Proton transfer and esterification reactions in EMIMOAc-based acidic ionic liquids

Tran, Anh Phuong; Lam, Phuoc H.; Miller, Alexandra; Walczyk, Dustin J.; Tomlin, Jay M.; Vaden, Timothy D.; Yu, Lei

doi:10.1039/c7ra00204a

Cited by 6 publications

(4 citation statements)

References 35 publications

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“…Although further studies are needed, we hypothesize that this behavior is due to esterification reactions that might involve the imidazolium cation and PhC to yield methyl‐substituted molecules, which hinder the gel formation. [ 43 ] For this purpose, two PVAs with different degrees of hydrolysis were studied, 87% and 99%, aiming to control the polymer/phenol supramolecular interactions. Only iongels prepared from fully hydrolyzed PVA (99%) are discussed here, because those with partially hydrolyzed PVA (87%) resulted in mechanically weak materials.…”

Section: Resultsmentioning

confidence: 99%

Elastic and Thermoreversible Iongels by Supramolecular PVA/Phenol Interactions

Luque

Picchio

Martins

et al. 2020

Macromolecular Bioscience

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Iongels have attracted much attention over the years as ion-conducting soft materials for applications in several technologies including stimuli-responsive drug release and flexible (bio)electronics. Nowadays, iongels with additional functionalities such as electronic conductivity, self-healing, thermo-responsiveness or biocompatibility are actively being searched for high demanding applications. In this work, we present a simple and rapid synthetic pathway to prepare hyperelastic and thermoreversible iongels. These iongels were prepared by supramolecular crosslinking between polyphenols biomolecules with a hydroxyl-rich biocompatible polymer such as poly(vinyl alcohol) (PVA) in the presence of ionic liquids. Using this strategy, a variety of iongels were obtained by combining different plant-derived polyphenol compounds such as gallic acid, pyrogallol, and tannic acid with imidazolium-based ionic liquids, namely [C 2 mim][N(CN) 2 ] and [C 2 mim][Br]. A suite of characterization tools was used to study the structural, morphological, mechanical, rheological and thermal properties of the supramolecular iongels. These iongels can withstand large deformations (40 % under compression) with full recovery, revealing reversible transitions from solid to liquid state between 87 to 125 °C. Finally, the polyphenol-based thermoreversible iongels shows appropriated properties for their potential application as printable electrolytes for bioelectronics.

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Section: Resultsmentioning

confidence: 99%

Elastic and Thermoreversible Iongels by Supramolecular PVA/Phenol Interactions

Luque

Picchio

Martins

et al. 2020

Macromolecular Bioscience

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“…Similar results have also been observed when MSA is dissolved in ILs BMITFSI or BMIBF 4 , data not shown in this paper. In our previous reports, we also found the addition of weak organic acids to ILs increased the overall conductivity of the solutions, as well as the addition of polar organic solvents [7,46,47]. On the other hand, the addition of strong acid such as HTFSI will increase the conductivity at lower concentrations and then reduce the conductivity at higher concentrations [3,4].…”

Section: Msa In Pyrrtfsimentioning

confidence: 88%

Conductivity, Viscosity, Spectroscopic Properties of Organic Sulfonic Acid solutions in Ionic Liquids

et al. 2019

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Sulfonic acids in ionic liquids (ILs) are used as catalysts, electrolytes, and solutions for metal extraction. The sulfonic acid ionization states and the solution acid/base properties are critical for these applications. Methane sulfonic acid (MSA) and camphor sulfonic acid (CSA) are dissolved in several IL solutions with and without bis(trifluoromethanesulfonyl)imine (HTFSI). The solutions demonstrated higher conductivities and lower viscosities. Through calorimetry and temperature-dependent conductivity analysis, we found that adding MSA to the IL solution may change both the ion migration activation energy and the number of “free” charge carriers. However, no significant acid ionization or proton transfer was observed in the IL solutions. Raman and IR spectroscopy with computational simulations suggest that the HTFSI forms dimers in the solutions with an N-H-N “bridged” structure, while MSA does not perturb this hydrogen ion solvation structure in the IL solutions. CSA has a lower solubility in the ILs and reduced the IL solution conductivity. However, in IL solutions containing 0.4 M or higher concentration of HTFSI, CSA addition increased the conductivity at low CSA concentrations and reduced it at high concentrations, which may indicate a synergistic effect.

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“…Furthermore, acidic pH can destabilize micelle structures 45,46 and induce reorganization of surfactant molecules on nanotube surface, which could provide a path through which the acid can reach the nanotube surface and quench the fluorescence. The pK a values of dodecyl sulfuric acid, cholic acid, and p-dodecylbenzenesulfonic acid are 1.9, 4.98, 47,48 and 0.7 (estimated) 49 respectively. Thus, SC is protonated at pH ≤ 4, which reduces its ionization and water solubility.…”

Section: Nanotube's Optical Responses To Solution Phmentioning

confidence: 99%