Patent GB-427323-A (GB)
Title: Manufacture of new vat dyes and intermediates therefor
IPC: C09B3/44
Filed: 1933-10-16
Abstract: Pyranthrones.--Addition products of pyranthrone appear to be formed by treating pyranthrone with anhydrous halogenating agents in the presence of anhydrous mild reducing agents (for example sulphur dioxide, hydrogen bromide or sulphur bromide) preferably in the presence of an anhydrous suspending medium resistant to halogenation (for example, nitrobenzene, o-dichlorbenzene, trichlorbenzene or tetrachlorethane) and preferably at a temperature up to about 60 DEG C.  The quantity of mild reducing agents required is small and may be generated in situ by the presence of small quantities of arylamines or salts thereof, phenols or hydrocarbons, which substances may be present in sufficient amount as impurities in the suspending medium (for example, commercial nitrobenzene), the halogenating agent being other than chlorine.  Suitable halogenating agents are bromine, hydrogen bromide, sulphur monobromide and sulphuryl chloride; chlorine may be used but in this case the mild reducing agent must be added in substance; a halogen carrier such as iodine may also be present.  The products are decomposed by moisture, heat, air, alcohol or acetic acid.  By heating with a halogenating agent, preferably one more powerful than that employed initially mono-, di, or trihalogenpyranthrones are obtained.  Thionyl chloride, sulphuryl chloride and chlorine are suitable halogenating agents and temperatures between about 55--120 DEG  C. are preferable.  In some cases the initial and second halogenating agent may be added together and the final halogenated product obtained in one operation.  In all cases the nature of the final product seems to be largely determined by the nature of the halogenating agent used in the first step.  The products may be condensed with a -aminoanthraquinones to give fast khaki to olive-green vat-dyes. Such condensation is preferably effected in presence of alkaline condensing agents and copper or copper compounds.  In examples: (1) pyranthrone is treated in nitrobenzene containing a small quantity of aniline hydrochloride with bromine at about 55--60 DEG  C. to give an intermediate addition product; iodine may also be present as catalyst, and aniline hydrochloride may be replaced by aniline base or phenol or sulphur dioxide; by replacing the bromine by sulphuryl chloride or hydrogen bromide analogous addition products are obtained; (2) the first-named addition product of (1) is treated with sulphuryl chloride, temperatures being raised by steps from 20 to 65 DEG  C. to 115--116 DEG  C., and a dibromo derivative admixed with a monobromomonochloro derivative (dyes orange to scarlet); instead of sulphuryl chloride, chlorine may be used, reaction first being conducted at room temperature and later at 75--80 DEG  C.; treatment with thionyl chloride, first at 20 DEG  C. then at 70--75 DEG  C. and finally at 110--115 DEG  C. yields a product which is probably a monobromo derivative; (5) the intermediate obtained by using sulphuryl chloride is treated with a stream of chlorine with subsequent raising of temperature to 70--75 DEG  C. and finally to 110--115 DEG  C.; a trichloropyranthrone appears to be formed (dyes orange-brown); treatment of this intermediate with bromine first at 20 DEG  C., then at 65--67 DEG  C. and finally at 110--115 DEG  C. yields a product containing both bromine and chlorine; (4) the intermediate obtained by using hydrogen bromide is treated with sulphuryl chloride at room temperature, then at 65--67 DEG  C. and finally at 110--115 DEG  C. to give a product containing bromine and chlorine; (5) pyranthrone is treated in nitrobenzene containing a little aniline hydrochloride with bromine and sulphuryl chloride, temperature being maintained first at 20--22 DEG  C., then raised to 80 DEG  C. and finally raised to 115 DEG  C.; a product which is probably a monobromo derivative is obtained (dyes orange shades); (6) the dibrompyranthrone of (2) is condensed with a -aminoanthraquinone (2 mols.; dyes olive-green), 1 . 4 - monobenzoyldiaminoanthraquinone (dyes dark green), 1 . 5 - monobenzoyldiaminoanthraquinone (dyes olive-green), 1-amino-2-methylanthraquinone (dyes green), 1,5-diaminoanthraquinone (dyes grey), 1.4-diaminoanthraquinone (dyes olive-green and brown shades according to the quantity of diaminoanthraquinone used), and 4,4<1>-diamino-1,1<1>-anthrimide (dyes grey and brown shades according to the quantity of anthrimide used); (7) the monobrompyranthrone of (5) is condensed with a -aminoanthraquinone (dyes khaki); (8) the chlorpyranthrone of (3) is condensed with a -aminoanthraquinone (dyes olive-green).  The Specification as open to inspection under Sect. 91 also relates to the treatment of the foregoing addition products with anhydrous oxidizing agents to give mono-, di- and tri-halogen substitution products but this subject-matter does not appear in the Specification as accepted.