Chromatographic Separation of Natural Oils
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Objective:
The objective of this experiment was to separate the carvone isomer found in caraway oil and analyze the quality of the separation process via gas chromatography. The carvone was then analyzed by infrared spectroscopy to confirm the presence of the different functional groups.
Procedure:
Refer to University of Victoria Laboratory Manual 232, Fall 2011/Spring 20121
Equations:
Table 1. Reactants
Compound
(g/mol)
Moles
Physical and Safety Data
Hexanes (C6H14)
86.18
80 mL
d= 0.672, bp=68-70oC. Flammable liquid, irritant. Dispse as non-halogenated waste.
Silica Gel (SiO2)
60.09
Hydroscopic, dust hazard. Wrap securely and dispose in landfill waste.
~ 5 mm
Caraway Oil
d= 0.91 g/mL, bp= 193-231oC Flammable, combustible liquid
Spearmint Oil
d= 0.918 g/mL, bp= 288oC. Clear, light yellow liquid
Ethyl acetate (CH3CO2C2H5)
88.11
14 mL
d=0.902, bp= 77oC. Flammable liquid. Dispose as non-halogenated waste
Isopropanol
60.10
d= 0.790 g/mL, bp=81 oC. Flammable liquid, irritant. Dispose as non-halogenated waste
Ethanol (C2H5OH)
46.07
d=0.790 g/mL, bp=78oC. Flammable liquid, irritant. Dispose as non-halogenated waste
Table 2. Products
Compound
MW (g/mol)
Isolated
Moles
Yield
Physical and Safety Data
Carvone (C10H14O)
150.22
0.578 g
0.0038
28.74 %
d=0.959 g/mL, bp=227-230oC
Limonene (C10H16)
136.24
d=0.842 g/mL, bp=176-177oC. Flammable, irritant, possible sensitizer. Dispose as non-halogenated waste
Percent Yield of Carvone Calculation:
Mass of caraway oil:
2.011 g
Mass of isolated carvone:
0.578 g
% Yield = (mass of carvone/ mass of caraway oil) x 100%
= (0.578 g / 2.011 g) x 100%
= 28.74 %
GC #2 Control Settings
Column 20%
DC200
Injection Port: B
Flow Rate: 60 mL/min
Injector temperature:
set: 60
read: 240
Detector temperature:
set: 65
read: 271
Column temperature:
set: 60
read: 190
Volume injected: 3 uL
Retention time for limonene: 100 seconds
Table 3. Gas Chromatography Data
Compound
Retention time (minutes)
Height (cm)
Width (@ ½ height) (cm)
Area (cm3)
Percent Composition
(R)-Carvone Standard
15.04
28.00
(S)-Carvone Standard
24.80
46.17
Caraway Oil
10.05
18.71
Spearmint Oil (partner)
Total Peak Area:
53.71 cm3
R-Carvone Standard:
Area:
9.4 x 1.6 = 15.04
% Composition:
(15.04/53.71) x 100% = 28.00 %
S-Carvone Standard:
Area:
15.5 x 1.6 = 24.80
% Composition:
(24.80/53.71) x 100% = 46.17 %
Caraway Oil:
Area:
6.7 x 1.5 = 10.05
% Composition:
(10.05/53.71) x 100% = 18.71 %
Spearmint Oil:
Area:
0.8 x 1.4 = 1.12
% Composition:
(1.12/53.71)