COPPER(I) CHLORIDE-PYRIDINE COMPLEX SUPPORTED ON SILICA-GEL AS ADSORBENT FOR CARBON-MONOXIDE

A copper(I) chloride-pyridine complex supported on silica gel was prep ared by mixing porous silica gel beads with an acetonitrile solution c ontaining the complex composed of copper(I) chloride (CuCl) and pyridi ne under nitrogen, followed by removal of liquid phase under reduced p ressure. The resulting silica gel, 5.8 g, contained 4.39 mmol of CuCl and 4.08 mmol of pyridine. It rapidly adsorbed carbon monoxide (CO) at 30 degrees C under 1.0 atm of CO, and the equilibrium amount of adsor bed CO was 3.29 mmol (80.6% against containing pyridine). The adsorbed CO was rapidly desorbed by maintaining it at 70 degrees C under 1.0 a tm or at 30 degrees C under 0.4 mmHg. The adsorption-desorption cycle was repeated without any deterioration. The equilibrium amount of adso rbed CO (3.29 mmol) was 5.5 times that of adsorbed carbon dioxide (0.6 0 mmol), and 36.6 times that of adsorbed methane (0.09 mmol) at 30 deg rees C under 1.0 atm. The reversible and selective adsorption of CO wa s attributed to formation of molar ratio 1 : 1 : 1 CuCl-pyridine-CO co mplex from CO molecule and molar ratio 1 : 1 CuCl-pyridine complex sup ported on silica gel. When the adsorbent contacted with oxygen, the CO adsorbing ability decreased. The adsorbing ability was completely rec overed by maintaining the adsorbent at 120 degrees C under 1.0 atm of hydrogen for 48 h.