Patent GB-749792-A (GB)
Title: Process for the manufacture of anthraquinone vat dyestuffs
IPC: C09B5/28
Filed: 1953-11-10
Abstract: In a process for the manufacture of anthraquinone vat dyestuffs by the carbazolization of a polyanthrimide built up exclusively of anthraquinone nuclei, the polyanthrimide is treated with a brominating or chlorinating agent before being subjected to carbazolization.  The polyanthrimides employed as starting materials contain no other ring systems, e.g. benzene, naphthalene or heterocyclic rings, bound to an anthraquinone residue either by a simple bond or in the form of a ring fused on an anthraquinone residue.  Linear-polyanthrimides which contain from 4 to 6 anthraquinone nuclei are especially suitable starting materials. Linear polyanthrimides are defined as anthrimides built up of at least three anthraquinone nuclei and in which all the anthrimide bonds as represented in the formula as normally written lie in a straight line, e.g. as in anthrimides wherein the 4-position of one anthraquinone nucleus is bound to the 1-position of the next anthraquinone nucleus by an - NH - group.  The starting materials are advantageously free from acylamino groups or other substituents. Non-linear polyanthrimides may be employed, e.g. 1 : 4 : 5 - tri - or 1 : 4 : 5 = 8 - tetra - (a - anthra - quin onylamino) anthraquinone. Bromide and sulphuryl chloride are the halogenating agents specified and iodine is optionally emplosed to assist the halogenation.  In the carbazolization step aluminium chloride may be used with fluxing agents such as aromatic compounds such is nitrobenzene and inorganic compounds such as sulphur trioxide which may be employed separately or in admixture.  With linear polyanthrimides aluminium chloride is preferably employed with the addition of a tertiary amine, e.g. a tertiary amine free from hydroxy groups such as triethylamine, cyclic bases such as quinoline, acridine, pyridine and homologues thereof such as a methyl pyridine, e.g. ae - picoline or mixtures of such bases, e.g. commercial b :g  - picoline mixture.  Reaction mixtures are worked up by rendering the reaction mixture alkaline with alkali hydroxide, adding a suitable reducing agent, e.g. sodium hydrosulphite, vatting the dyestuff and precipitating it by oxidation, e.g. with air.   The dyestuff may be purified by treatment with an oxidizing agent such as sodium hypochlorite. The products may be used for dyeing or printing cellulosecontaining fibres, if desired after conversion to leuco-ester salts by known methods.  In examples: 4 : 41 diamino - 1 : 11 - dianthrimide is heated with 1 - chloro - anthraquinone, sodium carbonate, cuprous chloride and nitrobenzene to form 1 : 11 - 41 : 411 : 1111 - tetranthrimide which is chlorinated with sulphuryl chloride and carbozolized by heating with aluminium chloride and pyridine (1); in a similar process naphthalene is employed as solvent in the initial condensation and the chlorination is carried out in nitrobenzene with sulphuryl chloride in the presence of iodine (2); in a similar process the chlorination is carried out in o - dichlorobenzene (3); in similar processes to (2) the initial condensation steps are carried out in an agitator batch drier (4) and (5); a tetranthrimide prepared as in (2) is suspended in 1 : 2 : 4 - tri - chlorobenzene and brominated in the presence of iodine and the bromine containing product is carbazolized as in (1) (6); 1 : 4 : 5 - tri - (ae - anthraquinonylamino) anthraquinone suspended in chlorobenzene is chlorinated with sulphuryl chloride and iodine and the product is carbazolized in the presence of sodium carbonate, aluminium chloride and sodium chloride (7); in a similar process 1 : 4 : 5 : 8 - tetra (ae - anthraquinonylamino) - anthraquinone is employed as starting material and carbazolization is carried out in a melt of aluminium chloride and sodium chloride, the product being treated with sodium hydroxide and hypochlorite (8); the dyestuff obtained in (1) is vatted with sodium hydroxide and hydrosulphite and used for dyeing cotton.  The dyes yield brown and grey shades on cotton.  The polyanthrimide-forming condensations are generally carried out in highboiling solvents or dispersing agents with the addition of an acid-binding agent such as sodium carbonate or acetate with copper salts as catalysts.  When a limited quantity of dispersing agent, e.g. naphthalene is employed so that the reaction mixture is in the form of a thick paste an apparatus capable of being heated and grinding or mixing the material is employed. Linear pentanthrimide is made by condensing 4 - amino - 1:11 - dianthrimide with 1 - chloranthraquinone.  Linear hexanthrimide is made by condensing 4-amino-:11-41:111-trianthrimide with 4 - chloro - 1:11 - 41:111 - trianthrimide.