Bimolecular liquid phase reactions with rate constants greater than around 3 × 10 9 M -1 s -1 at 298 K are usually influenced by diffusion limitations . While diffusion effects diminish as temperature increases, it can affect the reaction rates up to around 473 K for fast reactions. For diffusion-controlled reactions, experimentally measured or observed rate constants do not correspond to their intrinsic rate constants but are the function of both diffusion and intrinsic rate constants. Observed rate constants (𝑘 obs ) of bimolecular reactions can be estimated as: