5
ACCEPTED MANUSCRIPT
3
operating a 200 kV. Fatty Acids Methyl Esters (FAME) were
characterized using gas chromatography (GC) with flame
ionization detection (FID) using a polyethylene glycol phase
catalyst was diluted with 1.54 cm of ground molecular sieve 3Å.
The flow rate of the flow system was set 10 µL/min to serve
residence time of 4h. After removal of the solvent and
methanol under reduced pressure the residue was washed through
a very short silica gel plug using ethyl acetate/hexanes (1:99 v/v)
to give methyl octanoate for GC analysis.
(Agilent Technologies, BP20; 25 m x 0.32 mm x 0.25 µm).
Helium was used as the carrier gas and the gas line was equipped
with an oxygen scrubber. The following temperature program
-
1
was employed: 190
°C for 1 min and ramping at 10 °C min and
3
.6. General procedure for reactor testing of Biodiesel integrated
held at 260 C for 4 min.
°
flow system
3
.2. Synthesis of supported NHC catalyst 5.
Catalytic reaction runs were driven in a range of glass
To a suspension of the Merrifield’s peptide resin (3.0 g,~ 4.0
columns (Omnifit) fitted in a flow device (Vapourtec, E-series),
equipped with temperature controller and pressure monitor. All
vegetable feedstocks were purchased from the local super market.
In the case of vegetable oils we evaporated them using rotary
evaporator (equipped with oil bath) at 110 °C under reduced
pressure to remove water content. To have a clear and dried feed
from animal sources, animal tallow was purchased from local
mmol Cl-/g ) in dried CHCl (30 mL) under a N atmosphere 1-
3
2
methylimidazole 98% (1.45 mL,18 mmol) was added at room
temperature. The reaction temperature was increased to 50 C
and after 5 h the mixture cooled to ambient temperature. The
resin beads (i.e. 4) were filtered and washed with CHCl (3 x 50
3
mL), ethyl acetate (3 x 50 mL), then dried under high vacuum.
The transformation to NHC 5 was carried out in the flow system
by passing KO Bu (2 equivalents in THF) over imidazolium 4
butchers and heated at 110 °C in a silicon oil bath for 1h. Then
the solid portion was removed via filtration and the filtrate
extracted using hexanes/ethyl acetate (95/7, v/v). The organic
t
over 30 min under a N atmosphere. During this process the
2
colour of the column immediately changed from pale yellow to
red.
phase was dried over MgSO
then evaporated using rotary evaporator at 110
pressure to remove water content. In a typical example, olive oil
5 g), methanol (5.5 g, 172 mmol) and THF (10 mL) was pumped
4
followed by a second filtration and
°C under reduced
3
.3. Transesterification optimization (Table 1)
(
through two catalysts beds with flow rate 11 µL/min and
residence time 4 h. The first catalyst bed was containing
A reaction mixture containing glyceride trioctanoate 1 (2
mmol), methanol (1.28 g, 40 mmol, 20 equivalents) and THF (10
3
ZrCl /Ph-SBA-15 catalyst (1.23 mL, 858 mg, 20 mol % of Zr +
mL) was pumped through the NHC catalyst bed (0.50 cm , 400
4
1
.22 mL of grinded molecular sieve 3Å) at 65 °C. After inline
removal of the produced water in an intermediate molecular sieve
Å column at room temperature, the reaction mixture was passed
mg, 0.2 mmol NHC, 10 mol% NHC). The NHC catalyst was
diluted with the same volume of ground molecular sieve 3Å in
order to decrease the back pressure. The flow rate of the flow
system was set at 17
3
through the second column containing the supported NHC
catalyst 46 (1.63 mL, 1.24 g, 10 mol% of NHC + 0.82 mL of
ground molecular sieve 3Å) at room temperature. After removal
of the solvents under reduced pressure the residue was washed
µL/min to deliver a residence time of 60 min. After removal
of the solvent and methanol under reduced pressure the residue
was washed through a very short silica gel plug using ethyl
acetate/hexanes (1:99 v/v) to give, after evaporation pure
biodiesel for GC analysis.
through
a
very short silica gel column using ethyl
acetate/hexanes (1:99, v/v) to give pure biodiesel for GC
analysis. In experiments with larger amount of feed oil, the light
phase of biodiesel was separated, washed with hot distilled water
3
.4. General procedure for synthesis of ZrCl /Ph−SBA−15
4
(60-65 °C), heated at 100 °C for 30 min then dried with
18,19
SBA−15 was synthesised following literature procedures
anhydrous MgSO before filtration.
4
in which pluronic acid P123 (4.0 g) was dissolved in water (30
mL) and HCl (120 g of a 2M aqueous solution) with stirring at 35
°
C for 2 h. Then tetraethylorthosilicate (TEOS) (8.0 g) was added
Acknowledgments
to the solution with stirring at 35 °C for 20 h. The mixture was
aged at 80 °C overnight without stirring. The solid product was
recovered, washed and air-dried at room temperature for several
hours. The white powder was calcined by slowly increasing
temperature (1 °C /min) from room temperature to 500 °C in 8 h
and heating at 500 °C for 6 h.
The authors would like to acknowledge the financial support
of the Australian Research Council through the Discovery
(DP12010131, DP150101522), Future Fellowship (DWL
FT110100319). The authors acknowledge general assistance with
flow chemistry from Tash Polyzos (CSIRO).
To prepare ZrCl /Ph-SBA-15 a suspension of SBA-15 (1.25 g)
4
in toluene (50 mL) was treated with ZrCl (910 mg, 3.90 mmol)
References
4
then heated at reflux. After 2 h the reaction mixture was cooled to
ambient temperature and then 0.51 ml (2.77 mmol) of
PhSi(OCH ) was added and the resultant mixture refluxed. After
3
3
1.
2.
Directive 2009/28/EC of the European Parliament
Shandilya, K.; Kumar, A. Environ. Prog. Sustainable
Energy 2013, 32, 1134-1142.
2
h, toluene was removed in vacuo and the residue was washed
with toluene (3 50 mL) and then dried using high vacuum at 80
C for 2 h to give the final product ZrCl /Ph-SBA-15 as a pale
x
3
4
.
.
Travis, N. Biofuels 2012, 3, 285-291.
°
4
Kumar, A.; Kadiyala, A.; Somuri, D.; Shandilya, K. K.;
Velagapudi, S.; Nerella, V. K. V. Biodiesel 2014, 215-233.
Liu, D.; Chen Eugene, Y. X. ChemSusChem 2013, 6,
orange solid.
3
.5. FFA esterification optimization (Table 2)
5
6
.
.
2
236-9.
A reaction mixture containing octanoic acid 6 (4 mmol),
methanol (3.84 g, 120 mmol, 30 equivalents) and THF (10 mL)
Yusuf, N. N. A. N.; Kamarudin, S. K.; Yaakub, Z. Energy
Convers. Manage. 2011, 52, 2741-2751.
was pumped through the ZrCl /Ph-SBA-15 catalyst bed (0.86
4
3
cm , 600 mg, 0.80 mmol Zr, 20 mol% Zr). The ZrCl /Ph-SBA-15
4