Comparison of solvated electron reaction rates in water and ammonia

New and literature data of solvated electron reactions in ammonia with some inorganic ions and organic neutral molecules are compared with corresponding data in water. In ammonia only a few reactions with aromatic molecules are diffusion controlled and therefore faster than in water (k ≈ 1 × 10 11 and 1 × 10 10 M −1 s −1 ,respectively). After correcting for the electrostatic contribution to the rate constant of the other reactions it is concluded that in general the reactivity of the solvated electron in ammonia is appreciably lower, than in water. For the slow reactions of ammoniated electrons with acetonitrile and dimethylsulfoxide we find activation energies of 7 to 9 kcal/mol and activation volumes of −40 to −60 ml/mol. In these reactions it is suggested that the rate determining step is associated with the collapse of the large electron cavity in liquid ammonia.