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Assessment of commercial acidic ion-exchange resin for ethyl esters synthesis from Acrocomia aculeata (Macaúba) crude oil

Pasa, Thiago Luiz Belo, Souza, Gredson Keiff, Diório, Alexandre, Arroyo, Pedro Augusto, Pereira, Nehemias Curvelo
Renewable energy 2020 v.146 pp. 469-476
Acrocomia aculeata, active sites, biodiesel, catalysts, esterification, esters, free fatty acids, fuel production, gas chromatography, ion exchange, ion exchange resins, oils, petroleum, porous media, pulp, response surface methodology, surface area, temperature
This study aimed to obtain ethyl esters (EEs) from macauba pulp crude oil, using heterogeneous-acid catalyst, varying the temperature of (trans)esterification, ethanol-to-oil molar ratio (MR) and catalyst content. Catalyst Amberlyst 15 characterization showed high concentrations of active sites of 3400 μmol g−1 and a surface area of 31.3 m2 g−1, which associated with the resin macroporous structure. A Central composite rotational design (CCRD) 2³ design and response surface methodology (RSM) were used to analyze the studied variables effects on the EEs production: temperature (80–180 °C), ethanol-to-oil MR (4–14) and catalyst Amberlyst 15 content (1–20 wt%). EEs formed were quantified by gas chromatography, and the RSM showed that the reaction presented EEs yields greater than 85% with a high index selectivity (817.4). The desirability procedure showed, that for both Free fatty acids (FFAs) conversion and EEs yield, the optimum conditions were the same, being 130 °C, ethanol-to-oil MR 9 and 16 wt% of catalyst. The biodiesel obtained was characterized and all the analyzed parameters agreed with the national biofuel-monitoring agency. The process conditions and the characterization of produced EEs showed that macauba crude pulp oil has good potential for biodiesel production using heterogeneous acid-catalyst.