Sulphur Blue 7 -Leuco

Preparation

4-(4-Amino-3-methylphenylamino)phenol with Sodium polysulfide solution in return 106 ~ 112 ℃ heating 50 hours, then 70 ~ 80 ℃ blow air make precipitation. This indophenol?is by o- Toluidine and 4-Nitrosophenol in sulfuric acid in the condensation, then use Sodium sulfide reduction and have to. Sodium sulfide increase in the proportion of sulfur content and high temperature vulcanization, color is red and more bright-coloured dye.

Properties and Applications

red light blue to blue light purple. Dark brown liquid. PH value is 13.3; Viscosity 5.9 x 10-3 pa s.; Settleability (3000 r.p.m.); No separation, no settlement. In the Sodium sulfide solution solubility is good, for green grey; In concentrated sulfuric acid for blue purple, dilution of dark after precipitation.