Determination of Trichloroacetyl Chloride in Refine Titanium Tetrachloride by Acid Hydrolysis and Ion Chromatography

A method was proposed for the determination of trichloroacetyl chloride( CCl3COCl) in refined titanium tetrachloride( Ti Cl4) by ion chromatography after acid hydrolysis. Acid hydrolysis reaction was carried out according to the volume ratio( 1∶ 4,V / V) of Ti Cl4 samples to HCl solution( 2 mol / L HCl). Na OH and Ag2 O were added to hydrolysis solutions in sequence to remove and reduce metal cations( e. g. Ti4+,V5+,Fe3+) and Cl-,and then hydrolysis solutions was purified by H-type cation exchange column. Trichloroacetate( TCAA) was determined in the treated solutions after membrane filtration,and CCl3 COCl concentration was calculated according to molar amount conservation. Results showed that almost all of the target metal cations were removed in range of p H 9. 0- 10. 0 of hydroxide co-precipitation solutions, and the residual concentrations of Cl-,NO-3and SO2-4in solutions had no influence on the determination of TCAA after removal of Cl-. Quantitation limit of the method( MQL) for CCl3 COCl in refine Ti Cl4 samples was 2. 1 mg / L( 1. 2 μg /g),which was lower than the standard limit of refine Ti Cl4 of Russia( 5 μg / g). The recoveries of CCl3 COCl added to high pure Ti Cl4 were in the range of 84. 1%- 87. 3%,and the analytical results of5 replicates of refined Ti Cl4 sample were 45. 6,37. 9,40. 8,38. 9 and 43. 5 μg / g with RSD of 7. 7%. The method showed better reliability,stability and precision,which satisfied the requirement of quality control for CCl3 COCl in refined titanium tetrachloride.