Kinetic studies of the Hydrolysis of Diketene Catalyzed by the Chloropalladium(II) Complex

Article abstract of DOI:10.1246/bcsj.57.1217

When diketene and sodium tetrachloropalladate(II) are mixed in aqueous solution, color of the solution changes promptly from dark red to yellow.During this fast primary reaction about one equivalent of diketene is consumed and acetoacetic acid (H2A) is retained as a trihapto ligand in (1-) (2).The succeeding steady hydrolysis of diketene (S) proceeds as a pseudo first-order reaction, obeying the rate law: , where k₁=2.0E-5 s^-1 and k₂=2.96E-6 mol dm^-3s^-1 at 0 deg C and μ=1.0 mol dm^-3 (HClO4 and NaClO4).A mechanism which postulates complex 2 as the effective catalyst is proposed to explain the observed two-term rate equation.