Thermophysical properties of Tetraoxymethylene dimethyl ether H3CO(CH2O)4CH3 in a wide range of temperatures and pressures

Polyoxymethylene dimethyl ethers H 3 CO(CH 2 O) n CH 3 , n ≥ 2 (also known as Oxymethylendimethylether; OMDME or OME x ) are a potential substitutes for diesel fuels. However, the respective technology development requires detailed data on their thermophysical properties. In this work, the heat capacities, viscosities, densities, speeds of sound and surface tensions of OME 4 are reported. These data of OME 4 were investigated over a wide range of temperatures T = (263.15 to 468.26) K and pressures p = (0.101 to 200) MPa. The experimental density measurements at p = (0.101–140) MPa were performed on vibration tube densimeters with an estimated experimental relative combined average percentage deviation (APD) of Δ ρ / ρ = ±(0.01–0.03) %. The constant pressure specific heat capacity c p ( p 0 ,T )/J·kg −1 ·K −1 at ambient pressure and temperatures T = (268.761 to 381.116) was determined using differential scanning calorimetry (DSC) with Δ T = (5–10) K temperature interval and an uncertainty of Δ c / c p = ±0.1 %. Dynamic viscosity η ( p 0 ,T )/mPa·s values of OME 4 at ambient pressure p = 0.101 MPa and temperatures T = (273.15 to 471.15) K were measured using two different rheometers with an uncertainty of Δ η / η = ±0.35 % and Δ η / η = ±1 %, respectively. The speed of sound u ( p 0 ,T )/m·s −1 values for OME 4 at ambient pressure and temperatures T = (278.149 to 343.155) K were studied using a vibration tube densimeter and sound velocitymeter with intervals of Δ T = (5–10) K and an uncertainty of Δ u = ±0.1 m·s −1 . The surface tension σ ( p 0 ,T )/mN⋅m −1 values of OME 4 at ambient pressure p = 0.1 MPa and temperatures T = (288.55 to 345.45) K were measured using the Du Noüy ring method. An empirical correlation for the property data of OME 4 has been developed as a function of pressure and temperature. These data allow researchers from process development to engine research to perform efficient development and to tailor potential alternative OME fuels to actual demands.