Complexes of Uranium (VI) and Thorium (IV) with 2-Hydroxy - 5-Methyl-Acetophenone

The reactions of 2-hydroxy-5-methyl acetophenone with uranium (VI) and thorium (IV) have been studied by both conductometric and spectrophotometric methods. In acidic medium, uranyl ions develop instantaneously orange colour while thorium ions, yellow colour with this reagent. The colour intensity remains unchanged even on keeping for a week or so. Temperature variations up to 80° have no effect. Vosburgh and Cooper's method, .Job's method of continued variation and slope ratio method show that reagent forms only 2 : 1 complex with uranium only while l : 1 with thorium. The values of stability constants of uranium and thorium complexes are calculated to be 1·4X 107 and 2·66x 102 (or -∆Fº's of 9·91 Kcals and 3·35 Kcals/mol. respectively) at 30° respectively