Isolation and Characterization of Surface-Active Components in Crude Oil - Toward Their Application as Demulsifiers

Surface-active components in the form of intrinsic emulsifiers have been studied, and their possible role as demulsifiers has been assessed. Polar components were extracted from crude oil via three isolation methods involving liquid/liquid extraction at pH 14, liquid/liquid extraction at pH 1, and column chromatography. All three isolates were found to improve separation within hours independent of their concentration. The material isolated from acidic extraction was found to be the most efficient. An expanded chemical analysis of the isolates involving Fourier transform infrared spectroscopy, UV-vis spectroscopy, liquid chromatography-mass spectrometry, and liquid chromatography-tandem mass spectrometry analysis was employed to identify the polar compounds in the three isolates. The most polar components were found to be naphthenic acids and saturated and nonsaturated noncyclic carboxylic acids. The least polar compounds were found to be nitrogen-containing aromatic bases such as pyridines, quinolines, pyrroles, indoles, indolines, and carbazoles. A mixture of compounds with polarities between the acids and bases were identified as phenols, pyrans, benzopyrans, naphthopyrans, benzonaphtholpyrans, dibenzopyrans, dinaphthopyrans, and compounds containing both nitrogen and oxygen atoms. The fact that so many compounds are found in each extract makes it difficult to speculate on exactly what types of molecules are significantly contributing positively to the emulsion breaking and separation process. The suggested polar molecules from this work have been sufficiently precise for a follow-up study to be realistic and promising, where the dominating polar molecules in each category are synthesized and subjected to separation experiments. Finally, interesting observations were made that relate to oil aturity and origin.