| 摘要 |
Concentrated stable liquid preparations of anionic soluble optical bleaching agents or dyes are made by (1) pptg. a salt of the bleach or dye with a difficulty-sol. cation (esp. Ca, Mg, Zn or Ba salts), suspending the salt in aqs. or aqs. organic soln. of ammonia or org. base, adding an inorganic acid (esp. sulphuric acid, phosphoric acid or CO2) to ppte. an even more insoluble salt of the cation and separating off the pptd. salt to give a concentrated bleach or dye soln. which can be concentrated further by distillation. The resulting optical bleach or dye solutions are more convenient to handle when used for textile and paper treatment than powdered products. |
