Molecular Topology and Local Dynamics Govern the Viscosity of Imidazolium-Based Ionic Liquids

Zhang, Yong; Xue, Lianjie; Khabaz, Fardin; Doerfler, Rose; Quitevis, Edward L.; Khare, Rajesh; Maginn, Edward J.

doi:10.1021/acs.jpcb.5b08245

Cited by 59 publications

(65 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The relatively high viscosity for these ILs compared with their n -alkyl homologous depends heavily on the reorientation motion on ILs. Maginn and co-workers[28], based on the unpublished data by Xue et al [31], reported higher viscosities for branched aromatic ILs. According to the simulation study carried by the authors[28] these results were explained by a higher packing stability of the ion pairs in the liquid phase.…”

Section: Introductionmentioning

confidence: 99%

The effect of n vs. iso isomerization on the thermophysical properties of aromatic and non-aromatic ionic liquids

Rodrigues

Almeida

Freire

et al. 2016

Fluid Phase Equilibria

View full text Add to dashboard Cite

This work explores the n vs. iso isomerization effects on the physicochemical properties of different families of ionic liquids (ILs) with variable aromaticity and ring size. This study comprises the experimental measurements, in a wide temperature range, of the ILs' thermal behavior, heat capacities, densities, refractive indices, surface tensions, and viscosities. The results here reported show that the presence of the iso-alkyl group leads to an increase of the temperature of the glass transition, T g . The iso-pyrrolidinium (5 atoms ring cation core) and iso-piperidinium (6 atoms ring cation core) ILs present a strong differentiation in the enthalpy and entropy of melting. Non-aromatic ILs have higher molar heat capacities due to the increase of the atomic contribution, whereas it was not found any significant differentiation between the n and iso-alkyl isomers. A small increase of the surface tension was observed for the non-aromatic ILs, which could be related to their higher cohesive energy of the bulk, while the lower surface entropy observed for the iso isomers indicates a structural resemblance between the IL bulk and surface. The significant differentiation between ILs with a 5 and 6 atoms ring cation in the n-alkyl series (where 5 atoms ring cations have higher surface entropy) is an indication of a more efficient arrangement of the non-polar region at the surface in ILs with smaller cation cores. The ILs constituted by non-aromatic piperidinium cation, and iso-alkyl isomers were found to be the most viscous among the studied ILs due to their higher energy barriers for shear stress.

show abstract

Section: Introductionmentioning

confidence: 99%

The effect of n vs. iso isomerization on the thermophysical properties of aromatic and non-aromatic ionic liquids

Rodrigues

Almeida

Freire

et al. 2016

Fluid Phase Equilibria

View full text Add to dashboard Cite

show abstract

“…In two component ionic liquids, hydrogen bonding and salt bridges 29 as well as molecular stacking due to side chain length30 have been identified as viscosity contributors. Analogous to having a larger population of acid (non-charged) species in single…”

mentioning

confidence: 99%

Dynamic Acid/Base Equilibrium in Single Component Switchable Ionic Liquids and Consequences on Viscosity

Cantú

Lee

et al. 2016

J. Phys. Chem. Lett.

103

View full text Add to dashboard Cite

The deployment of transformational nonaqueous CO2-capture solvent systems is encumbered by high viscosities even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we present key molecular features that control bulk viscosity. Fast CO2-uptake kinetics arise from close proximity of the alcohol and amine sites involved in CO2 binding in a concerted fashion, resulting in a Zwitterion containing both an alkyl-carbonate and a protonated amine. The population of internal hydrogen bonds between the two functional groups determines the solution viscosity. Unlike the ion pair interactions in ionic liquids, these observations are novel and specific to a hydrogen-bonding network that can be controlled by chemically tuning single molecule CO2 capture solvents. We present a molecular design strategy to reduce viscosity by shifting the proton transfer equilibrium toward a neutral acid/amine species, as opposed to the ubiquitously accepted zwitterionic state. The molecular design concepts proposed here are readily extensible to other CO2 capture technologies.

show abstract

“…Rather, we suggest that the difference is due to a steric effect. Quantum chemistry calculations indicate that in the lowest energy configurations of [C n C 1 im] + cations, the linear alkyl chain is fully extended from the imidazolium ring . In contrast, in the lowest energy configuration of [BnzC 1 im] + , the phenyl ring and imidazolium ring of the [BnzC 1 im] + are oriented perpendicular to each other .…”

Section: Discussionmentioning

confidence: 99%

Kinetic Study of Curing Bisphenol A Dicyanate Ester with Ionic Liquid Additive

Zhai

Quitevis

Simon

2019

J Polym Sci B Polym Phys

Self Cite

View full text Add to dashboard Cite

A kinetic study of the trimerization reaction of bisphenol A dicyanate ester with an aromatic imidazolium-based ionic liquid (IL) as additive is performed using dynamic and isothermal differential scanning calorimetry. The reaction follows second-order autocatalytic kinetics, and a slight acceleration effect is observed in the presence of the aromatic IL relative to the neat resin. The activation energy also increases with the IL additive, whereas the glass transition temperature (T g ) is depressed, consistent with the Fox equation and a homogeneous one-phase material. A model incorporating diffusion effects is able to describe the dynamic and isothermal curing data for both the neat resin system and that containing aromatic IL. A comparison with aliphatic-based IL additive indicates that the reaction is more accelerated with aliphatic IL than with the aromatic IL in spite of the fact that the aliphatic additive phase separates during cure.

show abstract

Molecular Topology and Local Dynamics Govern the Viscosity of Imidazolium-Based Ionic Liquids

Cited by 59 publications

References 45 publications

The effect of n vs. iso isomerization on the thermophysical properties of aromatic and non-aromatic ionic liquids

The effect of n vs. iso isomerization on the thermophysical properties of aromatic and non-aromatic ionic liquids

Dynamic Acid/Base Equilibrium in Single Component Switchable Ionic Liquids and Consequences on Viscosity

Kinetic Study of Curing Bisphenol A Dicyanate Ester with Ionic Liquid Additive

Contact Info

Product

Resources

About