Thermodynamics’ of dissolution for 1-naphtol N-methylcarbamate in pure, mineral and Mediterranean sea water by dynamic saturation method

This paper mainly concerns the thermodynamic properties of dissolution for 1-naphtol N-methylcarbamate (or carbaryl), which will lead to the Heidman's thermodynamic equation application for this molecule dissolution in pure, mineral and Mediterranean sea water. In fact, the prediction of the transport and fate of hydrophobic organic chemicals in the environment requires the knowledge of their physical and chemical properties, the most important of which is their aqueous solubility. The aim of this work is to set the dynamic saturation method that enables us to measure the aqueous solubilities of organic compounds. Those suffer from lack of data due to solubility below 10−3 in mole fraction. The carbaryl aqueous solubility study, over a range of temperature between 273.15 K and 318.15 K, was carried out in three different aqueous solvents: pure, mineral, and Mediterranean sea water. An analytical procedure was set by means of GC–FID and optimized in order to quantify the carbaryl by an internal calibration method. The carbaryl showed an aqueous solubility ranging from 3 × 10−6 to 3.5 × 10−5 in mole fraction. A salting out effect was well observed and indicated in the solubility data obtained. The solubility values acquired form this method were then used to calculate thermodynamic properties such as Gibbs free energy (ΔsolG°), molar enthalpy of dissolution (ΔsolH°), molar entropy of dissolution (ΔsolS°).