Analysis of the Complexation Reaction between Ag⁺ and Ethylene

Abstract

In the present work the reversible, bimolecular (1,1) reaction between ethylene and Ag+ in concentrated AgNO3(aq) solutions is analyzed. Due to interactions between the positively charged Ag+ ions and the negatively charged NO3 - ions, the silver nitrate is not completely dissociated and the actual free silver ion concentration is considerably lower than the maximum theoretical concentration. Especially at low temperatures and high salt concentrations the reduction in the degree of dissociation is significant. The influence of this degree of dissociation of the silver salt is considered and incorporated in the interpretation of the experimentally obtained results. Physical−chemical characteristics, transport properties of the system, the equilibrium constant of complexation, and the order of magnitude of the kinetic constants of the reaction between Ag+ and ethylene are determined. Subsequent calculation of the enhancement factor shows that the actual enhancement factor is almost equal to the infinite enhancement factor, indicating that the complexation reaction is almost instantaneous. The process is diffusion limited and strongly enhanced by the chemical complexation reaction.

Modelling and experimental evaluation of reaction kinetics in reactive extraction for chiral separation of amines, amino acids and amino-alcohols

“…In other words, only the concentration of the 'extractable form' of a species should be taken into account in the kinetic model. A similar conclusion was drawn by Nymeijer et al (2004) for the reactive absorption of ethylene by AgNO 3 solution, concerning the availability of Ag + ion. Although this may sound very obvious, it is not common practice in reaction engineering to consider acid-base dissociation and other complexation reactions in the aqueous phase as real 'side reactions'.…”

Partial separation of polyunsaturated fatty acid esters from FAMEs mixtures by adsorption on silver nitrate‐impregnated silica gel

“…(iii) The third regeneration process sought to address the concern that some 18:3 and 18:2 might remain strongly adsorbed on the 20% AgNO 3 /SiO 2 and not be removed by the diethyl ether wash. It is well known that Ag + coordinates to a variety of olefins but especially to ethylene (13)(14)(15). To facilitate the removal of 18:3 and 18:2 from the 20% AgNO 3 /SiO 2 , ethylene gas was slowly bubbled through the third diethyl ether wash for 4 h. As in procedure (i), the adsorbent was dried under vacuum before being reused.…”

Optimization of multistage olefin/paraffin membrane separation processes through rigorous modeling

“…15,16 Among these, facilitated transport membranes can easily surpass the permeabilityselectivity trade-off of polymeric membranes thanks to the reversible reaction between the olefin and a carrier cation, typically silver, which is added to the membrane composition. 17,18 Facilitated transport membranes have been synthesized following different approaches, from supported liquid membranes (SLMs) 19,20 to supported ionic liquid membranes (SILM) 21 that replace organic solvents with nonvolatile room temperature ionic liquids (RTILs) 22 in order to avoid solvent losses through evaporation. 23 Recently, composite facilitated transport membranes prepared by solvent casting of a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymeric solution containing the ionic liquid and the silver salt have been reported.…”

“…Many membrane materials have been reported for olefin/paraffin separation, including polymers, and more complex materials, such as carbon molecular sieves (CMSs), zeolitic imidazolate frameworks (ZIFs), or facilitated transport membranes . Among these, facilitated transport membranes can easily surpass the permeability‐selectivity trade‐off of polymeric membranes thanks to the reversible reaction between the olefin and a carrier cation, typically silver, which is added to the membrane composition . Facilitated transport membranes have been synthesized following different approaches, from supported liquid membranes (SLMs) to supported ionic liquid membranes (SILM) that replace organic solvents with nonvolatile room temperature ionic liquids (RTILs) in order to avoid solvent losses through evaporation .…”