A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes
Pseudo-first-order rate constants (k(obs)) for the nucleophilic reaction of piperidine (Pip) with anionic phenyl salicylate (S(-)) in aqueous solution, obtained at constant content (=2%, v/v) of CH(3)CN, [Pip]T (=0.1 M), [S(-)](T) (=2 x 10(-4) M), [CTABr](T) (total concentration of cetyltrimethylamm...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Published: |
Elsevier
2010
|
| Subjects: |
| _version_ | 1825720484317102080 |
|---|---|
| author | Khan, M.N. Ismail, E. Yusof, N.S.M. |
| author_facet | Khan, M.N. Ismail, E. Yusof, N.S.M. |
| author_sort | Khan, M.N. |
| collection | UM |
| description | Pseudo-first-order rate constants (k(obs)) for the nucleophilic reaction of piperidine (Pip) with anionic phenyl salicylate (S(-)) in aqueous solution, obtained at constant content (=2%, v/v) of CH(3)CN, [Pip]T (=0.1 M), [S(-)](T) (=2 x 10(-4) M), [CTABr](T) (total concentration of cetyltrimethylammonium bromide), NaOH (<= 0.10 M) and varying concentration of inert salts, MX (=2-NaOC(6)H(4)CO(2)Na and 3-NaOC(6)H(4)CO(2)Na), follow the relationship: kobs,(ko oKx/simxivo + Kx/s, IMX]). derived from an empirical equation coupled with the pseudophase model of micelle. The empirical constants P and Kxis provide the respective parameters Fxis and Kx/s. The magnitude of Fxis gives the measure of the fraction of cationic micellized S- transferred to the aqueous phase by the limiting concentration of co-ions X- through the ion-exchange process X-/S-. In other words, the value of Fxis shows the cationic micellar penetration of ions X- relative to co-ions S. The values of Fxis and K(X/S) have been used to determine usual thermodynamic ion-exchange constant (K(X)(Y)). The values of K(X)(Y) (Y= Br) have been calculated for X = 2--OC(6)H(4)CO(2)(-) (2-0Bz(2-)) and 3-(-)OC(6)H(4)CO(2)(-) (3-OBz(2-)). The mean values of Kt are 44 +/- 7 and 4.9 0.7 for X- =2-0Bz2- and 3-0Bz2-, respectively. The value of K1 for 2-0Bz2- is nearly 9- and 16-fold larger than those for respective 3-0Bz2- and 4-006H4CO2- (4-OBz(2-)). These results are attributed to the presence and absence of viscoelasticity in CTABr aqueous solution with 2-0Bz2- and 3-0Bz2- as well as 4-0Bz2-, respectively. The mean values of Exis are 0.98 0.10. 0.24 0.07 and 0.14 0.02 for X- = 2-013z2-, 3-0Bz2- and 4-0Bz2-, respectively. The change in kinetic probe from piperidinolysis to hydrolysis of S- gives nearly same value, within the limits of experimental uncertainties, of IT for 2-0Bz2-. The mean value of Fxis x ((xis for 2-0Bz2- is decreased by 40-fold in the presence than in the absence of 0.05 M C16E20. 2010 Elsevier B.V. All rights reserved. |
| first_indexed | 2024-03-06T05:35:51Z |
| format | Article |
| id | um.eprints-14216 |
| institution | Universiti Malaya |
| last_indexed | 2024-03-06T05:35:51Z |
| publishDate | 2010 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | um.eprints-142162019-02-11T09:01:57Z http://eprints.um.edu.my/14216/ A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes Khan, M.N. Ismail, E. Yusof, N.S.M. Q Science (General) T Technology (General) Pseudo-first-order rate constants (k(obs)) for the nucleophilic reaction of piperidine (Pip) with anionic phenyl salicylate (S(-)) in aqueous solution, obtained at constant content (=2%, v/v) of CH(3)CN, [Pip]T (=0.1 M), [S(-)](T) (=2 x 10(-4) M), [CTABr](T) (total concentration of cetyltrimethylammonium bromide), NaOH (<= 0.10 M) and varying concentration of inert salts, MX (=2-NaOC(6)H(4)CO(2)Na and 3-NaOC(6)H(4)CO(2)Na), follow the relationship: kobs,(ko oKx/simxivo + Kx/s, IMX]). derived from an empirical equation coupled with the pseudophase model of micelle. The empirical constants P and Kxis provide the respective parameters Fxis and Kx/s. The magnitude of Fxis gives the measure of the fraction of cationic micellized S- transferred to the aqueous phase by the limiting concentration of co-ions X- through the ion-exchange process X-/S-. In other words, the value of Fxis shows the cationic micellar penetration of ions X- relative to co-ions S. The values of Fxis and K(X/S) have been used to determine usual thermodynamic ion-exchange constant (K(X)(Y)). The values of K(X)(Y) (Y= Br) have been calculated for X = 2--OC(6)H(4)CO(2)(-) (2-0Bz(2-)) and 3-(-)OC(6)H(4)CO(2)(-) (3-OBz(2-)). The mean values of Kt are 44 +/- 7 and 4.9 0.7 for X- =2-0Bz2- and 3-0Bz2-, respectively. The value of K1 for 2-0Bz2- is nearly 9- and 16-fold larger than those for respective 3-0Bz2- and 4-006H4CO2- (4-OBz(2-)). These results are attributed to the presence and absence of viscoelasticity in CTABr aqueous solution with 2-0Bz2- and 3-0Bz2- as well as 4-0Bz2-, respectively. The mean values of Exis are 0.98 0.10. 0.24 0.07 and 0.14 0.02 for X- = 2-013z2-, 3-0Bz2- and 4-0Bz2-, respectively. The change in kinetic probe from piperidinolysis to hydrolysis of S- gives nearly same value, within the limits of experimental uncertainties, of IT for 2-0Bz2-. The mean value of Fxis x ((xis for 2-0Bz2- is decreased by 40-fold in the presence than in the absence of 0.05 M C16E20. 2010 Elsevier B.V. All rights reserved. Elsevier 2010 Article PeerReviewed Khan, M.N. and Ismail, E. and Yusof, N.S.M. (2010) A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 361 (1-3). pp. 150-161. ISSN 0927-7757, |
| spellingShingle | Q Science (General) T Technology (General) Khan, M.N. Ismail, E. Yusof, N.S.M. A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes |
| title | A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes |
| title_full | A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes |
| title_fullStr | A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes |
| title_full_unstemmed | A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes |
| title_short | A new empirical kinetic method for the determination of ion-exchange constants for the counterions of cationic micelles: The rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes |
| title_sort | new empirical kinetic method for the determination of ion exchange constants for the counterions of cationic micelles the rate of piperidinolysis and hydrolysis of anionic phenyl salicylate as the kinetic probes |
| topic | Q Science (General) T Technology (General) |
| work_keys_str_mv | AT khanmn anewempiricalkineticmethodforthedeterminationofionexchangeconstantsforthecounterionsofcationicmicellestherateofpiperidinolysisandhydrolysisofanionicphenylsalicylateasthekineticprobes AT ismaile anewempiricalkineticmethodforthedeterminationofionexchangeconstantsforthecounterionsofcationicmicellestherateofpiperidinolysisandhydrolysisofanionicphenylsalicylateasthekineticprobes AT yusofnsm anewempiricalkineticmethodforthedeterminationofionexchangeconstantsforthecounterionsofcationicmicellestherateofpiperidinolysisandhydrolysisofanionicphenylsalicylateasthekineticprobes AT khanmn newempiricalkineticmethodforthedeterminationofionexchangeconstantsforthecounterionsofcationicmicellestherateofpiperidinolysisandhydrolysisofanionicphenylsalicylateasthekineticprobes AT ismaile newempiricalkineticmethodforthedeterminationofionexchangeconstantsforthecounterionsofcationicmicellestherateofpiperidinolysisandhydrolysisofanionicphenylsalicylateasthekineticprobes AT yusofnsm newempiricalkineticmethodforthedeterminationofionexchangeconstantsforthecounterionsofcationicmicellestherateofpiperidinolysisandhydrolysisofanionicphenylsalicylateasthekineticprobes |