Lipase-Catalyzed Esterification of Levulinic Acid in Solvent
Transcrição
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 0 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
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