scholarly journals Effect of Ionic Liquid Surfactants on Coal Oxidation and Structure

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Weiqing Zhang ◽  
Shuguang Jiang ◽  
Tong Qin ◽  
Jianfeng Sun ◽  
Chaowei Dong ◽  
...  

The effects of six ionic liquids with surfactant property (1-hydroxyethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide ([HOEtMIm][NTf2]), 1-hydroxyethyl-3-methyl imidazolium tetrafluoroborate ([HOEtMIm][BF4]), 1-dodecyl-3- methyl imidazolium bromide ([C12MIm]Br), 1-tetradecyl-3- methyl imidazolium bromide ([C14MIm]Br), trioctyl methyl ammonium chloride ([N8,8,8,1])Cl, and tetraethyl ammonium chloride ([N2,2,2,2]Cl)) on the oxidation characteristics and functional groups of coal were studied by means of critical micelle concentration, surface tension, thermogravimetric analysis, temperature-programmed oxidation, and Fourier transform infrared spectroscopy (FTIR) measurements. The lower critical micelle concentration for the ionic liquids except the [N2,2,2,2]Cl suggests the favorable surface activity of these ionic liquids. The surface activities of [N8,8,8,1]Cl, [C14MIm]Br, [C12MIm]Br, and [HOEtMIm][NTf2] were high, while that of [N2,2,2,2]Cl was relatively lower. The thermal stabilities of [HOEtMIm][NTf2] and [HOEtMIm][BF4] were high, while those of [N8,8,8,1]Cl and [N2,2,2,2]Cl were lower. The oxidation activities of ionic liquid-mixed coals were weakened to different degrees except [N8,8,8,1]Cl-mixed coal, because of the poor thermal stability and decomposition of [N8,8,8,1]Cl accelerating the coal oxidation. The other five ionic liquids were suitable for inhibiting coal oxidation, particularly the [HOEtMIm][BF4] and [HOEtMIm][NTf2] with higher inhibition rate, longer inhibition time, and also better thermal stabilities. The activation energy results further confirmed such inhibition effect. The functional group results showed that treatment of ionic liquids on coal can change the contents of hydrogen bonds, aliphatic groups, and aromatic groups in coal. It was inferred that the [HOEtMIm][BF4], [HOEtMIm][NTf2], and [C14MIm]Br were more effectively to affect coal structure and decrease coal oxidation activity.

2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Keith E. Gutowski

Abstract Ionic liquids are salts that melt at low temperatures (usually defined as less than 100 °C) and have a number of interesting properties that make them useful for industrial applications. Typical ionic liquid properties include high thermal stabilities, negligible vapor pressures, wide liquidus ranges, broad electrochemical windows, and unique solvation properties. Furthermore, the potential combinations of cations and anions provide nearly unlimited chemical tunability. This article will describe the diverse industrial uses of ionic liquids and how their unique properties are leveraged, with examples ranging from chemical processing to consumer packaged goods.


2013 ◽  
Vol 448-453 ◽  
pp. 765-770 ◽  
Author(s):  
Li Zhe Liang ◽  
Quan Gan ◽  
Paul Nancarrow

In recent years, the utilisation of ionic liquids supported on porous polymer membranes has been demonstrated to enhance gas separation performance by improving both permeability and selectivity for several industrially-relevant gas mixtures. However, the use of such supported ionic liquid membranes (SILMs) is normally not feasible at elevated process temperatures due to the resulting decrease in ionic liquid viscosity, which can lead to increased loss of ionic liquid from the membrane support during operation. In addition, many of the polymer membranes typically used in SILMs exhibit relatively poor mechanical and thermal stabilities at high temperatures. To overcome these problems associated with SILMs, thermally-stable composite ionic liquid and polymer membranes (CILPMs) have been fabricated in this study, thus exploiting the beneficial properties of ionic liquids for gas separation at elevated temperatures. Poly (pyromellitimide-co-4,4-oxydianiline) (PMDA-ODA PI) in combination with the ionic liquid, [C4mi [NTf2] were used to fabricate the CILPMs. A measurement rig was designed and built to determine permeabilities and selectivities of the CILPMs for H2, N2, CO, CO2 and CH4 over a range of pressures and temperatures. The fabricated CILPMs were shown to maintain excellent mechanical and thermal stability over a wide range of processing conditions. Temperature was shown to greatly affect both permeability and selectivity of the membranes, whilst pressure had less influence. The incorporation of [C4mi [NTf2] into the membranes was found to significantly increase CO2 permeation and, therefore, it is anticipated that these CILPMs hold significant potential for CO2 separation applications.


2016 ◽  
Vol 18 (4) ◽  
pp. 3339-3351 ◽  
Author(s):  
Matthew T. Clough ◽  
Karolin Geyer ◽  
Patricia A. Hunt ◽  
Alastair J. S. McIntosh ◽  
Rebecca Rowe ◽  
...  

Organic spirocyclic tetraalkylammonium chloride salts exhibit enhanced thermal stabilities relative to traditional dialkylimidazolium ionic liquid analogues.


2017 ◽  
Vol 70 (6) ◽  
pp. 699 ◽  
Author(s):  
Koki Munakata ◽  
Masahiro Yoshizawa-Fujita ◽  
Masahiro Rikukawa ◽  
Toyonobu Usuki

Lemon myrtle is the richest natural source of citral, which has potential medicinal applications. In this study, citral was extracted from lemon myrtle using cellulose-dissolving ionic liquids (ILs), 1-ethyl-3-methylimidazolium methylphosphonate ([C2mim][(MeO)(H)PO2]), N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium chloride ([DEME]Cl), and N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium 2-methoxyacetate ([DEME][MOAc]). The extraction yield of citral obtained using ILs was up to 2.1 times higher than that obtained using ethanol. The ILs could be recycled and reused nine times for the extraction of citral. The present method provides a greener process when compared with conventional approaches and may be applicable for the extraction of other natural products.


2017 ◽  
Author(s):  
Jose A. Pomposo

Understanding the miscibility behavior of ionic liquid (IL) / monomer, IL / polymer and IL / nanoparticle mixtures is critical for the use of ILs as green solvents in polymerization processes, and to rationalize recent observations concerning the superior solubility of some proteins in ILs when compared to standard solvents. In this work, the most relevant results obtained in terms of a three-component Flory-Huggins theory concerning the “Extra Solvent Power, ESP” of ILs when compared to traditional non-ionic solvents for monomeric solutes (case I), linear polymers (case II) and globular nanoparticles (case III) are presented. Moreover, useful ESP maps are drawn for the first time for IL mixtures corresponding to case I, II and III. Finally, a potential pathway to improve the miscibility of non-ionic polymers in ILs is also proposed.


2020 ◽  
Author(s):  
Swati Arora ◽  
Julisa Rozon ◽  
Jennifer Laaser

<div>In this work, we investigate the dynamics of ion motion in “doubly-polymerized” ionic liquids (DPILs) in which both charged species of an ionic liquid are covalently linked to the same polymer chains. Broadband dielectric spectroscopy is used to characterize these materials over a broad frequency and temperature range, and their behavior is compared to that of conventional “singly-polymerized” ionic liquids (SPILs) in which only one of the charged species is attached to the polymer chains. Polymerization of the DPIL decreases the bulk ionic conductivity by four orders of magnitude relative to both SPILs. The timescales for local ionic rearrangement are similarly found to be approximately four orders of magnitude slower in the DPILs than in the SPILs, and the DPILs also have a lower static dielectric constant. These results suggest that copolymerization of the ionic monomers affects ion motion on both the bulk and the local scales, with ion pairs serving to form strong physical crosslinks between the polymer chains. This study provides quantitative insight into the energetics and timescales of ion motion that drive the phenomenon of “ion locking” currently under investigation for new classes of organic electronics.</div>


2019 ◽  
Vol 16 (7) ◽  
pp. 550-555
Author(s):  
Dinesh K. Jangid ◽  
Keshav L. Ameta ◽  
Surbhi Dhadda ◽  
Anjali Guleria ◽  
Prakash G. Goswami ◽  
...  

Ionic Liquid assisted efficient synthesis of some 2-aminobenzenethiols has been reported using three different Ionic Liquids (ILs) namely methylimidazolium tetrafluoroborate [MIM]+[BF4]−, methylimidazolium chloride [MIM]+[Cl]− and methylimidazolium nitrate [MIM]+[NO3]−. A comparative study has been carried out for the synthesis of target molecules in the presence and absence of IL, leading to conclusion that maximum yield has been observed with [MIM]+[BF4]−.


2020 ◽  
Vol 16 (5) ◽  
pp. 652-659
Author(s):  
Asiye A. Avan ◽  
Hayati Filik

Background: An Ionic Liquid-based based Dispersive Liquid-Liquid Microextraction (IL-DLLME) method was not applied to preconcentration and determination of bilirubin. Ionic Liquids (ILs) are new chemical compounds. In recent years, Ionic Liquids (ILs) have been employed as alternative solvents to toxic organic solvents. Due to these perfect properties, ILs have already been applied in many analytical extraction processes, presenting high extraction yield and selectivity for analytes. Methods: In this study, IL-DLLME was applied to biological samples (urine and serum) for the spectrophotometric detection of bilirubin. For bilirubin analysis, the full-color development was based on the reaction with periodate in the presence of hydrochloric acid. The high affinity of bilirubin for the ionic liquid phase gave extraction percentages above 98% in 0.3 M HCl solution. Results: Several IL-extraction parameters were optimized and room temperature ionic liquid 1-butyl- 1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and ethanol were used as extraction and disperser solution. The linear range was found in the range of 0.5-6.0 μM (0.3-3.5 μg mL-1) and the limits of detection of the proposed method was 0.5 μM (0.3 μg mL-1). The proposed method was applied for the preconcentration and separation of trace bilirubin in real urine samples. Also, the recoveries for bilirubin in spiked biological samples (urine and serum) were found to be acceptable, between 95-102%. Conclusion: The proposed IL-DLLMEapproach was employed for the enrichment and determination of trace levels of bilirubin in urine samples using NaIO4 as an oxidizing agent and Uv-vis spectrophotometric detection. The periodate oxidation of bilirubin is rapid, effective, selective, and simple to perform. The method contains only HCl, NaOI4, and an anionic surfactant. The method may be useful for economizing in the consumption of reagents in bilirubin determining. The IL-DLLMEmethod ensures a high yield and has a low toxicity no skin sensitization, no mutagenicity and no ecotoxicity in an aquatic environment since only very low quantities of an IL is required. For full-color formation, no any extra auxiliary reagents are required. Besides, the IL-DLLME technique uses a low-cost instrument such as Uv-vis which is present in most of the medical laboratories.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debashis Majhi ◽  
Sergey V. Dvinskikh

AbstractIonic liquids crystals belong to a special class of ionic liquids that exhibit thermotropic liquid-crystalline behavior. Recently, dicationic ionic liquid crystals have been reported with a cation containing two single-charged ions covalently linked by a spacer. In ionic liquid crystals, electrostatic and hydrogen bonding interactions in ionic sublayer and van der Waals interaction in hydrophobic domains are the main forces contributing to the mesophase stabilization and determining the molecular orientational order and conformation. How these properties in dicationic materials are compared to those in conventional monocationic analogs? We address this question using a combination of advanced NMR methods and DFT analysis. Dicationic salt 3,3′-(1,6-hexanediyl)bis(1-dodecylimidazolium)dibromide was studied. Local bond order parameters of flexible alkyl side chains, linker chain, and alignment of rigid polar groups were analyzed. The dynamic spacer effectively “decouples” the motion of two ionic moieties. Hence, local order and alignment in dicationic mesophase were similar to those in analogous single-chain monocationic salts. Bond order parameters in the side chains in the dicationic smectic phase were found consistently lower compared to double-chain monocationic analogs, suggesting decreasing contribution of van der Waals forces. Overall dication reorientation in the smectic phase was characterized by low values of orientational order parameter S. With increased interaction energy in the polar domain the layered structure is stabilized despite less ordered dications. The results emphasized the trends in the orientational order in ionic liquid crystals and contributed to a better understanding of interparticle interactions driving smectic assembly in this and analogous ionic mesogens.


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