Data on the solubility of manganese sulphate monohydrate in water, and in aqueous alcohols is essential for salting-out crystallization studies. The solubilities of the quaternary system MnSO4 center dot H2O + MgSO4 center dot 7H(2)O + H2O + (CH3)(2)CHOH were determined in the temperature range 293.2-313.2 K over the 2-propanol mole fraction range of 0.00-0.07. The solubility data were used for modelling with the modified extended electrolyte non-random two-liquid (NRTL) equation. The present extension uses ion-specific parameters instead of the electrolyte-specific NRTL binary interaction parameters. This approach has feasibility for many electrolytes and mixed aqueous solution systems in principle. The model was found to correlate the solubility data satisfactorily. Crown Copyright (c) 2007 Published by Elsevier B.V. All rights reserved.