were calculated and are shown in Table IV. The distribution coefficient of dibenzothiophene in the unoxidized oil extraction was the highest (5.1). After oxidation, hexyl sulfide was not present in the oxidized oil. The distribution coefficients of dibenzothiophene and phenyl disulfide in the extraction of oxidized oil were increased: from 5.1 to 11.2 for dibenzothiophene and from 1.8 to 4.5 for phenyl disulfide. As for the phenyl sulfide, the distribution coefficient in both extractions was relatively low. These results are consistent with the results described previously.
ConclusionsOxidation of the Arabian AGO by nitrogen dioxide has converted the sulfur compounds of the oil to forms that are more polar in nature. These sulfur compounds are more readily extracted by polar solvents, such as lactone, that have been demonstrated to be aromatic/olefinic dissolving, thus resulting in higher sulfur removal, lower solvent-to-oil requirement, and hence, higher extraction This model employs lumping of the sulfur compounds in the oil into four groups, Si, S2, and S3, according to their retention times (hence, boiling points) in the gas chromatograph, and residue (R) containing some of the other three sulfur groups. The first group (Si) had a very fast reaction rate.