Vapor-liquid equilibria of monoacylglicerol + monoacylglicerol or alcohol or fatty acid at subatmospheric pressures

Abstract

Partial acylglycerols are relevant minor compounds in the oil/fat industry. They represent important role to the food industry, as surface-active agents and emulsifiers. Also, they are present in the biodiesel production and its separation steps. Therefore, knowledge of their thermophysical properties are critical to product and process design. Considering that, this study aims at determining by the DSC technique novel boiling point data for two monoacylglycerols, namely, monononanoin and monolaurin at subatmospheric pressures, and for four binary fatty mixtures at selected pressures (TPx data), i.e. lauric acid + monocaprylin (3.42 kPa), monononanoin + monolaurin (2.06 kPa), monononanoin + hexadecanol (2.02 kPa), and monolaurin + octadecanol (2.05 kPa). As expected, the system with two monoacylglycerols (monononanoin + monolaurin) showed an ideal behavior. On the other hand, the other systems presented non-ideal behavior. Experimental data were successfully regressed by the Wilson, the NRTL and the UNIQUAC models. Predictive capacity of the UNIFAC method and its different versions was tested, and results indicated that improvements concerning lipid systems are still necessary. These improvements must be based on diverse and qualified experimental data.