High-temperature and high-pressure experimental thermal conductivity for the pure methanol and binary systems methanol + n-propanol, methanol + n-octanol, and methanol + n-undecanol

Thermal conductivity of pure methanol and three mixtures, methanol + n-propanol, methanol + n-octanol, and methanol + n-undecanol, has been measured with a cylindrical tricalorimeter technique (λ-calorimeter). Measurements were made at nine isobars, 0.1013, 1, 5, 10, 20, 30, 40, 50, and 60 MPa. The range of temperatures was from 290 to 603 K. For each binary system, the measurements were made for three compositions: 25, 50, and 75 mass%. The total uncertainty of thermal conductivity, pressure, temperature, and concentration measurements was estimated to be less than 1.93%, 0.05%, 30 mK, and 0.001 mole fraction, respectively. The reliability and accuracy of the experimental method was confirmed with measurements on pure methanol for nine isobars, 0.1, 1, 5, 10, 20, 30, 40, 50, and 60 MPa, and at temperatures between 292 and 601 K. The present experimental data and the data reported by other authors for the thermal conductivity of pure methanol show excellent agreement within their experimental uncertainty (AAD is about 0.5–0.7%). Excess thermal conductivities were derived using measured values of thermal conductivity for the mixtures and for pure components covering the whole range of composition. A correlation equation for excess thermal conductivity was obtained as a function of temperature, pressure, and composition by a least-squares method from the experimental data. The AAD between measured and calculated values from this correlation equation for the thermal conductivity was 1% for the mixtures.