To a 500-ml 3-necked flask fitted with a stirrer, thermometer, pressure equalized addition funnel and nitrogen inlets and outlets were charged 13.5 grams (0.21 mole) of potassium hydroxide pellets and 10 ml of water. The resulting hot solution was diluted with 80 ml of methanol. After flushing with nitrogen, 16.5 grams (0.05 mole) of 2,4-di(α,α-dimethylbenzyl)phenol and 85 ml of methanol were added to give a clear solution which was then cooled to -4° C. A cold solution of o-nitrobenzenediazonium chloride in concentrated hydrochloric acid solution (42.9 grams=0.06 mole of diazonium solution) was added over a period of 15 minutes with rapid stirring while keeping the temperature between -2° and 0° C. The deep purple color of the azodye-phenoxide developed instantaneously as the diazonium solution was added. The resulting mixture was stirred for another 10 minutes at -1° to 1° C. The suspension was then acidified with 20 ml of glacial acetic acid over a 2-minute period at 1° to 3° C. The resulting brick red suspension was stirred for 15 minutes as the temperature was allowed to rise to ambient temperature and then filtered. The filter cake was washed with a cold solution of 40 grams ice in 160 ml of methanol and then with 1800 ml of water.
