Browsing by Author "Tadevosyan, Arevik"
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- Biodiesel production through esterification using ionic liquids as catalystsPublication . Tadevosyan, Arevik; Roman, Fernanda; Queiroz, Ana; Ribeiro, António E.; Brito, PauloThere is a growing interest in the development of alternative technologies to the oil economy, based on renewable energy sources. A possible solution is a biofuel usable in compression-ignition engines, produced from biomass rich in fats and oils. Biodiesel is an alternative fuel that can be produced from a wide range of raw materials such as vegetable oils and animal fats. Yet, the use of sources that do not compete with the food market, like waste cooking oils - which usually feature high levels of free fatty acids (FFA’s) -, can lead to problems in the process of biodiesel production through alkaline transesterification. Ionic liquids (ILs) could be employed in the biodiesel production to partially overcome these problems; since they are able to catalyze the esterification reaction of FFA’s to biodiesel. In this work, experimental results will be presented concerning the study of the influence of ILs in the catalysis of esterification reactions of organic acids to the corresponding methyl esters. Different imidazolium-based ILs were tested for biodiesel production through an esterification reaction of oleic acid, using a previously optimized reaction methodology [1]: 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM][HSO4]), 1-butyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium methyl sulfate, 1-metylimidazolium hydrogen sulfate ([HMIM][HSO4]) and tributylmethylammonium methylsulfate. The experimental values obtained for the conversion of the oleic acid through an esterification reaction showed that the ionic liquid ([BMIM][HSO4]) would be one of the most promising catalysts. The recovery of the selected [BMIM][HSO4] ionic liquid was studied for different catalyst loading: 10, 15 and 20 wt% - relative to the mass of oleic acid. The reaction yield was determined by acidity using a titrimetric method (EN 14104). The composition characterization of the biodiesel samples (identification of fatty acid methyl esters) was evaluated by gas chromatography with FID detector (EN 14103). The obtained results confirm that it is possible to reuse [BMIM][HSO4] ionic liquid in successive reactions without great loss of yield and, thereafter, to significantly reduce the costs associated with the use of ILs as catalysts. Moreover, the esterification reaction with the [HMIM][HSO4] IL was also studied and further comparison of the methyl esters content obtained with each catalyst will be possible.
- Biodiesel production through esterification using ionic liquids as catalystsPublication . Tadevosyan, Arevik; Roman, Fernanda; Queiroz, Ana; Ribeiro, António E.; Brito, PauloThere is a growing interest in the development of alternative technologies to the oil economy, based on renewable energy sources. Biodiesel is an alternative fuel that can be produced from a wide range of raw materials such as vegetable oils and animal fats. Yet, the use of sources that do not compete with the food market, such as waste cooking oils - which usually feature high levels of free fatty acids (FFA’s) -, can lead to problems in the process of biodiesel production through alkaline transesterification. Ionic liquids (ILs) could be employed in the biodiesel production to partially overcome these problems; since they are able to catalyze the esterification reaction of FFA’s to biodiesel (FAMEs) as well as the transesterification reaction of triglycerides. Ionic liquids are also viable due to the fact that they can be easily recovered and recycled, decreasing their cost. Experimental results concerning the recyclability of the ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate [BMIM][HSO4] and its influence on the conversion of organic acids to biodiesel and the content of FAMEs will be presented
- Biodiesel production through ionic liquid catalysed esterificationPublication . Tadevosyan, Arevik; Queiroz, Ana; Ribeiro, António E.; Brito, Paulo; Hovhannisyan, NellyBiodiesel is an alternative fuel diesel that can be produced from vegetable oils and animal fats. There is a recent growing interest in the development of alternative technologies to the oil economy, based on renewable energy sources. A possible solution is a biofuel usable in compression-ignition engines, produced from biomass rich in fats and oils. A wide range of raw materials can be used in the production of biodiesel. Nevertheless, the use of sources that do not compete with the food market like waste cooking oils, which usually feature high levels of free fatty acids (FFA’s), can put problems in the process of production of biodiesel through alkaline transesterification. These problems are partially overcome by the use of catalysts, such as ionic liquids (IL’s) that also promote reactions of esterification of FFA’s to biodiesel. Thus, the objective of this work consists in the study of the influence of IL's application in the catalysis of: esterification reactions of organic acids to the corresponding methyl esters. In the first part of the work the influence, as catalysts, of several ionic liquids in the esterification reaction of oleic acid was analyzed. The experimental conditions were as follows: reaction time 6 hours, oleic acid / methanol molar ratio = 1/10 and temperature 90 ° C. The ionic liquids evaluated were as follows: 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM][HSO4]), 1-butyl-3-methylimidazolium methanesulfonate ([BMIM][CH3SO3]), 1-butyl-3-methylimidazolium methylsulfate ([BMIM][CH3SO4]), 1-metylimidazolium hydrogen sulfate ([MIM][HSO4]) and tributylmethylammonium methylsulfate. The values obtained for the conversion of the oleic acid esterification reaction showed that the ionic liquid [BMIM] [HSO4] would be one of the most promising catalysts. In a second part of the work, the recovery of LI [BMIM] [HSO4] was studied and several esterification reactions of oleic acid were carried out using a quantity of catalyst of 10 wt%, 15 wt% and 20 wt% relative to the mass of oleic acid. The experimental conditions were as follows: reaction time 6 hours, oleic acid / methanol molar ratio = 1/10 and temperature 90 ° C. The reaction yield was found to be 76.6% to 10% IL, 83.3% to 15% IL and 84.8% to 20% IL. These yields decreased to 58.2% (10% IL) with 4 cycles of recycling, 75.2% (15% IL) with 5 cycles of recycling and 77.1% (20% IL) with 5 cycles of recycling. The results obtained confirm that it is possible to reuse this IL in successive reactions of esterification without great loss of yield and with this to significantly reduce the costs associated with the purchase of these compounds that are quite expensive.