Electron spin resonance studies on ziegler catalyst systems: Part I. The system titanium tetrachloride‐aluminium diethyl chloride

Abstract

Abstract Electron spin resonance was measured at room temperature in a mixture of TiCl 4 and Al(C 2 H 5 ) 2 Cl in heptane. No resonance could be demonstrated in the precipitate. At room temperature the concentration of unpaired electrons reaches its maximum value in approx. 10 minutes. At an Al/Ti ratio less than one the concentration of unpaired electrons remains for some hours at a constant value of about 4.6 × 10 −3 times the initial concentration of aluminium compound, a value which is only slightly dependent on the initial titanium concentration. At higher temperatures or at an Al/Ti ratio greater than one the number of unpaired electrons also reaches a maximum, but decreases afterwards. The concentration of unpaired electrons appeared to be highly governed both by the TiCl 3 precipitate formed and by other substances, such as water, alcohol, carbon tetrabromide and oxygen.