GB327141A - Improvements in the manufacture and production of vat dyestuffs containing nitrogen - Google Patents

Abstract

327,141. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). Dec. 27, 1928. Isodibenzanthrone dyes.-Vat dyes of the isodibenzanthrone series are made by subjecting isodibenzanthrone or its derivatives to the action of hydroxylamine or its salts. The reaction may be effected in the presence of inorganic dissolving or suspending media capable of splitting off water, such as sulphuric, phosphoric or chlorsulphonic acid, and condensing catalysts, for example metals or their compounds, such as iron, copper, and mercury may also be present. Alkylating agents, such as dimethylsulphate and p-toluenesulphonic esters or acylating agents, or halogens or agents which split off halogens may be brought into the reaction either simultaneously or subsequently, if desired. When the action of the hydroxylamine on the initial material is effected in concentrated sulphuric acid, the addition of an alcohol is usually sufficient to effect alkylation. The products may be purified by boiling them with organic solvents, or by way of their oxonium salts, or by treating their pastes with oxidizing agents, such as alkali metal hypochlorites. The products differ from the aminoisodibenzanthrones described in Specification 23052/10 in that they yield dyeings which are unaffected by treatment with hypochlorites. In examples, (1) isodibenzanthrone is treated with hydroxylamine sulphate in concentrated sulphuric acid, preferably with addition of ferrous sulphate; the product dyes cotton in dark blue shades, a product dyeing in more reddish shades being obtained if the condensation is carried out with addition of dimethylsulphate, (2) dibromisodibenzanthrone (made by brominating in nitrobenzene in presence of iodine) is similarly treated to yield a product which dyes cotton in reddish blue shades; a similar dyestuff may be obtained by brominating the product of example 1, (3) dichlorisodibenzanthrone (made by chlorinating in nitrobenzene by means of sulphuryl chloride) is similarly treated; the product dyes in blue shades, and (4) the product of example 1 is heated with benzoyl chloride; the resulting dyestuff dyes in navy blue shades.