Abstract: The solubility of C.I. Reactive Blue 221 in water was investigated at 25 oC using NaCl, AEO9, AEO3, JFC, AES and L-64 as the additives respectively. The results show that: the addition of NaCl will decrease the solubility significantly；while the surfactants improve solubility of C.I. Reactive Blue 221 to a certain degree. The solubilization effects of the five surfactants were followed by JFC ( L-64 ) >AEO9 > AEO3 > AES. When AEO9 or L-64 was added as a dosage of 80 g/L, the water solubility of C.I. Reactive Blue 221 was improved from 100 g/L to 190 g/L. When 15 g/L JFC, 20 g/L L-64 and 5 g/L AEO9 were added as the combination additives in the solution, the solubility of C.I. Reactive Blue 221 went up to 200 g/L, and the stability time of the liquid reactive dyes prepared was more than 20 hours.

Key words: C.I Reactive Blue 221, solubility, surfactant, stability