Ayuda
Ir al contenido

Dialnet


Protonation equilibria of l-dopa and 1,10 phenonthroline in propylene glycol-water mixtures

    1. [1] Andhra University

      Andhra University

      India

  • Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 56, Nº. 4, 2011, págs. 842-847
  • Idioma: inglés
  • Enlaces
  • Resumen
    • Protonation equilibria of L-Dopa and 1,10 phenonthroline have been studied in varying concentrations (0-60% v/v) of propylene glycol-water mixtures maintaining an ionic strength of 0.16 mol dm-3 at 303 K using pH metric method. The protonation constants have been calculated with the computer program MINIQUAD75 and the best fit models are arrived at based on statistical grounds employing crystallographic R factor, χ2 , skewness and kurtosis. Dopa has three dissociable protons and one amino group which associate with proton. It exists as LH4+ at low pH and gets deprotonated with the formation of LH3, LH2- and LH2- successively with increase in pH. Phen forms LH2(2+) at low pH and gets deprotonated with the formation of LH+ and L with increase in pH. Secondary formation functions confirm the existence of 3 and 2 protonation equilibria for dopa and phen, respectively. The linear increase of log values of protonation constants of Dopa with decreasing dielectric constant of PG-water mixtures indicates the dominance of electrostatic forces in the protonation-deprotonation equilibria. Phen exhibits non-linear trend indicating the dominance of non-electrostatic forces.

Los metadatos del artículo han sido obtenidos de SciELO Chile

Fundación Dialnet

Dialnet Plus

  • Más información sobre Dialnet Plus

Opciones de compartir

Opciones de entorno