Technical Note: Estimating fusion properties for polyacids

Abstract

Organic aerosol (OA) components are generally assumed to be liquid-like. Hence, to describe the partitioning of these components, the liquid vapor pressure of these components is desired. Polyacids and functionalized polyacids can be a significant part of OA. But often, measurements are available only for solid state vapor pressure, which can differ by orders of magnitude from their liquid counterparts. To convert such a sublimation pressure to a subcooled liquid vapor pressure, fusion properties (two out of these three quantities: fusion enthalpy, fusion entropy, fusion temperature) are required. Unfortunately, experimental knowledge of fusion properties is sometimes missing in part or totally, hence an estimation method is required. Several fusion data estimation methods are tested here against experimental data of polyacids. Next, we develop a simple estimation method, specifically for this kind of compounds, reducing significantly the estimation error

EVAPORATION: a new vapour pressure estimation methodfor organic molecules including non-additivity and intramolecular interactions

“…The conversion is especially relevant for the recent data on diacids and functionalised diacids (e.g., Booth et al, 2010;Chattopadhyay and Ziemann, 2005), where the temperature of measurement is far below T fus . In case no experimental H fus and/or T fus is available, it can be estimated by the simple method of Compernolle et al (2011a). Note that the up-…”

“…The other points are for diacids or functionalised diacids from various references, converted to subcooled liquid state, assuming C p,ls = S fus , if necessary. For a few compounds fromChattopadhyay and Ziemann (2005); Monster et al(2004), H fus is estimated by the method ofCompernolle et al (2011a).…”

EVAPORATION: a new vapor pressure estimation method for organic molecules including non-additivity and intramolecular interactions

“…The conversion is especially relevant for the recent data on diacids and functionalised diacids (e.g., Booth et al, 2010;Chattopadhyay and Ziemann, 2005), where the temperature of measurement is far below T fus . In case no experimental H fus and/or T fus is available, it can be estimated by the simple method of Compernolle et al (2011a). Note that the up- (Compernolle et al, 2011b) is not yet applied here.…”