EDTA titration of titanium and aluminium in Ziegler-Natta catalyst

Abstract

A method for the extraction of the titanium and aluminium from Ziegler-Natta catalyst systems into aqueous sulphuric acid followed by EDTA titration of each metal without prior separation is described. The sum of the two metals is determined in one aliquot by addition of excess of EDTA and isopropyl alcohol and back-titration with zinc to the dithizone end-point at pH 4·5. The titanium in a second aliquot is back-titrated at pH 1·2 in the presence of hydrogen peroxide with bismuth to the xylenol orange end-point. The aluminium concentration is obtained by difference.