Chemistry Reference
In-Depth Information
sample into a cylinder submerged in a cooling medium. The sample tem-
perature was measured in 3 1C increments at the top of the sample until the
material stopped pouring. The sample no longer poured when the material
in the test jar did not flow when held in a horizontal position for 5 s. The
temperature of the cooling medium was chosen based on the expected PP of
the material. Samples with PPs that ranged from
รพ
9to
6,
6to
24, and
24 to
42 1C were placed in baths of temperatures from
18,
33, and
51 1C, respectively. PP is defined as the coldest temperature at which the
sample still pours. All PPs were run in duplicate and averaged values are
reported.
10.2.5.2 Cloud Point
Cloud Point (CP) was determined following ASTM method D2500-99
10,11
to
an accuracy of
1 1C. The method involves placing a test jar with 50 mL of
the sample into a cylinder submerged in a cooling medium. The sample
temperature was measured in 1 1C increments at the bottom of the sample
until any cloudiness was observed at the bottom of the test jar. The tem-
perature of the cooling medium was chosen based on the expected CP of
the material. Samples with CPs that ranged from RT to 10, 9 to
6,
6to
24 and
24 to
42 1C were placed in baths of temperatures from 0
18,
33, and
51 1C, respectively. All CP measurements were conducted in
duplicate and averaged values are reported.
10.2.5.3 Oxidative Stability
10.2.5.3.1 Rotating Pressurized Vessel Oxidation Test. RPVOT experi-
ments were conducted on a RPVOT apparatus manufactured by Koehler
(Bohemia, NY) using ASTM method D2272-98.
12
A commercial anti-oxidant
package, Lubrizol
t
7652 (The Lubrizol Corporation, Wickliffe, OH), was
blended into the test oil samples on a wt% basis. Formulated samples
were stirred for 24 h before use in RPVOT experiments. All RPVOT experi-
ments were conducted at 150 1C. The copper catalyst used in the experi-
ments was 3 m long and sanded with 220 grit silicon carbide sandpaper
produced by Abrasive Leaders and Innovators (Fairborn, OH) and was
used immediately. The wire was wound to have an outside diameter of
44-48 mm, a height of 40-42 mm, and a weight of 55.6
0.3 g. In a typi-
cal experiment, 50.0
0.5 g of blended samples were weighed into the
pressure vessel, to which 5.0 mL of reagent-grade water and the freshly
prepared catalyst copper wire were added. The vessel was then assembled
and slowly purged with reagent-grade oxygen twice. The pressure vessel
was charged with 90.0
0.5 psi (620 kPa) of reagent-grade oxygen, and
then checked for oxygen leaks by immersing the vessel in water. The test
began after confirming no leaks, and was stopped and the time recorded
when the pressure in the vessel dropped by 175 kPa from the maximum
