- Extraction process of sulfur compounds from fuels with protic ionic liquids
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Sulfur compounds in fuels are hazardous to the environment and present a great challenge. In this study, a series of protic ionic liquids (PILs) was designed, such as N,N-dimethyl-N-cyanoethyl ammonium butyrate ([DMAPN]+[Bu]-), N,N-dimethyl-N-cyanoethyl ammonium propionate ([DMAPN]+[Pr]-), N,N-dimethyl-N-cyanoethyl ammonium acetate ([DMAPN]+[Ac]-), N,N-dimethyl-N-cyanoethyl ammonium formate ([DMAPN]+[Fo]-), N,N-dimethyl-N-(2-(2-hydroxyethoxy)) ammonium propionate ([DMEE]+[Pr]-), N,N-dimethyl-N-hydroxyethyl ammonium propionate ([DMEA]+[Pr]-), N,N-dimethyl-N-hydroxyethyl ammonium acetate ([DMEA]+[Ac]-), N,N-dimethyl-N-hydroxyethyl ammonium formate ([DMEA]+[Fo]-), N,N-dimethyl-N-butyl ammonium acetate ([DMBA]+[Ac]-), N-methyl-N-hydroxyethyl ammonium propionate ([MEA]+[Pr]-), and N-methyl-N-hydroxyethyl ammonium acetate ([MEA]+[Ac]-), and their extraction desulfurization capability was evaluated. Through selection, two PILs were chosen to optimize the desulfurization process. The results showed that benzothiophene (BT) and thiophene (T) can be removed using PILs effectively. Both cations and anions have an influence on the extraction efficiencies. However, cations have a greater influence on the desulfurization process. Under optimal conditions, the extraction efficiency can be higher than 80% for one cycle. After 6-8 cycles, the removal efficiency could reach up to 99.5%. It is worth noting that the PILs could be recycled via simple vacuum distillation. After 4 times of recycling, the desulfurization efficiency changed slightly. Finally, a mechanistic study shows that hydrogen bonding interactions between the sulfur atom and active hydrogen of the PILs account for the high desulfurization efficiency. This green process would provide a new route for the extraction desulfurization of fuels. This journal is
- Li, Zhuo,Xu, Jinggang,Li, Dan,Li, Changping
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- Hydroxyl ammonium ionic liquids as media for biocatalytic oxidations
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In this work, neoteric and biodegradable ionic liquids (ILs) based on various hydroxyl ammonium cations and formic acid anions have been used as media for biocatalytic oxidoreductions catalyzed by different metalloproteins. The effect of these ILs on the biocatalytic behavior and structure of solubilized enzymes was investigated using cytochrome c (cyt c) as a model protein. The use of IL-based media enhances the tolerance of cyt c against the denaturing effect of H2O2 and increases (up to 20 fold) its catalytic efficiency compared to that observed in buffer. This beneficial effect strongly correlates with the concentration of ILs used, as well as the chaotropicity of their cations. UV-vis, circular dichroism and Fourier transform infrared (FT-IR) spectroscopic studies indicated that, the effect of ILs on the catalytic behavior of cyt c could be correlated with slight structural changes on the protein molecule and/or perturbations of the heme microenvironment. The use of hydroxyl ammonium-based ILs as reaction media increased (up to 4-fold) the decolorization activity of cyt c. All ILs used were recycled and successfully reused three times indicating the potential application of these novel ILs as environmentally friendly media for biocatalytic processes of industrial interest.
- Papadopoulou, Athena A.,Tzani, Andromachi,Alivertis, Dimitrios,Katsoura, Maria H.,Polydera, Angeliki C.,Detsi, Anastasia,Stamatis, Haralambos
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p. 1147 - 1158
(2016/02/27)
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- Synthesis and structure-properties relationship studies of biodegradable hydroxylammonium-based protic ionic liquids
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In this work sixteen hydroxyl ammonium Protic Ionic Liquids derived from a proton transfer reaction between four different substituted amines and four different low molecular weight aliphatic and alicyclic carboxylic acids have been synthesized. The synthesized PILs were structurally characterized by NMR and FT-IR spectroscopy whereas two of their more important physicochemical properties namely viscosity and glass transition temperature (Tg) were evaluated. The effect of alkyl chain length and substitution on the anionic and cationic component of the PILs scaffold has been discussed for the studied properties. It seems that Tg values are mainly affected by the carboxylate anion structure whereas viscosity is controlled mainly by the structural features of the cationic part of the PILs. In order to estimate their environmental impact and reinforce their “green” character, biodegradation studies, as well as toxicity evaluation experiments have also been conducted. The synthesized PILs can be confidently labelled as green considering that they are not toxic or present low toxicity to the nauplii of the brine shrimp A. salina whereas they show biodegradability levels between 41–64%, according to the manometric respirometric method which measures the biological oxygen demand (BOD5) by microorganisms in order to degrade PILs via bio-oxidation in five days.
- Tzani, Andromachi,Elmaloglou, Marianthi,Kyriazis, Charalampos,Aravopoulou, Dionysia,Kleidas, Ioannis,Papadopoulos, Achilleas,Ioannou, Efstathia,Kyritsis, Apostolos,Voutsas, Epaminondas,Detsi, Anastasia
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p. 366 - 376
(2016/10/22)
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