Use of Electrochemistry To Predict Ethylene Absorption Capacities of Reactive Absorption Systems

Abstract

The ethylene absorption capacities of six nonaqueous reactive absorption solutions have been investigated by cyclic voltammetry and equilibrium cell experiments. Validation of the electrochemical method as a novel screening technique for ethylene-absorbing solutions was accomplished by qualitative comparison to equilibrium cell results. Metal salt-ligand pairs included combinations of cuprous chloride and cuprous bromide salts with pyridine, benzylamine, and aniline. The cyclic voltammetry experiments at 0.01 M copper concentration included multiple ligand concentrations over a range of scan rates to identify trends in ethylene complexation. Equilibrium cell experiments near 1 M copper were useful in examining chemical and physical effects as well as quantifying the ethylene capacity of the solutions at higher metal loadings. Results from both techniques suggested that the solution with the best ethylene capacity consisted of cuprous chloride with aniline ligand.

Deep Eutectic Solvents As Tuning Media Dissolving Cu+ Used in Facilitated Transport Supported Liquid Membrane for Ethylene/Ethane Separation

“…As shown in Figure , it could be observed that the copper-free DESs had a lower solubility selectivity than CuCl/DES systems, with a straight C 2 H 4 /C 2 H 6 solubility curve, which suggested that chemical effects played an important role in the absorption process. With respect to the lower C 2 H 6 solubility in the CuCl/ChCl-EG system than the copper-free DES, certainly, a salting-out effect was observed . To estimate H ethylene,Cu in the CuCl/ChCl-EG system considering the salting-out effect, an analogy with copper-free DES was utilized, assuming that the ratio of H ethylene to H ethane in a nonreactive system is the same as that in a reactive system .…”

A study of Cu(I)‐ethylene complexation for olefin–paraffin separation

“…4 The capability for a solution of CuCl or CuBr in dimethylformamide (DMF) to chemically absorb ethylene was proven via cyclic voltammetry (CV). Various ligands, such as aniline, benzylamine, and pyridine, were added to the system during the tests to aid solvation of CuCl and protect the copper ion from contaminants.…”

“…CV experiments proved that the combination of the weaker anion Cl À and the weakest ligand aniline yielded the highest capacity for ethylene, as they would be more easily displaced by ethylene molecules. 4 However, due to health concerns over the use of DMF as solvent, DMF was replaced with N-methylpyrrolidone (NMP), a chemically similar solvent. For reference, Figure 1 below shows the structures of aniline, DMF, and NMP.…”

“…the two ligands, which are nearly the same except for two methyl groups on each pyrazolyl group. 4 . The former possesses a tetrahedral structure as shown above.…”

“…1,3,4 A combination of CuCl, aniline, and N-methylpyrrolidone (NMP) exhibited optimal solution characteristics, including low cost, high ethylene capacity, low volatility, and high stability. However a lack of basic understanding regarding the structure of the Cu(I)-ethylene-aniline complex impedes the development of reactive absorption systems.…”