Chemical Reduction of Gold(III) Bromide Complexes Using Sodium Nitrite – Kinetic Aspects
In this work, the spectrophotometric studies on the kinetics of redox reaction between gold(III) bromide complexes and sodium nitrite, were carried out. From the kinetic curves collected under different conditions of reactants concentration, addition of bromide ions, temperature, pH and ionic streng...
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| Format: | Article |
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Polish Academy of Sciences
2020-05-01
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| Series: | Archives of Metallurgy and Materials |
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| Online Access: | https://journals.pan.pl/Content/116042/PDF/AMM-2020-2-19-Paclawski.pdf |
| _version_ | 1811314933637316608 |
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| author | K. Pacławski |
| author_facet | K. Pacławski |
| author_sort | K. Pacławski |
| collection | DOAJ |
| description | In this work, the spectrophotometric studies on the kinetics of redox reaction between gold(III) bromide complexes and sodium nitrite, were carried out. From the kinetic curves collected under different conditions of reactants concentration, addition of bromide ions, temperature, pH and ionic strength, corresponding rate constants have been determined. The obtained results suggest the complex path of the [AuBr4]– reduction consisting of two parallel, bimolecular reactions where different reductant species (HNO2 and NO2–) take place and consecutive step with the metallic gold production. The second-order rate constants at 20oC are equal to 2.948 and 0.191 M–1·s–1, respectively. The values of activation enthalpy and activation entropy for the first and the second parallel step of the reaction were found to be ΔH‡ = 29.18 kJ·mol–1 and ΔS‡ = –13.95 J·mol–1·K, and ΔH‡ = 40.75 kJ·mol–1 and ΔS‡ = –31.06 J·mol–1·K, respectively. It was found that the reaction accelerates significantly with the increase of pH and is inhibited with the increase of Br– concentration. The substitutive, inner-sphere mechanism of electron transfer in the studied system was also suggested. |
| first_indexed | 2024-04-13T11:21:17Z |
| format | Article |
| id | doaj.art-834072653581468ea070ef0a2cda9d08 |
| institution | Directory Open Access Journal |
| issn | 2300-1909 |
| language | English |
| last_indexed | 2024-04-13T11:21:17Z |
| publishDate | 2020-05-01 |
| publisher | Polish Academy of Sciences |
| record_format | Article |
| series | Archives of Metallurgy and Materials |
| spelling | doaj.art-834072653581468ea070ef0a2cda9d082022-12-22T02:48:50ZengPolish Academy of SciencesArchives of Metallurgy and Materials2300-19092020-05-01vol. 65No 2667675https://doi.org/10.24425/amm.2020.132805Chemical Reduction of Gold(III) Bromide Complexes Using Sodium Nitrite – Kinetic AspectsK. PacławskiIn this work, the spectrophotometric studies on the kinetics of redox reaction between gold(III) bromide complexes and sodium nitrite, were carried out. From the kinetic curves collected under different conditions of reactants concentration, addition of bromide ions, temperature, pH and ionic strength, corresponding rate constants have been determined. The obtained results suggest the complex path of the [AuBr4]– reduction consisting of two parallel, bimolecular reactions where different reductant species (HNO2 and NO2–) take place and consecutive step with the metallic gold production. The second-order rate constants at 20oC are equal to 2.948 and 0.191 M–1·s–1, respectively. The values of activation enthalpy and activation entropy for the first and the second parallel step of the reaction were found to be ΔH‡ = 29.18 kJ·mol–1 and ΔS‡ = –13.95 J·mol–1·K, and ΔH‡ = 40.75 kJ·mol–1 and ΔS‡ = –31.06 J·mol–1·K, respectively. It was found that the reaction accelerates significantly with the increase of pH and is inhibited with the increase of Br– concentration. The substitutive, inner-sphere mechanism of electron transfer in the studied system was also suggested.https://journals.pan.pl/Content/116042/PDF/AMM-2020-2-19-Paclawski.pdfkineticsmechanismredoxgold complexessodium nitrite |
| spellingShingle | K. Pacławski Chemical Reduction of Gold(III) Bromide Complexes Using Sodium Nitrite – Kinetic Aspects Archives of Metallurgy and Materials kinetics mechanism redox gold complexes sodium nitrite |
| title | Chemical Reduction of Gold(III) Bromide Complexes Using Sodium Nitrite – Kinetic Aspects |
| title_full | Chemical Reduction of Gold(III) Bromide Complexes Using Sodium Nitrite – Kinetic Aspects |
| title_fullStr | Chemical Reduction of Gold(III) Bromide Complexes Using Sodium Nitrite – Kinetic Aspects |
| title_full_unstemmed | Chemical Reduction of Gold(III) Bromide Complexes Using Sodium Nitrite – Kinetic Aspects |
| title_short | Chemical Reduction of Gold(III) Bromide Complexes Using Sodium Nitrite – Kinetic Aspects |
| title_sort | chemical reduction of gold iii bromide complexes using sodium nitrite kinetic aspects |
| topic | kinetics mechanism redox gold complexes sodium nitrite |
| url | https://journals.pan.pl/Content/116042/PDF/AMM-2020-2-19-Paclawski.pdf |
| work_keys_str_mv | AT kpacławski chemicalreductionofgoldiiibromidecomplexesusingsodiumnitritekineticaspects |