Viscosity of pure liquids at high pressures
Transcrição
Viscosity of pure liquids at high pressures
ECTP2014 - 20th European Conference on Thermophysical Properties ORAL O_C2.15, 2 Sept. 11:45 – 12:00, Room_C VISCOSITY OF PURE LIQUIDS AT HIGH PRESSURES; A CORRELATION SCHEME FOR A SUSTAINABLE FAMILY OF COMPOUNDS Helena M. N. T. Avelino1; João C. F. Diogo2; Fernando J. P. Caetano3; João M. N. A. Fareleira2 Centro de Química Estrutural, Instituto Superior Técnico and Instituto Superior de Engenharia de Lisboa, Portugal; de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Portugal; 3Centro de Química Estrutural, Instituto Superior Técnico and Universidade Aberta, Portugal. 1 2Centro Dialkyl adipates are “green” solvents currently used in a wide variety of applications, namely in the chemical, polymer and mechanical industries. Many of these applications need their viscosity in order to optimize the processes in which they are involved. Moreover, their main characteristics of stability, low toxicity, low vapour pressure and availability at reasonably low cost suggest theycan also be used as viscosity reference liquids for industrial applications. Thus we have developed a preliminary single correlation scheme of the viscosity of dialkyl adipates, in moderately wide ranges of temperature and pressure. The scheme is based on a semi-empirical method proposed by Li et al. [1] which is a heuristic development of the kinetic theory for dense hard-sphere fluids, applied to the van der Waals model of a liquid [2]. Assael et al. [3] have used the same hard-sphere model to correlate the transport properties of liquid n-alkanes. In the present communication, we propose a correlation of the same type for the viscosity of liquid dialkyl adipates. The method is based on recently obtained experimental viscosity and density data [4-6] of compressed liquid dialkyl adipates, namely, dimethyl, dipropyl and dibutyl adipates. All the experimental viscosity data is described by the present correlation scheme with a standard deviation of ± 0.5 %. The correlation scheme can be used to interpolate or extrapolate viscosity data of dialkyl adipates that entered in the development of the method. Furthermore, tests will be presented in order to assess its capability to estimate the viscosity of compressed liquid diethyl adipate, which was not used to develop the technique, by comparison to recently published data [7,8]. The utilisation of the scheme as a predictive tool makes use of a single molecular parameter for each dialkyl adipate. Acknowledgements: This work was supported by the Strategic Projects PEst-OE/QUI/UI0100/2011 and PEstOE/QUI/UI0100/2013, both funded by Fundação para a Ciência e a Tecnologia (FCT, Portugal). Furthermore, J.C.F.D. thanks FCT, Portugal, for his PhD grant (SFRH/BD/66736/2009). [1] Li, S.F.Y.; Trengove, R.D.; Wakeham, W.A.; Zalaf, M., Int. J. Thermophys.1986, 7, 273–284. [2] Dymond, J.H., Chem. Soc. Rev. 1985, 14, 317-356. [3] Assael, M.J.; Dymond, J.H.; Papadaki, M.; Patterson, P.M., Int. J. Thermophys.1992, 13, 269–281. [4] Diogo, J.C.F.; Caetano, F.J.P.; Fareleira, J.M.N.A., Fluid Phase Equilib. 2014, 367, 85–94. [5] Diogo, J.C.F.; Avelino, H.M.N.T.; Caetano, F.J.P.; Fareleira, J.M.N.A., Fluid Phase Equilib. (Accepted) 2014. [6] Diogo, J.C.F.; Caetano, F.J.P.; Fareleira, J.M.N.A., to be published. [7] Comuñas, M. J. P.; Bazile, J.-P.; Lugo, L.; Baylaucq, A.; Fernández, J.; Boned, C., J. Chem. Eng. Data 2010, 55, 3697–3703. [8] Meng, X.Y.; Zheng, P.J.; Wu, J.T.; Liu, Z.G. , J. Chem. Eng. Data 2008, 53,1474–1478.