W. Yang and A. Sen
GC and GC-MS Analysis Methods: For GC analysis, the initial oven
temperature was 408C; the temperature was then ramped at
38Cminꢀ1 until 1008C was reached; after that, the temperature
was ramped at 108Cminꢀ1 until 2008C was reached, and held for
5 min. For GC-MS analysis, the initial oven temperature was 408C
and held for 1 min; the program rate was 158Cminꢀ1 until 2908C
was reached, and held for 7 min. The total time elapsed was
25 min. The injector temperature was 2908C with a split of 20:1.
The helium flow rate was 0.5 mLminꢀ1. The temperature of the
mized yields of tetrahydrofuran derivatives from cellulose
(Table 5, entry 5) and corn stover (Table 6) appear to be the
highest reported, and the purity of DMTHF from hexose and
that of MTHF from pentose are relatively high. Finally, the cata-
lyst system has been shown to be robust and can be recycled
repeatedly without loss of activity.
Although the use of an expensive rhodium salt, the poten-
tially corrosive acid, and dihydrogen clearly make the process
uneconomical, we do show that in principle it is possible to
“devise a simple, one-step or one-pot process that directly con-
verts agricultural and municipal plant waste and other forms
of raw biomass to valuable products.”[12] A one-step, high-yield
chemical process also compares favorably with typical biocon-
versions of lignocellulose that require three steps: lignocellulo-
sic pretreatment, enzymatic hydrolysis of cellulose, and fer-
mentation of sugars to make ethanol or other biobased chemi-
cals.[26]
transfer line was 2208C. The mass scan was 35–650 Dasꢀ1
.
Quantification Methods: Products yields were determined from
1HNMR spectra and GC analysis of the organic layer by using nitro-
methane as the internal standard. The yields reported were repro-
duced to within 5%. Conversions were calculated based on
1HNMR analysis of the aqueous layer, by using DMSO as the inter-
nal standard.
Acknowledgements
We thank the US Department of Energy, Office of Basic Energy
Sciences for financial support. We thank Dr. Robert Minard for
GC-MS analysis. We thank the National Renewable Energy Labo-
ratory and Expansyn Technologies, Inc. for providing corn stover
samples.
Experimental Section
Materials: Rhodium(III)chloride hydrate (Rh, 38.5–45.5%) was pur-
chased from Alfa Aesar. All carbohydrates were purchased either
from Sigma–Aldrich or from Alfa Aesar. Cellulose was in powder
form, with a particle diameter of around 20 mm. Corn stover sam-
ples were provided by the National Renewable Energy Laboratory
(the compositional analysis of the sample is reported in the Sup-
porting Information). The particle size of the corn stover used was
ca. 0.5 mm. High-pressure hydrogen was obtained from GT&S, Inc.
and used without further purification. Isotopically enriched chemi-
cals, such as C6D6 and D2O, were obtained from Cambridge Isotope
Laboratories and used without further purification.
Keywords: biomass · carbohydrates · catalysis · renewable
resources · rhodium
Klass, Fossil Fuel Reserves and Depletion. Biomass for Renewable Energy,
Fuels and Chemicals; Academic Press, San Diego, 1998, pp. 10–19.
[2] a) T. E. Bull, J. A. Turner, Science 1999, 285, 1209; b) C. Okkerse, H. van
Biobased Industrial Products: Priorities for Research and Commercializa-
tion; National Academy Press, Washington, 2000.
[3] a) D. C. Elliott, D. Beckman, A. V. Bridgwater, J. P. Diebold, S. B. Gevert, Y.
Degnan, L. R. Koenig, CHEMTECH 1986, 16, 506–509; c) P. B. Weisz,
netti, R. M. West, J. C. Serrano-Ruiz, C. A. Gꢃrtner, J. A. Dumesic, Science
Typical Procedure for the Transformation of Carbohydrates to
DMTHF: Carbohydrates (1 mmol, 6 wt% in water), HI (1.5 mmol,
57 wt% in water), RhCl3·xH2O (0.1 mmol), and organic solvent
(4 mL) were added to a glass reaction vial in open air. The vial was
then placed into a high-pressure stainless steel reactor, flushed
with H2, and charged with 300 psi of H2. The reactor was then put
in an oil bath and heated to 1408C for 16 h. After the reaction was
completed, the top organic layer was directly removed for analysis.
Typical Procedure for Transformation of Cellulose and Lignocellu-
lose to DMTHF: Corn stover (0.18 g), RhCl3·xH2O (10 mg,
0.05 mmol), water (1.8 mL), HCl (70 mL, 0.8 mmol), NaI (300 mg,
2 mmol), and organic solvent (2 mL) were added to a glass reaction
vial in open air. The vial then was put into a high-pressure stainless
steel reactor, flushed with H2, and charged with 300 psi of H2. The
reactor was then put in an oil bath and heated to 1608C for 16 h.
After the reaction was complete, the top organic layer was directly
taken out for analysis. Procedures for the larger-scale reaction
(10ꢁ) and isolation are in the Supporting Information.
Foley, J. Hill, E. Larson, L. Lynd, S. Pacala, J. Reilly, T. Searchinger, C. Som-
[5] a) A. Aden, M. Ruth, K. Ibsen, J. Jechura, K. Neeves, J. Sheehan, B. Wal-
lace, L. Montague, A. Slayton, J. Lukas, Harris Group, Lignocellulosic Bio-
mass to Ethanol Process Design and Economics Utilizing Co-Current Dilute
Acid Prehydrolysis and Enzymatic Hydrolysis for Corn Stover, National Re-
newable Energy Laboratory, Seattle, 2002; b) New Biomass Technology
Dramatically Increases Ethanol Yield From Grasses And Yard Waste, Uni-
versity of Georgia, Science Daily, 29 July 2008. Available from http://
April 2010); c) M. Voith, Chem. Eng. News 2009, 87, 20–21.
[7] Y. Romꢄn-Leshkov, C. J. Barrett, Z. Y. Liu, J. A. Dumesic, Nature 2007, 447,
982–986.
1597–1600; b) Y. Su, H. M. Brown, X. Huang, X. Zhou, J. E. Amonette,
Analysis Methods: The products were analyzed by 1H NMR spec-
troscopy (Bruker Avance-360 spectrometer equipped with a quad-
nuclear probe operating at 360.13 MHz), GC (HP Hewlett Packard-
5890 series II with an FID detector; 95% dimethyl/5% diphenyl-
polysiloxane column), and GC-MS (Waters GC-TOF with Agilent
6890 GC; 20 meter 150 um i.d., 0.15 um 95% dimethyl/5% diphen-
1
yl-polysiloxane film column; 70 eV electron ionization). The HNMR
spectra and the GC retention times of the products were also com-
pared to authentic samples.
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ChemSusChem 2010, 3, 597 – 603