Paper
PCCP
Table 5 Kinetic parameters for the dehydration reactions of erythritol
not be dehydrated into dianhydrogalactitol products because
the hydroxyl groups at the C-3 and C-6 positions were oriented
in the opposite directions across the tetrahydrofuran ring.
Pentitols such as xylitol, ribitol, and L-arabitol were dehydrated
into several types of anhydropentitols. The dehydration rates of
the compounds containing hydroxyl groups in the trans form,
which remained as hydroxyl groups in the product tetrahydro-
furan, were larger than those containing hydroxyl groups in
the cis form because of the structural hindrance during the
dehydration process. In the case of tetritol dehydration, the
order of the rate constants for the dehydration was L-threitol
(k1TL) 4 DL-threitol (k1TDL) 4 erythritol (k1E). The dehydration
of erythritol was slower than the dehydration of threitol, which
could be explained by the structural hindrance of the hydroxyl
groups. The rate constant for the dehydration of L-threitol is
larger than that of DL-threitol, indicating that the dehydration
reaction of L-threitol or D-threitol proceeds with an interaction
with the other chiral molecule. We propose that molecular
clusters formed between the sugar alcohols in water via hydro-
gen bonding affect the effect the dehydration.
(initial erythritol concentration: 0.5 mol dmꢀ3
)
Reaction
temperature (K) 523
Activation energy
548
560
573
(kJ molꢀ1
)
k1E (mol hꢀ1
k2E (mol hꢀ1
k3E (mol hꢀ1
)
)
)
0.027
—
0.12
—
0.24
0.014 0.023
0.44
141
—
0.0045 0.020 0.043 0.097 152
Table 6 Kinetic parameters for the dehydration reactions of L-threitol and
DL-threitol (initial L-threitol or DL-threitol concentration: 0.5 mol dmꢀ3
)
Reaction
temperature (K) 523
Activation energy
548
560
573
(kJ molꢀ1
)
k1TL (mol hꢀ1
k2TL (mol hꢀ1
k3TL (mol hꢀ1
)
)
)
0.073
—
0.018
0.42
—
0.085 0.20
0.91
—
4.1
0.025
0.94
193
—
190
k1TDL (mol hꢀ1
k2TDL (mol hꢀ1
k3TDL (mol hꢀ1
)
)
)
0.036
—
0.16
—
0.29
—
0.80
0.011
150
—
165
0.0064 0.033 0.060 0.19
consistent with the results of the dehydration of six-carbon and
five-carbon sugar alcohols. The L-threitol dehydration is faster
than the DL-threitol dehydration. The physicochemical pro-
perties of enantiomers such as L-threitol and D-threitol should
be the same. If the dehydration reaction of L-threitol or
D-threitol proceeds without any interaction with the other
chiral molecules, the rate constants of L-threitol and DL-threitol
should be the same. However, the rate constant of L-threitol was
larger than that of DL-threitol, indicating that the dehydration
reaction of L-threitol or D-threitol proceeds with an interaction
with the other chiral molecule. We can explain this result by
considering the formation of molecular clusters between the
sugar alcohols in water via hydrogen bonding, which we have
discussed in Section 3.2. The DL-threitol dehydration is slower
than the L-threitol dehydration, which indicates that D-threitol
and L-threitol form clusters with each other with stronger
hydrogen bonds than the clusters formed by only D-threitol. In
other words, the interaction of the hydrogen bonds between a
‘‘right-hand’’ molecule and a ‘‘left-hand’’ molecule is larger than
that between ‘‘right-hand’’ molecules. We do not have any direct
evidence for the formation of these molecular clusters by hydro-
gen bonding; thus, computational simulation of this system
should be carried out to evaluate this possibility.
References
1 G. W. Huber, S. Iborra and A. Corma, Chem. Rev., 2006, 106,
4044–4098.
2 J. J. Bozell and G. R. Petersen, Green Chem., 2010, 12, 539–554.
3 C. O. Tuck, E. Perez, I. T. Horvath, R. A. Sheldon and
M. Poliakoff, Science, 2012, 337, 695–699.
´
´
4 R. D. Cortright, R. R. Davda and J. A. Dumesic, Nature, 2002,
418, 964–967.
5 PNNL, Top value added chemicals from biomass. Volume I:
Results of screening for potential candidates from sugars
and synthesis gas, Report Report, Pacific Northwest National
Laboratory (PNNL) and National Renewable Energy Laboratory
(NREL), 2004.
6 N. Yan, C. Zhao, C. Luo, P. J. Dyson, H. Liu and Y. Kou,
J. Am. Chem. Soc., 2006, 128, 8714–8715.
7 A. Fukuoka and P. L. Dhepe, Angew. Chem., Int. Ed., 2006, 45,
5161–5163.
8 C. Luo, S. Wang and H. Liu, Angew. Chem., Int. Ed., 2007, 46,
7636–7639.
9 L.-N. Ding, A.-Q. Wang, M.-Y. Zheng and T. Zhang, Chem-
SusChem, 2010, 3, 818–821.
10 S. Van de Vyver, J. Geboers, M. Dusselier, H. Schepers,
T. Vosch, L. Zhang, G. Van Tendeloo, P. A. Jacobs and
B. F. Sels, ChemSusChem, 2010, 3, 698–701.
4. Conclusions
The intramolecular dehydration of biomass-derived sugar alcohols 11 H. Kobayashi, Y. Ito, T. Komanoya, Y. Hosaka, P. L. Dhepe,
D-sorbitol, D-mannitol, galactitol, xylitol, ribitol, L-arabitol, erythritol,
L-threitol, and DL-threitol was carried out in high-temperature water
K. Kasai, K. Hara and A. Fukuoka, Green Chem., 2011, 13,
326–333.
at 523–573 K without the addition of any acid catalysts. We 12 A. M. Liu, K. Hidajat, S. Kawi and D. Y. Zhao, Chem.
estimated the kinetic parameters of the dehydration reactions. Commun., 2000, 1145–1146.
D-Sorbitol and D-mannitol were dehydrated into anhydrohexitols 13 S. Van de Vyver, J. Geboers, W. Schutyser, M. Dusselier,
and then dehydrated into isosorbide and isomannide, respectively,
as dianhydrohexitol products. Conversely, galactitol was dehydrated
into anhydrogalactitols; however, the anhydrogalactitols could
P. Eloy, E. Dornez, J. W. Seo, C. M. Courtin, E. M. Gaigneaux,
P. A. Jacobs and B. F. Sels, ChemSusChem, 2012, 5,
1549–1558.
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