Group-Contribution Modelling of Mixtures Containing Aromatic Ketones and Aromatic Esters

MARÍA FERNANDA BARRERA VÁSQUEZ; ALFONSINA ESTER ANDREATTA; RAQUEL MARTINI; SUSANA B. BOTTINI

Puerto Varas

Conferencia; IX IBEROAMERICAN CONFERENCE ON PHASE EQUILIBRIA AND FLUID PROPERTIES FOR PROCESS DESIGN - EQUIFASE 2012; 2012

Aromatic ketones such as anthraquinones (AQ) are an important category of secondary metabolites present in various vegetable species and constitute the most numerous group of quinones present in the vegetable kingdom [1]. They are highly bioactive and potentially useful for therapeutic applications. The extracts of anthraquinones possess several therapeutic properties including antiviral, anti-bacterial [2] and anti-cancer activities [3-4].Aromatics esters, on the other hand, are present in fruits, vegetables and they are used as essence and food preservative. One of the most studied aromatic esters is the esterified cholesterol, which is one of the predominant components in the biomembrane of most organisms and vital for human health. Besides their relevance in heart diseases [5], they are also very common biochemicals and important liquid crystals, potentially useful in clinical fields (such as thermal color sensor).Supercritical fluid extraction offers an alternative to traditional extracting and purifying methods applied to natural products. Phase equilibrium modeling of mixtures of aromatic ketones/ester with supercritical solvents is a fundamental tool for the simulation and design of such supercritical processes.In this work, a group-contribution with association equation of state GCA-EOS [6] was applied to represent phase equilibrium data from the literature, on mixtures containing aromatics ketones and aromatics esters with different solvents.When the equilibrium involved a solid phase, the equation was used to calculate the fugacity of the solid solute, relating it to the fugacity of the "hypothetical" sub-cooled vapor or liquid phase at the equilibrium temperature[7].Two new functional groups, (AC=O) and (AC=OO), were defined to represent, respectively, the aromatic ketones and aromatic esters present in the family of compounds under study. Parameters for theses news functional groups were determined by fitting pure component and binary experimental data.The aromatic ketone and aromatic ester groups were represented as having an electron-donor site. Thus, association in aromatic ketones and esters will take place through the electronegative site of the AC=O and AC=OO functional groups, capable of cross-associating with the electropositive site of other associating groups present in the solutions.The parameterization carried out in this work provided a satisfactory correlation of all the systems included in the experimental data bank. Furthermore, the GCA-EoS was able to give adequate phase equilibrium predictions in mixtures of anthraquinones with CO2, water and ethane and mixtures of cholesterol esters with CO2.The extension of the GCA-EoS model will allow to represent a large set of anthraquinones and cholesterol esters with complex chemical structures, and to evaluate traditional and supercritical processes using the equation predictive capability.