The Students' Guide in Quantitative Analysis - Free Ebooks Library

DISTILLATION OF PETROLEUM, i^t
of about 500 c. c. capacity ; connect this with a Liebig's
condenser, and arrange for distilling in the usual manner.
Through the tubulus of the retort insert a thermometer.
Provitk ten glass cylinders of 50 to 75
c. c. in capacity,
and mark each with a file, so as to show the volume occu-
pied by 25 c. c. of liquid. These cylinders are to serve as
recipients of the distillate.
Pour 250 c. c. crude petroleum into the retort, and apply
heat very gently at first, increasing gradually, and finally
heating until the residue in the retort is coked. Collect
25 c. c. of the distillate in the first cylinder, and note the
temperature indicated by the thermometer in the retort
collect the second 25 c c. in another recipient, note also
temperature, and continue in this manner, changing the
recipient for every 2$ c c. until the whole liquid has dis-
tilled over.
B. — Examination of the Distillates.
Determine the sp. gr. of each distillate by floating in it
a small Baumd Hydrometer, note the color of each sam-
ple, and determine its flashing point by means of Taglia-
bue's *' Open Tester," a figure and description of which are
found on page 41, Vol. HI. of the "American Chemist."
To test the flashing point, proceed as follows : pour a
small quantity of the sample to be e.Kamined into the open
cup, which is surrounded by a vessel of water. Light the
lamp beneath and apply heat very gradually the tempera-
;
ture should not rise faster than two degrees a mmute.
The thermometer bulb should dip beneath the surface of
the oil. From time to time test the inflammable vapors
which arise from the surface of the oil, using a small flame,
flitting it quickly across the surface, and noting simultane-
ously the height of the thermometer at the moment of
ignition. Record results with each distillate.
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