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Vapor Pressure Measurements on Biodiesel Esters by the Concatenated Gas Saturation Method



Jason A. Widegren, Thomas J. Bruno


The purpose of this work was to determine vapor pressures for saturated biodiesel esters at the low-temperature end of their liquid range. A "concatenated" gas saturation apparatus capable of simultaneous measurements on 18 samples was used for measurements on methyl palmitate, ethyl palmitate, methyl stearate, ethyl stearate, and eicosane (C_20 H_42 ) over the temperature range 323.15 K to 343.15 K. Eicosane, which has a well known vapor pressure curve in the same range as the biodiesel esters, was included as a control compound. Importantly, the measured vapor pressures for eicosane are in excellent agreement with reference values, which is good evidence of the low uncertainty of the measurements on the biodiesel esters. Over this temperature range, the measured vapor pressure ranges were 0.145 Pa to 1.11 Pa for methyl palmitate, 0.0687 Pa to 0.616 Pa for ethyl palmitate, 0.0159 Pa to 0.183 Pa for methyl stearate, and 0.00704 Pa to 0.0912 Pa for ethyl stearate.


concatenated gas saturation method, eicosane, ethyl hexadecanoate, ethyl octadecanoate, ethyl palmitate, ethyl stearate, methyl hexadecanoate, methyl octadecanoate, methyl palmitate, methyl stearate, transpiration method, vapor pressure


Widegren, J. and Bruno, T. (2011), Vapor Pressure Measurements on Biodiesel Esters by the Concatenated Gas Saturation Method, Fuel, [online], (Accessed June 16, 2024)


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Created January 2, 2011, Updated March 1, 2021