Novel Method To Isolate Interfacial Material

• Published in: Energy & fuels Vol. 29; no. 11; pp. 7058 - 7064
• Main Authors: Jarvis, Jacqueline M, Robbins, Winston K, Corilo, Yuri E, Rodgers, Ryan P
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19.11.2015
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/acs.energyfuels.5b01787

Isolation of crude oil components that concentrate at the oil/water interface [i.e., interfacial material (IM)] facilitates their molecular identification and quantitation, which is critical for advances in optimal petroleum production and processing. For a given crude oil, the molecular composition of IM determines its emulsion stability and identifies those chemistries that disproportionately contribute to the interfacial layer. Here, we describe a scalable, simple, quick, and efficient procedure to isolate IM from petroleum crude oils and/or other organic matrices. Hydrated silica (∼26 monolayers of water on a silica surface) enables separation of interfacially active species through their interaction with the immobilized water. Species with little or no interaction with the hydrated silica (water-laden) surface are eluted with a 1:1 (vol) mixture of heptane/toluene (heptol). The interfacially active species are subsequently isolated through the addition of methanol to the eluting solvent mixture, which partially strips water from the silica surface and releases the interfacially active species. Molecular-level characterization of the two fractions (fraction 1, non-interfacially active; fraction 2, interfacially active) by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) reveals that isolated IM contains a higher abundance of acidic oxygen- and sulfur-containing compounds relative to the parent crude oil. Emulsion stability tests of the isolated fractions demonstrate that fraction 2 (interfacially active) produces a much more stable emulsion than fraction 1 (non-interfacially active). Finally, a comparison of molecular-level characterization results obtained by the wet silica technique to that of the heavy water (Wu) method reveals a similarity between chemical functionalities (heteroatom classes) of isolated, interfacially active species.