Patent GB-629706-A (GB)
Title: Process for the manufacture of halogenated derivatives of the naphthoquinone series
Filed: 1947-07-22
Abstract: Halogenated 5 : 8-dihydroxy-1 : 4-naphthoquinone-imines-(1) of the general formula <FORM:0629706/IV (b)/1> where at least one of the positions X is halogenated, are prepared by hydrolysis of a halogenated amino - hydroxy - 1 : 4 - naphthoquinone-imine-(1) during or after its formation, to replace the amino group by a hydroxy group.  The halogenated amino-hydroxy-1 : 4-naphthoqyinone-imines-(1) used as starting materials may be prepared by halogenation of aminohydroxy - 1 : 4 - naphthoquinone - imines or by halogenation of the reduction products of a  : a -dinitronaphthalenes during or after the reduction process in sulphuric acid.  The hydrolysis may be carried out with aqueous mineral acids or mixtures of acids such as sulphuric acid and glacial acetic acid.  In examples: (1) and (2) 1 : 5-dinitronaphthalene is reduced with sulphur in strong sulphuric acid, the reaction mixture is diluted with water and treated with bromine in the presence of iodine as a catalyst, and on pouring into a large volume of water dibrom-5 : 8-dihydroxy-1 : 4-naphthoquinone-imine-(1) or a mixture thereof with other halogenated 5 : 8-dihydroxy-1 : 4-naphthoquinone-imines-(1) is obtained; (3) tribrom-5-amino-8-hydroxy-1 : 4-naphthoquinoneimine-(1) is treated with a mixture of sulphuric and glacial acetic acid to give tribrom-5 : 8-dihydroxy - 1 : 4 - naphthoquinone - imine - (1) and dibrom - 5 : 8 - dihydroxy - 1 : 4 - naphthoquinone-imine-(1). Specification 606,008 is referred to.ALSO:Halogenated - 5 : 8 - dihydroxy - 1 : 4-naphthoquinone - imines - (1) of the general formula <FORM:0629706/IV (c)/1> where at least one of the positions X is halogenated are prepared by hydrolysis of a halogenated amino - hydroxy - 1 : 4 - naphthoquinone imine-(1) during or after its formation, to replace the amino group by a hydroxy group.  The halogenated amino-hydroxy-4 : 4-naphthoquinone imines-(1) used as starting materials may be prepared by halogenation of aminohydroxy - 1 : 4 - naphthoquinone imines or halogenation of the reduction products of a  : a -dinitronaphthalenes during or after the reduction process in sulphuric acid.  The hydrolysis may be carried out with aqueous mineral acids or mixtures of acids such as sulphuric acid and glacial acetic acid.  The products dye cellulose acetate artificial silk and nylon violet to reddish-blue.  In examples: (1) and (2) 1 : 5-dinitronaphthalene is reduced with sulphur in strong sulphuric acid, the reaction mixture is diluted with water and treated with bromine in the presence of iodine as a catalyst and on pouring into a large volume of water dibrom-5 : 8-dihydroxy-1 : 4-naphthoquinone imine-(1) or a mixture thereof with other halogenated 5 : 8-dihydroxy-1 : 4-naphthoquinine-imines-(1) is obtained; (3) tribrom - 5 - amino - 8 - hydroxy - 1 : 4 - naphquinone-imine-(1) is treated with a mixture of sulphuric and glacial acetic acid to give tribrom-5 : 8 - dihydroxy - 1 : 4 - naphthoquinoneimine-(1) and dibrom - 5 : 8 - dihydroxy-1 : 4 - naphthoquinoneimine-(1).  Specification 606,008 is referred to.