Abstract
Hydrophobic dyes, i.e. Disperse Red 13 (DR-13), (2-[4-(2-chloro-4-nitrophenylazo)-N-ethylphenylamino]ethanol) and Jaune au gras W1201, (1H-indene-1,3(2H)-dione,2-(2-quinolinyl)), are solubilized in water with the help of different additives: acetone and 1-propanol as typical cosolvents, sodium xylene sulfonate (SXS) as a representative of a classical hydrotrope, sodium dodecyl sulfate (SDS) as a ...
Abstract
Hydrophobic dyes, i.e. Disperse Red 13 (DR-13), (2-[4-(2-chloro-4-nitrophenylazo)-N-ethylphenylamino]ethanol) and Jaune au gras W1201, (1H-indene-1,3(2H)-dione,2-(2-quinolinyl)), are solubilized in water with the help of different additives: acetone and 1-propanol as typical cosolvents, sodium xylene sulfonate (SXS) as a representative of a classical hydrotrope, sodium dodecyl sulfate (SDS) as a typical surfactant, and finally some "solvosurfactants" [propylene glycol monoalkyl ether derivs. (CiPOj: i = 1, j = 1 and 3; i = 3, j = 1 and 2; i = 4 and tert-Bu, j = 1) and 1-propoxy-2-ethanol (C3EO1)]. These solvosurfactants are short amphiphiles that do not form well-defined structures, such as micelles, in water. For all additives an exponential increase in the solubilizations of the 2 studied hydrophobic dyes was obsd. when their concns. in water were increased. Except for the SDS soln., no difference in the overall shapes of the solubilization curves (dye soly. against additive concn.) was found. All the studied mols. were classified according to their hydrotropic efficiencies, i.e., their abilities to solubilize a hydrophobic, sparingly sol. compd. in water. The vol. of the hydrophobic parts of the studied additives, roughly evaluated by simple calcns., influenced strongly the hydrotropic efficiency; i.e. The larger the hydrophobic part of the additive, the better the hydrotropic efficiency. By contrast, the hydrophilic part carrying a charge or not is of minor importance. Taking the hydrophobic part of the mols. as the key parameter, the water solubilization efficiency of cosolvents, hydrotropes, and solvosurfactants can be described in a coherent way.
Altmetric