Energy & Fuels, Vol.29, No.11, 7058-7064, 2015
Novel Method To Isolate Interfacial Material
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 deter-Mines 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 (similar to 26 monolayers of water on a silica surface) enables separation of initerfacially 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) mature 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.