2. Materials and methods
2.1. Transesterification
The reaction was carried out by mixing 1000.0 g
sunflower oil, 218.6 g methanol and 5.00 g NaOCH3 in
a 2 l jar fermentor. The temperature was maintained at
60–70 ◦C for 2 h under reflux with stirring at 500 rpm.
The reaction mixture was allowed to stand overnight
and the methyl ester layer was separated from the glycerol
layer using separatory funnel. Residual amount
of glycerol in the crude methyl ester was removed by
centrifugation. The crude methyl ester was further purified
by distilling-off the unreacted methanol under
normal atmospheric pressure, washing several times
with water, centrifugation and drying with anhydrous
Na2SO4.
2.2. Ozonation
Ozone/oxygen mixture containing 30–40 g/m3
ozone was bubbled into a 2 l jar fermentor containing
500 ml SFO methyl esters at a rate of 2.0 l/min for
35 h while stirring at 250 rpm. The amount of ozone
absorbed by the carbon–carbon double bond in SFO
methyl esters was monitored every hour. The concentration
of ozone (g/m3) coming in and going out from
the reactor was measured using TOA OZ-30 ozone
meter.
2.3. Spectroscopic analysis
IR spectra were recorded on thin films cast onto KBr
plates using Jasco FT-IR 300 Spectrometer. All spectra
were the result of 20 scans with a 4 cm−1 resolution.
For 1H and 13C NMR spectroscopy, about 30 mg of
the sample was dissolved in CDCl3 containing TMS
as standard. Both spectra were obtained using Bruker
Avance 600 Spectrometer. Trace amount of CHCl3 in
the solvent used exhibits signal at 7.26 and 77.0 ppm
in 1H and 13C NMR, respectively.