Synthesis of renewable diesel with 2-methylfuran and angelica lactone derived from carbohydrates

Article abstract of DOI:10.1039/c5gc02333e

Diesel and jet fuel range branched alkanes were first synthesized by the combination of hydroxyalkylation/alkylation (HAA) of 2-methylfuran with angelica lactone and subsequent hydrodeoxygenation. Compared with the previous ethyl levulinate route, the angelica lactone route exhibited evident advantages at higher HAA reactivity.

Full text of DOI:10.1039/c5gc02333e

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Synthesis of renewable diesel with 2-methylfuran
and angelica lactone derived from carbohydrates†
Cite this: DOI: 10.1039/c5gc02333e
Wei Wang,a,b Ning Li,*a,c Shanshan Li,a,d Guangyi Li,a Fang Chen,a,d Xueru Sheng,a,d
Received 29th September 2015,
Accepted 8th December 2015
Aiqin Wang,a,c Xiaodong Wang,a Yu Conga and Tao Zhang*a,c
DOI: 10.1039/c5gc02333e
www.rsc.org/greenchem
Diesel and jet fuel range branched alkanes were first synthesized alkanes can be prepared by the base catalysed dimerization
by the combination of hydroxyalkylation/alkylation (HAA) of and trimerization of angelica lactone, followed by HDO.11 To
2-methylfuran with angelica lactone and subsequent hydrode- the best of our knowledge, there is no report about the HAA of
oxygenation. Compared with the previous ethyl levulinate route, 2-MF and angelica lactone, let alone the utilization of the HAA
the angelica lactone route exhibited evident advantages at higher product as the precursor for the synthesis of diesel or jet fuel
HAA reactivity.
range branched alkanes. In this work, the HAA of 2-MF and
angelica lactone was carried out, for the first time, over a
series of acid catalysts. The HAA product was further hydro-
genated and hydrodeoxygenated to diesel and jet fuel range
alkanes over active carbon loaded noble metal catalysts.
The HAA of 2-MF and angelica lactone was carried out over
a series of acid catalysts under mild conditions (323 K) (see
Fig. 1–3). From the analysis of GC-MS and NMR (see Fig. S1–S3
in the ESI†), 4,4-bis(5-methylfuran-2-yl) pentanoic acid (i.e. 1a in
Scheme 1) was identified as the main product from the conden-
sation of 2-MF and angelica lactone. According to its chemical
structure, compound 1a as obtained can be used as a potential
precursor for diesel and jet fuel range branched alkanes.
As a solution to the energy and environment problems we are
facing today, the catalytic conversion of abundant, inedible
and renewable lignocellulosic biomass to fuels1 and chemi-
cals2 has drawn a lot of attention. Diesel and jet fuels are
two kinds of often used transportation fuels. Following the
pioneering work of Dumesic,3 Huber4 and Corma groups,5,6 tre-
mendous efforts have been devoted to the synthesis of jet fuel
range alkanes with lignocellulose derived platform compounds.7
2-Methylfuran (2-MF) is the selective hydrogenation product
of furfural which has been manufactured on the industrial
scale by the hydrolysis–dehydration of the hemicellulose part
of agricultural waste and forest residues.8 In the past few years,
several routes have been developed by the hydroxyalkylation/
alkylation (HAA) of 2-MF and lignocellulose derived carbonyl
compounds (such as furfural, 5-hydroxymethylfurfural,
butanal, acetone, hydroxyacetone, cyclopentanone, etc.), fol-
lowed by hydrodeoxygenation (HDO).5,9,10 Angelica lactone is
the dehydration product of lignocellulose derived levulinic
acid. Recently, it was found that gasoline and diesel range
The catalytic performances of several Brønsted acids for the
HAA of 2-MF and angelica lactone were studied. As shown in
aState Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian 116023, China. E-mail: taozhang@dicp.ac.cn,
lining@dicp.ac.cn; Fax: (+) 86 411 84691570; Tel: (+) 86 411 84379015
bShaanxi Key Laboratory of Catalytic Basis and Application, School of Chemical &
Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi 723001,
China
cCollaborative Innovation Center of Chemistry for Energy Materials (iChEM),
Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023,
China
dGraduate University of Chinese Academy of Sciences, Beijing 10049, China
†Electronic supplementary information (ESI) available: Detailed information of
Fig. 1 Conversions of angelica lactone (white bars) and the carbon
yields of 1a (black bars) under the catalysis of different Brønsted acids.
Reaction conditions: 323 K, 1 h; 0.98 g (10 mmol) angelica lactone,
1.68 g (20 mmol) 2-methylfuran (2-MF) and 0.05 g catalyst.
the preparation of catalysts and activity test, the GC-MS chromatogram and NMR
spectra of the HAA product, and the GC-MS chromatogram of the hydrogenated
HAA product. See DOI: 10.1039/c5gc02333e
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Table 1 Dissociation constant (pKa) values of the different Brønsted
acids12 used in HAA of 2-MF and angelica lactone
Catalyst
pKa
Triflic acid
H2SO4
H3PO4
0.52
1.99
2.16
4.76
CH3COOH
to the acid strength of the catalyst. A strong acid is more active
than a weak acid for this reaction. Furthermore, we also
studied the influence of the acid type on the HAA of 2-MF and
angelica lactone. From Fig. 2, we can see that the HAA of 2-MF
and angelica lactone can also be catalysed by some well-known
Lewis acid catalysts (such as FeCl3, SnCl4, ZnCl2 and TiCl4).
Based on the above results, we believe that both Brønsted
acids and Lewis acids have a promotion effect on the HAA of 2-
MF and angelica lactone.
Fig. 2 Conversions of angelica lactone (white bars) and the carbon
yields of 1a (black bars) under the catalysis of different Lewis acids.
Reaction conditions: 323 K, 1 h; 0.98 g angelica lactone, 1.68 g 2-MF,
and 0.1 g catalyst.
To avoid the corrosion and environmental problems which
may be caused by the utilization of liquid acids or metal chlor-
ides, we also explored the possibility to use a solid acid as the
catalyst for the HAA of 2-MF and angelica lactone. To do this,
we chose Nafion-212, Amberlyst-15 and Amberlite IRC 76CRF
as the representatives for solid acid catalysts with strong
acidity, medium strong acidity and weak acidity. According to
Fig. 3, the activities of the acidic resins decrease in the order
of Nafion-212 > Amberlyst-15 > Amberlite IRC 76CRF. This can
be explained by the chemical structure of these acidic resins.
As we know, Nafion is a perfluorinated sulfonic acid resin,
which is often denoted as a superacid.13 Amberlyst is a sulfo-
nic-acid-functionalized cross-linked polystyrene resin.14
However, Amberlite IRC 76CRF is a high capacity weakly acidic
cation exchange resin containing the carboxylic functionality
within a porous crosslinked acrylic matrix.15 In Nafion resins,
the acid strength of the SO3H group is enhanced by the pres-
ence of fluorine, which makes its acid strength higher than
the Amberlyst resin. Meanwhile, the SO3H group has a higher
acid strength than that of the COOH group. Due to these
reasons, the Nafion resin exhibits the highest activity for the
HAA of 2-MF and angelica lactone among the investigated
solid acid catalysts.
Fig. 3 Conversions of angelica lactone (white bars) and the yields of 1a
(black bars) over different acidic resins. Reaction conditions: 323 K; 1 h;
0.98 g angelica lactone, 1.68 g 2-MF and 0.1 g catalyst.
In the previous work of our group,9 it was found that the
Nafion-212 resin is also active for the HAA of 2-MF with levuli-
nic acid or ethyl levulinate. Compared to these compounds,
angelica lactone is more reactive in the HAA reaction with 2-
MF. Under the same reaction conditions, evidently a higher
carbon yield of the HAA product (81.3% vs. 12.0% and 4.8%)
can be achieved when angelica lactone was used as the feed-
stock (see Fig. 4). This can be considered as the advantage of
our new route. The higher reactivity of angelica lactone can be
rationalized by the competitive adsorption of water which will
be generated in the HAA of 2-MF and levulinic acid or ethyl
levulinate (see Scheme 2). As we know, water is a Lewis base.
Therefore, it can compete with 2-MF, levulinic acid or ethyl
levulinate for adsorption to the acid sites on the Nafion-212
Scheme 1 Reaction pathway for the synthesis of diesel and jet fuel
range alkanes with 2-methylfuran (2-MF) and angelica lactone (AL).
Fig. 1, the angelica lactone conversion and the carbon yield of
1a decrease in the order of triflic acid > sulphuric acid > phos-
phoric acid > acetic acid. This sequence is consistent with the
acid strength of these acids which is indicated by their dis-
sociation constants (pKa) listed in Table 1. From this result, we
can see that the HAA of 2-MF and angelica lactone is sensitive
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■
●
Fig. 4 Conversions of angelica lactone, ethyl levulinate or levulinic acid
(white bars) and the carbon yields of the corresponding HAA products
(see Scheme 2) (black bars). Reaction conditions: 323 K, 1 h; 1.68 g
(20 mmol) 2-MF, 10 mmol angelica lactone, ethyl levulinate or levulinic
acid and 0.1 g Nafion-212 resin.
Fig. 5 Conversion of angelica lactone ( ) and the carbon yield of 1a (
)
as a function of catalyst dosage. Reaction conditions: 323 K, 1 h; 0.98 g
angelica lactone and 1.68 g 2-MF.
Scheme 2 Reaction pathways for the synthesis of diesel and jet fuel
precursors by the HAA reactions between 2-MF and levulinic acid, ethyl
levulinate or angelica lactone.
■
●
)
Fig. 6 Conversion of angelica lactone ( ) and the carbon yield of 1a (
as a function of reaction temperature. Reaction conditions: 1 h; 0.98 g
angelica lactone, 1.68 g 2-MF and 0.1 g Nafion-212 resin.
resin. To verify this hypothesis, we studied the effect of water
on the catalytic performance of the Nafion-212 resin for the
HAA of 2-MF and angelica lactone. As we expected, the pres-
ence of stoichiometric water (the molar ratio of angelica
lactone to water is 1 : 1) significantly restrains the HAA of 2-MF
and angelica lactone (see Fig. S4 in the ESI†).
The effects of reaction conditions (such as catalyst dosage,
reaction temperature and reaction time) on the carbon yield of
1a over the Nafion-212 resin were investigated. According to
the results shown in Fig. 5–7, there is an optimum value for
the catalyst dosage, reaction temperature and reaction time,
respectively. The highest carbon yield of 1a (81.3%) was
achieved over 0.1 g Nafion-212 resin after reacting at 323 K for
1 h.
The reusability of the Nafion-212 resin was also studied. To
do this, the Nafion-212 resin was repeatedly used under the
optimum conditions (0.1 g catalyst, 323 K, 1 h). To exclude the
disturbance of the residues (including the HAA product,
■
●
)
Fig. 7 Conversion of angelica lactone ( ) and the carbon yield of 1a (
as a function of reaction time. Reaction conditions: 323 K; 0.98 g angel-
ica lactone, 1.68 g 2-MF and 0.1 g Nafion-212 resin.
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unreacted angelica lactone and 2-MF) on the used catalysts, tetrahydrofuran)
and
bis(5-methyltetrahydrofuran-2-yl)
the catalyst was washed thoroughly with 10 wt% hydrogen per- methane (i.e. 1c and 1d in Scheme 3) were also detected in the
oxide at 353 K for 2 h after each usage and dried at 353 K for hydrogenation product. These compounds may be generated
2 h. From the results illustrated in Fig. 8, the Nafion-212 resin by the hydrogenolysis of 1a.
is very stable under the investigated conditions. The carbon
After removal of methanol by vacuum distillation, the
yield of 1a over the Nafion-212 resin varied a little even after mixture of 1b, 1c and 1d was used in the solvent-free HDO
being used for 6 times (the slight decrease after the third run process. According to the analysis of GC and GC-MS, 1b, 1c
may be rationalized by the loss of the catalyst during the fil- and 1d were completely converted to alkanes over the activated
tration and drying process). Taking into account the high carbon loaded noble metal (Pt, Pd and Ru) catalysts at 623 K
activity and good stability of the Nafion-212 resin in the and 6 MPa H2. As we can see from Fig. 9, higher carbon yields
HAA of 2-MF and angelica lactone, we believe that it may be a of diesel and jet fuel range alkanes (81.0% and 81.6%) can be
promising catalyst in future application.
achieved over the 5 wt% Pt/C and 5 wt% Pd/C catalysts than
As the final aim of this work, we also investigated the that over the 5 wt% Ru/C catalyst (60.4%). Moreover, it is also
hydrodeoxygenation (HDO) of 1a from the HAA of 2-MF and noticed that the carbon yield of C1–C4 light alkanes over the
angelica lactone. Because 1a as obtained is a liquid with high 5 wt% Ru/C (25.1%) is evidently higher than those over the Pt/
viscosity, it is difficult to be delivered by an HPLC pump. As a C (1.3%) and Pd/C (1.6%) catalysts. Based on this result, we
solution to this problem, 1a was hydrogenated before being can attribute the lower selectivity of diesel and jet fuel range
used in the HDO process. The hydrogenation was carried out alkanes over the Ru/C catalyst to the higher activity of Ru for
over the 5 wt% Pd/C catalyst with the 30 wt% methanol solu- hydrogenolysis or methanation (leading to the generation of
tion of purified 1a. From the GC-MS analysis of the hydrogen- C1–C4 light alkanes).16 Taking into account the relatively lower
ation product (see Fig. S5–S8 in the ESI†), 1a was completely price of Pd than that of Pt, we think Pd/C is a promising HDO
converted after being hydrogenated at 433 K and 6 MPa H2. catalyst in future application.
4,4-Bis(5-methyl-tetrahydrofuran-2-yl)pentan-1-ol (i.e. 1b in
The stability of the Pd/C catalyst in the HDO process was
Scheme 3) was identified as the main product from the hydro- also investigated. From the result shown in Fig. 10, we can see
genation of 1a. Besides 1b, 5,5′-(ethane-1,1-diyl)bis(2-methyl- that the Pd/C catalyst is stable under the investigated con-
ditions. No evident decrease of activity was observed during a
24 h continuous test. The density and freezing point of the
alkane products from the HDO process over the Pd/C catalyst
were measured as 0.786 g mL−1 and 173 K, respectively.
According to the literature, levulinic acid can be obtained
from the hydrolysis–dehydration of cellulose at a high molar
yield of ∼61%, while furfural can be produced by the hydro-
lysis–dehydration of hemicellulose at
a carbon yield of
∼56%.17 The angelica lactone can be synthesized by the dehy-
dration of levulinic acid at a carbon yield of 90–97%.11 2-MF
can be prepared by the selective hydrogenation of furfural over
Fig. 8 Conversion of angelica lactone (white bars) and the carbon yield
of 1a (black bars) as a function of recycle time. Reaction conditions:
323 K, 1 h; 0.98 g angelica lactone, 1.68 g 2-MF and 0.1 g Nafion-212
resin.
Fig. 9 Carbon yields of C9–C15 diesel range alkanes (black bars), C5–C8
gasoline range alkanes (grey bars), and C1–C4 light alkanes (white bars)
over active carbon loaded noble metal catalysts. Reaction conditions:
Scheme 3 Reaction pathway for the generation of different products
from the hydrogenation of 1a over the 5 wt% Pd/C catalyst. Reaction
conditions: 433 K, 6 MPa H2, 1.8 g catalyst; liquid feedstock flow rate of
623 K, 6 MPa, 1.8 g catalyst; liquid feedstock flow rate 0.04 mL min−1
,
0.16 mL min−1; H2 flow rate of 120 mL min−1
.
hydrogen flow rate: 120 mL min−1
.
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new strategy for the synthesis of diesel and jet fuel range
branched alkanes with the platform chemicals from the
hydrolysis–dehydration products of both hemicellulose and
cellulose.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (no. 21106143; 21277140; 21476229;
2156213), a 100-talent project of Dalian Institute of Chemical
Physics (DICP) and the Research Programs Foundation of
Shaanxi University of Technology (no. SLGQD13(2)-1).
■
Fig. 10 Carbon yields of C9–C15 diesel range alkanes ( ), C5–C8 gaso-
line range alkanes ( ), and C1–C4 light alkanes ( ) over the Pd/C catalyst
as a function of time on stream. Reaction conditions: 623 K, 6 MPa, 1.8 g
catalyst; liquid feedstock flow rate 0.04 mL min−1, hydrogen flow rate:
Notes and references
120 mL min−1
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