Kinetics and Mechanism of Mn(II) Catalyzed Periodate Oxidation of p-anisidine: Effect of pH
The stoichiometry for the initial part of the reaction, Mn(II) catalysed periodate oxidation of p-anisidine (PMA), has been found to be 1 mol of PMA consuming 2 mol of periodate ion. The kinetic-mechanistic study of reaction in acetone-water medium was made spectrophotometrically by noting the incre...
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| Format: | Article |
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Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)
2014-12-01
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| Series: | Bulletin of Chemical Reaction Engineering & Catalysis |
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| Online Access: | https://journal.bcrec.id/index.php/bcrec/article/view/19401 |
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| author | Rajneesh Dutt Kaushik Jaspal Singh M. Manila Manmeet Kaur Prabha Singh |
| author_facet | Rajneesh Dutt Kaushik Jaspal Singh M. Manila Manmeet Kaur Prabha Singh |
| author_sort | Rajneesh Dutt Kaushik |
| collection | DOAJ |
| description | The stoichiometry for the initial part of the reaction, Mn(II) catalysed periodate oxidation of p-anisidine (PMA), has been found to be 1 mol of PMA consuming 2 mol of periodate ion. The kinetic-mechanistic study of reaction in acetone-water medium was made spectrophotometrically by noting the increase in the absorbance of reaction intermediate. Reaction is first order in reactants and catalyst each. A decrease in dielectric constant of the medium results in decrease in the rate of reaction suggesting an ion-dipole type interaction. Free radical scavengers do not affect the reaction rate. A special type of rate-pH profile shows a maximum at pH = 7.0. This pH effect also suggests the involvement of at least three differently reactive reactant species in the reaction and this fact has been considered by us while deriv-ing the rate law. Under pseudo first order conditions [IO4-] >> [PMA] and in agreement with the derived rate law, the 1/kcat versus [H+] plot passes through the minimum and the results can be fitted to the equation: 1/kcat = (K2 / k K3 K4 [H+]) + {(Kw + Kb K2) / k K3 K4 Kw} + Kb [H+] / k K3 K4 Kw, where kK3K4 is the empirical composite rate constant, Kw is ionic product of water, K2 is acid dissociation constant of H4IO6- and Kb is base dissociation constant of PMA. The experimental value of [H+]min is in good agreement with the value calculated by using the derived rate law equation and is character-istic of the substrate involved relating to the base dissociation constant of PMA. The value of thermo-dynamic parameters have been evaluated. © 2014 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0) |
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| id | doaj.art-d009564d2ae94d28bd7537eaf3744686 |
| institution | Directory Open Access Journal |
| issn | 1978-2993 |
| language | English |
| last_indexed | 2024-03-11T22:50:08Z |
| publishDate | 2014-12-01 |
| publisher | Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS) |
| record_format | Article |
| series | Bulletin of Chemical Reaction Engineering & Catalysis |
| spelling | doaj.art-d009564d2ae94d28bd7537eaf37446862023-09-22T03:55:57ZengMasyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)Bulletin of Chemical Reaction Engineering & Catalysis1978-29932014-12-019318219110.9767/bcrec.9.3.6823.182-1918114Kinetics and Mechanism of Mn(II) Catalyzed Periodate Oxidation of p-anisidine: Effect of pHRajneesh Dutt Kaushik0Jaspal Singh1M. Manila2Manmeet Kaur3Prabha Singh4Department of Chemistry, Gurukul Kangri University, Haridwar (Uttarakhand), IndiaDepartment of Chemistry, Gurukul Kangri University, Haridwar (Uttarakhand), IndiaDepartment of Chemistry, Gurukul Kangri University, Haridwar (Uttarakhand), IndiaDepartment of Chemistry, Gurukul Kangri University, Haridwar (Uttarakhand), IndiaDepartment of Chemistry, D. A. V. (P.G.) College, Muzaffarnagar (U.P.), IndiaThe stoichiometry for the initial part of the reaction, Mn(II) catalysed periodate oxidation of p-anisidine (PMA), has been found to be 1 mol of PMA consuming 2 mol of periodate ion. The kinetic-mechanistic study of reaction in acetone-water medium was made spectrophotometrically by noting the increase in the absorbance of reaction intermediate. Reaction is first order in reactants and catalyst each. A decrease in dielectric constant of the medium results in decrease in the rate of reaction suggesting an ion-dipole type interaction. Free radical scavengers do not affect the reaction rate. A special type of rate-pH profile shows a maximum at pH = 7.0. This pH effect also suggests the involvement of at least three differently reactive reactant species in the reaction and this fact has been considered by us while deriv-ing the rate law. Under pseudo first order conditions [IO4-] >> [PMA] and in agreement with the derived rate law, the 1/kcat versus [H+] plot passes through the minimum and the results can be fitted to the equation: 1/kcat = (K2 / k K3 K4 [H+]) + {(Kw + Kb K2) / k K3 K4 Kw} + Kb [H+] / k K3 K4 Kw, where kK3K4 is the empirical composite rate constant, Kw is ionic product of water, K2 is acid dissociation constant of H4IO6- and Kb is base dissociation constant of PMA. The experimental value of [H+]min is in good agreement with the value calculated by using the derived rate law equation and is character-istic of the substrate involved relating to the base dissociation constant of PMA. The value of thermo-dynamic parameters have been evaluated. © 2014 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)https://journal.bcrec.id/index.php/bcrec/article/view/19401kinetics-mechanisticmechanismmnii, periodatep–anisidine4-methoxy-1,2-benzoquinone |
| spellingShingle | Rajneesh Dutt Kaushik Jaspal Singh M. Manila Manmeet Kaur Prabha Singh Kinetics and Mechanism of Mn(II) Catalyzed Periodate Oxidation of p-anisidine: Effect of pH Bulletin of Chemical Reaction Engineering & Catalysis kinetics-mechanistic mechanism mnii, periodate p–anisidine 4-methoxy-1,2-benzoquinone |
| title | Kinetics and Mechanism of Mn(II) Catalyzed Periodate Oxidation of p-anisidine: Effect of pH |
| title_full | Kinetics and Mechanism of Mn(II) Catalyzed Periodate Oxidation of p-anisidine: Effect of pH |
| title_fullStr | Kinetics and Mechanism of Mn(II) Catalyzed Periodate Oxidation of p-anisidine: Effect of pH |
| title_full_unstemmed | Kinetics and Mechanism of Mn(II) Catalyzed Periodate Oxidation of p-anisidine: Effect of pH |
| title_short | Kinetics and Mechanism of Mn(II) Catalyzed Periodate Oxidation of p-anisidine: Effect of pH |
| title_sort | kinetics and mechanism of mn ii catalyzed periodate oxidation of p anisidine effect of ph |
| topic | kinetics-mechanistic mechanism mnii, periodate p–anisidine 4-methoxy-1,2-benzoquinone |
| url | https://journal.bcrec.id/index.php/bcrec/article/view/19401 |
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