Selective retention of oxygen using chromatographic columns containing metal chelate polymers

Abstract

Porous polymers containing various metal chelates bonded to nitrogen functionalities on the surface of the polymer have been synthesized and found to bind oxygen reversibly. The stationary phases containing [5,5'-(1,2-ethanediyldinitrilo)-bis(2,2,7-trimethyl-3-octanonato)]cobalt(II) were found to be the most suitable of the phases investigated for separating oxygen for argon, nitrogen, and carbon monoxide. At ambient temperatures, near 25 degrees C, the reversible interaction of molecular oxygen with the transition-metal complex bonded to the stationary phase results in a marked increase in the retention time of oxygen, relative to species that have similar retention times in columns that do not contain the metal chelate. The stationary phase can be used alone to achieve the separation of low molecular weight gases or in series with another column. The metal chelate stationary phase is selective for oxygen and little change in the retention time of oxygen is observed after hundreds of injections over a several-month period, indicating that no appreciable degradation of the stationary phase had taken place under these conditions.

Electrical Spectroscopy Studies of Lithium and Magnesium Polymer Electrolytes Based on PEG400

“…Poly(ethylene glycol) 400 (PEG400), poly[PEG400- alt -DEOS] (DEOS = diethoxydimethylsilane), [EDTA][PEG400] 2 , and [EDTA] 3 [PEG400] 7 were used as host polymers in the preparation of polymer electrolytes (EDTA = ethylenediaminetetraacetic acid). The first two host polymers were chosen because they offer the well-known coordination sites present in the polyether polymer electrolytes; , the second two were examined because they in addition present two different types of chelating sites based on EDTA moieties , of the chain polymer.…”

Detection of Argon by Penning Ionization and Competitive Absorption Using a Sensitized Photoionization Detector

“…The stationary phases have sufficiently different flow-restricting characteristics to prevent the two portions from coeluting, resulting in two sets of peaks per injection. Since oxygen and argon are difficult to separate at ambient temperatures, the CTR III uses an oxysorbent stationary phase in the inner column to remove oxygen. In normal analyses, oxygen is quantified by difference.…”

“…The permanent gases have been separated by gas chromatography using a variety of column types and detected by thermal conductivity, , mass spectrometry, ,, and the helium ionization detector. , Thermal conductivity is relatively insensitive, mass spectrometry is highly sensitive but expensive and difficult to deploy in the field, and the helium ionization detector is not commercially available. Therefore, we have developed a new approach to argon detection based on sensitization of a commercially available photoionization detector (PID).…”

Synthesis and characterization of lithium and magnesium complexes based on [EDTA][PEG400] 2 and [EDTA] 3 [PEG400] 7

“…In particular, our interest was focused on the preparation of polymers that on one hand are characterized by the flexibility, cation complexation, and ion-pair separation properties typical of polyether chains, and on the other hand by the high ion-chelating capability typically exhibited by ethylenediaminetetraacetic acid (EDTA). [7,8] Macrocyclic ligands consisting of EDTA and short poly(ethylene glycol) (HO(CH 2 CH 2 O) n H with n ¼ 1-5) chains were used as metal ion-selective reagents. [9] Methyl methacrylate copolymers with EDTA functional groups were proposed as suitable supports for the preparation of catalysts.…”