Facilitated transport of oxygen in ethyl cellulose membranes containing cobalt porphyrins as oxygen carriers

Facilitated transport of oxygen was investigated in ethyl cellulose membran es containing cobalt(II) meso-tetrakis (substituted phenyl) porphyrins [CoT PP, CoT(2-Cl)PP, CoT(4-Cl)PP, CoT(4-MeO)PP, and CoT(2,4-2MeO)PP] as fixed o xygen carriers. The oxygen permeability (P-O2) and oxygen/nitrogen selectiv ity (P-O2/P-N2,) Of the membranes containing oxygen carriers increase with a decrease in the upstream gas pressure, but the nitrogen permeability(P-N2 ) is almost independent of the upstream nitrogen pressure. This indicates t hat the fixed oxygen carriers in the polymer membranes can reversibly inter act with oxygen and facilitate oxygen transport in the membranes. The study on the influences of the substituents in the cobalt(III) porphyrins and th e fifth ligand (imidazole or pyridine) on the membrane permeation behaviors shows that the porphyrin complex with an electron-accepting substituent in the meso-phenyl ring or with imidazole as the fifth ligand could increase the permeability and oxygen/nitrogen selectivity of the membranes much more than that with an electron-donating substituent or with pyridine as the fi fth ligand. (C) 2000 John Wiley & Sons, Inc.