Levulinic acid production from Cicer arietinum, cotton, Pinus radiata and sugarcane bagasse

Article abstract of DOI:10.1039/c4ra06246a

Levulinic acid is a key platform chemical. Even gasoline range chemicals could be produced from levulinic acid making it a strategically significant compound. Producing levulinic acid from biomass is attractive from economic as well as environmental aspec

Full text of DOI:10.1039/c4ra06246a

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Levulinic acid production from Cicer arietinum,
cotton, Pinus radiata and sugarcane bagasse†
Cite this: RSC Adv., 2014, 4, 44706
a
a
ab
*
Amudhavalli Victor, Indra Neel Pulidindi and Aharon Gedanken
Levulinic acid is a key platform chemical. Even gasoline range chemicals could be produced from levulinic
acid making it a strategically significant compound. Producing levulinic acid from biomass is attractive from
economic as well as environmental aspects. An acid catalyzed hydrothermal process for converting
biomass to levulinic acid is reported. The effect of biomass type, acid (HCl) concentration, and reaction
temperature of hydrothermal treatment on the conversion of biomass and yield of levulinic acid were
studied. Widely available cellulosic biomass and agricultural wastes, namely, Cicer arietinum, cotton,
Pinus radiata and sugarcane bagasse were successfully converted to levulinic acid. Although HPCL
analysis could not be performed, qualitative and quantitative analysis of levulinic acid was conducted
using 13C and 1H NMR spectroscopy. Under optimal reaction conditions (423 K, 1 M HCl, 2 h) the yields
of levulinic acid obtained from Cicer arietinum, cotton, Pinus radiata and sugarcane bagasse were 32.6,
44.0, 19.0 and 36.5 wt%.
Received 7th August 2014
Accepted 9th September 2014
DOI: 10.1039/c4ra06246a
www.rsc.org/advances
sodium dodecyl sulfate is revealed recently.13 Levulinic acid is a
potential sanitizer for large-scale food processing facilities.
The current market price of levulinic acid is 3.2 $ per kg.4 The
production of levulinic acid from saccharose was rst reported
by Mulder.14 As new applications of levulinic acid are being
explored, the demand for levulinic acid is also expected to grow.
To meet the growing demand for levulinic acid and to keep its
price in control newer feedstocks and strategies are being
explored as exemplied in Table 1.
1. Introduction
Levulinic acid (CH3COCH2CH2COOH) is a valuable bulk chem-
ical. The key factor that makes levulinic acid important is the
presence of two reactive functionalities, namely, the carboxylic
acid (–COOH) and the ketone (]CO) groups in the same mole-
cule. This structural advantage facilitates the transformation of
levulinic acid to various other chemicals (Scheme 1).1
In addition, levulinic acid is designated by FDS as generally
recognized as safe (GRAS) for specic uses in foods. Moreover,
the antibacterial activity of levulinic acid in combination with
Several patents were granted for levulinic acid production
processes owing to the commercial importance of this
chemical.22–24
Currently, the only semi-commercial levulinic acid
production unit is based on Bione process using tobacco
bagasse and paper mill sludge with H2SO4 as catalyst.20,25 In
spite of the use of efficient reactors as well as the polymeri-
zation inhibitors to reduce char formation, in the two stage
biomass conversion in Bione process the maximum levulinic
acid yield is 70–80 wt% of the theoretical maximum of 71.6
wt% from cellulose. This corresponds to the conversion of
nearly 50% by mass of C-6 sugars to levulinic acid, 20% to
formic acid and 30% to tars.26 Effective separation of levulinic
acid and the recovery of sulphuric acid are the major draw-
backs of the Bione process.25
Scheme
1 Reactivity of levulinic acid making it a key platform
chemical.2–12
Moreover, due to the availability in the close proximity to the
industry, tobacco bagasse and paper mill sludge were employed
as feedstocks. These feedstocks alone cannot make the levulinic
acid production process sustainable. Thus the objective of the
current work is to evaluate a variety of potential cellulosic
feedstocks, Cicer arietinum (CA), cotton, pine cones from Pinus
aDepartment of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel. E-mail:
gedanken@mail.biu.ac.il; Fax: +972-3-7384053; Tel: +972-3-5318315
bNational Cheng Kung University, Department of Materials Science and Engineering,
Tainan 70101, Taiwan
† Electronic supplementary information (ESI) available. See DOI:
10.1039/c4ra06246a
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Table 1 Strategies for levulinic (LV) acid production
Feed stock
Strategy
LV acid yield (wt%)
Reference
15
Bagasse & paddy straw
Hydrothermal process in a
22.8 & 23.7 wt% for bagasse and
paddy straw respectively
cylindrical pressurized steel reactor
(220 ꢁC, 45 min), HCl, 4.45 wt%
Hydrothermal process in a stainless
steel tubular reactor at 180 ꢁC for
48.22 min, H2SO4 (3 wt%)
Galactose (Gelidium amansi)
Sugar cane bagasse
Rice husk
42.88%
16
17
18
Hydrothermal reactor, 150 ꢁC, 6 h,
stainless steel oor stand reactor,
H2SO4 (0.55 M)
19.4 wt%
Hydrothermal reaction in a
stainless steel autoclave at 170 ꢁC,
56 bar, 60 min, HCl, (4.5 wt%)
Microwave irradiation at 110–190 ꢁC
for 10–50 min, HCl or H2SO4 (2 M)
Microwave assisted ash hydrolysis
at 225 ꢁC and 40 bar N2 pressure,
HCl (1 M)
59.4 wt%
Carbohydrates of plant and animal
origin
Tomato plant wastes (TPW),
cellulose and chitosan
31.8 wt% from D-fructose
19
20
63, 90 and 95 wt% from TPW,
cellulose and chitosan
Sweet sorghum
Microwave irradiation at 160 ꢁC for
30 min, H2SO4 (2 M)
31.4 wt% yield
21
radiata (PR) and sugar cane bagasse (SCB), that could make the
Experimental methods
levulinic acid production process sustainable.
The biomass conversion involving hydrolysis, dehydration and
rehydration reactions yielding levulinic acid, were carried out in
a cylindrical stainless steel reactor with polytetrauoroethylene
lined inside to resist corrosion by the acid catalyst. The
dimensions (thickness ꢀ internal diameter ꢀ depth) of the
stainless steel reactor are (8 ꢀ 42 ꢀ 70 mm) and that of the
internal PTFE lining are (3 ꢀ 32 ꢀ 40 mm) and the volume of
the reactor is 32 mL. Typical batch process comprise of taking
1.0 g of biomass in 20 mL of HCl (1–5 M) in the reactor. A
preheated air oven is used for heating the reactor to the desired
temperature (393 and 423 K). The reaction was quenched by
immersing the reactor in a cool water bath aer the desired
reaction time. The reaction product was collected and separated
from the unreacted residual biomass by ltration through a
Whatman® (150 MM F) lter paper. The residue is washed with
excess distilled water and dried overnight at 373 K and weighed.
The difference between the initial and nal weight of the
biomass is a measure of the amount of biomass converted to the
reaction products.27 The yield of levulinic acid (wt%) is calcu-
lated from the following equation based on the weight of the
raw material.16
2. Experimental
Materials used
The biomass used as cellulosic feedstocks for levulinic acid
production are shown in Fig. 1. Cicer arietinum (CA) is
obtained from the agricultural elds of Israel aer the harvest.
Cotton (D50) and sugar cane bagasse (SCB) were supplied by
Milouban Cotton Linters Pulp, MCP Ltd., Israel. Pine cones
fallen from the trees were collected from the Eli Cohen park
near Bar Ilan University, Israel. CA, SCB and PR were grounded
by a mechanical blunder and sieved with a USA standard
testing sieve to a mesh size of 250 mm and used subsequently.
Cotton is used as received.
Yield of levulinic acid (wt%) ¼ [levulinic acid content after
reaction (g)/Initial biomass content (g)] ꢀ 100.
Analysis of reaction products
Even though HPCL analysis could not be conducted, the
potential of 13C and 1H NMR spectroscopy was exploited for the
identication and estimation of levulinic acid. Reaction prod-
ucts from the biomass were analyzed by 13C NMR spectroscopy
Fig. 1 Cellulosic feedstocks used for levulinic acid production.
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for the conrmation of levulinic acid formation and identi-
1
cation of other by products. H NMR spectroscopy is used for
the quantication of levulinic acid using pyrogallol as internal
standard.21 D2O was employed as solvent. Typical sample for
analysis comprise of 400 mL of the analyte and 200 mL of the
solvent and known amount of pyrogallol. Spectral analysis was
carried out at room temperature. 13C and 1H NMR spectra were
recorded on Bruker Avance DPX 300.
3. Results and discussion
Girisuta et al., investigated the kinetics as well as the sequence
of reactions involved in the conversion of glucose to levulinic
acid.28 Acid hydrolysis of lignocellulosic biomass leads to the
conversion of the cellulose component to glucose. The glucose
generated isomerizes to fructose which is dehydrated in situ to
form the intermediate product, hydroxyl methyl furfural, which
subsequently undergoes hydration to form the decomposition
products, levulinic acid and formic acid.19,29,30 A series of
hydrolysis, dehydration and rehydration reactions involved in
the conversion of biomass to levulinic acid in the presence of an
acid catalyst are shown sequentially in Scheme 2.
Fig. 2 Effect of nature of biomass on the hydrolysis reaction (393 K;
1 M HCl; 1 h).
conversion are achieved in the case of CA (66%), PR (47.5%) and
bagasse (55.8%). In spite of the high conversion values, the
yields of levulinic acid are low. Hydrolysis at 393 K with 1 M HCl
yielded monosaccharides as major product. The presence of
monosaccharides in the hydrolyzate is shown in the 13C NMR
spectra (Fig. S1†). Jeong et al., observed minimum production of
levulinic acid under the optimum conditions (139.4 ꢁC, 3%
H2SO4, 15 min) for sugars and major amount of levulinic acid
Levulinic acid formation through HMF intermediate is
always accompanied by the formation of formic acid as a
byproduct, which is unavoidable imposing a theoretical limit of
64.4 wt% yield of levulinic acid from glucose.
ꢁ
production at higher reaction temperature (160 C) from Geli-
HCl is used as acid catalyst for the conversion of different
biomass, namely, Cicer arietinum (CA), cotton, Pinus radiata (PR)
and sugar cane bagasse. Use of HCl is based on the reports of
Bevilaqua et al., 2013 and Tabasso et al., 2014. HCl was reported
to be more efficient than H2SO4 for levulinic acid production.18
Among various mineral, acids based on the reactivity and
volatile nature, HCl is preferred.20 Solid acid catalysts are also
being vigorously investigated as possible alternative to mineral
acids for making the process environmentally friendly which is
outside the scope of the present study.27,31
dium amansi.32
To improve the reactivity of cotton and optimize the reaction
conditions for levulinic acid, production the concentration of
HCl is varied from 1 to 5 M with other conditions being the
same (393 K, 1 h). The effect of concentration of HCl on the
conversion of cotton and the yield of levulinic and formic acids
is shown in Fig. 3. Even the poorly reactive cotton showed a
steep raise in the conversion from 7.1 to 56.3 wt% as the HCl
concentration is increased from 1 to 5 M. Proportionately, the
Initially, the suitability of various biomasses for producing
levulinic acid is tested under mild hydrothermal reaction
conditions (393 K, 1 M HCl, 1 h). The values of conversion of
biomass, yield of levulinic and formic acids are depicted in
Fig. 2. The nature of the biomass was found to have signicant
effect on the conversion and levulinic acid yield. A sharp
contrast is observed in the conversion of cotton compared to
other biomasses, CA, PR and bagasse. The lowest value of
conversion (7.1 wt%) of cotton is due to the structural rigidity.
The mild conditions used for the hydrolysis could not
convert cotton effectively even though relatively higher values of
Scheme 2 Schematic representation of conversion of biomass to Fig. 3 Effect of concentration of acid on the conversion of cotton and
levulinic acid.
yields of levulinic and formic acids.
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yields of levulinic acid also increased from 4.7 to 19.8 wt%. Even investigated as feedstock for levulinic acid production, there
though there is an 8 fold increase in the cotton conversion, the have been no reports on the feasibility of conversion of stalks of
yield of levulinic acid is enhanced only by 4 fold with 5 M HCl. Cicer arietinum, cotton, and pine cones from Pinus radiata to
This different is attributed to the unreacted glucose in the levulinic acid. In principle the ratio (wt/wt%) of levulinic and
solution along with levulinic and formic acids. The presence of formic acids in the product hydrolyzate should be 2.5 as only
glucose was observed in the 13C NMR spectrum of the one molecule of formic acid is formed per each glucose mole-
hydrolyzate.
cule that is converted to levulinic acid. In the present context,
Even though the use of higher acid concentration improved the ratio (wt/wt%) of levulinic to formic acids is observed to be
the conversion of cotton and yield of levulinic acid, corrosion of in the range of 2.7–4.7 which is greater than the expected ratio.
industrial installations may limit the practical utility of the This indicates the possibility of additional pathways being
process. Alternately, the path way of increasing the reaction operative for the formation of formic acid from the biomass. In
temperature for improving the levulinic acid yield has also been particular, the hemicellulose (polymer of C5 sugars) yields
evaluated.
xylose whose decomposition yields formic acid.28 The excess
The variation in the conversion of different biomasses and formic acid in the product than the usual equimolar product
the yields of levulinic and fomic acids in the hydrolysis process distribution of levulinic and formic acid could be attributed to
carried out at 423 K is shown in Fig. 4.
the xylose degradation. To substantiate this, pure xylose was
A steep increase in the levulinic acid yields is achieved by subjected to acid hydrolysis under identical conditions and
raising the reaction temperature from 393 to 423 K (Fig. 2 & 4). formic acid formation as a by product in addition to the main
Cotton which has been poorly reactive at 393 K showed a dehydration product furfural is noticed.
conversion value of 78.7 wt% at 423 K and a levulinic acid yield
The formation of levulinic and formic acids as a result of the
of 44 wt%. This indicates that the reaction temperature has a hydrothermal treatment of biomass (423 K, 1 M HCl, 2 h) is
more signicant effect on biomass conversion rather than the revealed from the 13C NMR spectra shown in Fig. 5.
acid concentration. The effect of reaction temperature on rate of
Signals typical of levulinic acid are observed in the reaction
chemical reactions is well studied and it is known that for every products from the biomasses tested. The peaks corresponding
10 ꢁC raise in temperature the reaction rate is doubled. The to levulinic acid are indicated and assigned to particular carbon
enhancement in the conversion of biomass as a function of nuclei in the levulinic acid structure from which the signal is
temperature could be due to reduced hydrogen bonding inter- originating (Fig. 5).
actions that facilitate easy accessibility of acidic protons to the,
Signals characteristic of the two methylene groups one
reaction site b-(1 / 4)-glycosidic bonds. In fact, the extensive adjacent to the carbonyl and the other adjacent to the carboxyl
inter and intra molecular bonding hydrogen as well as the type are observed at 28.3 and 38.2 ppm. Signals typical of the methyl
of linking of the D-anhydro-glucopyranose prevailing in the group and the carboxyl groups are observed at 29.6 and 177.8
cellulose structure makes the hydrolysis of cellulose nearly 2 ppm. Peak corresponding to the carboxyl carbon of levulinic
orders of magnitude tougher than starch hydrolysis.
acid that appeared at 214.2 ppm is not included in the pre-
The levulinic acid yields from Cicer arietinum (CA), Pinus sented region of the spectra. The 13C NMR spectra of the levu-
radiata (PR) and sugar cane bagasse (SCB) are 32.6, 19 and 36.5 linic acid produced from biomass matched well with the
wt%, respectively, which are lower than the yield obtained from standard spectrum of levulinic acid (Spectral Database for
cotton (44 wt%). Even though sugar cane bagasse was widely Organic Compounds, SDBS, National Institute of Advanced
Industrial Science and Technology, Japan). Further, the 13C
NMR spectrum of the levulinic acid sample procured from
13
Fig. 5
C NMR spectra of hydrolyzate from, (a) Cicer arietinum (b)
Fig. 4 Conversion of biomass and yield of levulinic and formic acids at cotton and (c) Pinus radiata, (d) sugar cane bagasse at 423 K using 1 M
423 K.
HCL for 2 h.
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Sigma Aldrich is recorded and shown in Fig. S2.† The 13C NMR
signals of the levulinic acid produced from different biomass
are in accordance with the signals of commercial LA. This
indicates that the biomass tested are potential sources of levu-
linic acid with varying yields.
In addition to the peaks typical of levulinic acid, signals
characteristic of formic acid (166.3 ppm) and acetic acid (21
ppm) are also observed. The formic acid formation is due to the
decomposition reaction of glucose produced from biomass to
levulinic acid and formic acid in accordance with Scheme 2. The
source of acetic acid is the hemicellulose component that is
present in the lignocellulosic biomasses, Cicer arietinum, Pinus
radiata and sugar cane bagasse. Rackemann et al., 2014 and
Dussan et al., 2013 reported hemicellulose as the origin of
formation of acetic acid in biomass conversion.25,33 Moreover,
the acetic acid (21 ppm) peak is absent in the reaction product
obtained from cotton which is pure cellulose and devoid of
hemicellulose. This further authenticate that the acetic acid by
product is originating from the hemicellulose component in the
conversion of lignocellulosic biomass. In the case of Cicer
arietinum and cotton additional signals in the range of 60–100
ppm attributable to undegraded glucose are observed (Fig. 5(a)
and (b)).
Fig. 7 13C NMR spectra of (a) residue and (b) distillate separated from
the hydrolyzate obtained from sugar cane bagasse using
rotoevaporation.
Levulinic acid in pure form could be isolated from the
product mixture containing the reaction by products based on
the difference in the boiling points using rotoevaporation
(evaporation under reduced pressure) technique. The high
Levulinic acid produced from biomass is further conrmed
from 1H NMR analysis (Fig. 6). The appearance of a singlet
signal at 2.2 ppm (3H, s), two triplets at 2.38 (2H, t) and 2.65
(2H, t) ppm conrm the presence of levulinic acid. For
ꢁ
boiling point of levulinic acid (245 C) facilitates easy evapora-
tion of low boiling point by products (formic and acetic acids).
The reaction product obtained from the hydrolysis of sugar
cane bagasse is subjected to rotoevaporation (Laborota 4000-
efficient) at 70 ꢁC for 1 h. Reaction byproducts as well as water
were completely removed from the container leaving behind
levulinic acid.
The product aer the rotoevaporation as well as the distillate
obtained were analyzed using 13C NMR to evaluate the effec-
tiveness of isolation of levulinic acid (Fig. 7). Exclusive presence
of levulinic acid is observed in the residue when the hydrolyzate
is subjected to rotoevaporation (Fig. 7(a)). The distillate con-
tained acetic acid and formic acid (Fig. 7(b)).
1
comparison the H NMR spectrum of the authentic sample of
levulinic acid procured from Sigma Aldrich is shown in Fig. S3†
which matched well with the spectra of levulinic acid produced
from biomass (Fig. 6). Complementary to the presence of a peak
at 21 ppm in the 13C NMR spectra (Fig. 5) a signal at 1.9 ppm is
evident in the 1H NMR spectra of the reaction product from
biomass (Fig. 6). This peak corresponds to the formation of
acetic acid as by product. Moreover, the peak at 1.9 ppm is only
present in the product obtained from lignocellulosic biomasses
(Cicer arietinum, Pinus radiata and sugar cane bagasse) and is
absent in the hydrolyzate from cotton which is pure cellulose.
Rotoevaporation is thus a simple method for the isolation of
levulinic acid from the hydrolyzate of biomass.
4. Conclusion
The feasibility of levulinic acid production from Cicer arietinum,
cotton, Pinus radiata and sugar cane bagasse is demonstrated.
Among various biomasses studied, cotton showed highest yield
(44 wt%) of levulinic acid under modest reaction conditions.
Widely available agricultural wastes Cicer arietinum and sugar-
cane bagasse were economically viable and environmentally
benign feedstock yielding 32.6 and 36.5 wt% levulinic acid
respectively. Reaction temperature was found to be a crucial
parameter compared to the concentration of acid in the
conversion of biomass. Levulinic acid could be easily separated
from the product mixture comprising the reaction by products
formic and acetic acids using rotary evaporation. Hydrothermal
method offered a simple means for the production of levulinic
acid from biomass.
Fig. 6 1H NMR spectra of hydrolyzate from, (a) Cicer arietinum (b)
cotton and (c) Pinus radiata, (d) sugar cane bagasse at 423 K using 1 M
HCl for 2 h.
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16 M. Kang, S. W. Kim, J. W. Kim, T. H. Kim and J. S. Kim,
Renewable Energy, 2013, 54, 173.
Acknowledgements
17 B. Girisuta, K. Dussan, D. Haverty, J. J. Leahy and
M. H. B. Hayes, Chem. Eng. J., 2013, 217, 61.
18 D. B. Bevilaqua, M. K. D. Rambo, T. M. Rizzetti, A. L. Cardoso
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19 A. Szabolcs, M. Molnar, G. Dibo and L. T. Mika, Green Chem.,
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Gedanken thanks the Ministry of Science and Technology for
the research grant 3-9802 and the Israel Science Foundation for
supporting the research via a grant 12/586. The authors are
thankful to Milouban Cotton Linters Pulp, MCP Ltd., Israel for
providing the biomass samples.
20 S. Tabasso, E. Montoneri, D. Carnarogiio, M. Caporaso and
G. Cravotto, Green Chem., 2014, 16, 73.
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