Solubility measurements of high molecular mass n-alkanes, n-alcohols and alcohol ethoxylates in supercritical propane

Pseudo binary high-pressure solubility measurements of a commercial mixture of high molecular mass n-alcohols (Mave = 566 g/mol) in propane and a commercial mixture of high molecular mass alcohol ethoxylates (50% ethoxylated, Mave = 1100 g/mol) in propane were conducted at temperatures between 375 and 410 K and pressures up to 275 bar. The propane–n-alcohol solubility curve shows complete solubility at pressures below 150 bar. At these conditions the propane–alcohol ethoxylate solubility curve shows a region of liquid-fluid immiscibility as well as a solubility inversion with temperature. Comparing the solubility of an n-alkane, an n-alcohol and a 50% ethoxylated alcohol ethoxylate, all with the same average hydrocarbon backbone length, in propane it is seen that the n-alkane is the most soluble, followed by the n-alcohol and the alcohol ethoxylate is the least soluble.