Page 280 - Biosystems Engineering

258 Cha pte r Ei g h t

1.00 27.50 5.47 5.54 9.55 7.71 24.23 36.22 28.72 237.94 37.84

7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0
ppm
FIGURE 8.1 NMR spectra of transesterifi ed Jatropha oil with methanol.

detector. The used capillary is 30 m long with an internal diameter of
0.25 mm. The carrier gas is nitrogen at a flow rate of 1 mL/min. The
injection port temperature is 150°C and the ionization detector tem-
perature is 170°C.
The transesterified product can also be analyzed by nuclear
magnetic resonance (NMR). A reaction aliquot is taken with CDCl in
3
a NMR tube and is placed in a NMR spectroscope (400 MHz, Bruker
BioSpin, Fällanden, Switzerland) for analysis. The percentage conver-
1
sion of reactant to product is analyzed by H NMR (Fig. 8.1), consid-
ering the peak of methoxy groups in the methyl esters at δ = 3.7 ppm
(singlet) and of the α-carbonyl methylene groups of fatty ester
derivatives at δ = 2.3 ppm. The percentage of conversion is equal to
(2 × A /3 × A ) × 100 where A is the integrated peak area at
δ = 3.7 δ = 2.3
different chemical shifts.

8.1.3 Property Measurement of Transesterified Oils
The suitability of any material as fuel, including biodiesel, is influ-
enced by the nature of its major components as well as that of minor
components arising from production or other sources. The nature of
these components ultimately determines the fuel and its physical