The synthesis of methyl lactate and other methyl oxygenates from cellulose

Article abstract of DOI:10.1016/j.catcom.2014.02.012

Light oxygenates, such as methyl lactate (MLA), methyl levulinate (MLE), methyl formate (MFO), methyl acetate (MAC), dimethoxymethane (DMM), and methoxyacetaldehyde dimethyl acetal (MADA) were synthesized from cellulose in the presence of promoted SnX

Full text of DOI:10.1016/j.catcom.2014.02.012

Catalysis Communications 49 (2014) 78–81
Contents lists available at ScienceDirect
Catalysis Communications
journal homepage: www.elsevier.com/locate/catcom
Short Communication
The synthesis of methyl lactate and other methyl oxygenates
from cellulose
1
⁎
Feng Huan Lv, Rui Bi, Yu Hang Liu, Wen Sheng Li , Xiao Ping Zhou
Department of Chemical Engineering, Hunan University, Changsha, 410082, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Light oxygenates, such as methyl lactate (MLA), methyl levulinate (MLE), methyl formate (MFO), methyl acetate
(MAC), dimethoxymethane (DMM), and methoxyacetaldehyde dimethyl acetal (MADA) were synthesized from
cellulose in the presence of promoted SnX2 (X = Cl−, Br−, and I−) salt catalysts in methanol. The presence of
halides in SnX2-MLn (MLn is metal salt) catalysts was found crucial for methyl lactate formation from sugar.
The investigation shows that ZnCl2 is an efficient promoter for SnX2 catalyst in converting cellulose to light
oxygenates. Up to 52.2% of total one-pass oxygenate yield was obtained in the presence of SnCl2–ZnCl2 catalyst.
© 2014 Elsevier B.V. All rights reserved.
Received 21 November 2013
Received in revised form 11 February 2014
Accepted 12 February 2014
Available online 19 February 2014
Keywords:
SnCl2 catalyst
Cellulose
Methyl lactate
Methyl levulinate
1. Introduction
sucrose could be directly converted to methyl lactate over Sn4+ doped
zeolite [10]. The active sites were thought to be the framework tin
Carbohydrates, such as sucrose, starch, and celluloses synthesized by
plants, are the most abundant renewable carbon sources. The high con-
tent of the functional groups in carbohydrate molecule has both priori-
ties and drawbacks in converting carbohydrates to valuable chemicals.
The active functional groups make it possible to convert these carbohy-
drates to liquid fuel [1,2] or fundamental building blocks [3–5]. How-
ever, many functional groups on the same molecular also bring in
problems in the selective conversion of carbohydrates to specific
chemicals. Different reactions could simultaneously occur on different
functional groups of the molecular, leading to unwanted by-products,
especially the tar like by-products (humins), which make the practice
of the process difficult. It is highly desired to develop a simple catalyst
that directly decomposes carbohydrates to light oxygenates, such as
MLA and MLE. MLA is a versatile platform compound, which could be
a potential feed stock for the synthesis of biodegradable polylactic
acid plastics [6], 1,2-propanediol [7], allyl alcohol, or acrylic acid.
Presently, large scale production of lactic acid is through fermenta-
tion of glucose [8]. However, the biological process generally suffers
from low reaction rate and low product concentration, which costs too
much energy in product purification.
ions that show Lewis acidity. The disadvantages of the tin-zeolite cata-
lyst are that it is difficult to synthesize (needs more than 48 days) and
to separate the zeolite particles from the tar like humins after reaction.
Generally, the channels in zeolite could accommodate monosaccharide
and disaccharide molecules. Larger molecules, such as starch and cellu-
lose, could not access these Lewis acid sites. Solid catalysts sulfonated
carbon (C-SO3H), H-ZSM-5, H-beta, sulfated zirconia, HY zeolite,
tungstated zirconia, and tungstated alumina [11,12] were reported ef-
fective in cellulose conversion. However, Chambon and coworkers'
work proved that these solid catalysts can only act on the pre-
hydrolyzed cellulose fragments (soluble oligomers and polymers)
[12]. In order to resolve the problems, we developed a type of simple
homogeneous catalyst, which could directly act on cellulose to prepare
MLA, MLE, and other oxygenates.
2. Experimental
Microcrystalline cellulose (MCC), sucrose, methanol, NaCl, KCl,
MgCl2 · 6H2O, CaCl2, BaCl2, AlCl3 · 6H2O, CrCl3 · 6H2O, FeCl3 · 6H2O,
CoCl2 · 6H2O, NiCl2 · 6H2O, SnCl2 · 2H2O, CdCl2, BiCl3, ZnCl2, SnO,
NH4Cl, SnO, and PbCl2 were bought from Guo Yiao Chemical Group
Inc. in China. These compounds are all in analytic purity.
The reactions were carried out in stainless steel batch reactors (hav-
ing inside volume of 20.0 or 100 mL) lined with poly tetrafluoroethyl-
ene. Reactant, catalyst, and methanol were charged into the reactors
at room temperature. The reactors were then sealed and placed onto a
rotation axis in an oven. Rotate the axis to achieve mixing and ramp
up the temperature of the oven to desired temperatures to run
Aqueous alkali hydroxides were reported to convert carbohydrates
to lactate salts [9]. However, the reaction consumes excess amount of al-
kali hydroxide. Holm et al. demonstrated that glucose, fructose, and
⁎
Corresponding author at: Lu Shan Nan Road 1#, Chang Sha, Hunan, 410082 PR China.
Tel./fax: +86 73188821017.
E-mail addresses: hgx2002@hnu.edu.cn (W.S. Li), hgx2002@hnu.edu.cn (X.P. Zhou).
Tel./fax: +86 73188821017.
1
http://dx.doi.org/10.1016/j.catcom.2014.02.012
1566-7367/© 2014 Elsevier B.V. All rights reserved.

F.H. Lv et al. / Catalysis Communications 49 (2014) 78–81
79
Table 2
reactions. The scaling up reactions were carried out in a batch reactor
Catalyst performance in MLA and MLE synthesis from cellulose, glucose, and sucrose.a
with an inside volume of 10 L (when carrying out reaction at 110 °C,
the inside pressure is 5.0 atm. The vapor pressure of CH3OH at 110 °C
is 4.8 atm. The difference could be measurement error. When running
reactions at 190 °C, the inside pressure is 35.0 atm. The vapor pressure
of CH3OH at 190 °C is 33.0 atm. The difference between the practice
pressure and the vapor pressure of methanol at 190 °C is because of
the formation of dimethyl ether, which was detected as a by-product
in our reactions). After completing the reactions, the batch reactors
were cooled to room temperature, and then opened to take samples.
The samples were centrifuged to separate the liquid from the solid.
The liquid sample was analyzed on a GC and a GC-MS to calculate the
yields of products.
Catalyst
T (K)
MLAY (%)
MLEY (%)
1
2
3
4
5
6
7
8
SnCl2 · 2 H2O
SnCl2 · 2 H2O/NaCl
SnCl2 · 2 H2O/KCl
453
453
453
453
453
453
453
453
453
453
453
453
453
463
463
463
463
463
463
463
463
11.6
1.0
0.8
1.8
1.0
6.4
1.4
9.4
9.8
4.5
0.8
0.3
0.4
0.3
1.9
0.5
2.6
2.8
4.3
4.6
4.4
11.0
12.2
5.9
7.2
13.8
4.0
SnCl2 · 2 H2O/MgCl2 · 6H2O
SnCl2 · 2 H2O/CaCl2
SnCl2 · 2 H2O/BaCl2
SnCl2 · 2 H2O/NH4Cl
SnCl2 · 2 H2O/CoCl2 · 6H2O
SnCl2 · 2 H2O/PbCl2
SnCl2 · 2 H2O/CrCl3 · 6H2O
SnCl2 · 2 H2O/FeCl3 · 6H2O
SnCl2 · 2 H2O/AlCl3 · 6H2O
SnCl2 · 2 H2O/ZnCl2
SnCl2 · 2 H2O
SnCl2 · 2 H2O/AlCl3 · 6 H2
SnCl2 · 2 H2O/SbCl3
SnCl2 · 2 H2O/ZnCl2
SnCl2 · 2 H2O/ZnCl2
SnCl2 · 2 H2O/ZnCl2
9
10
11
12
13
14
15
16
17
18
19
20
21
9.9
12.7
15.9
15.0
21.6
20.8
17.6
23.7
27.0
31.2
15.7
14.7
The samples were analyzed on a GC-MS (Agilent 6890N/5975B) with
a column Agilent DB-1701 (30 m × 320 μm × 0.25 μm) and a GC (Agilent
6820) with a column Agilent DB-WAX (30 m × 0.450 mm × 0.8 mm).
The calculations of the product yields are as follows:
b
c
MLA yield: YMLA = (mol number of MLA)/(2 × mol number of
C6H10O5 unit);
6.0
11.9
11.8
d
SnCl2 · 2 H2O/ZnCl2
SnCl2 · 2 H2O/ZnCl2
e
MLE yield: YMLE = (5 × mol number of MLE)/(6 × mol number of
C6H10O5 unit);
Methyl acetate yield: YMAC = (mol number of methyl acetate)/
(3 × mol number of C6H10O5 unit);
Methyl formate yield: YMFO = (mol number of methyl formate)/
(6 × mol number of C6H10O5 unit);
DMM yield: YDMM = (mol number of DMM)/(6 × mol number of
C6H10O5 unit);
In the reaction of sugar cane bagasse, the yields of products were calculated based on the
composition of 45% of cellulose, 27.5% of half cellulose, and 2.0% of sucrose. The
composition of the bagasse is 19% of lignin, 45% of cellulose, 27.5% of half cellulose, 2.5%
of protein, 2.5% of ash, 1.5% of pectic, and 2.0% of sucrose.
a
The yield is in mol. The relative errors are below 4.6%. Reactions were run at 180 °C for
4 h. The amount of microcrystal cellulose is 0.400
0.001 g for all of the reactions. The
amount of methanol is 8.000 g. The amount of other salt (except SnCl2) was
0.736 mmol, respectively. The amount of SnCl2 · 2H2O was 0.200 g (0.886 mmol).
b
The reactant was sugar cane bagasse (0.400 g). The amount of methanol is 8.000 g.
The amount of ZnCl2 was 0.736 mmol. The amount of SnCl2 · 2H2O was 0.200 g
(0.886 mmol).
MADA: YMADA = (4 × mol number of MADA)/(6 × mol number of
C6H10O5 unit).
c
The reactant was sugar cane bagasse. The SnCl2 · 2 H2O/ZnCl2 is 0.30 mmol/1.0 mmol,
and reaction time is 6 h. The amount of methanol is 8.000 g. The amount of ZnCl2 was
0.736 mmol.
d
3. Results and discussion
The reactant was glucose (0.400g). The amount of methanol is 8.000g. The amount of
ZnCl2 was 0.736 mmol. The amount of SnCl2 · 2H2O was 0.200 g (0.886 mmol).
e
The reactant is sucrose (0.400 g). The amount of methanol is 8.000 g. The amount of
In the present investigation, a few kinds of metal chlorides were
tested as catalysts in converting sucrose to MLA and other oxygenates
in methanol (Table 1s). Generally, MLA, MLE, MFO, MAC, DMM, and
MADA or some of them (depend on catalyst) were formed as products
in the reactions. For easy discussion, only the yields of major products
MLA and MLE were given in Tables 1 and 2. The mechanism for MLA for-
mation is generally believed to be the retro aldol reaction [10,13].
ZnCl2 was 0.736 mmol. The amount of SnCl2 · 2H2O was 0.200 g (0.886 mmol).
Among the mono-component catalysts, SnCl2 gave the highest MLA
and MLE yields (23.5% and 10.3%, respectively) at 403 K (Table 1),
while the other metal chlorides did not show much selectivity to form
MLA (Table 1s). The results indicate that the Sn2+ cation and halides
are necessary for MLA formation (Table 1, entries 1–15, 18–19). With-
out halides, the major product is MLE (Table 1, entries 20–22). Of
course, as shown in Table 1, entries 18 and 19, even the tin salts do
not contain halides, and the catalysts Sn(CH3SO3)2-NH4Cl and Sn(C6H5
SO3)2-NH4Cl still gave high MLA yields. The reason could be that the ha-
lides could come from the promoter by anion exchange between the tin
salts and the halide containing salts. We speculate that, possibly, the ha-
lides are involved in the MLA formation steps (the study is still in prog-
ress regarding to the role of halides).
It was found that adding promoters could either enhance or inhibit
the catalytic activity of SnCl2 for MLA formation. The addition of rela-
tively weaker Lewis acid (weak acceptors, such as NH+4 , Co2+, Ni2+, al-
kaline metal cation, and alkaline earth metal cation) into SnCl2 · 2H2O
catalyst improves the MLA yields. The SnCl2 · 2HO catalyst promoted
by NH4Cl, KCl, or MgCl2 (Table 1, entries 6, 7, and 18) gave relatively
higher MLA yields (N40%). The addition of relatively stronger Lewis
acids (such as FeCl3 · 6H2O, AlCl3, and ZnCl2) into SnCl2 · 2H2O gave
much low MLA yields.
Table 1
Catalyst performance in MLA and MLE synthesis from sucrose.a
Entry
Catalyst
T (K)
MLA (%)
MLE (%)
1
2
3
4
5
6
7
8
SnCl2 · 2H2O
SnCl2 · 2H2O/NH4Cl
SnCl2 · 2H2O/NaCl
SnCl2 · 2H2O/NaBr
SnCl2 · 2H2O/NaI
403
403
403
403
403
403
403
403
403
403
403
403
403
403
403
403
403
403
403
403
403
403
23.5
38.5
39.3
26.6
25.1
43.3
42.6
37.8
32.8
27.0
7.4
14.4
27.5
36.0
38.0
0.4
10.3
0
0
1.3
0.5
0
0
1
0
0.1
6.4
8.4
7.1
0.7
0
3.3
14.6
0
SnCl2 · 2H2O/KCl
SnCl2 · 2H2O/MgCl2
SnCl2 · 2H2O/MgBr2
SnCl2 · 2H2O/CaCl2
SnCl2 · 2 H2O/FeCl3 · 6H2O
SnCl2 · 2H2O/AlCl3
SnCl2 · 2 H2O/ZnCl2
SnCl2 · 2 H2O/SbCl3
SnCl2 · 2H2O/NiCl2
SnCl2 · 2 H2O/CoCl2 · 6H2O
SnCl2 · 2 H2O/PbCl2
SnCl2 · 2 H2O/CrCl3 · 6H2O
Sn(CH3SO3)2/NH4Cl
Sn(C6H5SO3)2/NH4Cl
Sn(CH3SO3)2/NH4(CH3C6H5SO3)
Sn(CH3SO3)2/NH4(C6H5SO3)
Sn(C6H5SO3)2/NH4(C6H5SO3)
9
10
11
12
13
14
15
16
17
18
19
20
21
22
4.5
In a kilogram level reaction (Section 1s) carried out in the presence
of SnCl2 · 2H2O-MgCl2 · 6H2O catalyst, 50% of MLA yield with 1.0% of
MLE yield was obtained. When reducing the amount of MgCl2 · 6H2O
to 41.6 g, 47.1% of MLA yield and 1.5% of MLE yield were obtained. How-
ever, further reducing the amount of SnCl2 · 2H2O led to MLA yield dra-
matically decreasing. The drawback of the reaction is to form large
amount of dark tar. Generally, the formation of MLE and tar is catalyzed
42.0
38.5
1.2
0.9
0.6
0
14.5
13.1
13.1
a
Sucrose 0.500 g, SnL2 0.220 mmol, MLn 1.87 mmol, CH3OH 4.000 g, and reaction time
2 h. The yield is in mol. The relative errors are below 4.6%.

80
F.H. Lv et al. / Catalysis Communications 49 (2014) 78–81
by BrØnsted acid. In the present cases, the hydrolysis of SnCl2 · 2H2O
(H2O is also a by-product in the formation of MLA, MFO, MAC, DMM,
and MADA) could generate BrØnsted acid HCl, which might catalyze
the dehydration reaction of sucrose to form MLE and humins.
It is known that the tin dihalides could combine with halide to form
SnX−3 type anions [14]. Our results indicate that the weak accepting salts
promote the MLA yield in sucrose reactions. It is known that the Lewis
acidity of Sn2+ in SnX3− is weaker than that in SnCl2 (also see PH
value in Section 1s). The results indicate that relatively higher MLA
yield was obtained over M(SnX3)n, in which, Mn+ has relatively weaker
acidity. Hence, reasonably reducing the Lewis acidity of Sn2+ (by adding
alkaline or alkaline earth metal halides) favors the MLA formation from
sucrose. High acidity leads to low MLA yield (Table 1, entries 10–13) and
favors the formation of dark tar.
Several metal salt catalysts were also tested for the purpose of
converting cellulose to light oxygenates. SnCl2 · 2H2O gave the highest
MLA yield, while CrCl3 · 6H2O gave the highest MLE yield (Table 2s).
Comparing with the reaction results from the sucrose reactions, the
SnCl2 · 2H2O-MCln catalyst behaves differently in catalyzing cellulose
conversion. In the reaction of microcrystal cellulose, SnCl2 · 2H2O gave
11.6% of MLA yield and 4.5% of MLE yield at 453 K. The addition of
NH4Cl, alkaline metal chloride, or alkaline earth metal chloride into
SnCl2 · 2H2O reduced the MLA yields (Table 2, entries 2–7). Adding
metal chlorides with medium accepting capability (Table 2, entries
8–10) into SnCl2 · 2H2O did not impact much on the MLA yields. Stron-
ger Lewis acids show improving effects on the activity of SnCl2 · 2H2O
catalyst for MLA formation (Table 2, entries 11 to 13). The results indi-
cate that the combination of SnCl2 · 2H2O-ZnCl2 is the most efficient cat-
alyst in converting cellulose to MLA and MLE. At elevated temperature
(210 °C), up to 32.1% of MLA and 10.6% of MLE yields were obtained
(Fig. 1). The catalyst also performed well in converting sugar cane ba-
gasse to MLA and MLE (31.2% and 6.0% yields, respectively, Table 2, en-
tries 18–19). However, these catalysts are not good for monosaccharide
and disaccharide involved reactions (Table 2, entries 20–21). The strong
acidity of these catalysts turned too much of monosaccharide and disac-
charide to humins.
In the reaction of cellulose, it was found that there was dark solid for-
mation. The formation of dark compounds might be one of the reasons
that retard the reaction. Although, we cannot confirm if the whole used
solid is cellulose, the XRD characterization shows that there was still cel-
lulose in the used cellulose (Fig. 1Sc). It was found that high catalyst
concentration turned cellulose to dark (Fig. 2). In order to reduce the
formation of dark compound, the reaction was run at more diluted con-
dition (cellulose 0.400 0.001 g, CH3OH 20.000 0.001 g, SnCl2 · 2H2-
O 1.50 mmol, ZnCl2 1.00 mmol, reaction temperature 190 °C) and for
longer time (7.0 h instead of 4 h). Even higher MLA yield (33.5%) and
MLE yield (14.3%) were obtained (comparing with that of Fig. 2A) and
the rest of the cellulose was not turned into dark (Fig. 2B). Clearly, the
formation of dark compound over cellulose particles is one of the rea-
sons that retard the reaction. However, prolonging the reaction time
to 8 or 9 h, the yields of MLA and MLE did not increase any more. The
results indicate that the catalyst did not continue acting its rule. One
of the possible reasons could be that some of the products poison the
catalyst. We speculated that the most possible component that poisons
the catalyst might be MLA, since that the hydroxyl group bearing com-
pounds could easily coordinate to Sn2+ [15,16]. In order to verify our
speculation, MLA was added to microcrystal cellulose to run reaction
at the optimized conditions. When small amount of MLA was added,
much low MLA yields were obtained. Adding more MLA could fully
stop the MLA formation reaction (see Section 2s for detail). However,
the MLA addition only slightly reduces the MLE yield. The results indi-
cate that the addition of MLA poisons the MLA formation pathway.
30
YMLA
YMLE
YMFO
YMAC
A
28
26
24
22
20
18
16
14
12
10
8
In order to check the influence of mechanical ball milling on product
yields, the cellulose was milled (ball milled at 200 rotations/min for 10
h, see pictures in Supplement material, see Fig. 1Sa and 1Sb), and then
run reaction at the same conditions as that in Table 2, entry 13. The re-
action gave 18.5% of MLA yield and 7.3% of MLE yield. Without milling
the cellulose, the reaction gave 15.0% of MLA yield and 11.0% of MLE
yield (Table 2, entry 13). The milled cellulose gave higher MLA yield,
but lower MLE yield than that not milled.
6
4
2
0
2
4
6
8
10 12 14 16 18 20 22
CH3OH (g)
33
YMLA
YMLE
B
30
27
24
21
18
15
12
9
YMFO
YMAC
6
4.000 g
CH3OH
3
20.000 g
CH
0
3OH
130 140 150 160 170 180 190 200 210 220
Reaction temperature (degree C)
Fig. 2. A: The influence of CH3OH amount on the yields of products. YMLA stands for the
yield of MLA. YMLE stands for the yield of MLE. YMFO stands for the yield of MFO.
YMAC stands for the yield of MAC. Reaction conditions: microcrystal cellulose 0.400
0.001 g, SnCl2 · 2H2O 1.50 mmol, ZnCl2 1.00 mmol, reaction temperature 190 °C, and re-
action time 4 h. B: The cellulose samples after reaction with 4.000 0.001 and 20.000
0.001 g of methanol.
Fig. 1. The influence of reaction temperature on the yields of products. YMLA stands for the
yield of MLA. YMLE stands for the yield of MLE. YMFO stands for the yield of MFO. YMAC
stands for the yield of MAC. Reaction conditions: microcrystal cellulose 0.400 0.001 g,
CH3OH 8.000
0.001 g,ZnCl2 · 2H2O 0.100
0.001 g (0.736 mmol), SnCl2 · 2H2O
0.200 0.001 g (0.886 mmol), and reaction time 4 h.

F.H. Lv et al. / Catalysis Communications 49 (2014) 78–81
81
The possible reason could be that MLA might react with Sn2+ through
the hydroxyl group to form a more stable coordination complex and
kikes out Cl− ligands from the coordination sphere of Sn2+ ions. The re-
sulted Sn2+ complexes (without halides) are not active for the topic re-
action (consistent with the results in Table 1, entries 20–22).
value oxygenates. The catalyst is simple metal chlorides, which could
be easily regenerated (Section 3s). The process has potential to be scaled
up to commercial stage. Research in this aspect is in progress.
Acknowledgements
As mentioned previously, the dark compound formation could be
one of the reasons that retard the reaction. If the dark layer was broken,
the reaction should be able to continue over the newly generated sur-
face. In order to verify the idea, reaction was run with fresh microcrystal
cellulose at optimized conditions (2.000 g of MCC, 7.50 mmol of
SnCl2 · 2H2O, 5.00 mmol of ZnCl2, 100.0 g of CH3OH, reaction time
7 h, temperature 190 °C). The reaction gave 33.6%, 9.2%, 1.2%, 0.3%,
3.7%, and 4.2% of MLA, MLE, MFO, MAC, DMM, and MADA yields, respec-
tively (total carbon yield of 52.2%). There was about half of the solid left.
The left solid is defined as used MCC. Without milling the used MCC,
even if we loaded it with fresh catalyst, there were still not much MLA
and MLE detected. After the used MCC was milled, the reaction of the
used MCC gave 6.1%, 7.8%, 0.7%, and 0.5% of MLA, MLE, MFO, and
DMM yields, respectively. The results indicate that the formation of
the dark compounds is one of the reasons that retard the reaction in
some degree. In our investigation, it was found that high reaction tem-
perature and high catalyst concentration usually lead to dark solid for-
mation in cellulose reaction. In order to obtain relatively higher MLA
yield and without turning cellulose to dark, we run the reactions at rel-
atively lower catalyst concentration and reasonably lower reaction tem-
perature (190 °C) for longer time (Fig. 2s).
This work was supported by the Chinese Ministry of Education
Project PCSIRT No. IRT1238.
Appendix A. Supplementary data
Supplementary data to this article can be found online at http://dx.
doi.org/10.1016/j.catcom.2014.02.012.
References
[1] G.W. Huber, J.N. Chheda, C.J. Barrett, J.A. Dumesic, Science 308 (2005) 1446–1450.
[2] Y. Roman-Leshkov, C.J. Barrett, Z.Y. Liu, J.A. Dumesic, Nature 447 (2007) 982–986.
[3] T. Werpy, G. Petersen, Technical Report No. DOE/GO-102004-1992, National Renew-
able Energy lab, Golden, CO, 2004. (available at www.Osti.gov/bridge ).
[4] W. J. Pentz, UK Patent 2131014A (1984).
[5] F. Jin, J. Yun, G. Li, A. Kishita, K. Tohji, H. Enemoto, Green Chem. 10 (2008) 612–615.
[6] R. Datta, S.P. Tsai, P. Bonsignore, S.H. Moon, J.R. Frank, FEMS Microbiol. Rev. 16
(1995) 221–231.
[7] R.D. Cortright, M. Sanchez-Castillo, J.A. Dumesic, Appl. Catal. B Environ. 39 (2002)
353–359.
[8] R. Datta, M. Henry, J. Chem. Technol. Biotechnol. 81 (2006) 1119–1129.
[9] B.Y. Yang, R. Montgomery, Carbohydr. Res. 280 (1996) 47–57.
[10] M.S. Holm, S. Saravanamurugan, E. Taarning, Science 328 (2010) 602–605.
[11] A. Onda, T. Ochi, K. Yanagisawa, Green Chem. 10 (2008) 1033–1037.
[12] F. Chambon, F. Rataboul, C. Pinel, A. Cabiac, Appl. Catal. B Environ. 105 (2011)
171–181.
[13] Y. Hayashi, Y. Sasaki, Chem. Commun. (2005) 2716–2718.
[14] F.A. Cotton, G. Wilkinson, Advanced inorganic chemistry, 5th ed., A Wiley-interscience
publication, New York, 1988, p. 272.
In conclusion, our investigations show that if SnCl2 · 2H2O was pro-
moted by suitable slats (MLn), it could be an efficient catalyst to catalyze
carbohydrate conversion to prepare light oxygenates, such as MLA and
MLE, in methanol. The MgCl2 promoted SnCl2 · 2H2O catalyst is efficient
to catalyze monosaccharides and disaccharide conversion to produce
MLA and MLE, while the ZnCl2 promoted SnCl2 · 2H2O catalyst is effi-
cient to catalyze cellulose conversion to produce MLA, MLE, MFO,
MAC, DMM, and MADA. These products are easily separatable high
[15] S.J. Blunden, P.A. Cusack, P.J. Smith, J. Organomet. Chem. 325 (1987) 141–152.
[16] S.J. Blunden, P.A. Cusack, P.J. Smith, P.W.C. Barnard, Inorg. Chim. Acta 72 (1983)
217–222.