CHEM 2410 Chapter Notes - Chapter 6.1: Screw Cap, Terpene, Graduated Cylinder
12 Sep 2016
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How To????
Part A: Liquid phase of CO2 to separate terpenes (essential oil) from citrus peel
• Terpenes are extracted, used for many purposes. They consist of different
forms of isoprene units (5x Carbon counts; terpene (5), monoterpene (10),
etc).
• CO2 is environmentally benign, non-polar, non-flammable, readily available,
non-toxic, organic solvent
• In pairs: one does orange, one lemon
o INSERT FOOTNOTE IN LAB REPORT TO CREDIT PARTNER
o Steps:
▪ Pre-weigh boat
▪ Finely grate peel, and collect peel in boat, until you have 2.5 g
(not including boat) of gratings
▪ Label NR and A07 on 15ml centrifuge tube, record mass of
empty tube
▪ Insert copper wire coiled 3x to fit tube, cap, weigh
▪ Add 2.5 g of grating, cap, and tap gently, record mass
▪ Fill graduated cylinder with warm water (10-20cm) , put in
hood
▪ Fill rest of space in tube with dry ice, cap tightly
▪ IMMEDIATELY drop tube into warm water so that it is
immersed
▪ After 15 seconds, liquid CO2 should appear, with the extracted
terpenes at bottom
▪ After 2-3 minutes, liquid disappears and leaves .1mL of oil at
bottom. MAKE SURE ALL LIQUID IS GONE
▪ Open cap slowly, and again: remove tube from cylinder, add
dry ice, screw cap, drop in warm water
▪ After liquid is gone again, remove solids (raise up copper piece,
dump peel) using tweezers
▪ Dry centrifuge tube off and record mass…should be about -
15 mg.
• GC info:
o Compounds which associate with stationary phase as a liquid, will
take longer to get through column…So BP is most important property
that distinguish during this experiment
o So lowest boiling point, and less polar will come out first
o Plot time versus appearance, and the retention time is from injection
point to peak; area under curve is relative abundance
o Peak areas calculated using Area = peak height * peak width at ½
height→this can give you the ratio of one component to another
o If only one peak, sample may be pure
o To identify sample components, compare unknown peak times to that
of known compounds
find more resources at oneclass.com
find more resources at oneclass.com
• PRINT 2 COPIES OF GC; USE COMPARISON TO LIMONENE, Y-TERPINENE, A-
PINENE, AND B MYRCENE TO IDENTIFY WHICH ONES. ALSO CALCULATE
THEIR RATIOS
• RECORD GC CONDITIONS!!! (ex. Column name, flow rate, injection port
temperature, column temperature); print and LABEL each chromatogram
• IR info:
o Confirm presence of functional group and indicate purity
o Plot of percent transmittance (%) vs, frequency (wavenumbers cm-1)
o Want largest peaks in range of 10-50% T
o Prepare by placing drop of liquid between two salt plates
o Evaluating unknown sample by IR: determine expected results, peak
position, # of peaks
o PRINT 2
Part B: Aqueous extraction to separate 3 component mixture based on different
acidities
• Pair aqueous phase with organic solvent
• Salts soluble in aqueous phase, organic materials soluble in organic phase
• Use organic material with salt, add water and tert butyl methyl ether, shake,
then salts go together and can be removed; and this allows you to remove
inorganic salts from organic materials
• You can also do it based on functional group acidity
• Here use differences of acid strengths of CA, phenols, and amides to separate
p-toluic acid, p-tert-butylphenol, and acetanilide from one another
• Each gets converted into a salt by specific bases sodium bicarbonate, NaOH
respectively, where acetanilide has neutral functional group so cannot be
converted into salt
• Procedure: LABEL FLASKS CAREFULLY
find more resources at oneclass.com
find more resources at oneclass.com
