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 maturity
and origin.
An α-cyclodextrin protected with 2,4-dichlorobenzyl groups on the primary alcohols and ordinary benzyl groups on the secondary alcohols was prepared and subjected to DIBAL (diisobutylaluminum hydride)-promoted selective debenzylation. Debenzylation proceeded by first removing two dichlorobenzyl groups from the 6A,D positions and then removing one or two benzyl groups from the 3A,D positions.
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