A fair amount of research has been carried out on the reactions of nitrous acid with aryl hydrazines, with marked differences in mechanism between the reaction of nitrous acid with 2,4-dinitrophenylhydrazine, and the reaction of nitrous acid with alkyl and halogen substituted aryl hydrazines. It was hoped that study of the electrophilic nitrosation of 2-nitrophenylhydrazine would serve as a link between the two sets of results. A large range of electrophilic nitrosating agents are known, and the spectra of two of these; dinitrogen trioxide (N<SUB>2</SUB>O<SUB>3</SUB>) and nitrosyl thiocyanate (ONSCN), have been studied using stopped flow spectrophotometry. Earlier studies of the nitrosation of hydrazine using sodium acetate/acetic acid buffers, produced discrepancies between observed rates compared to a rate calculated from measurements made in much more acidic conditions in HC1O<SUB>4</SUB>. Consequently the original study has been re-investigated and extended. There is considerable current interest in the electrophilic nitrosation of sulfur compounds, which leads to the formation of sulfur-nitroso intermediates, and in the subsequent decomposition reactions of these intermediates. Preliminary work on the reaction of nitrous acid with tetramethylthiourea (NMe)<SUB>2</SUB>CS, showed some unexpected <SUP>1</SUP>H NMR spectra for the products. A likely product of the decomposition of the S-nitrosothiouronium ion intermediate (NMe<SUB>2</SUB>)<SUB>2</SUB>CSNO<SUP>+</SUP> is [(NMe<SUB>2</SUB>)<SUB>2</SUB>CSSC(NMe<SUB>2</SUB>)<SUB>2</SUB>]<SUP>2+</SUP> and this species should also be formed in the oxidation of tetramethylthiourea by bromine. This led to an investigation of the reaction of (NMe<SUB>2</SUB>)<SUB>2</SUB>CS with bromine in aqueous solution, with a comparison made between the products gained by bromination and nitrosation, using <SUP>1</SUP>H NMR.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:637196 |
| Date | January 2000 |
| Creators | Haine, H. D. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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