Publicação
Evaluation of Alkaline ionic liquids for catalysis of biodiesel from cooking oil
| Resumo: | Biodiesel production is performed in the industry by alkaline transesterification of oils with a low amount of free fatty acids. Aiming to minimize its production costs, low quality, or waste oils have been investigated as an alternative source of triacylglycerols. In order to reduce the disposal of conventional catalysts used industrially, ionic liquids (ILs) have been studied to be applied as catalysts in transesterification, since they can be recovered and reused in next reaction cycles. The main objective of this work was to investigate the application of alkaline type ionic liquids in the catalysis of transesterification reactions of mixtures of triacylglycerols. In the present work, the ionic liquid bis-(3-methyl-1-imidazole)-ethylene dihydroxide (IMC2OH) synthesis was carried out. The use of the IL choline hydroxide (ChOH) as a catalyst was evaluated in the production of biodiesel through a kinetic modelling study under the specific conditions of 2 wt.% catalyst dosage, 1:10 oil/methanol molar ratio, for the periods of 0, 10, 20, 30, 45, 60, 120, 240, 360, and 480 minutes at 65 ℃. A possible way to recover this IL from liquid-liquid extraction with water/butanol and water/ethyl acetate has been evaluated. Due to some challenges occurred in IMC2OH synthesis, the conversion obtained in the second step of synthesis was lower than expected. Transesterification with choline hydroxide presented 85.21% of conversion in FAME content in 30 minutes of reaction, and the results of the kinetic study which was carried out demonstrated that the second-order model was the best fit for the reaction with a rate constant (k) estimated as 0.2930 L.mol-1.min-1. From the recovery of the IL, it was possible to conclude that although there was some separation of it from the glycerol by the extraction with butanol and water, an amount of ChOH remained in glycerol phase. In conclusion, ChOH revealed an excellent capacity for fast transesterification. Thus, based on a more detailed study of the optimal reaction parameters for ChOH and subsequent application of the recovered amount of this ionic liquid in new reaction cycles, there is a strong indication that its reuse as a catalyst is technically feasible for the conversion of triacylglycerols, which enables its possible industrial application. |
|---|---|
| Autores principais: | Lima, Ana Carolina Coelho |
| Assunto: | Biodiesel production Transesterification Ionic liquids Imidazolium Choline hydroxide |
| Ano: | 2020 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | Biodiesel production is performed in the industry by alkaline transesterification of oils with a low amount of free fatty acids. Aiming to minimize its production costs, low quality, or waste oils have been investigated as an alternative source of triacylglycerols. In order to reduce the disposal of conventional catalysts used industrially, ionic liquids (ILs) have been studied to be applied as catalysts in transesterification, since they can be recovered and reused in next reaction cycles. The main objective of this work was to investigate the application of alkaline type ionic liquids in the catalysis of transesterification reactions of mixtures of triacylglycerols. In the present work, the ionic liquid bis-(3-methyl-1-imidazole)-ethylene dihydroxide (IMC2OH) synthesis was carried out. The use of the IL choline hydroxide (ChOH) as a catalyst was evaluated in the production of biodiesel through a kinetic modelling study under the specific conditions of 2 wt.% catalyst dosage, 1:10 oil/methanol molar ratio, for the periods of 0, 10, 20, 30, 45, 60, 120, 240, 360, and 480 minutes at 65 ℃. A possible way to recover this IL from liquid-liquid extraction with water/butanol and water/ethyl acetate has been evaluated. Due to some challenges occurred in IMC2OH synthesis, the conversion obtained in the second step of synthesis was lower than expected. Transesterification with choline hydroxide presented 85.21% of conversion in FAME content in 30 minutes of reaction, and the results of the kinetic study which was carried out demonstrated that the second-order model was the best fit for the reaction with a rate constant (k) estimated as 0.2930 L.mol-1.min-1. From the recovery of the IL, it was possible to conclude that although there was some separation of it from the glycerol by the extraction with butanol and water, an amount of ChOH remained in glycerol phase. In conclusion, ChOH revealed an excellent capacity for fast transesterification. Thus, based on a more detailed study of the optimal reaction parameters for ChOH and subsequent application of the recovered amount of this ionic liquid in new reaction cycles, there is a strong indication that its reuse as a catalyst is technically feasible for the conversion of triacylglycerols, which enables its possible industrial application. |
|---|