Hexa-triethanolamine oleate esters as pour point depressant for waxy crude oils

New crystal modifier surfactants were developed by esterification of hexa-triethanolamine with oleic acid to prepare mono, di, and tri-esters. The synthesized esters were confirmed by IR spectroscopy and the molecular weight of the major compound in the reaction mixture was determined by MS analysis. Surface properties of the synthesized modifiers, including critical micelle concentration (CMC), effectiveness (πcmc), maximum surface excess (Ίmax) and minimum surface area (Amin) were determined at 30 °C. The synthesized esters were evaluated as flow improver (FI) and pour point depressant (PPD). Hexa-triethanolamine mono-oleate was most efficient for crude oil (I), and hexa-triethanolamine tri−oleate was most efficient for crude oil (II).