Polymer-Protected Metal Complex for Gas Separation. I. A Solution of Polystyrene-Protected Aluminium Copper(I) Halide as Water-Resistant Carbon Monoxide Absorbent

Carbon monoxide absorbents composed of linear polystyrene (PSt), aluminium halide, copper(I) halide, and toluene are prepared. The toluene solutions of polystyrene–protected aluminium copper(I) chloride (PSt–AlCuCl4) rapidly absorb CO at 20 °C under 1 atm (initial partial pressure of CO: 0.90 atm) and the equilibrium molar ratio of absorbed CO to the charged CuCl is 0.78. On the elevation of the temperature from 20 °C to 82 °C under 1 atm, the absorbed CO is released completely. The absorption-release cycles are repeated many times without measurable decrease in the absorbing capacity. The CO absorbing capacities of toluene solutions composed of aluminium halides, copper(I) halides, and polystyrene decrease as follows: AlCl3–CuCl system>AlBr3–CuBr system>>All3–CuI system=0. The CO absorbing activity of the toluene solution of PSt–AlCuCl4 remains virtually unchanged on the contact of the solution with nitrogen gas containing 10 mol% water to the charged CuCl (water content: 9000 ppm), when the molar ratio of phenyl residue of polystyrene (number-averaged degree of polymerization: 420, 50, or 4.0) to AlCuCl4 is unity or larger. This result is markedly in contrast with the fact that the activity of the toluene solution of AlCuCl4 without polystyrene significantly (25%) decreases on the contact.