When the liquid used is acetone or other low boiling, water-miscible liquid, it is preferred to dilute the mixture somewhat with water and to recover the acetone, or other liquid, by conventional distillation procedure using open steam as the source of heat. Such an operation leaves the pigment in a desirable aqueous slurry in suitable form for chemical extraction. When the liquid by steam distillation which, when properly mineral spirits,limestone grinding mill it is preferred to remove the liquid by steam distillation which, when properly carried out, leaves the pigment in an aqueous suspension suitable for chemical extraction. It is, of course, also possible to remove the liquid in either event by a simple drying operation, and to recover the liquid by suitable condensation of the gases from the dryer.
Without limiting this invention, the following examples describe various modifications of the process of this invention in more detail.Example 1 Forty-five pounds of a copper-phthalocyanine pigment containing about 4.5% chlorine (ob tained by the reaction of i-chloro-phtl'lalic acid, phthalic anhydride,gold ball mill urea and copper chloride in the presence of a suitable liquid carrier) together with 315 pounds of acetone (98-99% purity) were charged into a ball mill of about 200 gallons capacity (39 in. internal diameter by 39 in. long) containing about 3600 pounds of steel shot with an average diameter of about in. (40% nominal ball load). The mill was rotated at a speed of about 31 R. P. M. for 48 hours, the charge was then diluted with about 200 pounds of acetone, discharged from the mill and pumped to an acetone recovery still. The acetone was then removed by boiling with open steam and was recovered by the aid of a reflux column.
The residual aqueous slurry of the pigment was extracted by boiling with a 2% solution of sulfuric acid, filtered, washed free of sulfate ion, reslurried in sufiicient water to give a slurry containing about 5% of pigment and again extracted by heating near the boil with a 3% solution of ammonium hydroxide. It was then filtered. washed free of alkali and subsequently dried at about 60 C., which gave a brilliant blue dry powder adaptable for use as a phthalocyanine pigment of highly desirable, and to some extent, unusual properties.
Without limiting this invention, the following examples describe various modifications of the process of this invention in more detail.Example 1 Forty-five pounds of a copper-phthalocyanine pigment containing about 4.5% chlorine (ob tained by the reaction of i-chloro-phtl'lalic acid, phthalic anhydride,gold ball mill urea and copper chloride in the presence of a suitable liquid carrier) together with 315 pounds of acetone (98-99% purity) were charged into a ball mill of about 200 gallons capacity (39 in. internal diameter by 39 in. long) containing about 3600 pounds of steel shot with an average diameter of about in. (40% nominal ball load). The mill was rotated at a speed of about 31 R. P. M. for 48 hours, the charge was then diluted with about 200 pounds of acetone, discharged from the mill and pumped to an acetone recovery still. The acetone was then removed by boiling with open steam and was recovered by the aid of a reflux column.
The residual aqueous slurry of the pigment was extracted by boiling with a 2% solution of sulfuric acid, filtered, washed free of sulfate ion, reslurried in sufiicient water to give a slurry containing about 5% of pigment and again extracted by heating near the boil with a 3% solution of ammonium hydroxide. It was then filtered. washed free of alkali and subsequently dried at about 60 C., which gave a brilliant blue dry powder adaptable for use as a phthalocyanine pigment of highly desirable, and to some extent, unusual properties.