Abstract
This paper focuses on the phase equilibrium of volatile organic compounds in silicon oil chemically
known as PDMS (polydimethylsiloxane) at infinite dilution. Measurements can be expensive and time
consuming, hence the need for thermodynamic models which allow the calculation of the phase
equilibrium behavior using a limited number of experimental data. The objective of this study was to
predict infinite dilution activity coefficients of selected VOCs (volatile organic compounds) in PDMS
using the Original UNIFAC model. The predicted results show that PDMS can be used to abate volatile
organic compounds from contaminated air streams. The results obtained in this work are comparable to
those obtained by the same authors through measurements such as the static headspace and the dynamic
gas liquid chromatographic techniques as well as other literature. Although the UNIFAC group
contribution method over estimate the infinite dilution activity coefficients, the results of this work may
be applied in preliminary phases of process design, simulation and feasibility studies.