Patent GB-434132-A (GB)
Title: Dyestuffs of the dibenzanthrone series and their manufacture
IPC: C09B3/30
Filed: 1934-02-27
Abstract: The monoisopropyl- or monoisobutylether Bz2 Bz2<1>-dihydroxydibenzanthrone is heated at a temperature above 150 DEG  C. (for example 170--220 DEG  C.) in a high-boiling inert diluent, and preferably in the presence of an anhydrous alkaline reacting compound and of an alkylating or aralkylating agent (such as ethylenedibromide, dichlorhydrin, diphenyldichlormethane, benzalchloride or benzaldehyde.  The products, which are presumed to be dibenzanthrones wherein the Bz2. Bz2<1>-positions are linked as parts of a pyrane ring structure, are stable in strong acids and dye greenish shades.  Further dyes can be obtained by sulphonating, nitrating, nitrating and reducing, halogenating, oxidizing (to yield hydroxy derivatives), or condensing the products with an organic carboxylic acid halide in the presence of an aluminium chloride condensing agent, and these may be used for dyeing wool and silk or acetate artificial silk.  Suitable high-boiling diluents are anhydrous di- and trichlorbenzene, nitrobenzene, naphthalene; as alkaline acting agent sodium acetate or carbonate may be used; alkylating agents mentioned in addition to the above are monochlorhydrin, dibromstilbene, and fluorenone dichloride, and it is stated that all such agents have a catalytic effect on the process. In examples: (1) Bz2. Bz2<1>-dioxydibenzanthrone monoisopropylether is heated to 170--180 DEG  C. in dichlorbenzene in presence of sodium acetate; trichlorbenzene or naphthalene may replace dichlorbenzene as diluent and the reaction may be catalysed by addition of benzal chloride, benzaldehyde, mono- or dichlorhydrin, ethylenedibromide, p.p<1>-dibrombenzophenone dichloride, diphenyldichlormethane or dibromostilbene; the product may be purified by treatment with sulphuric acid for conversion to the sulphate which is separated and decomposed by water, or by heating in trichlorbenzene and p filtering; it dyes cotton fast green shades; (2) monoisobutylether of Bz2. Bz2<1>-dioxydibenzanthrone (prepared by reacting isobutylbromide with Bz2. Bz2<1>-dioxydibenzanthrone) is heated to 170--180 DEG  C. in dichlorbenzene in presence of sodium acetate; when purified as in (1) a similar but rather bluer dye is obtained; (3) the foregoing processes may undergo some modification; thus Bz2.Bz2<1>-dioxydibenzanthrone is converted to the sodium salt by treatment with soda ash and heated with isopropyl bromide in an autoclave to 120--130 DEG  C., followed by removal of excess isopropylbromide by distillation, and a heat treatment of the residue in dichlorbenzene in presence of sodium acetate at 175--180 DEG  C.; or the sodium salt of Bz2. Bz2<1>-dioxydibenzanthrone is heated in dichlorbenzene with the isopropyl ester of p-toluenesulphonic acid, p.p<1>-dichlorbenzophenone and sodium acetate are then added and the mixture heated to 175--180 DEG  C.; (4) the product of (1) is sulphonated with oleum to give a green dye for wool or silk; (5) the product of (1) is nitrated in monohydrate to give a mononitro derivative (green shades changed to grey to black by a bleach treatment), or in nitrobenzene at 80--90 DEG  C. to give a dinitro body; the mononitro derivative may be reduced to the amino body by alkaline hydrosulphite at about 55--60 DEG  C.; (6) the product of (1) is brominated in trichlorbenzene to a tribromo derivative (green), or chlorinated in sulphuric acid to give a yellow-green dye; (7) the product of (1) is treated with manganese dioxide in sulphuric acid at 15--20 DEG  C. and then with bisulphite to give an oxy derivative (yellowish-green); (8) the product of (1) is condensed with a -chloranthraquinone-b -carboxylic acid chloride in a melt of aluminium chloride and antimony trichloride at 110--120 DEG  C. (dyes greenish-blue).  The Specification as open to inspection under Sect. 91 relates to the heat treatment of a secondary monalkyl ether of Bz2. Bz2<1>-dioxydibenzanthrone above 150 DEG  C. in a high-boiling inert organic diluent and mentions in an example the isoamyl or cyclohexyl ethers.  It also relates to the introduction of substituents into the dyes so obtained and comprises the following further information in examples: the mononitro derivative of (5) above is sulphonated in oleum to give a bluish - green dye; the monamino body derived from this mononitro derivative may be similarly treated, and also condensed with phthalic anhydride (dyes yellowish-green shades); the bromo derivative of (6) above is sulphonated in oleum to give a green dye, also is treated with manganese dioxide in sulphuric acid to give a monobromodioxy derivative (greenish-grey) which can be methylated (greenish-blue), and also condensed with a -aminoanthraquinone (dyes grey); the oxy derivative of (7) above is sulphonated in oleum (yellowish-green); the chloro derivative of (6) above is sulphonated to give a yellowish-green-shade, and also is heated in sulphuric acid containing boric acid to give an oxy derivative (dyes acetate artificial silk green shades).  Reference is also made to the use of a -dibromoethylanthraquinone as a further catalytically acting alkylating agent for use in the process. This subject-matter does not appear in the Specification as accepted.