Thermodynamic and detailed kinetic study of the formation of orthophthalaldehyde-agmatine complex by fluorescence intensities.
The aim of this work is to determine the thermodynamic parameters and the kinetics of complex formation
between orthophthalaldehyde (OPA) and agmatine (AGM) in an alkaline medium (pH 13). Firstly, the
association constant (Ka) between orthophthalaldehyde and agmatine was determined at different
temperatures (between 298 K and 338 K) with a step size of 10 K. Secondly, the thermodynamic parameters
such as standard enthalpy (?H°), standard entropy (?S°),and Gibbs energy (?G) were calculated, where a
positive value of ?H° (+45.50 kJ/mol) was found, which shows that the reaction is endothermic. In addition,
the low value of ?S°(+0.24 kJ/mol) indicates a slight increase in the disorder in the reaction medium.
Furthermore, the negative values of ?G between ?35.62 kJ/mol and ?26.02 kJ/mol show that the complex
formation process is spontaneous. Finally, the parameters of the kinetics of the reaction between OPA and
AGM were determined as follows: when the initial concentration of AGM (5 × 10?6 M) is equal to that of the
OPA, the results show that the reaction follows an overall 1.5 order kinetics with an initial rate of 5.1 ×
Mmin?1 and a half-life of 8.12 min. The partial order found in relation to the AGM is 0.8. This work
shows that the excess of OPA accelerates the formation reaction of the complex.
Auteur(s) : Khémesse Kital, Moumouny Traoré, Diégane Sarr, Moussa Mbaye, Mame Diabou Gaye Seye, Atanasse Coly, François Delattre & Alphonse Tine.
Année de publication : 2020
Revue : Journal of Analytical Science and Technology
N° de volume : 11(41)
Type : Article
Mise en ligne par : COLY Atanasse