Prediction of critical micelle concentrations of nonionic surfactants in aqueous and nonaqueous solvents with UNIFAC

The UNIFAC group-contribution model is used to predict the critical micelle concentration (cmc) of nonionic surfactants in aqueous and nonaqueous solvents. For predicting the cmc, the phase-separation thermodynamic framework approach is used, where the micellar phase is approximated as a second liquid phase resulting from the liquid-liquid equilibrium between the solvent and the surfactant. The necessary activity coefficients are predicted by UNIFAC. The most promising UNIFAC model for this purpose was found to be the UNIFAC-Lyngby (Ind. Eng. Chem. Res. 1987, 26, 2274). To improve the results for surfactants containing oxyethylene chains, a new set of parameters was evaluated for this group, leading to still better cmc predictions for both water and organic solvents, as well as binary solvent systems

Solubility of glucose in mixtures containing 2-methyl-2- butanol, dimethyl sulfoxide, acids, esters, and water

Solubility measurements of glucose in a variety of binary, ternary, and multicomponent mixtures containing 2-methyl-2- butanol, dimethyl sulfoxide, acids, esters, and water at different temperatures are presented. The solubilities of crystalline beta-glucose, amorphous beta-glucose, and amorphous beta-glucose in 2-methyl-2-butanol at 60 degreesC have also been measured. The results show that the solubilities of the amorphous forms in 2-methyl-2-butanol are higher than that of the corresponding crystalline form. The presence of dimethyl sulfoxide significantly increases glucose solubility in 2- methyl-2-butanol. Finally, the presence of glucose ester increases glucose solubility in 2-methyl-2-butanol, while the presence of fatty acid has the opposite effect