Salting-out phenomenon and 1-octanol/water partition coefficient of metalaxyl pesticide

Abstract : In this paper, we present the effect of inorganic cations such as Na(+), K(+), Ca(2+), Mg(2+) on the salting-out phenomenon of metalaxyl from pure water to aqueous salt solutions. Moreover the 1-octanol/water partition coefficient in pure water is presented. To accomplish this, aqueous solubility of metalaxyl was determined in pure water, in different salt solution (NaCl, KCl, CaCl(2) and MgCl(2)), and at different concentration level ranging from 0.01 to 1.5 M. The 1-octanol/water partition coefficient was determined using the static shake-flask method. Solubility was determined using dynamic saturation method for pure water in the range of 298.15-325.15 K and at 298.15 K for different salt solutions. The solubility value in pure water for studied interval was found constant (m = 3.118 x 10(-2) mol kg(-1)). Solubility values were used to calculate the standard molar Gibbs free energy of dissolution (Delta(sol)G degrees) and transfer (Delta(tr)G degrees) at 298.15 K. The values of A G from pure to all studied aqueous salt solutions did not exceed 2 kJ mol(-1), the value of of dissolution is 18.5 +/- 0.72 kJ mol(-1). The 1-octanol/water partition coefficient in pure water log K(o/w) is equal to 1.69. The obtained results confirm the classification of the neutral metalaxyl as a slightly hydrophobic molecule.
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Submitted on : Monday, June 4, 2012 - 10:07:55 AM
Last modification on : Thursday, February 8, 2018 - 11:10:19 AM

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J. Saab, Georgio Bassil, Ramy Abou Naccoul, J. Stephan, Ilham Mokbel, et al.. Salting-out phenomenon and 1-octanol/water partition coefficient of metalaxyl pesticide. Chemosphere, Elsevier, 2011, 82 (6), pp.929-934. ⟨10.1016/j.chemosphere.2010.10.029⟩. ⟨hal-00703637⟩

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