Quaternary (liquid + liquid) equilibria for (water + 2-propanol + 1,1-dimethylethyl methyl ether + diisopropyl ether) at the temperature 298.15 K

(Liquid + liquid) equilibrium tie-lines were measured for one ternary system {x1H2O + x2(CH3)2CHOH + (1 − x1 − x2)CH3C(CH3)2OCH3} and one quaternary system {x1H2O + x2(CH3)2CHOH + x3CH3C(CH3)2OCH3 + (1 − x1 − x2 − x3)(CH3)2CHOCH(CH3)2} at T = 298.15 K and P∘ = 101.3 kPa. The experimental (liquid + liquid) equilibrium results were satisfactorily correlated by modified and extended UNIQUAC models both with ternary and quaternary parameters in addition to binary ones.