J. of Supercritical Fluids 47 (2008) 182–187 Contents lists available at ScienceDirect The Journal of Supercritical Fluids journal homepage: www.elsevier.com/locate/supflu Supercritical extraction process and phase equilibrium of Candeia (Eremanthus erythropappus) oil using supercritical carbon dioxide Alexandre Teixeira de Souza a , Toni Luis Benazzi a , Marcelo Boer Grings a , Vladimir Cabral a , Edson Antônio da Silva c , Lúcio Cardozo-Filho a,∗ , Octavio Augusto Ceva Antunes b a Universidade Estadual de Maringá (UEM), Av. Colombo, 5790, Bloco D-90, 87020-900 Maringá, Paraná, Brazil b Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua da Faculdade, 645, 85903-000 Toledo, Paraná, Brazil c Universidade Federal do Rio de Janeiro, Instituto de Química, CT Bloco A 641, Cidade Universitária, 21941-909, Rio de Janeiro , RJ, Brazil article info Article history: Received 2 April 2008 Received in revised form 31 July 2008 Accepted 1 August 2008 Keywords: Candeia oil Carbon dioxide Supercritical fluid extraction Phase equilibria Mass transfer model Peng–Robinson abstract In this work a kinetic experimental study of supercritical oil extraction of Candeia (Eremanthus ery- thropappus) oil was carried out. In addition, the phase equilibrium study of the essential oil in CO 2 was measured and modeled. The extraction was performed at temperatures of 308, 313 and 333K, from 100 to 200 bar, while the phase equilibrium experiments were obtained in the CO 2 overall composition range of 10–90wt.%, from 313 to 333K and pressures up to 250bar. The experimental data of the phase equi- librium for the Candeia Oil + CO 2 system were described satisfactorily by the Peng–Robinson equation of state with VdW2 mixing rule. To represent the kinetics of oil extraction in a fixed bed column, it was employed a 2nd order kinetic model. It was showed, based on the comparison between experimental and theoretical results, that the model satisfactorily describes the extraction kinetics in all the studied cases using just one parameter. The chemical characterization of the extracts (CO 2 and hydrodistillation) was done using gas chromatography coupled to mass spectrometry. © 2008 Elsevier B.V. All rights reserved. 1. Introduction The -bisabolol is a substance with great industrial applica- tion in the hygiene, cosmetics and pharmaceutical sectors. The applications of -bisabolol in the pharmaceutical sector are due to the anti-inflammatory, antispasmodic, antiflogistic, sedative, anti- allergic, and vermifuge properties, among others. The essential oil from chamomile flowers using supercritical fluid extraction and steam distillation is the most studied alternative source in litera- ture to obtain the -bisabolol [1–3]. Another source of -bisabolol which is less explored is the oil extracted from the wood of Can- deia (Eremanthus erythropappus). The essential oil from Candeia is constituted of approximately 85% of -bisabolol [4,5]. In gen- eral, extracts of plants are complex mixtures of organic compounds which request appropriate fractionation techniques to allow a suit- able analysis of their individual constituents [6,7], as in this case. Supercritical fluid extraction (SFE) of compounds from plants is the most appropriate technology to obtain good yields of clean extracts associated with short extraction time. The potential for selective extractions by varying the pressure and temperature is ∗ Corresponding author. Tel.: +55 44 32614749. E-mail address: cardozodequem@yahoo.com.br (L. Cardozo-Filho). enormous. In addition, the smooth conditions preserve thermo- labile compounds [8,9], in comparison [10], for example, with steam distillation which can lead to degradation of thermo-labile com- pounds and partial hydrolysis of water sensible components. A common characteristic of the processes of extraction, separa- tion, and purification of natural products is the need to know the behavior of the phase system of interest, which allows the defini- tion of the process operation conditions [9,11–14]. Besides, from the engineering point of view, the knowledge of phase equilib- rium behavior of the mixtures plays an important role in selecting adequate operating regions and process scale up. The aim of this work is to study the supercritical extraction process of Candeia oil and investigate theoretically and experimen- tally the kinetics of extractions in addition to studying the phases’ equilibrium system between this oil and CO 2 . Furthermore, a com- parative analysis of the extract components is to be done to compare the selectivity of both processes. 2. Materials and methods 2.1. Characterization of the extract: chemical composition The chemical composition of the extracts was analyzed by a gas chromatograph (Shimadzu, Model 17A) coupled with a mass 0896-8446/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.supflu.2008.08.001