Polarography of some sulphur-containing compounds: Part xv. polarographic and spectral investigation of acid-base equilibria in aqueous solutions of substituted 2-thiobarbiturates

作者: W.F. Smyth , G. Svehla , P. Zuman

DOI: 10.1016/S0003-2670(01)95745-9

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摘要: Abstract Changes of u.v. absorption spectra and polarographic reduction waves with pH indicate in solutions 5,5'-dialkyl-2-thiobarbiturates the presence four different species: diprotonated (AH2), monoprotonated (AH), zwitterion (BH) anionic (B). Dissociation constants pK2. were determined values pK1 pK3estimated. In attempts to elucidate electroactive forms, some tautomers excluded 4-electron H2A 2-electron reductions HA BH, electrolyses which gave varying yields hydrogen sulphide. The anion B gives no waves. 1,5,5'-Trialkyl-2-thiobarbiturates show corresponding forms BH. 1,3-Dimethyl-5,5'-dipropyl-2-thiobarbiturate is reduced possibly form. Predominant bulk solution at various most probable are discussed. Reduction 5,5'-dialkyl- 1,5,5'-trialkyl-2-thiobarbiturates 0.05 M borax suitable for analytical purposes.

参考文章(7)
G. A. Gilbert, E. K. Rideal, Direct estimation of the electrons involved in polarographic reduction Transactions of The Faraday Society. ,vol. 47, pp. 396- 400 ,(1951) , 10.1039/TF9514700396
John A. Page, James J. Lingane, A hydrogen-nitrogen gas coulometer Analytica Chimica Acta. ,vol. 16, pp. 175- 179 ,(1957) , 10.1016/S0003-2670(00)89908-0
Hans Wojahn, Ellen Wempe, Quantitative determination of thiobarbituric acids Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft. ,vol. 288, pp. 1- 6 ,(1955) , 10.1002/ARDP.19552880102
P. Zuman, Einfluss der adsorption auf anodische polarographische kurven; Bildung nichtwirbelnder maxima und minima Collection of Czechoslovak Chemical Communications. ,vol. 20, pp. 876- 882 ,(1955) , 10.1135/CCCC19550876
P. Zuman, Polarographie der barbitursäurederivate IV. Maximumdämpfung durch die derivate der thiobarbitursäure Collection of Czechoslovak Chemical Communications. ,vol. 20, pp. 883- 888 ,(1955) , 10.1135/CCCC19550883
P. Zuman, M. Kuik, Katalyse der wasserstoffabscheidung in gegenwart einiger schwefelderivate des hydantoins und pyrimidins Collection of Czechoslovak Chemical Communications. ,vol. 24, pp. 3861- 3880 ,(1959) , 10.1135/CCCC19593861