Patent GB-339626-A (GB)
Title: Improvements in the manufacture and production of vat dyestuffs
IPC: C09B3/74
Filed: 1929-08-08
Abstract: 339,626. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). Aug. 8, 1929. Anthraquinone vat dyes are obtained by treating 2 : 2<1>-dimethyl-1 : 1<1>-dianthraquinonyls or 2:2<1>- dimethyl-ms-benzo- or -naphtho-dianthrones in which the hydrogen atoms of both methyl groups' are partially or wholly replaced by halogen, with acid or alkaline reacting condensing agents having a reducing action and capable of splitting off halogen or hydrogen halide. As condensing agents, the usual acid or alkaline condensing- agents. to which reducing agents have been added. may be used, as well as compounds which act both as condensing and reducing agents. As acid condensing agents sulphuric acid or derivatives thereof, including oleum and chlorsulphonic acid, to which reducing agents such as metals, e.g. copper, aluminium or zinc, or reducing compounds thereof, e.g. cuprous oxide, cuprous halides or metal sulphides, have been added, are specified. Alkaline condensing agents include solutions of hydroxides of alkali metals or alkaline earth metals or alkaline compounds such as carbonates or acetates, to which reducing agents such as hydrosulphites, hydrazine, hydroxylamine, alkali or alkaline earth metal sulphides are added. As condensing agents which at the same time have a reducing action pyridine, hydrazine hydrate, phenylhydrazine, aniline, dimethylamine, ethanolamine, and cyclohexylamine are specified. The products obtained are 2 : 2<1>-ethylene-1 : 1<1>-dianthraquinonyls, allo-ms-naphthodianthrones and ms-anthradianthrones, according to the conditions. When starting from w : w<1>-halogen derivatives of 2 : 2<1>-dimethyl-1 : 1<1>-dianthraquinonyls, care must be taken to avoid saponification of the halogenated methyl groups prior to condensation between the 9- and 9<1>-positions of the anthraquinone nuceli. This may be effected bv employing weak alkaline reducing agents; if acid condensing agents are used they should be of high concentration and the reaction should be carried out at low temperatures, preferably below 50‹ C. The products mav be halogenated by known methods if desired. The parent materials may be obtained by halogenating the 2 : 2<1>- dimethyl - 1 : 11 - dianthraquinonyls or 2 : 2<1> - dimethyl - ms - - benzo- or - naphtho-dianthrones in organic solvents or suspending agents. The products may be purified by crystallization from organic solvents, or by way of their oxonium salts, or by treating with organic solvents or alkali or with oxidizing agents, e.g. with sodium hypochlorite. In examples, (1) u : w<1> - tetrabromo-2 : 2<1>-dimethyl-1 : 1'-dianthraquinonyl is triturated with pyridine and treated with caustic soda solution and sodium hydrosulphite ; the 2 : 2<1> - ethylene - 1 : 11 - dianthraquinonyl obtained dyed cotton in orange yellow shades, (2) w: w<1>-tetrabromo-2 : 2<1>-dimethyl-1 : 1<1>-dianthraquinonyl is treated with concentrated sulphuric acid and copper powder or other reducing agent, e.g. aluminium bronze, zinc dust or hydrazine hydrate; the product is identical with the allo-ms-naphthodianthrone described in Specification 303,184 and may be halogenated or further condensed to ms-anthradianthrone as described in that Specification or Specification 315,033, (3) tetrabromo-2 : 2<1>-dimethyl - ms benzdianthrone, containing the bromine in part in the nucleus, made by brominating 2 : 2<1>-dimethyl-ms-benzdianthrone in nitrobenezene, is treated with pyridine; the bromoallo-ms-naphthodianthrone obtained dyes cotton in brilliant red shades. (4) 4'-dichlorw : w<1>-tetrabromo-2 : 2<1> - dimethyl-1 : 1<1>-dianthraquinonyl, made by brominating 4 4<1>-dichlor-2- 2<1>-dimethyl-1 : 1<1>-dianthraquinonyl in nitrobenzene, is treated with concentrated sulphuric acid and copper chips, the 4 4<1>-dichlor-allo-ms-naphthodianthrone obtained dyes cotton in orange shades, and (5) w : w<1>-tetrachlor-2 : 21-dimethylms-naphthodianthrone, made by chlorinating 2 : 2<1>-dimethyl-ms-napthodianthrone in trichlorbenzene, is heated with ethyl alcohol and caustic potash; the product is ms-anthradianthrone.