Patent GB-373129-A (GB)
Title: The manufacture of new condensation products and dyestuffs
IPC: C09B3/00
Filed: 1931-02-12
Abstract: Methyleneanthrone and substitution products thereof are heated with a condensing agent in an acidic medium to give condensation products which are dyestuffs or which may be converted into dyestuffs by further treatment.  By using condensing agents of relatively mild action, such as alcoholic hydrochloric acid, alcoholic sulphuric acid and formic acid, or by using stronger condensing agents, such as anhydrous metallic halides, and working under milder conditions, for example, at lower temperatures or with the addition of a suitable diluent, the compounds obtained are yellowish alkali-soluble products.  By using more powerful acid condensing agents, such as aluminium chloride, under stronger reacting conditions colourless alkali-insoluble condensation products are obtained; such products are also obtained from the similar treatment applied to the above yellowish alkali-soluble products.  These alkali-soluble and alkali-insoluble condensation products can be converted into dyestuffs by heating them at a higher temperature and advantageously in the presence of a suitable diluent, solvent or fluxing material, such as ethylcarbazol, b -naphthol, caustic alkalis, sulphuric acid and aluminium chloride.  When using caustic alkalis the dyestuffs are partly isolated as leuco-compounds and may be oxidized to the dyestuffs in the customary manner.  When using sulphuric acid simultaneous sulphonation may occur to give products which are acid wool dyestuffs.  When using aluminium chloride as condensing agent the dyestuffs may be obtained directly from methyleneanthrone and its substitution products without isolation of the above intermediate products.  In examples (1) methyleneanthrone is heated with methanol and hydrochloric acid, or with methanol and sulphuric acid, or with formic acid to give a yellow alkali-soluble product: (2) the product of (1) is heated with sodium-aluminium chloride at 140 DEG  C. to give a colourless alkali-insoluble product; this product is also obtained by the similar treatment of methyleneanthrone itself: (3) methylene-2-chloranthrone (the reaction product of formaldehyde and 2-chloranthrone) is treated with a mixture of glacial acetic and sulphuric acids to give a yellow alkali-soluble product: (4) the alkali-insoluble product of (2) is heated alone at 320 DEG  C., or with sodium-aluminium chloride at about 200 DEG  C., or with ethylcarbazole, or with caustic potash at about 280 DEG  C. to give a violet vat-dye which appears to be 5,6 : 11.12-dibenzoperylene-4.10-quinone (cf. French Specification 601,856); if concentrated sulphuric acid at a temperature of about 200 DEG  C. is used a sulphonic acid derivative dyeing wool violet-blue shades from an acid bath is obtained: (5) methyleneanthrone is heated with sodium-aluminium chloride at about 210 DEG  C. to give the foregoing vat dyestuff: (6) the alkali-soluble product of (1) is heated with caustic potash at 280 DEG  C. to give the foregoing vat dyestuff: (7) methylene-2-chloranthrone is heated with sodium-aluminium chloride at about 210 DEG  C. to give a reddish-violet vat dyestuff. Methyleneanthrone and its substitution products are obtained by condensing formaldehyde with the corresponding anthranol in dilute alkali or acid solution (cf. German Specification 330,550).