Selective synthesis of dimethoxyethane via directly catalytic etherification of crude ethylene glycol

Article abstract of DOI:10.1039/c7gc00659d

Etherification of ethylene glycol with methanol provides a sustainable route for the production of widely used dimethoxyethane; dimethoxyethane is a green solvent and reagent that is applied in batteries and used as a potential diesel fuel additive. SAPO-34 zeolite was found to be an efficient and highly selective catalyst for this etherification via a continuous flow experiment. It achieved up to 79.4% selectivity for dimethoxyethane with around 96.7% of conversion. The relationship of the catalyst's structure and the dimethoxyethane selectivity was established via control experiments. The results indicated that the pore structure of SAPO-34 effectively limited the formation of 1,4-dioxane from activated ethylene glycol, enhanced the reaction of the activated methanol with ethylene glycol in priority, and thus resulted in high selectivity for the desired products. The continuous flow technology used in the study could efficiently promote the complete etherification of EG with methanol to maintain high selectivity for dimethoxyethane.

Full text of DOI:10.1039/c7gc00659d

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Selective synthesis of dimethoxyethane via directly catalytic
etherification of crude ethylene glycol
Weiqiang Yu,a Fang Lu,* a Qianqian Huang, a,b Rui Lu,a,b Shuai Chena and Jie Xu*a
Received 00th January 20xx,
Accepted 00th January 20xx
Etherification of ethylene glycol with methanol provides
a sustainable technology for producing widely used
DOI: 10.1039/x0xx00000x
dimethoxyethane, which was green solvent and reagent applied in batteries and as potential diesel fuel additives. SAPO-34
zeolite was found to be an efficient and highly selective catalyst for such etherification by continuous flow experiment. It
can reach the selectivity of dimethoxyethane up to 79.4% with around 96.7% of conversion. The relationship of the
catalysts structure and the dimethoxyethane selectivity was established by control experiments.The results indicated that
the pore structure of SAPO-34 effectively limited the formation of 1,4-dioxane from activated ethylene glycol and ehanced
the reaction of the activated methanol with ethylene glycol in priority, which results high selectivity of desired products.
The continuous flow technology used in the study could efficiently promoted the deeply etherification of EG with
methanol to maintain high selectivity of dimethoxyethane.
www.rsc.org/
chemistry and could be sustainably developed for industrial
application.
Introduction
The catalytic etherification of EG with methanol was limited
Ethers, such as dimethyl ether and methyl tert-butyl ether, are
known as attractive candidates for fuel additives because of their
reported in literatures. Scheffel et. al. used H2SO4 as the catalyst,
the conversion of EG was 61.2% and the concentration of
dimethoxyethane was only 9.9% in the mixture solutions less than
that of 2-methoxyethanol (23.5%)18. Due to the environmental
impact by liquid acid, solid acid was reported to be applied in the
etherification. Baimbridge et. al. used Nafion 15 as catalyst for
etherification of EG with methanol, and selectivity of 2-
methoxyethanol and dimethoxyethane was respectively 67% and
28% with 75.7% of EG conversion19. Ikariya et. al. used Cs-Si-P
(1:5:0.8) oxide catalyst to give 2-methoxyethanol with 76%
selectivity at 23% conversion under 300 oC and 12 MPa. Sadly, there
ability to reduce soot formation during the combustion process1-4
.
Dimethoxyethane, known as ethylene glycol dimethyl ether,
attracts increasing interest in recent years because of its
advantageous properties (high energy density and cetane number) 5,
6. It also shows excellent solubility, widely used as green solvent
and good etherification agent in cosmetics, perfumes,
pharmaceuticals and especially applied in batteries and electrolyte7-
11
.
Industrial preparation of dimethoxyethane was via the
reaction of 2-methoxyethanol with CH3Cl in the existence of sodium
or NaOH by Williamson method12. However, amount of halon and
base used in this process brought the issues of separation and
environment pollution. Another common used method for the
production of dimethoxyethane is by the cleavage of ethylene oxide
in presence of dimethyl ether over Lewis acids 13. While, ethylene
oxide is extremely flammable and explosive, and derived from the
unsustainable petroleum resources. Catalytic etherification of
ethylene glycol (EG) with methanol could be a potential green
method for producing dimethoxyethane. The feedstock could be
generated from biomass source. For example, the feedstock of EG
could be derived from the renewable cellulose14, 15, or biomass-
derived polyols (sorbitol, xylitol, glycerol, etc.)16, 17 Their availability
and non-petroleum route source could meet the rule of green
is no dimethoxyethane detected in the products under such harsh
21
conditions20,
. From the above reports, we found that 2-
methoxyethanol was the main product during the etherification of
EG with methanol, and it could not be efficiently converted to
dimethoxyethane in further which resulted low yield. Another
finding for the above reports was that the by-product of 1,4-
dioxane was detected. EG was easily activated in the existence of
acid catalyst, and self-etherification would be finally formed the
1,4-dioxane 22, 23. Besides the formation of by-product 1,4-dioxane,
etherification of EG with methanol is an equilibrium reaction24-26
.
The generated water or the existence of water in solvent may affect
the reaction equilibrium, which inhibited the further formation of
dimethoxyethane. Traditionally, etherification reaction was inclined
to be conducted under a water-free environment. However,
separation of water from industrial EG and methanol feedstock is
an energy-consuming process. The direct using crude feedstock will
largely improve the economics of the etherification process, and
will exhibit great prospect for industrialization. Therefore, the main
challenge for high yield production of dimethoxyethane using crude
a.Address here. State Key Laboratory of Catalysis, Dalian Institute of Chemical
Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean
Energy, Dalian 116023, P. R. China. E-mail: xujie@dicp.ac.cn
；lufang@dicp.ac.cn
b.University of the Chinese Academy of Sciences, Beijing 100049, P. R. China
†Electronic Supplementary Information (ESI) available: See
DOI: 10.1039/x0xx00000x
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another one was monitoring the reaction temperature. The catalyst
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DOI: 10.1039/C7GC00659D
(1 g) with a diameter of 20-40 mesh was placed between two layers
of quartz sands for each test. N2 was passed through the catalyst
bed at a total flow rate of 40ml/min with pressure of 0.3-0.4 MPa.
Liquid reactants were continuously pumped into the fixed-bed
reactor with a high-pressure pump (Agilent 1100 Pump). For
example, 85 w.t. % ethylene glycol aqueous solution mixed with 90
w.t. % methanol (molar ratio was around 1:3.5) was used to test the
etherification performance over SAPO-34 catalyst. N2 and solution
flows were mixed at the inlet of the reactor. All the effluent flowed
Scheme 1 Catalytic etherification of EG with methanol using
fixed-bed reactor
o
from the reactor were maintained at high temperature (eg. 215 C)
feedstock (aqueous solution) is how to efficient shift the reaction
equilibrium and avoid the formation of by-product 1, 4-dioxane.
Thus, the aim of this study is to develop efficient solid catalyst
systems associated with continuous flow strategy for highly
selective etherification of crude EG with methanol to
dimethoxyethane (Scheme 1). Microporous zeolites were selected
as solid acid catalyst to perform the etherification reaction. Fixed
bed was used as the reactor to reduce the contact time between
water and the catalyst bed. The relationship between the catalysts
structure and the dimethoxyethane selectivity was also established.
and then partial were directly introduced into the chromatography
and online analysed automatically (GC-7890 gas chromatograph
equipped with 10-way valve, a FID conductivity detector and a HP-5
column). Products identification was performed by GC-MS. The
products of EG reacted with ethanol was collected in a separator at
room temperature and analysed using GC auto injector. Conversion
and selectivity were calculated by peak area normalization method.
Results and Discussion
Catalytic performance of different catalysts
Experimental
Catalysts
We initiated the investigations for the etherification EG with
methanol over different kinds of catalysts. The reaction was stable
in 100-120 min after the liquid reactants pumped into the fixed-bed
reactor under the desired conditions, therefore samples was
analysed in this time period and the results are shown in Table 1.
The products included 2-methoxyethanol, dimethoxyethane, and 1,
4-dioxane identified by GC online analysis. According to the results,
it could be seen that no etherification product listed above were
detected using alkaline, like Ca(OH)2 and Mg(OH)2 as catalyst (Table
1, entry 1-2). When γ-Al2O3 was used as catalyst, 2-methoxyethanol
The following catalysts were used in the present work. HY (ratio of
SiO2/Al2O3 was 7, 11 and 14), H-beta (ratio of SiO2/Al2O3 was 25 and
40), HZSM-5(ratio of SiO2/Al2O3 was 25,100 and 300), HZSM-35
(ratio of SiO2/Al2O3 was 30), SAPO-11 (ratio of SiO2/Al2O3 was 0.5)
SAPO-34(ratio of SiO2/Al2O3 was 1) and Mordenite (ratio of
SiO2/Al2O3 was 25) were purchased from the Catalyst Plant of
Nankai University. Al2O3, Ca(OH)2 and Mg(OH)2 were derived from
Tianjin Kemiou Chemical Reagent Co., Ltd. All the catalysts were
calcined at 550oC for 5h under air conditions, and then pressed into
pellets, crushed and sieved to 20-40 mesh.
Table
1 Performance of different catalysts in catalytic
etherification of EG with methanol. [a]
Characterizations of catalyst
Distribution of Products (%)
EG
Conv.
(%)
NH3-temperature-programmed desorption (NH3-TPD) were used to
study catalyst acidity on a Micromeritics AutoChem II 2920
instrument. All the samples (0.1 g) were pre-treated at 473 K for 30
min in flowing Ar (25 ml/min) in order to remove the surface
impurities. Then, samples were saturated with NH3 at 323 K for 15
min by flowing 5% NH3-He (25 ml/min). After saturation, the
temperature was increased from 323 to 873 K at 10 oC min-1 in
flowing helium (25 ml/min). Thermogravimetric analysis (TGA) was
carried out on a NETZSCH STA 409 PC instrument with mass
spectrometry (MS) detector. Samples were heated at a rate of 10 oC
min-1 from 100 oC to 800 oC in an N2 flow of 30 mL min-1.
Ent
ry
Catalysts
1,4-
dioxane
MME
DME
Others
1
2
3
4
5
6
7
8
Ca(OH)2
-
n.d.
n.d.
52.6
14.5
48.4
5.0
n.d.
n.d.
n.d.
n.d.
n.d.
43.9
26.6
66.2
44.6
n.d.
n.d.
n.d.
15.0
18.6
n.d.
2.3
Mg(OH)2
γ-Al2O3
-
3.6
32.4
23.0
25.1
26.4
25.9
79.4
HY(7)
67.5
64.5
88.4
73.0
96.7
HZSM-5(25)
H-beta(25)
SAPO-11
SAPO-34
26.1
3.4
Catalytic reaction and analysis
The etherification of EG with methanol was performed in a
continuous flow fixed bed made of a 1/2 inch stainless steel reactor
(length: 300 mm, Swagelok Company) mounted inside a tubular
furnace (1000 W/12 V). Two thermocouples (K-Type) were used,
one of which was for controlling the furnace’s temperature and
17.3
3.4
[a] Reaction conditions: 483 K (entry3, 473K; entry 4 and 6, 488K), 0.3 MPa N2,
LHSV entry 4-7,
1.5 h-1 h-1). DME, MME were represented
dimethoxyethane and 2-methoxyethanol.
=
(
3
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and dimethoxyethane were detected (Table 1, entry 3). The EG
conversion was only 3.6%. When introduced microporous zeolites
(HY, HZSM-5, H-Beta and SAPO-11) in the etherification, the
conversion of EG were increased dramatically (Table 1, entry 4-7).
However, the selectivity of desired product of dimethoxyethane
was low over above catalysts, in the range of 20%-30%. The by-
products of 1, 4-dioxane were also detected in these zeolites, the
selectivity was even higher than dimethoxyethane. SAPO-34
exhibited best catalytic performance in the etherification of EG with
methanol, with 96.7% conversion of EG and 79.4% selectivity of
dimethoxyethane (Table 1, entry 8). The results showed that SAPO-
34 can efficiently catalyse the etherification of EG with methanol
and provide the high selectivity to dimethoxyethane.
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DOI: 10.1039/C7GC00659D
Effect of acidity of microporous zeolites on its catalytic
performance in etherification
Fig.2 NH3-TPD curves of zeolites.
The surface acid sites played crucial roles for catalytic etherification,
which provided the catalytically active centres for reaction of EG
with methanol. To verify the above information, we did series of
experiments to understand it. As well-known, the ratio of
SiO2/Al2O3 in zeolites could influence the acidity. Therefore,
different SiO2/Al2O3 ratio of zeolites was studied. Fig.1 showed the
catalytic performance of HZSM-5, HY and H-Beta in the
etherification of EG and methanol with different SiO2/Al2O3 ratio.
For HZM-5, the EG conversion was promoted with ratio of
SiO2/Al2O3 increased from 25 to 300. As shown, HZSM-5 with
intermediate acidic content (SiO2/Al2O3=25) gives the EG conversion
of 64.5% and that with strong acidic content (SiO2/Al2O3=300) gives
the conversion close to 100%. HY (SiO2/Al2O3=7, 11, 14) and H-beta
(SiO2/Al2O3=25, 40) were also conducted the similar etherification
reactions. As seen from the Fig. 1, EG conversion was promoted
from 67.5% to 89.0% for HY zeolites with the increased ratio of
SiO2/Al2O3. Same trend was also found for H-beta zeolites and EG
was almost completely converted with SiO2/Al2O3=40. It was
indicated that the increasing of SiO2/Al2O3 ratio improve the acid
Table 2 Acidity of HZSM-5, HY and SAPO-34
Desorption in LTa
Desorption in HTa
Total acid
sites
(mmol/g)
Catalysts
Temp.
Acid sitesb
(mmol/g)
Temp.
Acid sitesb
(mmol/g)
（oC）
（oC）
HZSM-5(25)
HY(7)
1.0
1.6
1.7
151
165
130
0.8
435
425
421
0.2
0.1
0.5
1.5
SAPO-34
1.2
a LT: low temperature; HT: high temperature.
b Determined by NH3-TPD.
strength for the zeolites, which generated the influences on the
conversion. These experiments were evidences for revealing that
the strong acid sites in the zeolites was contributed to the EG
conversion.
The acidity of the catalysts was further studied via NH3-TPD
technology. HZSM-5, HY and SAPO-34 were characterized and the
results were shown in Fig.2. There were two kinds of NH3
desorption peak in the studied three zeolites according to the NH3-
TPD curves. Desorption peak in the temperature range of 100-300oC
(defined as LT) were attributed to the weak acid sites and in the
range of 400-500 oC (defined as HT) were attributed to the strong
acid sites. The total acid amount of the acid sites is calculated from
the TPD curves, and the results were shown in Table 2. It can be
seen that the total acid amount varied in the following order:
HZSM-5 (1.0mmol/g) < HY (1.6 mmol/g) < SAPO-34 (1.7mmol/g).
The EG conversion was compatible with the acidity order, indicated
that acidity of zeolites effected the EG conversion. An interesting
phenomenon was found that the acidity of HY and SAPO-34 was
close, but the EG conversion have big difference. Therefore, the
strength distribution of the acid sites is also calculated in Table 2.
The amount of strong acid sites in the SAPO-34 was 0.5mmol/g,
higher than that of HZSM-5 and HY. The results indicated that the
strong acid sites in zeolites were probably contributed to the EG
conversion.
Fig.1 Different ratio of SiO2/Al2O3 of zeolites for the etherification
of EG with methanol. Reaction conditions: 488 K, 0.3 MPa N2,
LHSV=3 h-1. [a] 483K. DME, MME represent dimethoxyethane and 2-
methoxyethanol.
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Pore structure of microporous zeolites for catalytic etherification
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DOI: 10.1039/C7GC00659D
Above results described that the surface acid sites of zeolites were
beneficial for the conversion, but there is no big difference for the
selectivity when the ratio of Si/Al was changed using same zeolite.
The pore structure of zeolites could be another important aspect
for the etherification reaction. The different pore window size of
zeolites would give the influence on the distribution of the final
products. We firstly analyse the structure of the used zeolites. HY
and H-beta have 12-membered rings (12R) in their structures,
attributed to the large pore zeolites27, 28. HZSM-5 and SAPO-11
frameworks can be accessed via a 10R window, and attributed to
medium pore zeolites. SAPO-34 has CHA topology, the framework
can be accessed via an eight-membered ring (8R) window SAPO-
3429,30, attributed to the small pore zeolites. From the analysis and
association with the reaction results, it could be indicated that the
smaller pore size of zeolites was effective for promoting the
selectivity of dimethoxyethane in the etherification of EG with
methanol. In order to study such effect, zeolites that framework
contains 8R window were used in the reaction, including ZSM-3531
and mordenite32, and their catalytic performance were tested. The
results were shown in Fig.3. From the results, it can be seen that
mordenite and HZSM-35 gave 76.5% and 47.3% selectivity of
dimethoxyethane respectively. They exhibited same phenomenon
Fig. 4 The continuous production dimethoxyethane via
etherification over SAPO-34. Reaction conditions: 483 K, 0.3 MPa
N2, LHSV=1.5 h-1.
Continuous producing dimethoxyethane via etherification over
SAPO-34
in promoting the selectivity of dimethoxyethane as the SAPO-34. SAPO-34 exhibited a good catalytic performance in etherification of
By-product of 1, 4-dioxane was also detected over both of the two EG with methanol. To study the long-term behaviour of the tested
zeolites. In fact, these two zeolites have not only one kind of pore catalysts and understand the deactivation mechanism, the
window size, but also have bigger pore size than 8R. The existence continuously producing dimethoxyethane was performed over
of bigger pores takes the similar effect as HY, H-beta and H-ZSM-5. SAPO-34 catalyst in a flow-type reactor. Fig.4 shows a plot of
These results suggested that the structure of zeolites having 8R catalytic activity of SAPO-34 for etherification of EG with menthol as
windows was essential for promoting the selectivity of a function of time. It reveals the change of conversion of EG and
dimethoxyethane and zeolites structures having >8R windows selectivity of 2-methoxyethanol and dimethoxyethane over the
would resulted the generation of by-product of 1,4-dioxane which course of the reaction. As noted, the selectivity of dimethoxyethane
decreased the selectivity of dimethoxyethane.
was decreased slowly in 150 min, and then keeps stable in
subsequent 150 min, maintained by ca. 70%. 2-methoxyethanol
was gradually climbing in the 150mins and then kept stable by ca.
20% in the last 150 min. 2-methoxymethanol was the precursor of
Fig.3 8R-containing zeolites for catalytic etherification of EG with
methanol. Reaction conditions: 483 K, 0.3 MPa N2, LHSV = 1.5 h−1
DME, MME were represented dimethoxyethane and 2-
methoxyethanol.
.
Fig.5 TPR analysis of the used SAPO-34 in etherification of EG with
methanol. a) the photo of used catalyst and b) the MS detected
signals during TG course.
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dimethoxyethane, so the total selectivity of ethers was always keep
at around 90%, which indicated that the as-used SAPO-34 was
highly selective catalyst for the etherification of EG with methanol.
For the EG conversion, it was ca. 95% at the beginning and
decreased with the time prolonging to 300 min, which indicated
that the catalyst was deactivated in the long-term run.
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Such deactivation may be due to the deposition of organic
compounds, which formed in the cavities of SAPO-34 and trapped
inside33. Therefore, the used SAPO-34 was subsequently
characterized by TPR technology and mass spectrometry (MS) as
the detector. The results were seen in Fig.5. The colour of the used
SAPO -34 was turned to yellow, indicating that the coke was formed
in the SAPO-34.From the TG curves, it can be seen that the catalyst
weight were decreased by 10% when temperature was elevated to
800oC. Mass frag of m/z=16, 28 and 44 was detected, which
represented that the compounds of CH4, CO and CO2 were released
during the test course. These organic carbon-containing compounds
were probably derived from the decomposition of the coke formed
in the SAPO-34 in high temperature under air atmosphere. Because
of catalyst deactivation with the long-term run, regeneration or
catalyst pre-treatment was conducted (Results was listed in Fig S18
and Fig.19). Sadly, the catalyst activity has not been fully recovered
after regeneration. New catalyst modification method and
regeneration method would be studied in the further work.
Fig.6 Etherification of EG with ethanol over SAPO-34 and HY(7).
Reaction conditions: 483 K, 0.3 MPa N2, LHSV = 1.5 h−1, 4 h.
14.8%, with 38.6% selectivity of 2-ethoxyethan-1-ol and no 1,4-
dioxane was detected. As the catalyst changed to HY, the
conversion was increased obviously and nearly to 91.5%. The
byproduct of 1, 4-dioxane was appeared which selectivity was
26.3%.
Although the SAPO-34 faced the issues of deactivation, the
continuous flow strategy was effective keeping the selectivity of
desired products. As known, the existence of water and newly
formed water in the etherification would take great influence on
the reaction equilibrium. Amount of water stayed could inhibit the
reaction progressed, and probably made the reaction kept in the 2-
methoxyethanol stage and was not continuously formed the final
dimethoxyethane. Fixed bed was used as the reactor to reduce the
contact time between water and the catalyst bed34 and increase the
From the results, it can be found that EG conversion was lower
over SAPO-34 than HY when using ethanol as etherification agent. It
was probably ascribed to the relationship of reactant molecular
dimensions with zeolites pore size. The detailed relationship
between the reactant molecular dimensions and zeolites pore size
was studied. SAPO-34 has an eight-membered ring (8R) window
with a pore diameter of ~0.43 nm39. The kinetic diameter of
methanol is 0.38nm which is smaller than the pore size of SAPO-34
40. Ethanol, which molecular size is around 0.43 nm (bigger than
methanol), is a good candidate as etherification agent for the
comparison study. The kinetic diameter data of EG was not found in
literature. Because its molecular was bigger than ethanol, kinetic
diameter of EG was estimated as exceeded 0.43 nm. From the
analysis, low EG conversion generated over SAPO-34 was probably
attributed to that the diameter of ethanol and EG were similar or
larger than SAPO-34 and decreased its probability accessing into the
pores of zeolites. For HY, the pore size was allowed the entrance of
ethanol and EG easily, which resulted conversion increased and 1,4-
dioxane appeared.
Another result in Fig.5 was found that 1, 4-dioxane was not
detected using SAPO-34 when ethanol was used as etherification
agent. The phenomenon was similar with the methanol reacted
with EG. It was speculated that EG was not sufficiently formed 1,4-
dioxane due to the structure of SAPO-34, because 1,4-dioxane is
the main product of EG self-etherification. As a 6-membered
molecular, the kinetic diameter of 1,4-dioxane was estimated
similar with benzene, which kinetic diameter was 0.585nm, higher
than that of pore size of SAPO-3439. Therefore, 1,4-dioxane could be
hardly formed in the SAPO-34 pores. However, large pore zeolites
of HY allowed the EG into its pores to be activated, generating
amount of 1, 4-dioxane and increasing the EG conversion, which
give the similar results in the etherification of EG with methanol
process efficiency35-37
.
Insights of dimethoxyethane production by the etherification of
EG with methanol overs SAPO-34
Base on above results, it can be seen that SAPO-34 provides very
high selectivity to dimethoxyethane, whereas HY with larger pore
size gives different results with amount of 1, 4-dioxane. The
comparison results encouraged us to further understand the
mechanism of the reaction. As for the etherification, the hydroxyl in
the alcohol was first activated by the hydrogen proton over zeolite
catalyst38, and then the activated species attacked another alcohol
molecular. The reactant used in this work was methanol and EG,
and generally EG was more easily to be activated than methanol
over acid catalyst and resulted the increasing of 1,4-dioxane.
Therefore, it was important to understand the mechanism of
products generation in the studied zeolites catalyst and find
effective method to enhance the selectivity of dimethoxyethane.
Control experiments were conducted using candidate etherification
agent reacted with EG for the comparison study. As methanol
homologues, ethanol was selected as the etherification agent to
react with EG over SAPO-34 and HY catalysts. The results were
shown in Fig.6. It can be found that when ethanol was involved in
the etherification over SAPO-34, EG conversion was detected as
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Scheme 2 Proposed mechanism over microporous zeolites
1.
2.
3.
4.
5.
6.
7.
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According to the control experiments, the process of
etherification of EG with methanol were proposed as in Scheme 2.
It can be found that the kinetic diameter of methanol is smaller and
matching with pore structure of SAPO-34, can enter into the pores
of SAPO-34 and then activate by the inside acid site of catalyst. The
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In summary, an efficient microporous zeolite has been developed to
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crude ethylene glycol with methanol, using fixed bed reactor. SAPO-
34 was the most appropriate catalyst for such etherification, which
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Acknowledgements
This work was supported by the National Natural Science
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DOI: 10.1039/C7GC00659D
Selective synthesis of dimethoxyethane via directly catalytic
etherification of crude ethylene glycol
Weiqiang Yu,a Fang Lu,*, a Qianqian Huang, a, b Rui Lu, a, b Shuai Chena and Jie Xu* ,a
a. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese
Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, P.
R. China.
b. University of the Chinese Academy of Sciences, Beijing 100049, P. R. China
Potential diesel fuel additive of dimethoxyethane was highly selective produced by
etherification of crude ethylene glycol over SAPO-34.