Reactivities of methyl naphthalene-2-sulfonate, MeONs, and its 6-alkyl derivatives, alkyl = Me, n-C6 H13 and n-C12 H25 , 6-Me- MeONs, 6-Hex-MeONs, and 6-Do-MeONs, respectively, are com- pared for reactions in cetyl trialkylammonium bromide micelles, n- C16H33NR3Br, R=Me, Et, n-Pr, n-Bu, CTABr, CTEABr, CTPABr, CTBABr, respectively. Similar experiments were made on reac- tions of Br− with n-butyl and n-decyl naphthalene-2-sulfonates, BuONs, and DeONs, respectively. Reactions with OH− were fol- lowed in cetyl trialkylammonium hydroxide, alkyl = Me, Et, n- Pr, CTAOH, CTEAOH, and CTPAOH, solubility permitting. Some reactions with OH− or Br− were also followed in mixed-ion sys- tems of CTAOMs or CTPAOMs (OMs = MeSO3). Micellar rate effects were analyzed by using pseudophase treatments including interionic competition in mixed-ion systems. Second-order rate con- starts in the micellar pseudophase increase systematically with in- creases in substrate hydrophobicity and for reactions with Br−, but not OH−, they also increase with bulk of the cationic head group.
Micellar Effects on SN2 Reactions of Alkyl Naphtalen-2-solfonate. The Role of Hydrophobic Substituents
BRINCHI, Lucia;DI PROFIO, Pietro;GERMANI, Raimondo;SAVELLI, Gianfranco;
2001
Abstract
Reactivities of methyl naphthalene-2-sulfonate, MeONs, and its 6-alkyl derivatives, alkyl = Me, n-C6 H13 and n-C12 H25 , 6-Me- MeONs, 6-Hex-MeONs, and 6-Do-MeONs, respectively, are com- pared for reactions in cetyl trialkylammonium bromide micelles, n- C16H33NR3Br, R=Me, Et, n-Pr, n-Bu, CTABr, CTEABr, CTPABr, CTBABr, respectively. Similar experiments were made on reac- tions of Br− with n-butyl and n-decyl naphthalene-2-sulfonates, BuONs, and DeONs, respectively. Reactions with OH− were fol- lowed in cetyl trialkylammonium hydroxide, alkyl = Me, Et, n- Pr, CTAOH, CTEAOH, and CTPAOH, solubility permitting. Some reactions with OH− or Br− were also followed in mixed-ion sys- tems of CTAOMs or CTPAOMs (OMs = MeSO3). Micellar rate effects were analyzed by using pseudophase treatments including interionic competition in mixed-ion systems. Second-order rate con- starts in the micellar pseudophase increase systematically with in- creases in substrate hydrophobicity and for reactions with Br−, but not OH−, they also increase with bulk of the cationic head group.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
