| production method | with 2-amino -4 (and 5)-nitrophenol, 1-phenyl -3-methyl -5-pyrazolone as raw material, first 2-amino -4 (and 5)-nitrophenol diazotization, it is then coupled with 1-phenyl-3-methyl-5-pyrazolone, followed by addition of chrome alum for complexation, filtration, drying and pulverization to give a dry powder of the original dye. The dry powder raw dye is dissolved in ethanol ether, ethanol mixed solvent, and the solution is obtained by sedimentation and filtration. The dye can be packaged... |