Solvatochromic effect and kinetics of methyl violet reduction with potassium iodide in water–isopropanol mixtures

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• 作者：Maria Ashfaq ; Rehana Saeed ; Sameera Razi Khan…
• 关键词：solvatochromic parameters ; reduction ; polynomial equation ; CNIBS/R ; K model ; thermodynamic parameters
• 刊名：Russian Journal of Physical Chemistry A, Focus on Chemistry
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：90
• 期：13
• 页码：2556-2563
• 全文大小：285 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Physical Chemistry
  Russian Library of Science
  
• 出版者：MAIK Nauka/Interperiodica distributed exclusively by Springer Science+Business Media LLC.
• ISSN：1531-863X
• 卷排序：90

文摘

The solvent influence on the reduction kinetics of methyl violet with iodide in binary mixture of aqueous isopropanol was investigated spectrophotometrically. The absorption spectra of methyl violet were recorded in water, aqueous isopropanol and absolute isopropanol. In these solvents λ_max was in the range from 580.5 to 582.5 nm. The CNIBS/R-K model was used to calculate the solvatochromic parameters in a binary mixture; polynomial equation was also applied to describe the experimental data. The transition energies (E_T) were calculated. They show bathochromic shift with the decrease in the polarity of the solvent. The temperature was varied from 298–318 K, while the pH of the reaction was maintained at 4.99 and 6.00. The reduction reaction was found to be first order by potassium iodide and zero order by methyl violet. The thermodynamic parameters were also evaluated to support the kinetic data.