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Jeff Weidenhamer, Ph.D.

Professor of Chemistry and
Chair, Department of Chemistry, Geology & Physics

Report, initial tests on evaporative loss of fuels

A.    Materials:  Gasoline (E0) and ethanol (E100) were provided by Marathon Oil Co.  Fuel samples containing 10% (E10), 50% (E50) and 85% (E85) ethanol by volume were prepared by mixing on a volume basis.  Approximately twenty mL of each fuel was placed in a 40 mL headspace vial, capped and the mass of fuel determined by weighing.  Vials were then opened and maintained at 30^oC in a water bath for four hours.  The water bath was placed in a fume hood with a constant draw, and the position of vials was randomized.  The experiment was performed in triplicate.  After four hours, vials were capped and reweighed to determine the mass of fuel lost.

1.        Results:

a.       Gasoline (E0) and E10 showed the greatest evaporative loss under these conditions.  Gasoline mass loss was approximately three times the mass loss of the E85 blend, and more than five times the mass loss of ethanol.  Standard deviations ranged from 0.34% (E50) to 0.69% (E100) for the averaged trials.

Figure 1.  Average evaporative loss from each of five fuel blends over four-hour period at 30^oC.