Patent GB-687456-A (GB)
Title: Improved method of preparing sulfuric acid half esters of leuco anthraquinones in mildly alkaline aqueous medium
IPC: C09B9/02
Filed: 1951-06-18
Abstract: Leuco-sulphuric esters of anthraquinone compounds are made by simultaneous reduction and esterification of anthraquinone compounds in an alkaline aqueous medium having a pH not greater than 11.5, using a sulphur trioxide addition compound of a tertiary amine having a dissociation constant of at least 1 X 10-7 at 25 DEG  C.  An organic liquid inert to the reducing and esterifying agents, and a water-soluble sulphonate of the benzene or naphthalene series may be present.  In examples, the following compounds are treated with sodium hydrosulphite and triethylamine-sulphur trioxide in aqueous sodium carbonate together with certain of the organic liquids and sulphonic acids specified below: (1) anthraquinone; (2) the dicarbazole from 1.4-di(-anthraquinonylamino) - anthraquinone; (3) a - chloroanthraquinone; (4) 2-acetylamino-3-chloro or bromoanthraquinone; (5) the carbazole from 1-(Bz.1.-benzanthronylamino)-anthraquinone; (6) C.C.-diphenyl - 1.2 - (N) - thiazolo - 5(s).6 - isothiazolo - anthraquinone; (7) the carbazole from 1.11 - dianthrimide; (8) 2-(p-toluyl) anthraquinone; (9) 1-phenoxyanthraquinone; (10) p  1.2-phthaloyl-carbazole; (11) 1.2-benzanthraquinone.  Other sulphur trioxide compounds specified in the examples are those with cyclohexyldimethylamine, N-ethyl-morpholine, and tributylamine.  Organic liquids specified are benzene and its homologues and chlorinated benzenes, carbon tetrachloride, chloroform, trichloroethylene, methyl ethyl ketone, acetophenone, cyclohexane, dibutyl ether, amyl acetate, ethyl benzoate, pyridine, quinoline, dimethylaniline, benzonitrile, and furan.  Sulphonic acids specified are those of benzene, toluene, xylene, chlorobenzene, dimethylaniline, anisole, naphthalene, chloronaphthalenes, and naphthyl methyl ethers.  Specification 585,106 is referred to.ALSO:Leuco-sulphuric esters of anthraquinone compounds are made by simultaneous reduction and esterification of anthraquinone compounds in an alkaline aqueous medium having a pH not greater than 11.5, using a sulphur trioxide addition compound of a tertiary amine having a dissociation constant of at least 1 X 10-7 at 25 DEG  C.  An organic liquid inert to the reducing and esterifying agents, or a water-soluble sulphonate of the benzene or naphthalene series may be present.  In examples, the following compounds are treated with sodium hydrosulphite and triethylamine-sulphur trioxide in aqueous sodium carbonate together with certain of the organic liquids and sulphonic acids specified below: (1) anthraquinone, (2) the dicarbazole from 1,4 - di - (a  - anthraquinonylamino) - anthraquinone, (3) a  - chloroanthraquinone, (4) 2-acetylamino-3-chloro- or bromoanthraquinone, (5) the carbazole from 1-(Bz.1-benzanthronylamino) - anthraquinone, (6) C,C-diphenyl - 1,2 - thiazolo - 5,(S)6 - isothiazolo-anthraquinone, (7) the carbazole from 1,11-dianthrimide, (8) 2-(p-toluyl) anthraquinone, (9) 1 - phenoxyanthraquinone, (10) 1,2 - phthaloylcarbazole, (11) 1,2-benzanthraquinone.  Other sulphur trioxide compounds specified in the examples are those with cyclohexyldimethylamine, N-ethyl-morpholine, and tributylamine. Organic liquids specified are benzene and its homologues and chlorinated benzenes, carbon tetrachloride, chloroform, trichloroethylene, methyl ethyl ketone, acetophenone, cyclohexane, dibutyl ether, amyl acetate, ethyl benzoate, pyridine, quinoline, dimethylaniline, benzonitrile, and furan. Sulphonic acids specified are those of benzene, toluene, xylene, chlorobenzene, dimethylaniline, anisole, naphthalene, chloronaphthalenes, and naphthyl methyl ethers.  Specification 585,106 is referred to.