Density ρ(p0,T)/kg·m−3, viscosity η(p0,T)/Pas, heat capacity cp(p0,T)/Jkg-1K-1 and speed of sound u(p0,T)/m·s-1 of 1-octyl-3-methylimidazolium tetrafluoroborate [OMIM][BF4] over a wide range of temperatures at T = (278.15 to 413.15) K and ambient pressure p=0.101 MPa are reported with an estimated experimental relative combined average ρ/ρ = ±(0.01 to 0.08) % percent deviation (APD) in density, cp/cp= 1 % in constant pressure specific heat capacity, / = ±0.35 % in dynamic viscosity and standard Δu= ± 0.1 m·s-1 deviation in speed of sound values. Measurements were carried out using the Anton Paar DMA 5000M, DSA 5000M, DMA HPM vibration tube densimeters, SVM 3000 Stabinger Viscometer and Perkin Elmer Pyris 1 DSC Differential Scanning Calorimeter

The constant pressure specific heat capacity ( , , ) 0 or c p T x p s /Jkg-1K-1 of 1-butanol and Diesel fuel blends at temperatures T = (253.15 to 468.15) K are reported with an estimated average cp/cp = ±0.5% deviation. Measurements were carried out using a Perkin Elmer’s Pyris 1 differential scanning calorimetry (DSC). The excess heat capacity ( , , ) 0 or c p T x s Ep/Jkg-1 K -1 of 1-butanol and Diesel fuel blends were calculated. Polynomial equation as a function of temperature was used for the fitting of measured data,