Transport of oxygen facilitated by peroxo-bis [N, N′-ethylene bis-(salicylideneiminato)-dimethylformamide-cobalt (III)] embedded in liquid membranes immobilized by photografting onto cellulose

A novel method to prepare liquid membranes, suitable to obtain facilitated transport of oxygen, incorporating the title complex (I) or the same without dimethylformamide (II), is reported. These membranes were obtained by photochemically grafting an epoxy-diacrylate copolymer onto cellulose in the presence of (I) or (II) together with dimethylformamide. Sorption isotherms of oxygen into deoxygenated membranes were obtained by Langmuir plots at 343-373 K. By these isotherms the molar ratio (0.5) between sorbed oxygen and cobalt in the membrane corresponding to saturation was evaluated, and constants K (bar-1) of heterogeneous equilibrium (Equation (2) in the text) involving (I) and (II) were obtained as a function of temperature. From K values, a mean enthalpy change of - 84 ± 1 kJ mol-1 and entropy change of -220 ± 3 J mol-1 K-1 were calculated. This latter reflects the high order in binuclear dioxygen complex formation. Permeability coefficients of oxygen and nitrogen from air through the photosynthetic membranes at 343 K (4.60 × 10-5 and 9.23 × 10-7 cm2 s-1 bar-1, respectively) were measured: These values show, within a certain range of pressure drop of air, an efficient O2/N2 separation, with a very advantageous ratio (50) between their fluxes. © 1987.