The cloud point of aqueous solutions of ethoxylated monoalkylphenols in the individual state and in the presence of electrolytes

Abstract

© 2017 Taylor & Francis The cloud points t cp of aqueous solutions of ethoxylated monoalkylphenols, AF9-n (n = 8,9,10,12), were measured in the concentration (C) range of 0.25-40 wt.%. t cp increased as C decreased at C < 1 wt.%. At 1 < С < 10 wt.%, t cp changed insignificantly; Δt cp /t cp did not exceed 5%. Solutions transformed into the gel state at С > 10-20 wt.% and t cp sharply increased. The dependence of t cp on the length of the oxyethylene chains of ethoxylated nonylphenols at C = 1 wt.% can be described by the equation t cp = b·ln(n-n 0 ), where n 0 = 6. The cloud points of aqueous solutions (C = 1 wt.%) of the ethoxylated nonylphenols were measured at different concentrations of NaI, NaCl, NaF, Na 2 CO 3 , and Na 2 SO 4 salts. For all of these solutions, t cp decreased in the presence of NaCl, NaF, Na 2 CO 3 , Na 2 SO 4 and increased in the presence of NaI. To describe the dependence of t cp on the salt concentration, the equation (Formula presented.) was suggested, where (Formula presented.) and t cp are the cloud points of a neat aqueous solution of ethoxylated nonylphenols and of the solution in the presence of electrolytes, respectively.