RATE OF BACK-EXTRACTION OF TRIS(ACETYLACETONATO)CHROMIUM(III) AND TRIS(TRIFLUOROACETYLACETONATO)CHROMIUM(III) FROM CARBON-TETRACHLORIDE INTO AQUEOUS ACID PERCHLORATE SOLUTIONS

The rate of back-extraction of tris(acetylacetonato)chromium(III) ([Cr(acac)3]), and tris(trifluoroacetylacetonato)chromium(III) ([Cr(tfa)3]), from carbon tetrachloride into aqueous acid perchlorate solutions was measured. The rate of [Cr(acac)3] was much higher and that of [Cr(tfa)3] was also a little higher in the higher acid concentration range. This was concluded to be due to formation of the [Cr(acac)3(H+)2] and the [Cr(tfa)3H+] species which increased the concentration of the tris-complex species in the aqueous phase. With the both complexes, the rate was not affected by the ligand concentration in the aqueous phase. From these results, the controlling reaction was concluded to be the dissociation of the first ligand from the tris-complex or from the proton associate of the tris-complex in the aqueous phase.