitution products in general, including the N-aryl and N-aralkyl derivatives. 4-Chlor-N-methylnaphthalimide is made by boiling 4-chlornaphthalimide with p-toluenesulphonic acid methyl ester and sodium carbonate in trichlorbenzene.