Chemistry Reference
In-Depth Information
used as the eluent with flow rate of 1.00 mL min
1
at 40 1C. The injection
volume was 100 mL. Two PL gel 3 mm mixed E columns (300
7.5 mm) were
used in series. The GPC was calibrated using a mixture of polystyrene (MW
1700, 2450, 5050, 7000, 9200, and 10 665 Da), methyl oleate (296.48), methyl
linoleate (294.48), monoolein (353), diolein (619.2), and triolein (885.4) in
THF at 40 1C.
11.2.4 Performance Properties
The kinematic viscosity of vegetable oils was measured using a Cannon-
Fenske calibrated viscometer (Cannon Instrument Co., State College, PA) in
a Cannon temperature bath (CT-1000) at 40 and 100 1C according to ASTM
(American Society for Testing and Materials) standard method D445-95. The
viscosities obtained are average values of 2-3 determinations and the pre-
cision is within the limits of the ASTM method specification. To compare
base oils with respect to viscosity variations with temperature, the ASTM
method D2270 provides a means to calculate a viscosity index (VI). VI values
were therefore calculated using the kinematic viscosity at 40 and 100 1C.
Pour Points were measured by following the ASTM D-5949 method using a
Phase Technology Analyzer, Model 70X (Phase technology, Hammersmith Gate,
Canada). The Pour Point is defined as the temperature in 1C when the sample
still pours when the jar is tilted. Statistically the method has shown quite good
consistency for determining the low-temperature flow properties of fluids.
The free FA content, iodine value and peroxide value for the vegetable oils
were determined as per AOCS (American Oil Chemists' Society) ocial
methods Ca 5a-40, Cd 1-25 and Cd 3-25, respectively.
The anti-oxidant used for chemically modified soybean oils (CMSBO) is an
alkylated phenolic compound (Lubrizol
t
7652) from Lubrizol, Wickliffe,
OH. It was blended into the CMSBO at 40 1C in various concentrations (0.5,
1.0, 1.5 and 2.0 wt%).
11.2.4.1 Thin Film Micro Oxidation
A small amount of oil (25 mL) was oxidized as a thin film on a freshly polished
high-carbon steel catalyst surface with a steady flow (20 cm
3
min
1
) of dry air.
Oxidation tests were done at various temperatures (175, 200, 225, 250 and
275 1C) and time lengths (30, 60, 90, 120 and 150 min) inside a bottom-less
glass reactor. The temperature was maintained at
1 1C with a heated
aluminum slab placed on top of a hot plate. This arrangement eliminates the
temperature gradient across the aluminum surface and transfers heat to the
catalysts placed on the slab. The constant airflow ensured removal of volatile
oxidation products. The test was designed to eliminate any gas diffusion
limitation.
After oxidation, the catalyst containing the oxidized oil sample was re-
moved from the oxidation chamber and cooled rapidly under a steady flow of
dry N
2
and transferred to a desiccator for temperature equilibration. After
