The mechanism of oxidation of 3-mercaptopropionic acid
The mechanism of the oxidation of 3-mercaptopropionic acid (3-MPA) by hydrogen peroxide was studied in the acidic pH range. The nucleophilic attack by sulphur on the peroxide bond controls the rate. Extrapolation of the pH dependency suggests that the rate of attack by the deprotonated dianion is hi...
Guardado en:
| Autores principales: | , , , |
|---|---|
| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00084042_v75_n1_p9_Forlano |
| Aporte de: |
| id |
todo:paper_00084042_v75_n1_p9_Forlano |
|---|---|
| record_format |
dspace |
| spelling |
todo:paper_00084042_v75_n1_p9_Forlano2023-10-03T14:05:59Z The mechanism of oxidation of 3-mercaptopropionic acid Forlano, P. Olabe, J.A. Magallanes, J.F. Blesa, M.A. 3-mercaptopropionic acid Autooxidation Electrochemistry Kinetics Catalysis Charge transfer Cyclic voltammetry Electrochemistry Electrons Hydrogen peroxide Iron compounds Organic acids pH Polarographic analysis Reaction kinetics Autooxidation Deprotonated dianion Mercaptopropionic acid Nucleophilic attack Second electron transfer step Oxidation The mechanism of the oxidation of 3-mercaptopropionic acid (3-MPA) by hydrogen peroxide was studied in the acidic pH range. The nucleophilic attack by sulphur on the peroxide bond controls the rate. Extrapolation of the pH dependency suggests that the rate of attack by the deprotonated dianion is highest. Traces of Fe(III), at levels below 10-7 mol dm-3, do not catalyze efficiently the process through one-electron mechanisms; at higher concentrations, or on the surface of iron(III) oxides, this type of catalysis becomes important. The electrochemical oxidation of 3-MPA was also studied, using differential pulse polarography and cyclic voltammetry techniques. The mechanism is of the EC2E type, the second electron transfer step corresponding to the oxidation of the disulphide RS-SR. The rate constant for the dimerization of the RS. radicals was 1.8 × 103 mol-1 dm3 s-1; the slowness of this step agrees with the mechanisms observed in the course of one-electron oxidations by metal ions. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00084042_v75_n1_p9_Forlano |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
3-mercaptopropionic acid Autooxidation Electrochemistry Kinetics Catalysis Charge transfer Cyclic voltammetry Electrochemistry Electrons Hydrogen peroxide Iron compounds Organic acids pH Polarographic analysis Reaction kinetics Autooxidation Deprotonated dianion Mercaptopropionic acid Nucleophilic attack Second electron transfer step Oxidation |
| spellingShingle |
3-mercaptopropionic acid Autooxidation Electrochemistry Kinetics Catalysis Charge transfer Cyclic voltammetry Electrochemistry Electrons Hydrogen peroxide Iron compounds Organic acids pH Polarographic analysis Reaction kinetics Autooxidation Deprotonated dianion Mercaptopropionic acid Nucleophilic attack Second electron transfer step Oxidation Forlano, P. Olabe, J.A. Magallanes, J.F. Blesa, M.A. The mechanism of oxidation of 3-mercaptopropionic acid |
| topic_facet |
3-mercaptopropionic acid Autooxidation Electrochemistry Kinetics Catalysis Charge transfer Cyclic voltammetry Electrochemistry Electrons Hydrogen peroxide Iron compounds Organic acids pH Polarographic analysis Reaction kinetics Autooxidation Deprotonated dianion Mercaptopropionic acid Nucleophilic attack Second electron transfer step Oxidation |
| description |
The mechanism of the oxidation of 3-mercaptopropionic acid (3-MPA) by hydrogen peroxide was studied in the acidic pH range. The nucleophilic attack by sulphur on the peroxide bond controls the rate. Extrapolation of the pH dependency suggests that the rate of attack by the deprotonated dianion is highest. Traces of Fe(III), at levels below 10-7 mol dm-3, do not catalyze efficiently the process through one-electron mechanisms; at higher concentrations, or on the surface of iron(III) oxides, this type of catalysis becomes important. The electrochemical oxidation of 3-MPA was also studied, using differential pulse polarography and cyclic voltammetry techniques. The mechanism is of the EC2E type, the second electron transfer step corresponding to the oxidation of the disulphide RS-SR. The rate constant for the dimerization of the RS. radicals was 1.8 × 103 mol-1 dm3 s-1; the slowness of this step agrees with the mechanisms observed in the course of one-electron oxidations by metal ions. |
| format |
JOUR |
| author |
Forlano, P. Olabe, J.A. Magallanes, J.F. Blesa, M.A. |
| author_facet |
Forlano, P. Olabe, J.A. Magallanes, J.F. Blesa, M.A. |
| author_sort |
Forlano, P. |
| title |
The mechanism of oxidation of 3-mercaptopropionic acid |
| title_short |
The mechanism of oxidation of 3-mercaptopropionic acid |
| title_full |
The mechanism of oxidation of 3-mercaptopropionic acid |
| title_fullStr |
The mechanism of oxidation of 3-mercaptopropionic acid |
| title_full_unstemmed |
The mechanism of oxidation of 3-mercaptopropionic acid |
| title_sort |
mechanism of oxidation of 3-mercaptopropionic acid |
| url |
http://hdl.handle.net/20.500.12110/paper_00084042_v75_n1_p9_Forlano |
| work_keys_str_mv |
AT forlanop themechanismofoxidationof3mercaptopropionicacid AT olabeja themechanismofoxidationof3mercaptopropionicacid AT magallanesjf themechanismofoxidationof3mercaptopropionicacid AT blesama themechanismofoxidationof3mercaptopropionicacid AT forlanop mechanismofoxidationof3mercaptopropionicacid AT olabeja mechanismofoxidationof3mercaptopropionicacid AT magallanesjf mechanismofoxidationof3mercaptopropionicacid AT blesama mechanismofoxidationof3mercaptopropionicacid |
| _version_ |
1807316189608673280 |