Patent GB-522127-A (GB)
Title: Manufacture of quinhydrone-like derivatives of vat-dyestuffs
IPC: C09B7/00
Filed: 1938-12-06
Abstract: 522,127. Vat dye derivatives ; dyeing. SOC. OF CHEMICAL INDUSTRY IN BASLE. Dec. 6, 1938, Nos. 35513, 35514 and 35515. Convention dates, Dec. 6, 1937, July 11, 1938 and Nov. 10, 1938. [Classes 2 (iii) and 15 (ii)] Quinhydrone-like compounds of vat dyestuffs are manufactured by treating vat dyestuffs by any of the methods known to be capable of converting quinones into quinhydrones, e.g., by reacting a vat dyestuff with a leuco-compound of the same or of a different vat dyestuff, or by subjecting a vat dyestuff to reduction under conditions which suffice to cause a reduction of only a part of the vat dyestuff to the leuco-compound, or by subjecting a leuco vat dyestuff to oxidation under conditions which suffice to cause an oxidation of only a part of the leuco-compound to the vat dyestuff. The reaction is advantageously effected in an aqueous medium which is preferably maintained alkaline, e.g. with caustic alkali or with alkali carbonates, alkali sulphides, ammonia or organic bases such as alkylamines or alkanolamines. Alternatively there may be used organic solvents, e.g. alcohol, with or without the addition of water and in the presence or absence of an agent of alkaline reaction. The products may be used for dyeing, especially in processes in which the dyestuff is brought on to the fibre previous to the vatting. If desired, combined alkali is first removed by treatment with acids, e.g. acetic or formic acid or mineral acids, with or without heating. By long standing or heating in aqueous alkaline suspension, if desired with access of air or in the presence of an oxidizing agent, the products may be reconverted at least in part into the vat dyestuffs, which are obtained in a finely divided state suitable for dyeing purposes. As starting materials may be employed vat dyestuffs of the bisindol-indigoid, indoethionaphthene - indigoid, bis - thionaphthene - indigoid or naphthalene-indol-indigoid series or of the anthraquinone series, particularly those which contain substituents and/or fusedon rings. In examples : (1) leuco-thioindigo is partially oxidized in alcoholic solution by introduction of air ; (2) leuco-thioindigo is partially oxidized in glacial acetic acid solution by means of sodium bichromate or potassium permanganate ; (3) leuco-thioindigo and thioindigo are heated together in chlorobenzene in an atmosphere of hydrogen ; (4) 6: 6<SP>1</SP>- diethoythioindigo and its leuco-compound are reacted together in an aqueous-alcoholic caustic soda solution ; (5) 4 : 4<SP>1</SP>-dimethyl-6: 6<SP>1</SP>-dichlorothioindigo and its leuco-compound (prepared by acting on the dyestuff with hydrogen and a nickel catalyst) are similarly reacted ; (6) 4 : 4<SP>1</SP>- dimethyl-6 : 6<SP>1</SP>-dichlorothioindigo is similarly reacted with leuco-6 : 6<SP>1</SP>-diethorythioindigo or 6 : 6<SP>1</SP>-diethoythioindigo with leuco-4 : 4<SP>1</SP>-dimethyl-6 : 6<SP>1</SP>-dichlorothioindigo; (7) leuco- 6:6 <SP>1</SP>- diethoythioindigo is similarly reacted with bis-2 : 1-naphththioindigo ; (8) 6 : 61-diethoythioindigo and its leuco-compound are heated together in aqueous caustic soda solution ; 4 : 4<SP>1</SP>-dimethyl-6 : 6<SP>1</SP>-dichlorothioindigo and other indigoid dyestuffs may be similarly reacted with their respective leuco-compounds; (9) 4 : 4<SP>1</SP>-dimethyl-6 : 6<SP>1</SP>-dichlorothioindigo is similarly reacted with leuco-6 : 6<SP>1</SP>-diethoxythioindigo ; (10) 6 : 6<SP>1</SP>-diethoxythioindigo is partially reduced by means of sodium hydrosulphite in aqueous caustic soda solution; the product may be treated with hydrochloric acid ; (11) the dyestuff obtained by condensing 4 : 5-dichloro-7-methoxyisatin-α-chloridewith 4- chloro-1-hydroxynaphthalene, or 4-chloro-4- bromo - 7 - methoxyisatin - α - chloride with 4 - bromo - 1 - hydroxynaphthalene, is similarly treated ; (12) the product of (8) is treated with isobutyric acid or other acid, e.g. sulphuric, hydrochloric or acetic acid ; (13) flavanthrone is partially reduced by shaking an aqueous alcoholic caustic soda solution thereof with hydrogen and a nickel catalyst ; (14) dibenzanthrone is completely reduced as in (13) and the product is heated with an alcoholic paste, of dibenzanthrone ; (15) 4 : 5 : 4<SP>1</SP> : 5<SP>1</SP>-dibenzothioindigo is completely reduced as in (13) and the product is heated with an aqueous alcoholic paste of 4 : 5 : 4<SP>1</SP> : 5<SP>1</SP>-dibenzothioindigo; the product may be treated with hydrochloric acid ; (16) 5 : 5<SP>1</SP> : 7 : 7<SP>1</SP>-tetrabromindigo is completely reduced as in (13) and the product is heated with an alcoholic suspension of 5 : 5<SP>1</SP> : 7 : 7<SP>1</SP>-tetrabromindigo; (17) cotton is dyed from a vat obtained by treating the. product of (5) with sodium hydrosulphite in aqueous caustic soda solution ; wool, silk and artificial silk may be dyed with the same compound. Specification 522,128 is referred to.