Effects of [NaOH] and [KBr] on Intramolecular General Base-Catalyzed Methanolysis of Ionized Phenyl Salicylate in the Presence of Cationic Micelles.
Pseudo-first-order rate constants obtained for methanolysis of ionized phenyl salicylate (PS(-)) at constant [MeOH], [MeCN], [NaOH] or [KOH], and [KBr] and at 35 degrees C show a decrease with the increase in [CTABr] (where CTABr represents cetyltrimethylammonium bromide) from 0.0-0.01 M. These observed data obey a pseudophase model of the micelle. The micellar binding constants (K(S)) of PS(-), pseudo-first-order rate constants (k(M)) for methanolysis of PS(-) in the micellar pseudophase and cmc are almost unchanged with the change in [NaOH] from 0.005-0.050 M. The increase in [KBr] from 0.0 to 0.3 M at 0.01 M KOH decreases K(S) from 5140 to 653 M(-)(1) and cmc from 1.9 x 10(-)(4) to 0.2 x 10(-)(4) M. Pseudo-first-order rate constants, k(M), are almost independent of [KBr] at 0.01 M KOH.
Khan
M. Niyaz
MN
Department of Chemistry, Universiti Malaya, 50603 Kuala Lumpur, Malaysia.