- Synthesis of palladium nanoparticles supported on mesoporous n-doped carbon and their catalytic ability for biofuel upgrade
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We report a catalyst made of Pd nanoparticles (NPs) supported on mesoporous N-doped carbon, Pd@CN0132, which was shown to be highly active in promoting biomass refining. The use of a task-specific ionic liquid (3-methyl-1-butylpyridine dicyanamide) as a precursor and silica NPs as a hard template afforded a high-nitrogen-content (12 wt %) mesoporous carbon material that showed high activity in stabilizing Pd NPs. The resulting Pd@CN 0.132 catalyst showed very high catalytic activity in hydrodeoxygenation of vanillin (a typical model compound of lignin) at low H2 pressure under mild conditions in aqueous media. Excellent catalytic results (100% conversion of vanillin and 100% selectivity for 2-methoxy-4-methylphenol) were achieved, and no loss of catalytic activity was observed after six recycles.
- Xu, Xuan,Li, Yi,Gong, Yutong,Zhang, Pengfei,Li, Haoran,Wang, Yong
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- Correlation between lipophilicity of newly synthesized ionic liquids and selected: Fusarium genus growth rate
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The purpose of the present study was to examine the effectiveness of 23 different synthesized ionic liquids (ILs) on Fusarium culmorum and Fusarium oxysporum growth rate. The strategy of IL synthesis was a structural modification of ionic liquids through changing the polarity of imidazolium and pycolinium cations and replacing halide anions with well known antifungal anions (cinnamate, caffeate and mandelate). The findings clearly suggest that the type of alkyl chain on the cation is the most determining factor for IL toxicity. In order to examine how IL structure affects their toxicity towards Fusarium genus, lipophilic descriptor AlogP is calculated from density functional theory and correlated with Fusarium growth rate. All these results demonstrate the high level of the interdependency of lipophilicity and toxicity for investigated ILs towards the Fusarium genus. The data collected in this research suggest that the inhibitory influence of ILs is more pronounced in the case of F. oxysporum.
- Vrane?, Milan,Tot, Aleksandar,?osi?, Jasenka,Papovi?, Sne?ana,Pani?, Jovana,Gad?uri?, Slobodan,Jankovi?, Nenad,Vrande?i?, Karolina
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p. 19189 - 19196
(2019/07/04)
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- Ion pairing in 1-butyl-3-methylpyridinium halide ionic liquids studied using NMR and DFT calculations
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We present the 1H, 13C and 15N NMR chemical shifts of bulk ionic liquids based on 1-butyl-3-methylimidazolium (the cation also known as 1-butyl-3-picolinium) halides (Cl-, Br- and I-) and tribromide (Br3-) salts. A characterization in solution of the analogous ICl2- and I3- salts is also reported. A series of DFT calculations has been run to predict the features of the NMR spectra of the pure ILs based on a few selected supramolecular ionic aggregates. To test the effect of temperature, and vibrational and conformational motions, only for the chloride salt, we also run first-principles molecular dynamics simulations of the ion pair in the gas phase, using the ADMP scheme (Atom Centered Density Matrix Propagation molecular dynamics model). The aim of our investigation is to test whether a simple DFT based approach of ion-pairing in ionic liquids is capable of providing reliable results and under which conditions the protocol is robust. We obtained a very good agreement between the calculated and experimental spectra for the three halides, where the bulk structure of the ILs is dominated by H-bond interactions between the X- anion (X = Cl, Br and I) and the ortho protons of the pyridinium ring (a structural arrangement not too different from the solid-state structure of pyridinium halides). In contrast, when the H-bond is weak, as in the Br3- case, a number of supramolecular arrangements exist in solution and the simple DFT calculations of a few selected cases cannot exhaustively explore the complete energy landscape. Moreover, the dynamic effects due to thermal motion, evaluated by ADMP MD simulations of the chloride salt, appear to be not very significant.
- Swamy, Vincent P.,Thulasiram, Hirekodathakallu V.,Rastrelli, Federico,Saielli, Giacomo
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p. 11470 - 11480
(2018/05/14)
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- N-doped hierarchical porous carbon anchored tiny Pd NPs: A mild and efficient quinolines selective hydrogenation catalyst
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Chemoselective hydrogenation of quinolines is often subjected to the problems of leaching and poisoning of catalytic active site as well as harsh reaction conditions. Developing a novel and high-performance heterogeneous catalyst is of paramount importance yet a huge challenge. Herein, we report a facile and efficient strategy for preparing the large surface area and highly N-doped hierarchical porous carbon anchored tiny Pd NPs catalyst, in which the low-cost chitosan, nitrogen-rich ionic liquids are served as composite precursors and KZ molten salt as friendly pore-forming agent. And a series of Pd@CIL-T (C refers to chitosan, IL refers to ionic liquid, T = 600–900 °C) catalysts are successfully fabricated via pyrolyzing aforesaid composites at different temperatures followed by anchoring the highly dispersed and small-sized Pd NPs on their surface. Among all the prepared catalysts, Pd@CIL-900 exhibits the optimal catalytic performance towards the selective hydrogenation of quinoline under extremely mild conditions (0.6 mol% Pd, 0.1 MPa H2 and 50 °C). The kinetic experiments further reveal that such hydrogenation is subject to a pseudo-first order reaction and the apparent activation energy is as low as 41.1 kJ/mol, demonstrating excellent hydrogenation reaction rate. Moreover, the catalytic activity and selectivity are well maintained even after being reused for fifth reaction cycles.
- Zhang, Fengwei,Ma, Chunlan,Chen, Shuai,Zhang, Jianfei,Li, Zhihong,Zhang, Xian-Ming
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p. 145 - 153
(2018/04/27)
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- Selective hydrogenation of phenol to cyclohexanone in water over PD@N-doped carbon derived from ionic-liquid precursors
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In this report, a kind of mesoporous N-doped carbon (CN-x) derived from N-containing ionic-liquid (IL) precursors were synthesized, and Pd@CN-x prepared by a simple ultrasound-assisted method showed higher catalytic activity for the selective hydrogenation of phenol and its derivatives under mild reaction conditions in water than commercial Pd@C and other common Pd heterogeneous catalysts. The catalytic activities of Pd@CN-x derived from different ILs were different, and further study into the influencing factors, including physical properties, N species of CN-x, and Pd status of Pd@CN-x, were performed. Being picky: N-Doped carbon (CN-x) derived from N-containing ionic-liquid precursors are used as Pd nanoparticle supports for the selective hydrogenation of phenol to cyclohexanone with high activity and selectivity under mild reaction conditions. The activities of the Pd@CN-x catalysts derived from a variety of ionic liquids are different, and studies on the physical properties, Pd status, and N species of the catalysts are performed.
- Xu, Xuan,Li, Haoran,Wang, Yong
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p. 3328 - 3332
(2015/04/16)
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- Nitrogen-containing ionic liquids: Biodegradation studies and utility in base-mediated reactions
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Several ionic liquids (ILs) were prepared in order to study the susceptibility of various cores and substituents to biodegradability using the 'CO2 headspace' test (ISO 14593). Several of the ILs contained tertiary amine substituents and were tested as solvents and reagents for several base mediated processes including Suzuki-Miyaura, Sonogashira, Knoevenagel, and Morita-Baylis-Hilman reactions. It was found that although these ILs contain basic functionality, they do not promote base mediated reactions. Density functional theory molecular calculations confirmed that the protonation of these ILs is energetically unfavourable. Journal compilation
- Ford, Leigh,Ylijoki, Kai E.O.,Garcia, M. Teresa,Singer, Robert D.,Scammells, Peter J.
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p. 849 - 857
(2015/06/23)
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- PROCESSES FOR PREPARING L-ALKYL-3-ALKYL-PYRIDINIUM BROMIDE AND USES THEREOF AS ADDITIVES IN ELECTROCHEMICAL CELLS
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The invention relates to the use of at least one l-alkyl-3- alkyl-pyridinium halide, in particular l-alkyl-3-methyl- pyridinium bromide, as an additive in bromine-generating electrochemical cells, such as zinc/bromine cells. Processes for preparing l-alkyl-3-methyl-pyridinium bromide and concentrated aqueous solutions comprising same for use as additives in the aforementioned cells, are also disclosed.
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Page/Page column 24
(2014/08/20)
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- Thermal properties of 1-alkyl-3-methylpyridinium halide-based ionic liquids
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This study was carried out for the comparison of thermal properties that determine various conditions and methods, including the differential scanning calorimetry (DSC), thermogravimetry (DTG) and the Bo?tius heated stage. Series of 1-alkyl-3-methylpyridinium chloride- and bromide-based ionic liquids having alkylic chain lengths ranging from C2 to C10 were synthesized, and their thermal characteristics were defined: glass transitions, melting and decomposition. Detailed thermal properties of ionic liquids, obtained in this work, can be useful in a variety of chemical engineering processes that are related with their application.
- Sashina, Elena S.,Kashirskii, Dmitrii A.,Janowska, Grazyna,Zaborski, Marian
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p. 185 - 188
(2013/10/08)
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- Synthesis and dissolving power of 1-Alkyl-3-methylpyridinium-based ionic liquids
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1-Alkyl-3-methylpyridinium-based ionic liquids with substituents from C2 to C10 and anions Cl- and Br- were synthesized, and their dissolving power toward the cellulose was investigated. The results of quantum-chemical calculations of molecules of ionic liquids are presented.
- Sashina,Kashirskii,Zaborski,Jankowski
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p. 1994 - 1998
(2013/06/04)
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- A convenient and efficient protocol for the synthesis of acylals catalyzed by Br?nsted acidic ionic liquids under ultrasonic irradiation
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The synthesis of acylals (1,1-diacetates) via the reactions of aldehydes with acetic anhydride was carried out in 85-97% yields at room temperature under ultrasound irradiation catalyzed by the Br?nsted acidic ionic liquid [bmpy]HSO4. This method provides several advantages, such as solvent-free conditions, operational simplicity, higher yields, and reduced environmental consequences. The ionic liquid was recovered and reused.
- Borikar, Sanjay P.,Daniel, Thomas
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scheme or table
p. 928 - 931
(2012/03/08)
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- Biodegradable pyridinium ionic liquids: Design, synthesis and evaluation
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A range of ionic liquids (ILs) with a pyridinium cation were synthesised and their biodegradability was evaluated using the CO2 Headspace test (ISO 14593). ILs bearing an ester side chain moiety were prepared from either pyridine or nicotinic acid and showed high levels of biodegradation under aerobic conditions and can be classified as 'readily biodegradable'. In contrast, pyridinium ILs with alkyl side chains showed significantly lower levels of biodegradability in the same test. The utility of the biodegradable IL 6c as a reaction solvent for the Diels-Alder reaction was also investigated.
- Harjani, Jitendra R.,Singer, Robert D.,Garcia, M. Teresa,Scammells, Peter J.
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experimental part
p. 83 - 90
(2010/04/22)
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