this kind of dye is by?4-(2,4-Dinitrophenylamino)phenol?aqueous solution and sulfide. Change the purity and degree of oxidation can get different colored light blue dye,usually the color brilliance and purity of direct proportion, and oxidation of the final product is red. (a) will be the?4-(2,4-Dinitrophenylamino)phenol?75% paste which in 90 ~ 92 ℃, at least 2 hours to add Sodium polysulfide, and in 106 ℃ reflux 3 hours, and Sodium chloride, and heating to 109 ~ 110 ℃, heat preservation 10 hours, diluted, 45 ℃ filtering, 70 ℃ drying; By this method the paste things in air oxidation, get color bright dye, its method is as follows: (b) water dilution from (a) paste content, add Sodium hydroxide, air oxidation 5 hours, salting out, filtering, and add Sodium carbonate drying; (C) if the increase of Sodium hydroxide to join quantity, air oxidation 14 ~ 16 hours, can further improve the brilliance, (d) will come from (C) with Sodium hydroxide has been the filter cake in 30 ℃ air oxidation about 18 hours, and then salting out, filtering and drying; (e) from the above product in disulfide and diacetyl Sodium acetate trihydrate solution, 95 ℃ treatment 5 hours, can still generate color is red and a brilliant dye. Dye with conventional method separation and drying (FIAT1313, 3229 -, – 230). Some vulcanization direct blue is by?4-(2,4-Dinitrophenylamino)phenol?with Sodium polysulfide solution in 135 ~ 140 ℃ calcination, then according to the above method and oxidation.
