Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

As the important industrial raw materials, n-pentene, n-hexene and n-heptene are widely used as gasoline additives to improve the combustion characteristics of gasoline and polymerized monomer to synthesize many important polymer compounds. So the reliable density data are significant for these fluids to apply in industry. In this work, new experimental densities of n-pentene, n-hexene and n-heptene have been measured at pressures up to 100 MPa along nine isotherms between (283 and 363) K by using a high pressure vibrating-tube densimeter. The experimental system was calibrated using water and vacuum, and was tested with R134a over the entire temperature and pressure ranges. The combined expanded uncertainties of the temperature, pressure and density with a level of confidence of 0.95 (k = 2) are estimated to be 16 mK, 0.062 MPa (pless than 60 MPa), 0.192 MPa (60 MPa less than p less than 100 MPa), and up to 0.6 kg*m-3 depending on the temperature and pressure ranges. The density data were correlated with the Tait-like equation, and the average absolute deviations are 0.06%, 0.04% and 0.05%. Furthermore, the isothermal compressibility and the isobaric thermal expansivity were derived from the Tait-like equation over the experimental temperature and pressure ranges. 1. INTRODUCTION As significant industrial linear alpha olefins, n-pentene, n-hexene and n-heptene are not only widely used as gasoline additives to improve the octane number and the combustion characteristics of gasoline, but also the raw materials to synthesize many important polymer compounds.1, 2 The accurate density data of these fluids in a wide range of temperature and pressure are extremely important for flow simulation, system design and optimization, etc. Furthermore, to measure density accurately of these fluids is necessary for the scientific interest, such as, to develop the accurate equations of state and the accurate theoretical predictive models for deeply understanding the physical and chemical nature of the processes occurring in fluids at high temperature and high pressure. However, to the best of our knowledge, limited data sources for the density of n-pentene, n-hexene and n-heptene were found in literatures with high temperature and high pressure.3-11And the literature search was based on TRC/NIST archive12 and our own search. For n-pentene, only two density data sources were reported by Day and Felsing3 and Wolfe et al.4 measured by using volume