Abstract

Menadione or vitamin K3 (2-methyl-1,4-naphthoquinone) and its derivatives 2-((4-chlorobenzyl)amino-3-methylnaphtalene-1,4-dione (DM1) and 2-((4-chlorophenethyl)amino-3-methylnaphtalene-1,4-dione (DM2) are compound with potential biological significance for the human health as well as positive pharmacological effects [1]. In order to use carbon dioxide (CO2) at supercritical (SC) conditions as a solvent for insolation and purification of DM1 and DM1 from complex reaction mixtures, data about its individual solubility in SC-CO2 (molar fraction of solute in CO2-rich phase) as a function of temperature and pressure, is basic information required to conceptualize, design and model new separation processes [2]. The synthesis of DM1 and DM2, solid menadione derivatives, were carried out according [3]. The structures of both solid products were confirmed through Nuclear Magnetic Resonance (NMR) and Infrared Resonance (IR), its purity was > 70 % molmol-1. Solubilities measurements of each pure solute in SC-CO2 were accomplished using a dynamic-analytical methodology [4] at three isothermal conditions, 313.2 K, 323.2 K and 333.2 K. Results indicated that the experimental pressure ranged from 9 MPa to 30 MPa, and values of solute molar fraction were lower than 450·10-6 molmol-1. For both pairs of solubility data sets the uncertainties (specifically combined expanded uncertainties) were estimated < 150·10-6 molmol-1 [5]. The reliability of the experimental solubility data was verified by using a thermodynamic consistency test, adapted from tools based on Gibbs-Duhem equation, and a self-consistency test, based on the semi-empirical model of Mendes-Santiago and Teja [5].