The kinetics of solvolysis of trans-[Co(3 4-dimethylpyridine)4Cl2]ClO4 was measured over a wide range of solvent compositions (0-60% v/v) and temperatures (40-55 °C) in water  water-ethanol and water-propan-1-ol Plots of log(rate constant) versus the reciprocal of the relative permittivity of the co-solvent are non-linear for both co-solvents