Abstract
Small amounts of titanium in silicate materials were determined by spectrophotometric method after an extraction of titanium (IV) into benzene with N-benzoylphenylhydroxylamine (BPA).
A sample was disintegrated with hydrofluoric acid in the presence of sulfuric acid, treated with potassium pyrosulfate, and then finally made up to about 8N hydrochloric acid solution. (A sample which could be easily taken up with hydrochloric acid was directly dissolved in hydrochloric acid). Titanium (IV) in an aliquot of the resulting solution was extracted into benzene phase with BPA, and the absorbance was measured at 380 mμ against a reagent blank.
The extraction of titanium (IV) into benzene phase from 7 to 10N hydrochloric acid solution was quantitative. The extracted complex had a composition of 1 to 2 (metal to ligand) and showed characteristic absorption in visible and near ultraviolet regions. There was a linear relationship between the amounts of titanium (IV) and absorbance, the molar extinction coefficient at 380 mμ being 7, 100. Diverse ions usually found in silicate materials did not interfere with the determination except vanadium (IV and V) and chromium(VI). Vanadium must be removed before the extraction, and chromium (VI) must be reduced to non-interfering chromium (III).
The method was applied satisfactorily to several silicate materials. The results were comparable to those by other analytical methods.
The paper also presents some extraction characteristics of titanium (IV) -BPA complex in benzenehydrochloric acid solution system.
