Fluid Phase Equilibria 251 (2007) 8–16 Isothermal vapour–liquid equilibrium for cyclic ethers with 1-chloropentane Beatriz Giner, Ana Villares, Santiago Mart´ ın, Carlos Lafuente, F´ elix M. Royo ∗ Departamento de Qu´ ımica Org´ anica-Qu´ ımica F´ ısica, Facultad de Ciencias, Universidad de Zaragoza, Ciudad Universitaria, Zaragoza 50009, Spain Received 26 September 2006; received in revised form 25 October 2006; accepted 30 October 2006 Available online 7 November 2006 Abstract Isothermal vapour–liquid equilibrium measurements for mixtures containing cyclic ethers: tetrahydrofuran, tetrahydropyran, 1,3-dioxolane or 1,4-dioxane and 1-chloropentane at the temperatures of 298.15, 313.15 and 328.15 K are reported. The thermodynamic consistency of the VLE measurements was satisfactorily checked with the van Ness method. Activity coefficients were correlated with Wilson, NRTL, and UNIQUAC equations. The calculated excess Gibbs functions for tetrahydrofuran and tetrahydropyran are negative over the whole composition range while for 1,3-dioxolane and 1,4-dioxane the excess Gibbs functions are positive. © 2006 Elsevier B.V. All rights reserved. Keywords: Isothermal; Vapour–liquid equilibrium; Cyclic ethers; 1-Chloropentane 1. Introduction We have previously reported measurements on isobaric vapour–liquid equilibrium of mixtures containing a cyclic ether and normal and branched chloroalkanes [1–5]. Now we start the determination of vapour–liquid equilibrium of these kind of mixtures at isothermal conditions that provides more interesting information from a theoretical point of view. Here we present isothermal vapour–liquid equilibrium measurements for the mixtures formed by a cyclic ether: tetrahy- drofuran, tetrahydropyran, 1,3-dioxolane or 1,4-dioxane with 1-chloropentane at the temperatures of 298.15, 313.15 and 328.15 K. The VLE experimental results have been checked for thermodynamic consistency and the corresponding activity coef- ficients and excess Gibbs functions have been correlated with the following equations: Wilson [6], NRTL [7] and UNIQUAC [8]. To our knowledge, the VLE data for these mixtures have not been reported before. ∗ Corresponding author. Tel.: +34 976761198; fax: +34 976761202. E-mail address: femer@unizar.es (F.M. Royo). 2. Experimental 2.1. Chemicals The liquids used were: tetrahydrofuran (better than 99.5 mol%), 1,3-dioxolane, 1,4-dioxane and 1-chloropentane (better than 99 mol%) obtained from Aldrich and tetrahydropy- ran (better than 99 mol%) provided by Acros. No additional purification has been carried out. A comparison between exper- imental densities and vapour pressures and literature values [9–14] at 298.15 K is reported in Table 1. 2.2. Methods The vapour–liquid equilibrium was studied using an all-glass dynamic recirculating type still that was equipped with a Cottrell pump. It is a commercial unit (Labodest model) built in Ger- many by Fischer. The equilibrium temperature were measured to an accuracy of ±0.01 K by means of a thermometer (model F25 with a PT100 probe) from Automatic Systems Laborato- ries, and the pressure in the still was measured with a Digiquartz 735-215A-102 pressure transducer from Paroscientific equipped with a Digiquartz 735 display unit. The uncertainty of the pres- sure measurements is ±0.005 kPa. Equipment and experimental procedure has been previously described [15,16]. The vapour 0378-3812/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.fluid.2006.10.024