Cascade of liquid-phase catalytic transfer hydrogenation and etherification of 5-hydroxymethylfurfural to potential biodiesel components over Lewis acid zeolites

Article abstract of DOI:10.1002/cctc.201300978

We report a one-step process for the production of diesel fuel from biomass-derived 5-hydroxymethylfurfural (HMF). The reaction proceeds through the sequential transfer hydrogenation and etherification of HMF to 2,5-bis(alkoxymethyl)furan, a potential biodiesel additive, catalyzed by a Lewis acid zeolite, such as Sn-Beta or Zr-Beta. An alcohol is used as a hydrogen donor and as a reactant in etherification. This cascade reaction can selectively produce high yields of the biodiesel additive (>80 % yield) from HMF with the Sn-Beta catalyst and secondary alcohols, such as 2-propanol and 2-butanol. Diesel addiction: Biomass-derived 5-hydroxymethylfurfural (HMF) is converted to 2,5-bis(alkoxymethyl)furan, a potential biodiesel additive, through sequential transfer hydrogenation and etherification reactions catalyzed by a Lewis acid zeolite, such as Sn-Beta or Zr-Beta. Sn-Beta selectively produces high yields of the biodiesel additive (>80 % yield) with secondary alcohols, such as 2-propanol and 2-butanol, as hydrogen donors and as etherification agents. Copyright

Full text of DOI:10.1002/cctc.201300978

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DOI: 10.1002/cctc.201300978
Cascade of Liquid-Phase Catalytic Transfer Hydrogenation
and Etherification of 5-Hydroxymethylfurfural to Potential
Biodiesel Components over Lewis Acid Zeolites
Jungho Jae, Eyas Mahmoud, Raul F. Lobo,* and Dionisios G. Vlachos*[a]
We report a one-step process for the production of diesel fuel
from biomass-derived 5-hydroxymethylfurfural (HMF). The reac-
tion proceeds through the sequential transfer hydrogenation
and etherification of HMF to 2,5-bis(alkoxymethyl)furan, a po-
tential biodiesel additive, catalyzed by a Lewis acid zeolite,
such as Sn-Beta or Zr-Beta. An alcohol is used as a hydrogen
donor and as a reactant in etherification. This cascade reaction
can selectively produce high yields of the biodiesel additive
(>80% yield) from HMF with the Sn-Beta catalyst and secon-
dary alcohols, such as 2-propanol and 2-butanol.
Introduction
Lignocellulosic biomass is being studied worldwide for the re-
newable production of liquid fuels.[1] The major building blocks
of the hemicellulosic and the cellulosic part of lignocelluloses
are C5–C6 carbohydrates, such as xylose and glucose. These
carbohydrates are dehydrated to furfural or 5-hydroxymethyl-
furfural (HMF) under aqueous acidic conditions, which are spe-
cies that can be used as intermediates in the production of bi-
ofuels, such as transportation fuels and chemicals.[2] It is thus
critical to develop catalytic strategies for the production of
fuel-compatible species from these furan compounds.
Another promising approach for the production of biodiesel
components is the etherification of HMF with alcohols. The re-
sulting product HMF ether, such as 5-(ethoxymethyl)furfural,
could serve as a potential biodiesel additive owing to its high
miscibility in diesel fuel and a high energy density of 30.3 MJ/
L, which is similar to that of diesel (33.6 MJ/L).[4] Several groups
have reported the production of 5-(ethoxymethyl)furfural from
either HMF or glucose/fructose in excess ethanol with homo-
geneous acid catalysts[5] or solid acid catalysts: the H+ form of
zeolites,[4d] Al-containing mesoporous silica,[4c] ion-exchange
resins,[4a] and heteropolyacids[4e] with moderate yields and se-
lectivity (31–92%). The remaining aldehyde functional group in
5-(ethoxymethyl)furfural, however, reduces the stability of the
molecule, and it is desirable to hydrogenate aldehydes to alco-
hols[6] or subsequent ether linkages.[5]
Several groups have reported catalytic processes that con-
vert furan compounds to diesel range fuels.[3] Huber et al. in-
troduced a catalytic process in which HMF first undergoes
aldol condensation with acetone and then hydroprocessing of
the products to produce C9–C15 alkanes.[3a] Sutton et al. modi-
fied the Huber process by additional conversion of aldol inter-
mediates to polyketones, which allows for mild hydroprocess-
ing to produce alkanes.[3c] Corma et al. reported the Sylvan
diesel process, in which 2-methylfuran, obtained from the hy-
drogenation of furfural, is trimerized or condensed with alde-
hydes or ketones followed by hydrodeoxygenation of these
compounds to an alkane mixture.[3e] The key step in all these
processes is the increase in the number of carbon atoms of
the furan compounds through aldol condensation or alkylation
to make them suitable for diesel range molecules.
To this end, Balakrishnan et al. studied the one-pot reductive
etherification of HMF to 2,5-bis(alkoxymethyl)furan with PtSn/
Al2O3 and Amberlyst 15 catalysts under hydrogen pressure.[5]
They obtained the corresponding 2,5-bis(alkoxymethyl)furan in
yields of 64 and 47% for ethanol and n-butanol, respectively.
Gruter studied the production of 2,5-bis(ethoxymethyl)furan
through the sequential hydrogenation and etherification of
HMF, in which HMF is first hydrogenated to 2,5-bis(hydroxyme-
thyl)furan (BHMF) over a Pt/C catalyst at room temperature
and 5 bar (1 bar=0.1 MPa) of hydrogen pressure and is then
etherified to 2,5-bis(ethoxymethyl)furan at 348 K without hy-
drogen.[7] He obtained a 2,5-bis(ethoxymethyl)furan yield of
75%. Importantly, the two ether linkages lead to a higher mis-
cibility in commercial diesel and to a lower crystallization tem-
perature than does 5-(ethoxymethyl)furfural.[8]
[a] Dr. J. Jae,+ E. Mahmoud, Prof. R. F. Lobo, Prof. D. G. Vlachos
Catalysis Center for Energy Innovation
Department of Chemical and Biomolecular Engineering
University of Delaware, Newark, DE 19716 (USA)
Fax: (+1)302-831-1048
Because 2,5-bis(alkoxymethyl)furan is a higher-grade fuel
than 5-(alkoxymethyl)furfural, it is of considerable interest to
produce 2,5-bis(alkoxymethyl)furan from HMF by using a less
energy intensive process. The hydrogenation of HMF to BHMF
requires the use of noble metals (e.g., Ru[9] or Pt[5]) and high
hydrogen pressures (>5 bar). In addition, complete hydroge-
nation and etherification requires the use of two catalysts
E-mail: lobo@udel.edu
vlachos@udel.edu
Homepage: http://www.efrc.udel.edu/
[+] Current Address:
Korea Institute of Science and Technology
Seoul 136-791 (Republic of Korea)
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/cctc.201300978.
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(metal and acid catalysts) in-
creasing the process cost. Trans-
fer hydrogenation (TH) via the
Meerwein–Ponndorf–Verley
(MPV) reaction using sacrificial
alcohols as hydrogen donors is
an alternative to this hydrogena-
tion step. Importantly, dehydro-
genated products of alcohols
can easily be recycled through
hydrogenation
over
base
metals[10] or used as chemicals.[11]
Because the formation of ether
requires alcohols, we envision
a one-step process in which the
alcohol is used as a hydrogena-
tion and as an etherification
agent. Many catalysts, such as
aluminum alkoxides,[12] transition
metals,[11,13] and metal oxides,[10]
are used as TH catalysts. Zeolites
with framework Sn or Zr are
solid Lewis acids and are active
for the TH reaction, as originally
reported by Corma et al.[14]
Moreover, these isolated Lewis
acid sites in the beta framework
can catalyze etherification.[14b,15]
Herein, we report a one-step
catalytic process for the efficient
production of 2,5-bis(alkoxyme-
thyl)furan through sequential TH
and etherification reactions of
HMF catalyzed by a Sn-contain-
ing zeolite (Scheme 1). We show
specifically that a solid Lewis
acid catalyst, zeolite beta with
framework Sn (Sn-Beta), can se-
lectively hydrogenate HMF to
BHMF followed by etherification
of BHMF to 2,5-bis(alkoxyme-
thyl)furan with an excellent yield
(>80%). Sn-Beta appears to be
better than zeolite beta with
Scheme 1. Reaction network of sequential catalytic TH and etherification of HMF to 2,5-bis(alkoxymethyl)furan
with 2-propanol and Sn-Beta catalyst. Compounds obtained are as follows: HMF, BHMF, 5-[(1-methylethoxy) meth-
yl]furfural (compound 1), 5-[(1-methylethoxy)methyl]-2-furanmethanol (compound 2), 2,5-bis[(1-methylethoxy)me-
thyl]furan (compound 3), 2-methyl-5-[(1-methylethoxy)methyl]furan (compound 4), 5-[bis(1-methylethoxy)methyl]-
2-furanmethanol (compound 5), and 2-[bis(1-methyl ethoxy)methyl]-5-[(1-methylethoxy)methyl]furan (compound
6). IPA = 2-propanol.
Figure 1. HMF conversion and product selectivity as a function of temperature. Reaction conditions: batch reactor,
1.2 wt% HMF in 2-propanol solution with Sn-Beta (molar ratio of HMF to Sn=100:1), 20.4 bar N2, and 6 h of the
reaction time at defined temperatures.
framework Zr (Zr-Beta) and superior to nonframework Sn-Beta
(EF-Sn-Beta) zeolites and Sn-MFI.
lectivity as a function of temperature at 6 h of the reaction
time is plotted in Figure 1. The conversion of HMF increases
from 17.3 to 98.3% with the increase in temperature from 363
to 483 K. The selectivity toward the products at 363 K is 29.4%
for 3, 27.4% for 5, 19.4% for 2, 10.0% for BHMF, and 4.6% for
1. The formation of acetal 5 indicates that the acetalization of
the aldehyde group of HMF with 2-propanol occurs in parallel
with the MPV reaction. The selectivity toward the targeted
product 3 increases with the increase in temperatures up to
a point. The selectivity quickly reaches 73.1% at 393 K and in-
creases up to 87% at 453 K at the expense of other intermedi-
ates. Increasing the temperature to 483 K decreases the selec-
tivity toward bis-ether 3 to 68% and increases the selectivity
Results and Discussion
Effect of temperature
Initial tests were performed with 1.2 wt% HMF in 2-propanol
with a Sn-Beta catalyst (Si/Sn=120), which gave an HMF/Sn
ratio of 100:1. XRD, UV/Vis spectroscopy, and 119Sn MAS NMR
analyses of the calcined catalysts confirmed their crystallinity
and the presence of isomorphically substituted Sn sites (see
the Supporting Information). HMF conversion and product se-
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toward 4 to 8%, which indicates that some hydrogenolysis
occurs at temperatures above 483 K, presumably by using the
hydrogen produced from the dehydrogenation of 2-propanol.
Reaction evolution
Conversions and product yields in a reaction starting from
HMF and BHMF as a function of time at 403 K are plotted in
Figures 2 and 3, respectively. Bis-ether 3 is the major product,
whereas furfural ether 1 (2.4%) and compound 2 (1.2%) are
present in low concentrations during the entire reaction time.
Figure 3. Conversion and product yields as a function of time at 403 K start-
ing from BHMF. Reaction conditions: batch reactor, 1.2 wt% BHMF in 2-prop-
anol solution with Sn-Beta (molar ratio of BHMF to Sn=100:1), and 20.4 bar
N2.
Active sites and pore size
To better understand the active sites of the catalyst, we pre-
pared four catalyst samples (Figure 4): the siliceous form of
zeolite beta (Si-Beta), EF-Sn-Beta, zeolite beta with framework
Al (Al-Beta), and Sn-Beta. Textural properties of these catalysts
as well as concentration and strength of the acid sites are
given in our previous report.[16] The same amounts of the cata-
lysts based on metal (Al or Sn) sites were used for each reac-
tion to see the intrinsic activity of different sites (molar ratio of
HMF to metal Sn or Al=100:1). Si-Beta, having a zeolite beta
structure without any active sites, is completely inactive for
the reaction. EF-Sn-Beta shows some reactivity toward the pro-
duction of BHMF and some ether intermediates; however, the
conversion of HMF is less than 20%, which indicates that the
activity of nonframework Sn is small for both MPV reaction
and etherification. Al-Beta, having both Brønsted and Lewis
acid sites, shows 98% conversion of HMF and comparable ac-
tivity to Sn-Beta. However, Al-Beta produces 1 as a major prod-
uct (70% selectivity). As expected, etherification occurs over
Brønsted acid sites of Al-Beta whereas the MPV reaction is not
catalyzed by the Lewis acid sites of Al-Beta. Al-Beta also shows
Figure 2. Conversion and product yields as a function of time at 403 K start-
ing from HMF. Reaction conditions: batch reactor, 1.2 wt% HMF in 2-propa-
nol solution with Sn-Beta (molar ratio of HMF to Sn=100:1), and 20.4 bar
N2.
It is clear that HMF is first hydrogenated to BHMF via the MPV
reaction and quickly undergoes subsequent etherification.
However, the presence of compound 1 over time suggests
that HMF could first be etherified to 1 with 2-propanol and
then undergo the MPV reaction (Scheme 1). The yield of acetal
5 steadily decreases over the entire reaction time, and it could
be converted to other products such as bis-ether 3. The con-
version of BHMF is much faster than that of HMF (Figure 3).
The conversion of BHMF reaches 100% at 403 K after 6.5 h,
whereas the conversion of HMF is only 41% under the same
conditions. BHMF is progressively etherified to compound 2
and then to bis-ether 3 during the reaction. The fast etherifica-
tion of BHMF suggests that the
MPV reaction of HMF to BHMF
and of 1 to 2 is the rate-deter-
mining step to produce bis-
ether 3. As a control experiment,
the classical MPV reduction of
cyclohexanone to cyclohexanol
was studied with use of 2-propa-
nol and the Sn-Beta catalyst at
373 K for 4 h. The conversion of
cyclohexanone was 92% and
the selectivity toward cyclohexa-
nol was 98%, which indicated
that the MPV reaction of cyclo-
hexanone is fast, as reported
previously.[14c]
Figure 4. HMF conversion and product selectivity over different catalysts such as EF-Sn-Beta, Si-Beta, Al-Beta, Sn-
Beta, Zr-Beta, and Sn-MFI at 453 K for 6 h. Reaction conditions: batch reactor, 1.2 wt% HMF in 2-propanol solution
with various catalysts (molar ratio of HMF to metals Al, Sn, or Zr=100:1), and 20.4 bar N2.
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significant formation of diisopropyl ether (18% yield) through
the self-etherification of 2-propanol. Overall, these control ex-
periments suggest that isolated Lewis acid sites in Sn-Beta are
the active sites for both MPV reaction and etherification to se-
lectively produce bis-ether 3.
Zr-Beta, also an active catalyst for the classical MPV reaction,
is highly active for this cascade reaction. The conversion of
HMF is 100% and the selectivity to bis-ether 3 and compound
2 are 77 and 17%, respectively. The etherification activity of Zr-
Beta is, however, lower than that of Sn-Beta under the reaction
conditions investigated. In addition to the active sites, structur-
al effects may play a role. Sn-MFI has a lower activity for HMF
conversion and etherification to bis-ether than Sn-Beta. The
bis-ether 3 selectivity is low (44%) and the selectivity to com-
pound 2 and BHMF is high (33 and 10%, respectively) with Sn-
MFI. This result is attributed to the slower diffusion of the reac-
tants and products, such as bis-ether 3 with the kinetic diame-
ter of 7.4 ꢁ, within the channels of the MFI structure (pore size
of 6.2–6.3 ꢁ adjusted by Norman radii) than within Sn-Beta
(6.3–7.4 ꢁ by Norman radii).[17]
Figure 6. IR spectra of fresh Sn-Beta (black), spent Sn-Beta from the reaction
of 1.2 wt% HMF (blue), and spent Sn-Beta from the reaction of 4.0 wt%
HMF (red).
spent Sn-Beta catalysts for the reactions of 1.2 and 4.0 wt%
HMF, respectively. The band associated with the carbonyl
group at 1670–1750 cmÀ1 is clearly visible on the spent catalyst
for the reaction of 4.0 wt% HMF, which reveals the accumula-
tion of more organic compounds on this sample during the re-
action. This result also suggests that heavy byproducts are
likely produced through the reactions of HMF.
To investigate the deactivation of the catalyst from the for-
mation of heavy byproducts, the spent catalyst for the reaction
of 1.2 wt% HMF was reused under the same reaction condi-
tions. As shown in Table 1, the recycled catalyst showed
a lower activity than the fresh Sn-Beta (68% vs 92% HMF con-
version) and a lower selectivity toward bis-ether 3 (87.0% vs
81.1%). However, after simple
Effect of initial HMF concentration and catalyst stability
The effect of HMF concentration on catalytic TH and etherifica-
tion of HMF was studied at 453 K (Figure 5). The selectivity
toward bis-ether 3 decreased from 87.3 to 57.7% with the in-
crease in HMF concentration from 1.2 to 8.0 wt%. The selectivi-
calcination of the spent catalysts
in air at 773 K, the catalytic activ-
ity was recovered completely.
This result indicates that the de-
crease in catalytic activity is at-
tributed to the loss of some
active sites by deposition of
heavy byproducts. We further in-
vestigated the reuse of catalyst
samples for the etherification of
BHMF to determine whether the
catalyst is stable. The conversion
of BHMF over the fresh catalyst
reached 97.7% and the selectivi-
Figure 5. Effect of the initial HMF concentration on HMF conversion and product selectivity at 453 K for 6 h. Reac-
tion conditions: batch reactor, HMF in 2-propanol solution with Sn-Beta (molar ratio of HMF to Sn=100:1), and
20.4 bar N2.
ty toward bis-ether 3 and com-
pound 2 was 72.1 and 14.5%, re-
spectively, after 0.83 h at 453 K.
The reuse of the spent catalyst
ty toward unidentified species (undetectable by using GC) in-
creased significantly from 8.0 to 35.7% with the increase in
HMF concentration. These results indicate that heavy byprod-
ucts (presumably humins) are formed at high HMF concentra-
tions. It is possible that these heavy byproducts are produced
through the self-etherification of HMF as their selectivity in-
creases with the increase in HMF concentration. The tempera-
ture programmed oxidation of solid residues obtained through
the reactions of 1.2 and 4.0 wt% HMF confirmed the presence
of 5.0 and 12.0 wt% solid products, respectively. In addition,
Figure 6 shows the IR spectra (500–2000 cmÀ1) of the fresh and
also shows loss of catalytic activity. The conversion of BHMF
decreased to 29.8% and the selectivity toward 2 (64.6%) was
higher than that toward bis-ether 3 (19.7%) after 0.83 h. The
deactivation of the catalyst appears to be more significant
with BHMF than with HMF, which could be due to the fact that
BHMF has two hydroxyl groups. BHMF could be more suscepti-
ble to the formation of heavy byproducts via self-etherification
than HMF, which has only one hydroxyl group. Overall, these
results suggest that heavy byproducts are formed from both
HMF and BHMF; in both cases, the catalyst is reusable after re-
generation in air.
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bis(hydroxymethyl)furan (BHMF), followed by etherification of
BHMF to 3 in greater than 80% yield over solid Lewis acid cat-
alysts, such as Sn-Beta and Zr-Beta. The etherification of BHMF
or HMF with alcohols is a fast reaction over Sn-Beta, whereas
the Meerwein–Ponndorf–Verley conversion of HMF to BHMF is
the rate-determining step. Importantly, the molecular mass of
the biodiesel components can be tuned from C10 to C14 with
use of different alcohols (EtOH, PrOH, or BuOH). The results of
these investigations demonstrate the upgrading of biomass-
derived oxygenates to fuels through transfer hydrogenation
and condensation reactions using a solid Lewis acid catalyst.
Table 1. Stability of the Sn-Beta catalyst in the MPV reaction and etherifi-
cation of HMF and BHMF at 453 K.[a]
Feed
Catalyst
t
[h]
Conv.
[%]
Selectivity [%]
1
2
3
4
5
HMF
HMF
HMF
BHMF
BHMF
BHMF
BHMF
fresh
6
6
6
3
0.83
5.5
0.83
91.5
68.0
90.5
100.0
97.7
100.0
29.8
1.1
1.9
0.7
–
–
–
1.2
2.4
2.7
0.7
14.5
0.0
87.0
81.1
86.8
85.6
72.1
67.3
19.7
2.4
2.0
2.7
–
–
–
0.0
0.9
0.4
–
–
–
spent
regen.[b]
fresh
fresh
spent
spent
–
64.6
–
–
[a] Reaction conditions: batch reactor, 1.2 wt% of HMF or BHMF in 2-
propanol solution with Sn-Beta (molar ratio of HMF or BHMF to Sn: 100),
and 20.4 bar N2; [b] Regenerated catalyst.
Experimental Section
Catalyst preparation
Alcohol structure
Sn-Beta with a Si/Sn ratio of 118 was prepared by the method de-
scribed by Corma et al.[14a] Si-Beta and EF-Sn-Beta with a Si/Sn ratio
of 106 were prepared by the method reported by Roy et al.[16a] In
brief, EF-Sn-Beta was prepared through the simple impregnation of
Sn into Si-Beta with use of SnCl4·5H2O dissolved in methanol. Al-
Beta used herein was obtained by thermal treatment in air (1 h at
368 K and 8 h at 723 K, with heating rates of 2 KminÀ1) of the com-
mercial ammonium form (CP 814N, powder, Zeolyst International)
of zeolite beta. The SiO2/Al2O3 ratio of the zeolite is 18 according
to the provider’s specifications. Sn-MFI with a Si/Sn ratio of 120
and Zr-Beta with a Si/Zr ratio of 100 were prepared by the method
reported by Mal et al.[20] and Corma et al.,[21] respectively.
In addition to the use of 2-propanol as a hydrogen donor,
a number of alcohols such as 1-propanol, 1-butanol, 2-butanol,
and ethanol were tested for the catalytic TH and etherification
of HMF. Of the alcohols examined, secondary alcohols (2-prop-
anol and 2-butanol) were more selective than primary alcohols
(1-propanol, 1-butanol, and ethanol) toward the production of
bis-ether 3. The selectivity toward bis-ether 3 using secondary
alcohols was greater than 85% in all cases. All the tested pri-
mary alcohols produced approximately 10% of 1 along with
70% of bis-ether 3, which indicated that TH using primary al-
cohols was slower than that using secondary alcohols, as ex-
pected from previous reports.[18] This result is attributed to the
fact that secondary alcohols are more susceptible to dehydro-
genation than primary alcohols.[19]
Characterization
The XRD patterns were recorded by using a Philips X’Pert X-ray dif-
fractometer with CuKa radiation. The samples were analyzed by
using a UV/Vis spectrometer (Jasco V-550) equipped with a diffuse
reflectance cell.[22] The micropore volumes of the samples were de-
termined from nitrogen adsorption isotherms at 77 K measured by
using a Micromeritics ASAP 220 instrument. All samples were de-
gassed for 8 h under vacuum at 573 K before adsorption. The mi-
cropore volumes and surface areas of zeolite beta were deter-
mined by using the t-plot method. The 119Sn MAS NMR spectra
were recorded by using a Bruker AVIII 500 MHz solid-state NMR
spectrometer operating at a Larmor frequency of 186.5 MHz for
119Sn. A 4 mm HX MAS probe was used. The magic angle spinning
rate was set to 12000Æ2 Hz for all measurements. The 908 119Sn
Overall, the high selectivity for the production of bis-ether 3
with various alcohols demonstrates the versatility of this pro-
cess, in which the molecular mass of the biodiesel compounds
can easily be tuned with use of different alcohols. In compari-
son to previous studies, our highest yields are higher than
those obtained through the one-pot reductive etherification of
HMF to 2,5-bis(alkoxymethyl)furan with two catalysts (PtSn/
Al2O3 and Amberlyst 15) under hydrogen pressure[5] (64 and
47% in ethanol and n-butanol, respectively) or those obtained
through the two step process, hydrogenation with a Pt/C cata-
lyst followed by etherification
(75% yield of 2,5-bis(ethoxyme-
thyl)furan) (Figure 7).[7]
Conclusions
We developed a one-step pro-
cess to selectively convert 5-hy-
droxymethylfurfural (HMF) to
2,5-bis(alkoxymethyl)furan (3), a
potential biodiesel component.
The reaction proceeds through
the Meerwein–Ponndorf–Verley
reaction via hydride transfer
Figure 7. HMF conversion and product selectivity over Sn-Beta with different alcohols at 453 K for 6 h. Reaction
conditions: batch reactor, 1.2 wt% HMF in different alcohol solutions with Sn-Beta (molar ratio of HMF to
from a secondary or primary al-
cohol to HMF to produce 2,5- Sn=100:1), and 20.4 bar N2.
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[1] a) G. W. Huber, S. Iborra, A. Corma, Chem. Rev. 2006, 106, 4044–4098;
b) V. Mendu, T. Shearin, J. E. Campbell, J. Stork, J. Jae, M. Crocker, G.
Huber, S. DeBolt, Proc. Natl. Acad. Sci. USA 2012, 109, 4014–4019.
[2] a) J. H. Jae, G. A. Tompsett, Y. C. Lin, T. R. Carlson, J. C. Shen, T. Y. Zhang,
B. Yang, C. E. Wyman, W. C. Conner, G. W. Huber, Energy Environ. Sci.
2010, 3, 358–365; b) J. N. Chheda, Y. Roman-Leshkov, J. A. Dumesic,
Green Chem. 2007, 9, 342–350; c) Y. Roman-Leshkov, J. N. Chheda, J. A.
Dumesic, Science 2006, 312, 1933–1937.
pulse was calibrated to 6.0 ms with use of the saturated SnCl4 solu-
tion. The single-pulse experiment with a recycle delay of 50 s was
used with the number of scans ranging from 1024 to 4320, and it
depended on the signal-to-noise ratio of the spectrum. The spectra
were referenced externally to a peak of the 119Sn spectrum of SnO2
at À604.3 ppm.[23] The results for catalyst characterization are given
in the Supporting Information.
[3] a) G. W. Huber, J. N. Chheda, C. J. Barrett, J. A. Dumesic, Science 2005,
308, 1446–1450; b) H. Olcay, A. V. Subrahmanyam, R. Xing, J. Lajoie,
J. A. Dumesic, G. W. Huber, Energy Environ. Sci. 2013, 6, 205–216;
c) A. D. Sutton, F. D. Waldie, R. L. Wu, M. Schlaf, L. A. Silks, J. C. Gordon,
Nat. Chem. 2013, 5, 428–432; d) A. Corma, O. de La Torre, M. Renz, N.
Villandier, Angew. Chem. 2011, 123, 2423–2426; Angew. Chem. Int. Ed.
2011, 50, 2375–2378; e) A. Corma, O. de La Torre, M. Renz, Energy Envi-
ron. Sci. 2012, 5, 6328–6344.
[4] a) C. M. Lew, N. Rajabbeigi, M. Tsapatsis, Ind. Eng. Chem. Res. 2012, 51,
5364–5366; b) L. Bing, Z. H. Zhang, K. J. Deng, Ind. Eng. Chem. Res.
2012, 51, 15331–15336; c) P. Lanzafame, D. M. Temi, S. Perathoner, G.
Centi, A. Macario, A. Aloise, G. Giordano, Catal. Today 2011, 175, 435–
441; d) E. Salminen, N. Kumar, P. Virtanen, M. Tenho, P. Maki-Arvela, J. P.
Mikkola, Top. Catal. 2013, 56, 765–769; e) H. L. Wang, T. S. Deng, Y. X.
Wang, Y. Q. Qi, X. L. Hou, Y. L. Zhu, Bioresour. Technol. 2013, 136, 394–
400; f) B. Liu, Z. H. Zhang, RSC Adv. 2013, 3, 12313–12319; g) M. Mascal,
E. B. Nikitin, ChemSusChem 2009, 2, 423–426; h) S. De, S. Dutta, B. Saha,
ChemSusChem 2012, 5, 1826–1833; i) H. L. Wang, T. S. Deng, Y. X. Wang,
X. J. Cui, Y. Q. Qi, X. D. Mu, X. L. Hou, Y. L. Zhu, Green Chem. 2013, 15,
2379–2383; j) M. Mascal, E. B. Nikitin, Angew. Chem. 2008, 120, 8042–
8044; Angew. Chem. Int. Ed. 2008, 47, 7924–7926.
Catalytic experiments
The catalytic TH and etherification of HMF were performed in
a 100 mL stainless steel Parr reactor. For a typical reaction, the re-
actor was charged with HMF (160 mg, 99%, Sigma–Aldrich), Sn-
Beta catalyst (80 mg), and 2-propanol (16 mL). The reactor was
sealed, purged with air along with N2, and charged with N2 to
a pressure of 20.4 bar. The reactor was heated to the reaction tem-
perature with a silicon oil bath and mixing was accomplished with
a magnetic stirrer. After the reaction, the reactor was quenched in
ice water and the liquid products were collected, filtered, and ana-
lyzed. The liquid products were identified with a combination of
GC–MS (Shimadzu GCMS-QP2010 Plus) and H and 13C NMR spec-
1
troscopy, whereas they were quantified with a gas chromatograph
(Agilent 7890A) equipped with a flame ionization detector by cre-
ating a calibration curve with use of standard solutions. The de-
tailed method is described elsewhere.[11] Herein, conversion is de-
fined as the moles in the feed that reacted (determined from GC
analysis) divided by the initial moles in the feed loaded in the reac-
tor. Product selectivity is defined as the moles in the product divid-
ed by the moles in the feed that reacted. Yield is defined as the
moles in the product divided by the initial moles in the feed
loaded in the reactor.
[5] M. Balakrishnan, E. R. Sacia, A. T. Bell, Green Chem. 2012, 14, 1626–1634.
[6] E. J. Ras, S. Maisuls, P. Haesakkers, G. J. Gruter, G. Rothenberg, Adv.
Synth. Catal. 2009, 351, 3175–3185.
[7] G. J. M. Gruter, US8231693B2, 2012.
[8] a) G. J. M. Gruier, US8277521B2, 2012; b) G. J. M. Gruter, EP2197862B1,
2012.
[9] R. Alamillo, M. Tucker, M. Chia, Y. Pagan-Torres, J. Dumesic, Green Chem.
2012, 14, 1413–1419.
[10] M. Chia, J. A. Dumesic, Chem. Commun. 2011, 47, 12233–12235.
[11] J. Jae, W. Q. Zheng, R. F. Lobo, D. G. Vlachos, ChemSusChem 2013, 6,
1158–1162.
[12] R. Anwander, C. Palm, G. Gerstberger, O. Groeger, G. Engelhardt, Chem.
Commun. 1998, 1811–1812.
[13] H. Kobayashi, H. Matsuhashi, T. Komanoya, K. Hara, A. Fukuoka, Chem.
Commun. 2011, 47, 2366–2368.
[14] a) A. Corma, M. E. Domine, S. Valencia, J. Catal. 2003, 215, 294–304;
b) A. Corma, M. Renz, Angew. Chem. 2007, 119, 302–304; Angew. Chem.
Int. Ed. 2007, 46, 298–300; c) A. Corma, M. E. Domine, L. Nemeth, S. Va-
lencia, J. Am. Chem. Soc. 2002, 124, 3194–3195.
[15] O. Casanova, S. Iborra, A. Corma, J. Catal. 2010, 275, 236–242.
[16] a) S. Roy, K. Bakhmutsky, E. Mahmoud, R. F. Lobo, R. J. Gorte, ACS Catal.
2013, 3, 573–580; b) J. S. Kruger, V. Choudhary, V. Nikolakis, D. G. Vla-
chos, ACS Catal. 2013, 3, 1279–1291.
[17] J. Jae, G. A. Tompsett, A. J. Foster, K. D. Hammond, S. M. Auerbach, R. F.
Lobo, G. W. Huber, J. Catal. 2011, 279, 257–268.
[18] M. A. Aramendꢃa, V. Borau, C. Jimenez, J. M. Marinas, J. R. Ruiz, F. J.
Urbano, J. Colloid Interface Sci. 2001, 238, 385–389.
HMF (99%) and BHMF (98%) were purchased from Sigma–Aldrich
and Penn A Kem LLC, respectively. Compound 1 was obtained
from the isolation of the reaction mixture with a Waters Fraction
Collector III attached to the HPLC with a Bio-Rad HPX-87H (300ꢂ
7.8) column. Compound 3 was obtained from the product mixture
by removal of the solvent with a rotary evaporator. For quantifica-
tion, the GC sensitivity for compounds 2 and 4 was assumed to be
equal to that for compound 1. The GC sensitivity for compounds 5
and 6 was assumed to be equal to that for compound 3.
Acknowledgements
This work was supported as part of the Catalysis Center for
Energy Innovation, an Energy Frontier Research Center funded by
the U.S. Department of Energy, Office of Science, Office of Basic
Energy Sciences under Award no. DE-SC0001004. This material is
also based upon work supported by the National Science Foun-
dation Graduate Research Fellowship under Grant No. 1247394.
Any opinion, findings, and conclusions or recommendations ex-
pressed in this material are those of the authors(s) and do not
necessarily reflect the views of the National Science Foundation.
We acknowledge Dr. S. Bai for collecting the solid-state 119Sn MAS
NMR spectra and Dr. Tsilomelekis for collecting the IR spectra.
[19] M. Glinski, U. Ulkowska, Catal. Lett. 2011, 141, 293–299.
[20] N. K. Mal, V. Ramaswamy, P. R. Rajamohanan, A. V. Ramaswamy, Micropo-
rous Mater. 1997, 12, 331–340.
[21] C. Paris, M. Moliner, A. Corma, Green Chem. 2013, 15, 2101–2109.
[22] F. C. Jentoft, in Advances in Catalysis, Vol. 52 (Eds.: B. C. Gates, H. Kno-
zinger), Elsevier Academic Press Inc, San Diego, 2009, pp. 129–211.
[23] R. Bermejo-Deval, R. Gounder, M. E. Davis, ACS Catal. 2012, 2, 2705–
2713.
Keywords: alcohols
· biomass · etherification · transfer
Received: November 14, 2013
hydrogenation · zeolites
Published online on January 22, 2014
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