Temperature dependence of limiting activity temperature coefficients in C18 Ester solvents - part 2

Abstract

This work continued our focus on the influence of temperature on the activity coefficients of biodiesel ester/ VOC (volatile organic compound) interactions. The VOC families studied in this work were alkenes, alkynes, halogenated alkanes and amines. Solubility predictions in the form of infinite dilution activity coefficients were made using the Modified UNIFAC Dortmund group contribution model, and were computed using a Microsoft Excel spreadsheet specifically designed for this purpose. It was found that, with the exception of cyclopentadiene, alkene activity coefficients decreased slightly with increasing temperature thereby generally deviating from ideality. Solubility of alkyne interactions with unsaturated esters increased with increasing temperature, but decreased with saturated ester interactions for the terminal alkynes. With the exception of trichloromethane halogenated alkane activity coefficients decreased with increasing temperature, thus deviating from ideality. Interactions of esters with amines yielded a decrease in activity coefficients with increasing temperature, hence also deviating from ideality