Bio-oil is classified as second-generation biofuel and it is produced mainly through the pyrolysis of a waste lignocellulosic biomass base. The application of this product is still very limited, due to some of its chemical characteristics. This paper presents a proposal for the reduction of the acidity of bio-oil obtained from waste fish oil, previously produced and characterized as described in the literature, applying the reactive distillation process. This process is primarily based on the conversion of carboxylic acids into their corresponding esters by adding a widely available alcohol and a simple and cheap catalyst in the process for the fractional distillation of crude bio-oil to obtain light and heavy bio-oil, that is, fractions which are equivalent to the fossil fuels gasoline and diesel, respectively. The alcohols tested were methanol and ethanol and the catalysts were H2SO4, H3PO4, NaOH and Na2CO3, in proportions of 10 and 0.5 wt.%, respectively. The light bio-oil was obtained within a temperature range of 42 to 198 ºC with yields of 27.0 to 43.1% and the heavy bio-oil was recovered at 93 to 230 ºC with yields of 42.6 to 49.2%. The greatest acidity reduction was observed employing methanol+H2SO4 (95% and 43% for light and heavy bio-oils, respectively). The fractions produced were characterized by gas cromatography/mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID), applying the compound classification process PIONA (Paraffins, Iso-paraffins, Olefins, Naphtenes and Aromatics), revealing a homologous series of 1-alkenes and n-alkanes along with some aromatic compounds. The 1H and 13C NMR analysis showed that the process had no significant influence in relation to the carbons and hydrogens associated with the methyl, methylene, methyne and olefinic groups.

Nos poucos estudos publicados comparando óleos essenciais de espécimes femininos e masculinos de espécies Baccharis, fortes diferenças entre as composições de ambas as amostras foram sempre encontradas. Os experimentos realizados nesta pesquisa utilizam estratégias para minimizar a interferência de fatores genéticos e ecológicos. Os óleos essenciais das folhas de espécimes femininos e masculinos de cinco espécies Baccharis foram pesquisados com uso de um cromatógrafo gasoso acoplado a um espectrômetro de massas e a um detector de ionização de chama (CG-EM-DIC): B. caprariaefolia e B. dracunculifolia, já pesquisadas anteriormente com objetivos similares; e B. coridifolia, B. semiserrata var. elaegnoides e B. pentaptera, as duas últimas ainda não mencionadas na literatura química. Os resultados foram acompanhados por análise hierárquica de grupos, verificando-se a formação de grupos indicativos da grande similaridade entre óleos essenciais dos espécimes masculinos e femininos de todas as cinco espécies. O estudo reafirma o valor das observações de campo na pesquisa de produtos naturais, e aponta fatores genéticos e ecológicos como principais responsáveis por diferenças no metabolismo secundário das plantas estudadas.

In the few studies published on essential oils from female and male specimens of Baccharis species, strong differences between the compositions of both samples were always found. The experiments conducted in this study make use of strategies to minimize the interference from genetic and environmental factors. Essential oils from leaves of female and male specimens of five Baccharis species were investigated by gas chromatography-mass spectrometry plus flame ionization detector (GC-MS-FID): B. caprariaefolia and B. dracunculifolia, which have been previously studied with similar aims; and B. coridifolia, B. semiserrata var. elaegnoides and B. pentaptera, the latter two not yet mentioned in the literature. The results were followed by hierarchical cluster analysis, verifying the formation of groups indicative of the great similarity of essential oils from male and female specimens of all five species. The study reinforces the value of field observation in natural product research and points genetic and ecological factors as main responsible for differences in the secondary metabolites of the studied plants.