Chromatographic Separation of Natural Oils

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 MW

(g/mol) Used Moles Physical and Safety Data

Hexanes (C6H14) 86.18 80 mL 0.93 d= 0.672, bp=68-70oC. Flammable liquid, irritant. Dispse as non-halogenated waste.

Silica Gel (SiO2) 60.09 15 g 0.23 Hydroscopic, dust hazard. Wrap securely and dispose in landfill waste.

Sand N/A ~ 5 mm N/A

Caraway Oil 2 g d= 0.91 g/mL, bp= 193-231oC Flammable, combustible liquid

Spearmint Oil 2 g d= 0.918 g/mL, bp= 288oC. Clear, light yellow liquid

Ethyl acetate (CH3CO2C2H5) 88.11 14 mL 0.16 d=0.902, bp= 77oC. Flammable liquid. Dispose as non-halogenated waste

Isopropanol 60.10 N/A N/A d= 0.790 g/mL, bp=81 oC. Flammable liquid, irritant. Dispose as non-halogenated waste

Ethanol (C2H5OH) 46.07 N/A N/A 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 N/A N/A N/A 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 3.05 9.4 1.6 15.04 28.00

(S)-Carvone Standard

3.07 15.5 1.6 24.80 46.17

Caraway Oil 2.7 6.7 1.5 10.05 18.71

Spearmint Oil (partner) 2.60 3.00 0.8 1.8 1.4 1.5 1.12 2.70 2.09 5.03

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)