ALUMINUM(III)-ISOCITRATE SOLUTION CHEMISTRY - A POTENTIOMETRIC STUDY

The equilibrium reactions of isocitrate with protons and Al3+ have bee n studied by potentiometric titration in aqueous 0.10M KCl at 25 degre es C. The protonation constants, corrected for K+-isocitrate complexin g, were log beta(0,1,1) = 5.838, log beta(0,2,1) = 10.126 and log beta (0,3,1) = 13.219. The stabilities and stoichiometries of the complexes , Al(p)H(q)L(r), were defined by the constants log beta(1,1,1) = 9.55( 05), log beta(1,0,1) = 6.90(02), log beta(1,-1,1) = 3.06(04) and log b eta(2,-3,2) = 4.08(04) or log beta(3,-4,3) = 10.36(06). Compared with the Al3+-citrate system, complexes are of lower thermodynamic stabilit y, but equilibrate more rapidly.