title: Reduction of methylene green by EDTA: a relation between dielectric constant of medium and activated state.
abstract: Kinetics of an alkaline reduction of the methylene green with ethylenediaminetetraaceticacid (EDTA) as a role of dielectric constant of the medium with anecdotal ionic strength in a diverse solvent system (aqueous mixtures of methanol) (10-30%)  was studied by measuring the specific rate constant of the reaction spectrophotometrically at λ (max) = 660nm.  An effort has been made to give an elucidation of vital role of dielectric constant of the medium captivating into reflection of single sphere and double sphere complex in reaction assortment. This investigation leads to disclose that single sphere complex of the dye and reductant was found to be the most suitable complex existed in a varied organic solvent. The deviation of the theoretical values from experimental results for single sphere and double sphere complex model in the presence of an alkali and nitrate ions were justified through HPLC analysis. HPLC analysis recommended that a considerable amount of the dye degrades in the existence of nitrate ion and alkali and additional peaks which may be of by-product were obtained. This leads to confirm the non identical values of single sphere and double sphere model in the occurrence of nitrate and an alkali. Rate of deletion of color showed a linear liaison with respect to water content below 30% and temperature between 20-40(o)C whereas an increase in the concentration of organic solvent showed the inhibition of dye decoloration at given optimum condition. Therefore study was restricted up to 30% of methanol binary mixtures. A mechanism of reduction of dye has been proposed based on verdict.
authors.affiliation: Department of Chemistry, Jinnah University for Women, 5C Nazimabad, Karachi, Pakistan.
authors.forename: Noshab
authors.initials: N
authors.lastname: Qamar
authors.forename: Rafia
authors.initials: R
authors.lastname: Azmat
authors.forename: Raheela
authors.initials: R
authors.lastname: Naz
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D016014:Linear Models; D013058:Mass Spectrometry; D000432:Methanol / Q000737:chemistry; D008751:Methylene Blue / Q000031:analogs & derivatives* / Q000737:chemistry / Q000528:radiation effects; D008956:Models, Chemical; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D019163:Reducing Agents / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013057:Spectrum Analysis; D013696:Temperature; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D004396:Coloring Agents; D019163:Reducing Agents; D012997:Solvents; D014867:Water; D004492:Edetic Acid; C028673:methylene green; D008751:Methylene Blue; D000432:Methanol