Lipase-Catalyzed Esterification of Levulinic Acid in Solvent

Lipase-Catalyzed Esterification of Levulinic Acid
in Solvent-Free System under Batch and
Continuous Flow Conditions
Felipe Korbus Sutili* (PQ), Yasmin Furtado Ramalho (IC), Leandro Soter
de Mariz e Miranda (PQ), Rodrigo Octavio Mendonça Alves de Souza
(PQ).
Biocatalysis and Organic Synthesis Group, CT Bloco A, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro,
Brazil.*[email protected]
Keywords: levulinic acid, green chemistry, lipase.
INTRODUCTION
Ethyl levulinate is an important derivative of
levulinic acid synthesized by esterification of its
carboxyl group with ethanol. This ester has similar
biodiesel properties and a high power oxygenator
and can be used, for example, as an additive in
1
diesel engines . The levulinic acid comprises the
principles of green chemistry because it is an
organic compound derived from the conversion of
1
lignocellulosic biomass .
Lipase-catalyzed esterification have been
investigated as a potential substitute to the
traditional chemical, demanding milder reaction
conditions, allowing better reaction control and
1
providing higher-quality products .
In present research, we carried out the
esterification of levulinic acid with ethanol in a batch
reactor at atmospheric pressure in solvent-free
system. The best results obtained were translated to
a continuous flow environment. The esterification
reactions were performed by immobilized lipase B of
Candida antarctica (Novozym® 435), as well as
further optimization was done by experimental
design (CCRD) under batch.
RESULTS AND DISCUSSION
The solvent-free reactions were investigated in
batch system in 4 mL vials. In order to identify the
relevant variables, we purposed an experimental
design (CCRD) that investigated the best amount of
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enzyme (10-450 mg), temperature (25-75 C) and
molar ratio ethanol:acid (1:1 – 7:1). Conversion rates
were measured by gas chromatography/mass
spectroscopy (GC/MS). As a result, the lipase
catalyzed under batch condition showed conversion
rate 83.4%, in 90 minutes (Figure 1).
Aiming to reduce the reaction time and improve
the productivity, we decided to reproduce under
continuous flow conditions, the best results of batch
system. The achieved conversions are shown on
table 1.
Figure 1. Response surface for the esterification
reaction lipase-catalyzed under batch system.
Table 1. Conversion rates obtained under continuous flow
for the esterification reaction lipase-catalyzed.
Flow Rate (raction time)
0.1 ( 46.8 min)
0.5 ( 9.36 min)
1 ( 4.68 min)
1.5 ( 3.12 min)
2 ( 2.34 min)
Conversion (%)
91,9
91,3
90,8
88,3
84,7
According to the experiments, very similar results
could be obtained between 0.1 and 1.5 mL/min,
allowing higher productivity under shorter residence
times (3.12 minutes).
CONCLUSION
In conclusion we have developed a batch and
continuous flow approach to the synthesis of ethyl
levulinate. The results indicated continuous flow as
the best system for the ester production, leading to
high conversions in shorter residence times.
ACKNOWLEDGEMENTS
We thank FAPERJ (Fundação Carlos Chagas Filho
de Amparo à Pesquisa do Estado do Rio de Janeiro)
REFERENCES
1
Lee, A.; Chaibakhsh, N.; Basyaruddin, M.; Basri, M.; Tejoa, A.,
Optimized enzymatic synthesis of levulinate ester in solvent-free system
Industrial Crops and Products, 2010, 32, 246–251.
VII Workshop on Biocatalysis and Biotransformations and 1o Simposio Latinoamericano de Biocatalisis y Biotransformaciones