Viscosities of Liquid Fluorocompounds

Abstract

In spite of their interest, viscosities of fluorocarbon compounds are scarce, and the available data are unreliable and of poor accuracy. In this work, viscosity measurements of linear, cyclic, aromatic, and R-substituted perfluorocarbons were carried out in the temperature range between (298.15 and 318.15) K using an Ubbelohde viscometer. The experimental results show that fluorinated compounds present viscosities considerably higher than their hydrocarbon homologues as expected. The viscosities increase from linear to aromatic to cyclic perfluorocarbons and within each family with the molecule size. The R-fluorine substitution by bromine increases the fluorocarbon viscosity due to the molecular weight increase. The Sastri-Rao method, a group contribution method for the liquid viscosity prediction, was applied for all the fluorocarbons where the viscosity was experimentally measured in this work. Using the new experimental data from this work, new group contribution values are proposed for fluorocarbon compounds allowing for a reduction of the average relative deviation from 12.0 % to 1.3 %.

Dynamic Molecular Behavior of Semi-Fluorinated Oleic, Elaidic and Stearic Acids in the Liquid State

“…6. Freire et al 32 reported that perfluoroalkane has a higher viscosity than its alkane homologues. In general, the perfluoroalkyl group is thought to be rigid when compared with the normal alkyl group.…”

Viscosity of Liquid Perfluoroalkanes and Perfluoroalkylalkane Surfactants

“…Experimental data on the viscosity of fluorocarbons are rather scarce in literature. In perhaps the only study to date, Freire et al 65 have measured the viscosity of several linear (F6 to F9), cyclic, aromatic, and R-substituted perfluorocarbons, over a relatively limited range of temperature.…”

Solubility of water in fluorocarbons: Experimental and COSMO-RS prediction results

“…By contrast, the carbon-fluorine bond creates strong intramolecular forces [1,2]. As a result, PFCs and FCs present unusual and interesting properties, as for example, large solubility for gases, exceptional chemical and biological inertness, excellent spreading characteristics, low surface tension and refractive index, density higher than water, and high isothermal compressibility [3][4][5][6][7]. Due to their intrinsic properties, PFCs and FCs are commonly used in the most diverse commercial and industrial applications ranging from cleaning solvents, fire suppression agents, heat transfer fluids, surfactants in supercritical solvents, in uranium enrichment, and as aerosol solvents [8].…”