Precise measurements of properties of aqueous methanol mixtures and discussion on their composition dependence

Recently methanol and its aqueous mixtures have attracted much attention due to their potentialityin use as recovery and fixation for CO - 22 D2 being one of greenhouse gases，and as transport and storage of hydrogen fuel. Renewed interest in这些材料shows also to其他various applications such as natural refrigerantsand working fluids in new power cycles. Thermophysical property data for these materials arefundamental information to industrialize these new and renewed applications.In the present study，bubble point pressures，saturated liquid densities and PVT properties of {xCH D23 D2OH+(1-x)H D22 D2O} with x=（1.0000）0.1984) have been measured by a variable volume method with metal bellows in the temperaturerange from 320k to 400k at pressures up to 200mpa . The uncertainties in measurements areestimated no greater than 3 mK in temperature, and 0.1% in pressure, density and composition，respectively. By the aid of these measurements, isothermal compressibility, isobaric expansivityand non-ideality in bubble point pressures as well as PVT properties have been calculated.The studyconcluded with followings:(1) Deviations of bubble point pressure from Raoult's law show positive. (1) Deviations of bubble point pressure from Raoult's law show positive.mixture deviations of 20 mol% methanol decrease with increasing temperature，当那些与50 mol% methanol are constant with temperature variation .(2) Excess molarvolumes show negative，and approach zero being the behavior of ideal mixtures with increasing pressure. As for temperaturedependence of the mixtures，behavior of those with 50 mol% methanol changes at a pressure of about 20 Mpa，但没有such behavior is observed for the mixture with 20 mol% methanol。

Recently methanol and its aqueous mixtures have attracted much attention due to their potentiality in use as recovery and fixation for COィイD22ィエD2 being one of greenhouse gases, and as transport and storage of hydrogen fuel. Renewed interest in these materials shows also to other various applications such as natural refrigerants, and working fluids in new power cycles. Thermophysical property data for these materials are fundamental information to industrialize these new and renewed applications.In the present study, bubble point pressures, saturated liquid densities and PVT properties of {xCHィイD23ィエD2OH+(1-x)HィイD22ィエD2O} with x=(1.0000 and 0.1984) have been measured by a variable volume method with metal bellows in the temperature range from 320 K to 400 K at pressures up to 200 Mpa. The uncertainties in measurements are estimated no greater than 3 mK in temperature, and 0.1% in pressure, density and composition, respectively. By the aid of these measurements, isothermal compressibility, isobaric expansivity, and non-ideality in bubble point pressures as well as PVT properties have been calculated.The study concluded with followings:(1) Deviations of bubble point pressure from Raoult's law show positive. The deviations of mixture with 20 mol% methanol decrease with increasing temperature, whereas those with 50 mol% methanol are constant with variation of temperature.(2) Excess molar volumes show negative, and approach zero being the behavior of ideal mixtures with increasing pressure. As for temperature dependence of the mixtures, behavior of those with 50 mol% methanol changes at a pressure of about 20 Mpa, but no such behavior is observed for the mixture with 20 mol% methanol.