(Liquid + liquid) equilibria of (sulfolane + benzene + n-hexane), (N-formylmorpholine + benzene + n-hexane), and (sulfolane + N-formylmorpholine + benzene + n-hexane) at temperatures ranging from (298.15 to 318.15)K: Experimental results and correlation Mahmoudi, J.; Lotfollahi, M.N.; The Journal of Chemical Thermodynamics 2010, 42, 466-471