Journal of Supercritical Fluids 23 (2002) 225 – 231 Solubility determination of nitrophenol derivatives in supercritical carbon dioxide Mojtaba Shamsipur a, *, Mohammad Reza Fat’hi b , Yadollah Yamini b , Ali Reza Ghiasvand b a Department of Chemistry, Razi Uniersity, Kermanshah, Iran b Department of Chemistry, Tarbiat Modarres Uniersity, Tehran, Iran Received 23 April 2001; received in revised form 12 November 2001; accepted 7 December 2001 Abstract Equilibrium solubilities of m-nitrophenol, p -nitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol and picric acid at 308, 318, 328, 338 and 348 K in supercritical CO 2 over a pressure range of 121.6–485.4 bar have been measured using a simple and reliable static method. The experimental data were correlated using a density-based model proposed by Chrastil. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Solubility; Supercritical CO 2 ; Nitrophenols www.elsevier.com/locate/supflu 1. Introduction Supercritical fluid extraction (SFE) with carbon dioxide is an attractive alternative to traditional extraction techniques, in order to avoid or mini- mize the use of organic solvents. SFE has proved to be an efficient technique for extraction of a wide range of analytes in several matrices, both on analytical and industrial scales. SFE has been used for the extraction of trace organics from many solid matrices, including flavors and fra- grances from natural products [1 – 4], additives from polymers [5,6], polycyclic compounds and polychlorinated biphenyls from environmental solids [7 – 9], hydrocarbons from geological sam- ples [10], organotin compounds from soil and aqueous matrices [11,12], pesticides, fungicides, and herbicides from different matrices [13 – 18], and phenol compounds from plant and soil sam- ples [19–21]. For the design of chemical processes which use supercritical fluids as solvents (e.g. extraction, chemical and biochemical reactions, microniza- tion), solubility or phase equilibria data are very important. Solubility data for a number of differ- ent compounds have been tabulated in the litera- ture [22,23]. The solubility of some phenols in supercritical carbon dioxide has also been re- ported in recent years [24–28]. Different nitrophenol derivatives are of critical importance in laboratory, medicine and industry; many of them are widely used as herbicides (spe- * Corresponding author. Tel.: +98-831-723307; fax: +98- 831-831618. E-mail address: mshamsipur@yahoo.com (M. Shamsipur). 0896-8446/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved. PII:S0896-8446(01)00143-7