Interfacial tension in water/n-decane/naphthenic acid systems predicted by a combined COSMO-RS theory and pendant drop experimental study. (16th September 2020)

• Record Type: Journal Article
• Authors: Olesen, Kristian B.; Pedersen, Anne-Sofie Dahl; Nikolajsen, Lasse V.; Andersson, Martin P.; Sølling, Theis I.; Sauer, Stephan P. A.; Mikkelsen, Kurt V.
• Is Part Of: Molecular physics. Volume 118:Number 18(2020)
• Publication Date: 2020-09-16
• Subjects: Interfacial tension -- water/n-decane/naphthenic acid systems -- COSMO-RS theory -- pendant drop experiment; Molecules -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Molécules -- Périodiques; Chimie physique et théorique -- Périodiques; 539.6.05
• DOI: 10.1080/00268976.2020.1764645
• Languages: English
• ISSNs: 0026-8976

Abstract

Abstract : The interfacial tension of systems containing water, n-decane, and model naphthenic acids were investigated using a predictive model based on COSMO-RS theory and experimental pendant drop measurements. Five naphthenic acid homologues that are considered to be representative of surfactants inherent to crude oil were dissolved in n-decane at equal concentrations. The interfacial tensions of the five systems at an acid concentration of 1.66 mol% relative to n-decane were experimentally determined to be 27–30 mN/m. The interfacial tensions of the five different acid-decane phases against water were also predicted using density functional theory (DFT) calculations and COSMO-RS theory. The accuracy of the predictions was very good as confirmed through pendant drop measurements of the interfacial tension. The mean-absolute-deviation between experimental and predicted values was 2.6 mN/m thus demonstrating the high predictive power of COSMO-RS theory for calculating the interfacial tension at oil–water interfaces in the presence of surface-active compounds. GRAPHICAL ABSTRACT: