SURFACTANT EFFECTS UPON CYCLIZATION OF O-(OMEGA-HALOALKOXY)PHENOXIDE IONS - THE ROLE OF PREMICELLAR ASSEMBLIES

Aqueous cationic micelles of R'NR(3)Br (R' = C12H25, R = Me, DoTABr; R ' = C16H33, R = Me, CTABr; R' = C16H33, R = Bu, CTBABr) and R'NMe(2)(C H2)(4)NMe(2)R'2Br (R' = C16H33) increase rates of cyclization of o-(OC 6H4O)-O--(CH2)(n-4)Y (X = Br, I) designated PhXn. Rate increases are s mall, except for PhI7 in CTBABr(1), and activation parameters are simi lar to those in water or 75% aqueous EtOH. In very dilute surfactant t here are large rate increases, by factors of up to 39 with PhI16 in CT ABr, but CTBABr is less effective. These rate increases are ascribed t o formation of substrate-premicellar complexes of PhBr10, PhBr12, and PhX16 with all the surfactants. These complexes dissolve into normal m icelles at higher [surfactant], and the unusual rate effects disappear .