Patent GB-559247-A (GB)
Title: Method of producing pigments of the copper phthalocyanine type
IPC: C09B47/067
Filed: 1942-08-14
Abstract: 559,247. Dyes. FAIRWEATHER, H. G. C. (American Cyanamid Co.). Aug. 14, 1942, No. 11431. [Class 2 (iii)] A copper phthalocyanine pigment is prepared by reacting an aromatic o-dinitrile in the substantial absence (as defined) of water with a cupric salt in the presence of a practically inert organic diluent liquid (as defined) and of an amount of ammonia at least sufficient to combine with all the anion of the cupric salt set free in the reaction to produce the corresponding ammonium salt of the anion and nitrogen. The dinitrile may be phthalonitrile ; 3:4-dimethyl-, 4-phenyl-, 4-chloro-, 4:5- dichloro-, 3-nitro-, 4-ethoxy-, or 4-acetaminophthalonitrile ; 3:4-dicyanobenzophenone ; 2:3- dicyanofluorenone; 2:3-dicyanopyrazine; 2:3- dicyanodiphenylene oxide ; 1:2-dicyanonaphthalene ; 6-methyl-2:3-dicyanoquinoxaline; 3:4- dicyanodiphenyl ; 2-(3<SP>1</SP>:4<SP>1</SP>-dicyanodiphenyl)- benzthiazole ; or an o-dicyanophenylpyridine. A small quantity of the corresponding imide may be added, or a crude phthalonitrile may be employed. The diluent may be nitrobenzene or a di- or tri-chlorobenzene. Heterocyclic bases may be added. After the reaction is over, the pigment is filtered off and the pigment recovered. The preferable temperature is from 180-220‹C. The cupric salt may be anhydrous cupric chloride or bromide or a mixture, monohydrate cupric sulphate which is first dehydrated by passing ammonia through the reaction mixture at 100-110‹C., or anhydrous cupric sulphate. When cupric halides are used, a small amount of ammonium chloride may be added. The ammonia may be passed through the reaction mixture and recovered or may be recycled through it, or the reaction may be carried out in the presence of ammonia in an autoclave. In example 1, crude phthalonitrile (containing phthalimide), CuSO 4 .1H 2 O, ammonium sulphate, and nitrobenzene are heated together at 100-105‹C., and the air replaced by ammonia. The reaction mixture is saturated with NH 3  with rapid stirring and heated to 225-230‹C. in a slow stream of NH 3 . The filtered and washed pigment is dissolved in concentrated H 2 SO 4  and reprecipitated by pouring into water. In example 2, the same process is applied to a mixture of pure phthalonitrile and phthalimide. In example 3, crude phthalonitrile, phthalimide, and anhydrous CuSO  4  are added to nitrobenzene in an autoclave, which is evacuated, dry NH  3  added, and heated to 210-215‹C. The nitrobenzene is recovered from the filter cake by steam distillation. The anhydrous double salt CuSO 4 . (NH 4 ) 2 SO 4  may be substituted for the CuSO 4 . In example 4, a mixture of 1:2-dicyanonaphthalene, anhydrous CuSO 4 , phthalimide, and nitrobenzene saturated with NH 3  is refluxed in an ammonia atmosphere. In example 5, 6-methyl-2:3-dicyanoquinoxaline is used in the method of example 4. In example 6, a mixture of anhydrous CuCl 2 , phthalonitrile, and nitrobenzene saturated with NH 3  is refluxed while kept saturated with NH 3 . If NH  3  is omitted, a monochloro derivative of copper phthalocyanine is obtained. In example 7, a mixture of phthalonitrile, phthalimide, anhydrous CuCl 2 , and nitrobenzene is heated to 100-105‹C. and the air replaced by NH 3  and the mixture saturated therewith. The mixture is then kept at the boiling point. Crude phthalonitrile may replace the mixture of pure phthalonitrile and phthalimide. In example 8, a mixture of crude phthalonitrile, NH 4 Cl, anhydrous CuCl 2 , and nitrobenzene is similarly treated. The nitrobenzene may be replaced by 1:2:4-trichlorbenzene or 1:2-dichlorbenzene. In example 9, a mixture of phthalonitrile, anhydrous CuBr 2 , and nitrobenzene is similarly treated. In example 10, a mixture of 1:2-dicyanonaphthalene, anhydrous CuCl 2 , and nitrobenzene is similarly treated. In example 11, a mixture of 6-methyl-2:3- dicyanoquinoxaline, anhydrous CuCl 2 , and nitrobenzene is similarly treated. 3:4-dimethylphthalonitrile is prepared by brominating o-xylene to 1:2-dimethyl-4-bromobenzene, aminating to form the 4-amino derivative, sulphonating to form the 1:2- dimethyl-4-aminobenzene-5-sulphonic acid, replacing the amino group by a cyanogen group by means of Sandmeyer's reaction, and heating the sodium salt of the compound obtained in vacuo in the presence of anhydrous potassium ferrocyanide to give the desired compound. 2-(3<SP>1</SP>:4<SP>1</SP>-dicyanophenyl)-benzthiazole is prepared by heating 4<SP>1</SP>-cyanophenylbenzthiazole- 31-sulphonic acid with sodium cyanide and anhydrous potassium ferrocyanide. 6-methyl-2:3-dicyanoquinoxaline is made by reducing m-nitro-p-toluidine to the corresponding toluylene-diamine, condensing with the disodium salt of dioxytartaric acid to give 6-methylquinoxaline-2:3-dicarboxylic acid disodium salt, forming the anhydride by treating with acetic anhydride, passing dry ammonia gas through the boiling benzene solution of the anhydride to form the monamide of the monoammonium salt, reacting this with thionyl chloride to produce the imide of 6-methylquinoxaline-2:3-dicarboxylic acid, stirring the imide with concentrated aqueous ammonia to form the diamide, treating the pyridine solution of the diamide of 6-methylquinoxaline-2:3- dicarboxylic acid with phosphorus oxychloride to give 6-methyl-2:3-dicyanoquinoxaline. Specifications 410,814, 441,399, 468,043, 470,499, 470,542, 470,703, 471,418 and 488,201 and U.S.A. Specifications 2,133,340 and 2,211,947 are referred to.