Mills, A. and Hazafy, D. and Parkinson, J. and Tuttle, T. and Hutchings, Michael G. (2010) Effect of alkali on methylene blue (C.I. basic blue 9) and other thiazine dyes. Dyes and Pigments, 88 (2). pp. 149-155.Full text not available in this repository. (Request a copy from the Strathclyde author)
A detailed study of the action of alkali on methylene blue (C.I. Basic Blue 9) and other thiazine dyes was carried out through a combination of UV/visible spectroscopy, thin layer chromatography, mass and NMR spectrometry and computational methods. In 0.1 M aq alkali solution, methylene blue forms a highly coloured, lipophilic species that is mainly Bernthsen's methylene violet i.e. a hydrolysis decomposition product, this being contrary to the report of a red N-hydroxy methylene blue adduct. The nature of the heterocyclic nitrogen atom in C.I. Basic Blue 9 is discussed and it is concluded there is no basis for the proposal of nucleophile addition at this site of the dye. In contrast, other thiazine dyes are deprotonated by alkali to form their neutral, highly coloured, lipophilic conjugate base forms.
|Keywords:||methylene blue, hydrolysis, thiazine, C.I. basic blue 9, methylene violet, DFT, Physical and theoretical chemistry, Chemical Engineering(all), Process Chemistry and Technology|
|Subjects:||Science > Chemistry > Physical and theoretical chemistry|
|Department:||Faculty of Science > Pure and Applied Chemistry|
|Depositing user:||Mrs Roslyn MacDonald|
|Date Deposited:||16 May 2011 11:00|
|Last modified:||21 Oct 2016 02:21|