Polarography of some sulphur-containing compounds : Part XVI. Polarographic and spectral investigation of acid-base equilibria in aqueous solutions of 2-thiobarbituric acids with substituents on sulphur
✍ Scribed by W.F. Smyth; G. Svehla; P. Zuman
- Publisher
- Elsevier Science
- Year
- 1970
- Tongue
- English
- Weight
- 807 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0003-2670
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✦ Synopsis
OF SUBSTITUTED X-THIOBARBITURATES. SVI 131 half-wave potentiaM9f this wave is shifted to negative potentials with increasing PH (Fig. 3). At low,cr pH values only a small anodic adsorption pre-wave limiting at 5 .x0-5 M occurs. No reduction waves were observed for the r-ethyl-2-allylthio-5-(2-methylbutyl)barbituric acid (Il) . Electronic s$ectra The U.V. spectra of the S-methyl derivative I below pH 4 show an absorption band of medium intensity (&=g -103) at 277 nm, accompanied by a weaker band (E= 7 a 103) at 244 nm. At higher PH values these bands are replaced by a mediumintensity band (E= 8 -103) at 260 nm, accompanied by a shoulder at 245 nrn and -O*lO -I-&S .