Ionic liquid silver salt complexes for propene/propane separation

Abstract

Properties of the room-temperature liquid complex salt [Ag(propene)(x)][Tf(2)N] have been studied to probe its suitability for acting as active separation layer in immobilised liquid membrane (ILM) concepts for propane/propene separation. The pressure/temperature range of complex formation has been determined and the thermal properties of Ag[Tf(2)N] and [Ag(propene)(x)][Tf(2)N] have been studied by DSC (differential scanning calorimetry) and TGA (thermogravimetric analysis) measurements. Pressure dependent measurements of solubility and diffusivity showed that the observed membrane selectivity is dominated by the solubility selectivity. The self-diffusion coefficient of propene is always smaller compared to propane as propene is temporarily bound to the silver ion in the [Ag(propene)(x)][Tf(2)N] ionic liquid.

Gaseous Hydrocarbon Separations Using Functionalized Ionic Liquids

“…A This salt was also successfully used to create an adaptive self-healing propane/propene separation membrane, although the details of its long term stability were not provided [34,35].…”

“…The propylene absorption capacity for the ionic liquids-silver salt solution was compared to aqueous solutions with the same silver salt concentration and it was found that the aqueous solutions presented lower propylene capacities. Although allowing the increase of the capacity and selectivity of the selected support for the unsaturated gas, the use of metals presents drawbacks due to their cost, contamination, degradation, safety problems, limited metal salt solubility and high viscosities of the resulting liquid absorbent [26,35,37,38,39]. A detailed engineering analysis is out of the scope of the present paper but would most certainly be necessary in order to properly compare these new technologies based on the use of ionic liquids with traditional processes such as cryogenic distillation.…”

Screening of RTILs for propane/propylene separation using COSMO-RS methodology

“…Nevertheless, for propane the only absorption is due to physical solubility, even when silver cations are dissolved in the ionic liquid. Therefore in order to enhance the separation performance it is desirable to find an ionic liquid with low affinity for propane and at the same time, [17][18][19][20][21]. Although in recent years a steeply growing amount of experimental solubility data has been published in this field [22], the huge amount of ionic liquids that can be synthesized suggest the need of a tool to estimate the equilibrium solubility of a gas in different ionic liquids.…”

Application of Ionic Liquids for the Separation of Rare Earth Metals

“…There is a growing recognition of the need to develop efficient and environmentally benign processes in the nuclear fuel cycle. Ionic liquids (ILs) are currently being investigated as alternative reaction media to conventional solvents in organic synthesis, catalysis, separation and electrochemistry [9][10][11][12][13][14][15][16][17][18][19]. ILs, which are molten salts of low melting point, have unique properties such as non-flammability, Solvent Extraction Research and Development, Japan, Vol.…”