Unusual oxygen affinity of linear polyvinyl amine–cobalt complexes with hydroxyl counter ions: an efficient way of separation and chemical storage of molecular oxygen

Abstract

Methylated poly(vinyl amine) and its copolymer with diallyldimethylammonium chloride (DADMAC) were prepared by polymerization of N-vinyl formamide (NVF) or copolymerization with DADMAC. Acid hydrolysis of the polymers and subsequent methylation yielded corresponding polyamines. Co(II) complexes of the polyamines were demonstrated to be reasonably fast in molecular oxygen binding, when counter anions of cobalt are exchanged with hydroxyl ions. The oxygenation tests performed with oxygen sensor, FT-IR, and gas-volumetric methods revealed that complexes either with 4/1 or with 2/1 [amine]/[Co] ratios give 1:1 molecular oxygen adducts. Fast oxygenation (c.a. 2-4 min), high storage capacity, and smooth oxygen releasing within 70-120 °C are typical characteristics of the oxygenation-deoxygenation. The system seems to be useful for harvesting and chemical storage of air oxygen.

Cobalt-Chelated Polyamine Brushes on Solid Microspheres for Rapid Binding and Chemical Storage of Molecular Oxygen

“…These complexes with either 2/1 or 4/1 [amine]/[cobalt] ratios undergo rapid oxygenation by aeration in water or in diethylene glycol to give 1:1 oxygen adducts when counteranions of the cobalt are replaced by hydroxyl ions. This result is also quite consistent with the former study, in which the linear polyvinylamine-based complexes bound 0.8 mol of oxygen per mole of cobalt . Having high capacities (80 L/kg resin), fast oxygenation capabilities, and reusability, complexes of PAGR series of resin materials are superior to the current cobalt systems.…”

“…Complexation of methylated poly(vinyl amine) brushes on the PS-DVB microbeads with cobalt was accomplished by applying the previously described method. 30 Chelation was performed with excess amine−cobalt(II) molar ratios (2/1 mol/mol) under continuous nitrogen flow due to oxygen sensitiveness of the microbeads. In this procedure, 1.5 mmol of amine-containing microbeads (0.2 g) was wetted by mixing 15 mL of distilled water in a flask.…”

“…Afterward, the typical oxygenation procedure was done as given in the literature. 30 Simply, the complex microbeads were interacted with 20 mL of water, and air oxygen was bubbled (30 mL s −1 ) for 5.0 min through the solution. The color of the resin turned dark green from beige during air exposure.…”

“…29 In a previous study, the synthesis, oxygen affinity, and oxygen-releasing properties of nonhydrolyzable highly hydrophilic linear polyvinyl amine−cobalt complexes have been demonstrated. 30 This material is a promising candidate for chemical storage of oxygen due to its high and rapid oxygenbinding capacity and smooth oxygen release in the temperature range of 70−120 °C. The only drawback of this material in the solution form might be difficult handling in the process.…”

“…In this way the hairy brushes gained extra hydrophilicity, easy reachability, and pseudohomogenous behavior. Herein, the oxygen storage 30 and chain extension behavior on the solidsupported resin 31 features were combined on the brushes to accomplish oxygen storage on the solid-supported material with an easy handling and packaging ability. Resulting material could be separated easily from the medium by a simple filtration process and used repeatedly.…”