| 摘要 |
PURPOSE:Ammonium carbonate is added to an aqueous solution of a water-soluble dye to effect the salting-out of the dye, and the resulting cake is dissolved in an aqueous medium and kept at elevated temperature to lower the content of inorganic salt readily whereby the dye is purified. CONSTITUTION:Ammonium carbonate, ammonium bicarbonate or ammonium carbamate is added to an aqueous solution of a water-soluble dye (e.g., C, I, Direct Yellow 50) to effect the salting-out of the dye. Then, the precipitate is filtered off and the resultant cake is dissolved or suspended in an aqueous medium, then the solution or suspension is kept over 40 deg.C, preferably at 50-100 deg.C over 0.5hr, preferably for 2-20hr to purify the dye.
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