THE REPORT deals specifically with that part of the Bureau of Standards' program involving vapor-pressure measurements. A description is given of a method and apparatus for the removal of dissolved gases from dried gasolines, without appreciably affecting the propane content and without otherwise changing their composition.
Vapor-pressure measurements with a small bubble of vapor present have been made on 10 motor gasolines over a considerable temperature range. Log p, 1/T plots of these data were found to be linear in the case of all the fuels within 1 to 2 mm. on the average, p representing the pressure and T the absolute temperature. The normal bubble-points (p = 760 mm.) of the 10 gasolines were shown to be equal to the 10-per cent A.S.T.M. temperatures, corrected for loss, within the accuracy of determining the latter. Initial liquid temperatures in the A.S.T.M. distillation were also found to be equal to the 10-per cent A.S.T.M. vapor temperatures and to the normal bubble-points obtained from the vapor-pressure data.
A general correlation of the measurements on the 10 gasolines indicated the possibility of computing all of the data by means of a single equation from either the normal bubble-point or the 10-per cent A.S.T.M. temperature. Although 10 gasolines only were employed in the work, their diversity makes it reasonable to assume that the vapor-pressure data on any commercial motor gasoline, freed from water and dissolved gases, can be computed from the 10-per cent A.S.T.M. temperature with considerable accuracy. Appendix 1 describes a vapor pressure-temperature chart.