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mogravimetric analysis of the catalyst was performed by using a Di-
amond TG-DTA (PerkinElmer, USA) instrument from room tempera-
Hydrogenation of aldol product (HAc)
À1
Catalytic HDO of HAc was carried out in a stainless steel Parr reac-
tor equipped with a stirring impeller, gas line and programmable
control device for setting reaction time and temperature. In this
experiment, the reactor was loaded with 35 mg isolated HAc,
ture to 7008C at a heating rate of 108Cmin . The basicity of the
[41]
catalyst was determined by the benzoic acid titration method. In
this method, 0.1 g of catalyst was suspended in 2 mL of water/eth-
anol (4:1 v/v) solvent with constant stirring for 30 min. Using phe-
nolphthalein as an indicator, this solution was then titrated against
1
00 mg Pd/Zeolite-b (5 wt% Pd) and 20 mL ethanol and then
properly sealed with the reactor head. After purging the mixture
0
.01m benzoic acid (in toluene) until the pink color of the basic so-
with UHP grade H for a couple of minutes, the reactor was pres-
2
lution disappeared. The concentration of the total basic density
was calculated from the volume of benzoic acid solution. The titra-
tion was repeated 3 times to obtain an average basic density of
the catalyst.
surised with 50 bar H and heated with stirring at 2308C for 8 h.
2
The reactor was then cooled to room temperature and the pres-
sure was released. The solution was filtered and the collected fil-
trate was analysed by GC and GC–MS.
The yield of the hydrogenation products of HAc were measured by
analysing the product solutions on a GC instrument (Agilent
6
890N) equipped with an FID detector and DB-5 capillary column
Aldol condensation reaction
of dimension 0.25 mm ID 0.25 mm30 m. The essential parame-
ters of the GC analysis were as follows: injection volume 1.0 mL,
inlet temperature 2508C, detector temperature 2508C and a split
ratio 1:5. The initial column temperature was 508C (2 min) with
Zr(CO ) -catalysed aldol condensation between HMF and acetone
3
x
was carried out in the temperature range of 20–548C. All reactions
were performed in a 5 mL round-bottom flask. In a typical experi-
ment, HMF (63 mg), acetone (580 mg) and catalyst (100 mg) were
mixed with 1 mL distilled water. The reaction mixture was then
heated with constant stirring in a temperature-controlled oil bath
at the desired temperature. Upon completion of reaction for the
desired time of 2–24 h, the reaction mixture was cooled to room
temperature and the catalyst was separated by filtration. The or-
ganic product was extracted by liquid–liquid separation using
ethyl acetate as an organic phase. Upon removal of ethyl acetate
by rotary evaporator under vacuum, the crude product was collect-
À1
a temperature rise of 108Cmin and the final temperature was
3008C. n-Nonane was identified by its retention time in compari-
son with an authentic sample and by GC–MS analysis. 1-Ethoxyno-
nane was characterised by GC–MS. Both peaks in the GC chroma-
togram were properly integrated and the actual concentration of
n-nonane was obtained from a pre-calibrated plot of peak area
against concentrations. The yield of 1-ethoxynonane was deter-
mined from its peak area and the response factor, calculated by
considering n-nonane as a standard. GC–MS spectrometry analyses
were carried out on an Agilent 5975C (Agilent Labs, Santa Clara,
CA) mass spectrometer system. The typical electron energy was
70 eV with the ion source temperature maintained at 2508C. The
individual components were separated using a 30 meter DB-5 ca-
pillary column (250 mm ID 0.25 mm film thickness). The initial
column temperature was set at 358C (for 3 min) and programmed
1
13
ed and analysed by NMR. Both H and C NMR spectra of the
brown oily liquid revealed the formation of 4-(5-hydroxymethyl)fur-
an-2-yl) but-3-en-2-one (HAc) as a sole product, and its observed
1
characteristic signals in the NMR spectra are as follows; H NMR
(
400 MHz, CDCl ): d=2.29 (s, CH ), 4.62 ppm (s, CH OH), 6.37 (d,
3 3 2
13
ÀCH), 6.58 (d, ÀCH), 6.60 (d, ÀCH), 7.22 (d, ÀCH); C NMR
À1
(
400 MHz, CDCl ): d=27.51, 110.14, 116.92, 123.59, 129.44, 150.24,
to reach 2808C at 10.08Cmin . The flow rate is typically set at
1 mLmin . The injector temperature was set at 2508C.
3
À1
1
57.38, 198.42 ppm (Figure S3 and S4). A few reactions were also
replicated three times to determine the experimental uncertainty
in the HMF conversions and HMF yields, which were found to be
within Æ4%.
Acknowledgements
B.S. acknowledges the Council of Scientific and Industrial Re-
search (CSIR), New Delhi, Government of India, for funding this
research (Project Number No. 01 (2686)/12/EMR-II). M.M.A.-O. ac-
knowledges the Center for Direct Catalytic Conversion of Biomass
to Biofuels (C3Bio), an Energy Frontier Research Center funded by
the U.S. Department of Energy, Office of Science and Office of
Basic Energy Sciences under Award Number DE-SC0000997 for
supporting this research. A.B. acknowledges the University Grant
Commission, India for a DS Kothari Postdoctoral Research Fellow-
ship.
Determination of HAc yield
1
[42]
The HAc yield was measured using H NMR spectroscopy. In this
method, a known concentration of mesitylene (internal standard)
was added into the crude HAc product in CDCl . The yield of HAc
3
was calculated from the integrated values of the ÀCH OH proton
2
(d=4.62 ppm) of HAc and the three aromatic ring protons of mesi-
tylene (d=6.79 ppm).
Recyclability study of Zr(CO3)x
Keywords: aldol condensation · 5-hydroxymethylfurfural ·
hydrodeoxygenation · zeolites · zirconium carbonate
The recycling efficiency of the Zr(CO ) catalyst was determined for
3
x
the reaction between HMF and acetone under the following condi-
[
tions: HMF=63 mg, acetone=580 mg, Zr(CO ) =100 mg, reaction
3
x
time=24 h and T=548C using 1 mL distilled water as a solvent.
After the reaction, the reaction mixture was cooled down to room
temperature and the catalyst was separated by filtration. The re-
[
[
covered Zr(CO ) catalyst was washed with distilled water, dried
3
x
and reused for three consecutive cycles by adding fresh HMF, ace-
tone and water. The HAc yield was determined after each run.
ChemSusChem 2015, 8, 4022 – 4029
4028
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