Patent GB-351948-A (GB)
Title: Improvements in the manufacture and production of halogencontaining vat dyestuffs of the dibenzanthrone series
IPC: C09B3/32
Filed: 1930-01-25
Abstract: Chlorobromodibenzanthrones are prepared by treating derivatives of dibenzanthrones, other than iodo derivatives, with anhydrous metal halides which supply halogen, if desired, with the addition of further halogenating agents, and/or substances which lower the melting point, and/or catalysts, and/or solvents or diluents which do not injuriously affect the activity of the metal halides. Suitable metal halides are those of iron, aluminium, antimony or mercury or mixtures of these halides; alkali or alkaline earth metal halides are suitable for lowering the metal point; and suitable solvents or diluents are halogen benzenes or naphthalenes, benzophenone, nitrobenzene, quinoline, pyridine or collidine.  Iodine, or other non-metals or compounds thereof may be employed as catalysts.  The products dye violet to blue shades and have good fastness, particularly to water.  In examples (1) dibromodibenzanthrone (prepared by brominating dibenzanthrone in chlorsulphonic acid) is treated (i) in trichlorbenzene with ferric chloride, (ii) in trichlorbenzene with a mixture of ferric chloride and bromide, (iii) in dichlorbenzene with mercuric chloride or a mixture of ferric and mercuric chlorides; monchlor- or trichlorbenzene or nitrobenzene may replace dichlorbenzene, (iv) in collidine with ferric chloride, (v) with an aluminium sodium-chloride melt in the presence of iodine: (2) dibrombenzanthrone (prepared by treating dibenzanthrone with 2 1/2 atomic proportions of bromine in chlorsulphonic acid at about 40 DEG C. in the presence of antimony) is treated in trichlorbenzene with ferric chloride: (3) dibenzanthrone brominated in nitrobenzene is treated in trichlorbenzene with ferric chloride: (4) tetrabromdibenzanthrone (prepared by brominating dibenzanthrone in chlorsulphonic acid) is treated in trichlorbenzene with ferric chloride: (5) tribromdibenzanthrone (prepared by brominating dibenzanthrone in chlorsulphonic acid in the presence of antimony) is treated with a ferric chloride-sodium chloride melt; other derivatives may be treated in similar manner, for example the tribrom-monochlordibenzanthrone prepared by treating dibenzanthrone with 3 1/2 atomic proportions of bromine in chlorsulphonic acid at 50-55 DEG  C. in the presence of iodine: (6) tetrabromdichlordibenzanthrone (prepared according to Example (3) of Specification 325,525, [Class 2 (iii), Dyes &c.]), is treated in trichlorbenzene with ferric chloride: (7) dibenzanthrone brominated in trichlorbenzene and in presence of iodine, is treated with ferric chloride; nitrobenzene may also be used as diluent: (8) pentabromdibenzanthrone (prepared by bromination in chlorsulphonic acid in the presence of iron) is treated in trichlorbenzene with antimony pentachloride: (9) bromnitrodibenzanthrone (prepared by brominating in nitrobenzene and in presence of iron the nitrodibenzanthrone obtainable according to Specification 220,212, [Class 2 (iii), Dyes &c.]), is treated in trichlorbenzene with ferric chloride.  The Specification as open to inspection under Sect. 91 (3) (a) claims the production of vat-dyes containing chlorine, bromine, or iodine, or several of these halogens simultaneously by treating isodibenzanthrone or derivatives thereof or derivatives of dibenzanthrone according to the process specified above. Reference is also made in an example to the treatment of dichlor- and iododibenzanthrone in trichlorbenzene with ferric chloride.  This subject-matter does not appear in the Specification as accepted.