Open AccessContribution to the termodynamics of 1-(2-thiazolylazo)-2-naphthol in the water-nitrobenzene extraction system
Author(s) -
Emanuel Makrlík,
Petr Vaňura
Publication year - 2000
Publication title -
journal of the serbian chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.227
H-Index - 45
eISSN - 1820-7421
pISSN - 0352-5139
DOI - 10.2298/jsc0008581m
Subject(s) - nitrobenzene , dissociation constant , chemistry , extraction (chemistry) , aqueous two phase system , aqueous solution , dissociation (chemistry) , partition coefficient , analytical chemistry (journal) , thermodynamics , chromatography , organic chemistry , physics , catalysis , biochemistry , receptor
General relations among thermodynamic parameters characterizing chemical equilibria including species ?2?+, HA, H+ and A- in both phases of a two-phase water-nitrobenzene extraction system have been derived. From the extraction measurements, the equilibrium distribution constant of electroneutral 1-(2-thiazolylazo)-2-naphthol (TAN, HA) between the nitrobenzene and aqueous phases has been determined: log ATD(HA) = 3.90?0.02. By using this value and further known constants and applying the mentioned relations, the following values of dissociation constants of TAN in nitrobenzene saturated with water have been calculated for a temperature of 25?C: pKdnb(H2A+) = -log Kdnb(H2A+) = 4.9 and pKdnb(HA) = -log Kdnb(HA) = 16.5.