Condensation of supersaturated vapors of hydrogen bonding molecules: Ethylene glycol, propylene glycol, trimethylene glycol, and glycerol

Authors

David B. Kane, Virginia Commonwealth University
M. Samy El-Shall, Virginia Commonwealth UniversityFollow

Document Type

Article

Original Publication Date

1996

Journal/Book/Conference Title

The Journal of Chemical Physics

Volume

105

Issue

17

DOI of Original Publication

10.1063/1.472548

Comments

Originally published at http://dx.doi.org/10.1063/1.472548

Date of Submission

October 2015

Abstract

The critical supersaturations required for the homogeneous nucleation (rate of 1 drop cm⁻³ s⁻¹) of ethylene glycol, propylene glycol, trimethylene glycol and glycerol vapors have been measured over wide temperature ranges (e.g., 280–400 K) using an upward thermal diffusion cloud chamber. At lower temperatures the experimental nucleation rates are much higher than the predictions of the classical nucleation theory. Glycerol shows the best agreement between experiment and theory in the temperature range of 340–370 K. An apparent increase in the critical supersaturation of glycerol is observed with increasing carrier gas (helium) pressure and this effect is more pronounced at lower temperatures. The results from corresponding states and scaled nucleation models indicate that the nucleation behavior of glycerol is quite different from other glycols. Glycerol requires higher critical supersaturations compared to the other glycols at the same reduced temperatures. This implies quite small critical clusters for glycerol (20–50 molecules) in the temperature range 300–380 K. The discrepancy between experiment and theory at lower temperatures may be explained by considering that the surface tension of the critical clusters is lower than the bulk surface tension. It is, however, surprising that a Tolman type correction for the curvature dependent surface tension could be applicable for such small critical clusters. Further theoretical work is required in order to fully understand the observed higher nucleation rates at lower temperatures of glycols and glycerol.

Rights

Kane, D., and El-Shall, M. S. Condensation of supersaturated vapors of hydrogen bonding molecules: Ethylene glycol, propylene glycol, trimethylene glycol, and glycerol. The Journal of Chemical Physics, 105, 7617 (1996). Copyright © 1996 American Institute of Physics.

Is Part Of

VCU Chemistry Publications