Estimating fusion properties for functionalised acids

Abstract

Abstract. Multicomponent organic aerosol (OA) is likely to be liquid, or partially liquid. Hence, to describe the partitioning of these components, their liquid vapour pressure is desired. Functionalised acids (e.g. diacids) can be a significant part of OA. But often measurements are available only for solid state vapour pressure, which can differ by orders of magnitude from their liquid counterparts. To convert such a sublimation pressure to a subcooled liquid vapour 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 completely, hence an estimation method is required. Several fusion data estimation methods are tested here against experimental data of functionalised acids, and a simple estimation method is developed, specifically for this family of compounds, with a significantly smaller estimation error than the literature methods.

Henry's law constants of diacids and hydroxy polyacids: recommended values

“…Therefore, the lowering of solubility with chain length must be due to a more difficult mixing, or equivalently an increase in activity coefficient. We showed previously (Compernolle et al, 2011) that for the longer chain diacids (starting from C7) UNIFAC-Peng and UNIFAC-Raatikainen underestimate γ sat s , which should be close to γ ∞ s for these low-soluble acids. These longer chain molecules were not in the data set used to develop UNIFAC-Peng or UNIFACRaatikainen, and this can explain the lower performance of both methods for these compounds.…”

Ozonolysis of methyl oleate monolayers at the air–water interface: oxidation kinetics, reaction products and atmospheric implications

“…11, are expected to be -in analogy to oleic acid ozonolysis -nonanal, nonanoic acid, 9-oxo-nonanoic acid methyl ester, azelaic acid methyl ester and octanoic acid methyl ester (see Scheme 1). The water solubility (following the approach of Kühne et al, 1995) 30 and volatility (following the approach of Compernolle et al, 2011) 31 of all of these products together with the main ozonolysis products of oleic acid are presented in Table 2 together with experimental values (where available). There is a considerable discrepancy between estimated and experimental solubility values, so interpretation of the data is a challenge which is further exacerbated for those compounds where experimental values are missing.…”

“…The calculation of the volatilities is based on the method 'Evaporation (full method)', proposed by Compernolle and co-workers. 31 Estimated water solubilities are obtained using the method proposed by Kühne et al (1995). 30 All values quoted are for a temperature of 298 K unless stated otherwise.…”

Henry's law constants of diacids and hydroxypolyacids: recommended values

“…Therefore, the lowering of solubility with chain length must be due to a more difficult mixing, or equivalently an increase in activity coefficient. We showed previously (Compernolle et al, 2011) that for the longer chain diacids (starting from C7) UNIFAC-Peng and UNIFAC-Raatikainen underestimate γ sat s , which should be close to γ ∞ s for these low-soluble acids. These longer chain molecules were not in the data set used to develop UNIFAC-Peng or UNIFAC-Raatikainen, and this can explain the lower performance of both methods for these compounds.…”