Molecular interaction study of the diisopropyl ether-propionic acid mixture by spectroscopic and dielectric studies

► Predominance of parallel alignment of dipoles in diisopropyl ether rich solutions. ► Positive deviation of excess permittivity ɛE - complexation with higher dipole moment. ► Stronger H-bond in complex molecule than in acid dimer. ► Greater influence of more polar solvent on acid dimers in acid rich solutions. ► Stronger H-bond of propionic acid with less polar solvent.