Speeds of sound and isentropic compressibilities of mixtures containing some polyethers + propylene carbonate at 298.15 K

Abstract

The speeds of sound have been measured at 298. 15 K as a function of composition for the four binary liquid mixtures: propylene carbonate (PC) (4-methyl- 1,3-dioxolan-2-one, C₄H₆O₃: PC) + ethylene glycol dimethyl ether ( 1,2-dimethoxy C₄H₁₀O₂: EGDME) + diethylene glycol dimethyl ether (bis(2- methoxyethyl)ether, C₆H₁₄O₃ : di -EGDME) + triethylene glycol dimethyl

ether (1,2-bis(2-methoxyethoxy)ethane, C₈H₁₄O₃: tri - EGDME), and + tetraethylene glycol dimethyl ether (2,5,8,11,14-pentaoxapentadecane, C₁₀H₁₂O₅ : tetra-EGDME) using a Nusonic velocimeter based on the sing around technique. Their values have been combined with those of the excess molar volumes converted to densities to give estimates of the product <i>K</i>_s,m of the

molar volumes and isentropic compressibility <i>k</i>_s,<i> </i>and the excess quantity <i>K</i>^E_S,m. The <i>K</i>^E_S,m values are negative for all mixtures. Measurements have been carried out in order to assess the effects of inserting oxyethylene groups with a common alkyl group in polyether. The deviation <i>μ</i>^D of the speeds of sound from their values in an ideal mixture were also evaluated for all measured values of <i>x</i>. These values are compared with the mixing function δ<i>μ </i>in the paper. The behaviour of <i>μ</i>^D, δ<i>μ </i>and <i>K</i>^E_S,m with composition and the number of -OC₂H₄-units of the ether molecule is discussed.

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