Polarographic determination of vanadium valent forms in the VOCl3-Al(iso-C4H9)3

Suggested is polarographic determination method of vanadium tetravalent forms (V5+ - V2+) in catalytic complex VOCl3-Al(iso-C4H9)3 detected at the change of Al:V molar ratio from 0.1 to 10.0 in the temperature range from -20 deg to +50 deg. It is shown that in the catalytic complex studied which has been held at room temperature for 30 minutes with the increase of the Al:V ratio from 0.1 to 3.0 gradual increase of V5+ reduction degree to V2+ takes place. V5+ presence in solution is detected only at Al:V ratio <0.4. At the temperature change from -20 deg to +50 deg at Al:V=2.0 and time of hold-up of the catalytic complex of 30 minutes V3+ content decreases from 65 to 25%