Measurement of the critical temperatures, pressures, heat capacities, and thermal diffusivities of four furanic compounds involved in the production of second-generation biofuels

Abstract

The critical temperatures, critical pressures, heat capacities, and thermal diffusivities have been measured for furfural, furfuryl alcohol, furfuryl acetate, and tetrahydrofurfuryl alcohol, the compounds of industrial importance because they are involved in the production of biofuels. The critical properties have been measured using the pulse-heating method applicable to thermally unstable compounds. The relative combined expanded uncertainties with the 0.95 level of confidence are 0.01 and 0.03 for the critical temperature and pressure of furfural and furfuryl acetate and 0.015 and 0.04 for furfuryl alcohol and tetrahydrofurfuryl alcohol. The acentric factors of the compounds have been calculated based on the experimental data. The critical properties of the compounds have also been calculated by the group contribution methods of Wilson and Jasperson, Nannoolal et al. Marrero and Gani, Hukkerikar et al. in two variants. The Wilson and Jasperson and Nannoolal et al. techniques provide the best estimation of the critical temperature; for the critical pressure, the Nannoolal et al. method gives the best results. The heat capacities in the liquid phase have been measured at atmospheric pressure in the temperature range from 298.15 to 451.15 K by DSC technique with relative combined expanded uncertainty 0.03. The data obtained have been approximated by third-order polynomials. The experimental heat capacities have been compared with those calculated by the group-contribution method of Kolska et al. The thermal diffusivities have been measured by laser flash method at atmospheric pressure in the temperature range from 313.15 to 373.15 K with relative combined expanded uncertainty 0.05. The experimental data have been approximated by first-order polynomials. The thermal conductivities have been calculated using the experimental data obtained.