Metal ion effects have been revealed on nucleophilic substitution reactions of n-octyl sulfonates 1-3 promoted by complexes of polyether ligands (PEGs, crown ethers, cryptands) with alkali metal salts MY (M = Li, Na, K; Y = I, Br) in low polarity solvents (chlorobenzene, o-dichlorobenzene, toluene) at 60 degrees C. Rate constants increase, in the order K+ < Na+