Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model
Pseudo-first-order rate constants (k(obs)) for alkaline hydrolysis of N-benzylphthalimide (1) show a nonlinear decrease with the increase in [C,,,E,,]T (total concentration of Brij 58, m = 16, n = 20 and Brij 56, nt = 16, n = 10) at constant [CH3CN] and [NaOH]. These nonionic micellar effects, withi...
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my.um.eprints.80502019-08-27T06:12:40Z http://eprints.um.edu.my/8050/ Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model Ariffin, Azhar Khan, M.N. Cheong, M.Y. QD Chemistry Pseudo-first-order rate constants (k(obs)) for alkaline hydrolysis of N-benzylphthalimide (1) show a nonlinear decrease with the increase in [C,,,E,,]T (total concentration of Brij 58, m = 16, n = 20 and Brij 56, nt = 16, n = 10) at constant [CH3CN] and [NaOH]. These nonionic micellar effects, within the certain typical reaction conditions, have been explained in terms of the pseudophase micellar (PM) model. The values of micellar binding constants (K-s) of I are 1.04 x 101 M-(1) (at 1.0 x 10-(3) M NaOH) and 1.08 x 10(3) M-(1) (at 2.0 x 10-(3) M NaOH) for C16E20 as well as 600 M-1 (at 7.6 x 10-(4) M NaOH) and 670 M-1 (at 1.0 x 10-3 M NaOH) for C16E10 micelles. The pseudo-first-order rate constants (km) for hydrolysis of I in C16E20 micellar pseudophase are similar to 90-fold smaller than those (k(w)) in water phase. The values of km for hydrolysis of 1 in C16E10 micelles are almost zero. Kinetic coupled with UV spectral data reveals significant irreversible nonionic micellar binding of I molecules in the micellar environment of nearly zero hydroxide ion concentration at :>= 0.14 M C16E20 and 1.0 x 10-3 M NaOH while such observations could not be detected at :<= O.17 M C16E20 and 2.0 x 10-(3) M NaOH., Significantly, such irreversible C16E10 micellar binding of I molecules could be detected at 8.8 x 10-(2) M C16E10 and 1.0 x 10-3 M NaOH as well as at >= 3 x 10-3 M C16E10 and 7.6 x 10-(4) M NaOH, while the rate of hydrolysis of 1 is completely ceased at >= 0.05 M C16E10 and 7.6 x 10-(4) M NaOH. The rate of hydrolysis of 1 at 5.0 x 10-2 and 8.8 x 10-2 M C16E10 and 1.0 x 10-3 M NaOH reveals the formation of presumably phthalic anhydride, whereas such observation was not observed in the C16E20 micellar system under similar experimental conditions. 2007 Article PeerReviewed Ariffin, Azhar and Khan, M.N. and Cheong, M.Y. (2007) Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model. Journal of Physical Chemistry B, 111 (42). pp. 12185-12194. ISSN 1520-6106 http://pubs.acs.org/doi/pdfplus/10.1021/jp073980j 10.1021/jp073980j |
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QD Chemistry Ariffin, Azhar Khan, M.N. Cheong, M.Y. Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model |
| description |
Pseudo-first-order rate constants (k(obs)) for alkaline hydrolysis of N-benzylphthalimide (1) show a nonlinear decrease with the increase in [C,,,E,,]T (total concentration of Brij 58, m = 16, n = 20 and Brij 56, nt = 16, n = 10) at constant [CH3CN] and [NaOH]. These nonionic micellar effects, within the certain typical reaction conditions, have been explained in terms of the pseudophase micellar (PM) model. The values of micellar binding constants (K-s) of I are 1.04 x 101 M-(1) (at 1.0 x 10-(3) M NaOH) and 1.08 x 10(3) M-(1) (at 2.0 x 10-(3) M NaOH) for C16E20 as well as 600 M-1 (at 7.6 x 10-(4) M NaOH) and 670 M-1 (at 1.0 x 10-3 M NaOH) for C16E10 micelles. The pseudo-first-order rate constants (km) for hydrolysis of I in C16E20 micellar pseudophase are similar to 90-fold smaller than those (k(w)) in water phase. The values of km for hydrolysis of 1 in C16E10 micelles are almost zero. Kinetic coupled with UV spectral data reveals significant irreversible nonionic micellar binding of I molecules in the micellar environment of nearly zero hydroxide ion concentration at :>= 0.14 M C16E20 and 1.0 x 10-3 M NaOH while such observations could not be detected at :<= O.17 M C16E20 and 2.0 x 10-(3) M NaOH., Significantly, such irreversible C16E10 micellar binding of I molecules could be detected at 8.8 x 10-(2) M C16E10 and 1.0 x 10-3 M NaOH as well as at >= 3 x 10-3 M C16E10 and 7.6 x 10-(4) M NaOH, while the rate of hydrolysis of 1 is completely ceased at >= 0.05 M C16E10 and 7.6 x 10-(4) M NaOH. The rate of hydrolysis of 1 at 5.0 x 10-2 and 8.8 x 10-2 M C16E10 and 1.0 x 10-3 M NaOH reveals the formation of presumably phthalic anhydride, whereas such observation was not observed in the C16E20 micellar system under similar experimental conditions. |
| format |
Article |
| author |
Ariffin, Azhar Khan, M.N. Cheong, M.Y. |
| author_facet |
Ariffin, Azhar Khan, M.N. Cheong, M.Y. |
| author_sort |
Ariffin, Azhar |
| title |
Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model |
| title_short |
Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model |
| title_full |
Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model |
| title_fullStr |
Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model |
| title_full_unstemmed |
Kinetic coupled with UV spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model |
| title_sort |
kinetic coupled with uv spectral evidenc for near-irreversible nonionic micellar binding of n-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model |
| publishDate |
2007 |
| url |
http://eprints.um.edu.my/8050/ http://pubs.acs.org/doi/pdfplus/10.1021/jp073980j |
| _version_ |
1643688204207915008 |
| score |
13.250246 |