Porous ionic liquids prepared from phosphonium‐based ionic liquids and metal‐organic frameworks (MOFs) are fluid in large ranges of temperature including ambient. It is shown that the ion pairs are too voluminous to enter the pores of the MOF, so the porous liquids remain several months as suspensions with permanent free volume, capable of absorbing large quantities of gases. The increase in gas absorption, when compared with the pure ionic liquids, is proportional to the amount of porous solid in suspension. Structural features of the MOFs and of the ionic liquids are maintained in the suspensions. Thermodynamic analysis and molecular simulations show that the driving force for gas absorption by the porous ionic liquids is energetic as well as structural being controlled by gas‐solid affinity or by the porous liquid free volume. The enthalpy of gas absorption allows easy regeneration of the porous liquid in all cases. The dissolved gases fluidify the porous ionic liquids, different gases having distinct effects on mass transport. The molecular mechanisms that explain the stability of the suspensions and their capacity for gas absorption are identified and point toward easy design rules that will enable numerous applications of these innovative materials as reaction or separation media.

Porous ionic liquids are non-volatile,v ersatile materials that associate porosity and fluidity.N ew porous ionic liquids,b ased on the ZIF-8 metal-organic framework and on phosphonium acetate or levulinate salts,were prepared and showa ni ncreased capacity to absorb carbon dioxide at low pressures.P orous suspensions based on phosphonium levulinate ionic liquid absorb reversibly 103 %m ore carbon dioxide per mass than pure ZIF-8 at 1bar and 303 K. We show howthe rational combination of MOFs with ionic liquids can greatly enhance low pressure CO 2 absorption, paving the way towards an ew generation of high-performance,r eadily available liquid materials for effective lowp ressure carbon capture.

Porous ionic liquids combining alkylphosphonium halides with ZIF–8 absorb large amounts of carbon dioxide that can be catalytically coupled with epoxides to form cyclic carbonates. High activity and selectivity under...

Understanding the transport of sodium ion in ionic liquids is key to design novel electrolyte materials for sodium-ion batteries. In this work, we combine molecular dynamics simulation and experiments to...

In recent years, the fight against climate change and the mitigation of the impact of fluorinated gases (F-gases) on the atmosphere is a global concern. Development of technologies that help to efficiently separate and recycle hydrofluorocarbons (HFCs) at the end of the refrigeration and air conditioning equipment life is a priority. The technological development is important to stimulate the F-gas capture, specifically difluoromethane (R-32) and 1,1,1,2-tetrafluoroethane (R-134a), due to their high global warming potential. In this work, the COSMO-RS method is used to analyze the solute−solvent interactions and to determine Henry's constants of R-32 and R-134a in more than 600 ionic liquids. The three most performant ionic liquids were selected on the basis of COSMO-RS calculations, and F-gas absorption equilibrium isotherms were measured using gravimetric and volumetric methods. Experimental results are in good agreement with COSMO-RS predictions, with the ionic liquid tributyl(ethyl)phosphonium diethyl phosphate, [P 2444 ][C 2 C 2 PO 4 ], being the salt presenting the highest absorption capacities in molar and mass units compared to salts previously tested. The other two ionic liquids selected, trihexyltetradecylphosphonium glycinate, [P 66614 ][C 2 NO 2 ], and trihexyl(tetradecyl)phosphonium 2cyano-pyrrole, [P 66614 ][CNPyr], may be competitive as far as their absorption capacities are concerned. Future works will be guided on evaluating the performance of these ionic liquids at an industrial scale by means of process simulations, in order to elucidate the role in process efficiency of other relevant absorbent properties such as viscosity, molar weight, or specific heat.

Four divalent ionic liquids based on imidazolium cations with alkyl or ether functional- ized side-chains were synthesised and characterized: 3,3’-(tetraethyleneglycol-1,11-diyl)bis(1- methyl-1H-imidazolium) bromide, [tetraEG(mim)2][Br]2, 3,3’-(tetraethyleneglycol-1,11-diyl)bis(1- methyl-1H-imidazolium) acetate, [tetraEG(mim)2][OAc]2, 3-butyl-1-methylimidazolium malonate, [C4mim]2[Mal],...

AAfter reviewing the synthesis, characterisation and applications of more than 150 porous suspensions reported so far in the literature, we conclude that type III porous liquids are either suspensions of...

Understanding the structure-property relationship and nanoscopic behaviour of ionic liquids is of utmost importance for their potential applications. Focusing these studies on sets of homobaric ionic liquids could provide important...