Oxygenates are usually used as fuel additives. Recently, di-isopropyl ether (DIPE) has been considered as the potential fuel additive for the replacement of methyl tert-butyl ether (MTBE). So it is essential to research its thermophysical properties. In this paper, the speed of sound in DIPE was measured from 303.15 K to 673.15 K up to 10 MPa using Brillouin light scattering (BLS), including saturated liquid/ vapour, and the liquid and supercritical regions. The saturated liquid/vapour and single phase liquid results were fitted as functions of temperature and pressure. The correlations represent the data with AADs of 0.62% for the saturated liquid, 0.44% for the saturated vapour and 0.73% for the liquid, respectively. Moreover, the variation of speed of sound with temperature and pressure was also analysed. (C) 2016 Elsevier Ltd.