Micellar head-group size and anion nucleophilicity in SN2 reactions

Effects of Amine Oxide Surfactants on Reactions of Bromide and Hydroxide Ions with Methylnaphthalene-2-Sulfonate

“…Under these conditions nucleophilic attack by the amine oxide is suppressed, but there is probably a minor contribution of reaction with water, which can be neglected, and reaction with Br Ϫ is all important. An increase in head group bulk increases k obs , the same as for reaction in other cationic micelles, but with fully bound substrate overall reaction with Br Ϫ is somewhat slower than in micelles of quaternary ammonium ions (10). Protonation of the amine oxide by acids with weakly nucleophilic anions, e.g., methane sulfonic acid, decreases k obs , but dilute H 2 SO 4 slightly increases it (Table 1), possibly because there is a minor contribution of reaction with SO 4 2Ϫ in the cationic micelles.…”

“…The simulation of rate-surfactant profiles followed earlier methods, but the derived parameters are least reliable with weakly bound ions (9,10). In this situation data can be fitted by a combination of values of KЈ Nu and k M and an increase in one decreases the other.…”

Comparative study of the cationic surfactants and their influence on the alkaline hydrolysis of acetylsalicylic acid

“…Therefore, it becomes necessary to collect kinetic data on the influence of cationic surfactants on the alkaline hydrolysis of aspirin. In comparison to reactions in aqueous solutions, reaction kinetics in micellar solutions may undergo alterations, which may be favorable or unfavorable in nature, depending on micelle charge [18][19][20], micelle counterion [21], head group size [22,23], and the chain length of the hydrophobic tail of the surfactant [24]. Kinetically, micelles make a highly appealing reaction medium.…”

Hydrolysis of carboxylate and phosphate esters using monopyridinium oximes in cationic micellar media

“…The majority of fundamental studies on micellar S N 2 reactions have been conducted in the presence of cationic micelles of quaternary ammonium surfactants such as those with trialkylammonium and quinolinium bromides and chlorides [23,24]. Scheme 1 shows the reaction for the nucleophlic attack of oximate ions on PNPA and PNPDPP in the presence of surfactants.…”