Síntese enzimática do biodiesel de Jatropha curcas pela rota etílica

Abstract

The expected increase in the biodiesel demand worldwide has brought a constant evolution in its production system in order to make it more efficient and environmentally favorable. The objective of present work was to verify the potential of Jatropha oil as raw material to produce biodiesel by enzymatic route using ethanol as acilant agent. To attain the proposed objective, the experimental activities were starting by treating the oil to attain suitable properties to be used in the transesterification reaction, including the degumming, neutralization and drying steps. The treated oil, after physico-chemical characterization was used to carry out a screening test to select the most suitable biocatalyst by means of testing different preparations of lipases (EC 3.1.1.3) in free form as well as immobilized in SiO 2-PVA, to mediate the biodiesel synthesis in solvent free system. The assays indicated that the immobilized lipases were more efficient than free ones and allowed selecting the immobilized derivatives from Burkholderia cepacia and Pseudomonas fluorescens as the most suitable preparations to catalyze biodiesel synthesis from Jatropha oil, attaining yields of 93.18% and 85.67%, respectively. In the second step, the selected immobilized derivatives were used to catalyze the reaction of interest maintaining the previous set conditions (temperature 45 o C, 1:9 molar ratio oil/ethanol and 500 units of lipolytic activity per gram of oil) using a glass reactor coupled with condenser to avoid ethanol loss. The reaction was monitored by determining the formed ethyl esters by gas chromatography and viscosity in samples taken from the reactor during the reaction. The transesterified product (biodiesel) was purified and submitted to further analyses for physico-chemical properties, including rheological study, FTIR, TG and 1 H NMR. The obtained results confirmed that the lipase from Burkholderia cepacia was the most efficient biocatalyst to mediate the biodiesel synthesis from Jatropha oil, attaining transesterification yields higher than 97% (72h. The product biodiesel was thermo stable up to 128 o C and no residual glycerol or water contaminations were detected, assuring the efficiency of the down stream process. Additional experiments were performed under microwave irradiation and the results suggested that the microwave heating constitutes a potential procedure to enhance the reaction rate by reducing the global reaction time. The operational stability of the immobilized lipase was determined in repeated batch runs under conventional and microwave heating systems, revealing biocatalyst half-life time of 110 and 26.5 h, respectively. Therefore, the real contribution of the microwave irradiations to enhance the reaction should be revalued by taking into account the lost of the biocatalyst activity.

Simulação numérica da síntese de Biodiesel a partir do óleo de Pinhão Manso em microcanais

“…Umas das mais promissoras atualmente são as do gênero Jatropha, em destaque a espécie curcas (Nazir et al, 2009). A planta Jatropha curcas (Pinhão Manso no Brasil) além de ter o seu óleo utilizado para produção de biocombustíveis, tem aplicações farmacêuticas, médicas, inseticida, fabricação de sabão entre outras (Souza, 2010;Arruda et al, 2004).…”

Síntese de biodiesel em microcanais

“…As propriedades físicas do óleo e do etanol a 40 °C são apresentadas na Tabela 3.2. Essa temperatura foi escolhida com base na temperatura dos ensaios experimentais de Souza (2010) sobre as propriedades físico-químicas do óleo de Pinhão Manso. A reação de transesterificação consiste de uma série de reações consecutivas e reversíveis (Equações 3.19-3.21), e na presença de catalisador básico ocorre a reação de triglicerídeos (TG) com álcool (A) formando diglicerídeos (DG) e etil estér (E).…”