Polar aromatics fractions

Table IX shows a similar method of calculating the polar aromatics factor. The data for these calculations are derived from Table III. Table III indicates that the polar aromatic fractions from the three slurry oils have an aromaticity of approximately 0,75. The calculation shows that approximately 45.7% of the polar aromatic molecules remain in the slurry oil. Similar calculations with a number of reduced crudes and slurry oils derived from those reduced crudes has indicated that approximately 46% of the polar aromatic molecules remain in the slurry oil.

Separations. The asphaltene fractions were obtained by solvent extraction with benzene and subsequent precipitation with cyclohexane. The cyclo-hexane-soluble fractions were separated into saturate, aromatic, and polar aromatic fractions by the clay-gel technique, ASTM D-2007 (modified). This separation is also applicable to asphaltenes. 

In the manufacture of base oils, one of the refining operations is to extract with the aid of an appropriate solvent (furfural most often) the most aromatic fractions and the polar components. When free of solvent, the extracted aromatic fraction can eventually be refined, particularly to remove color or to thicken it, or still further, to fractionate it. The term, aromatic extract is used in every case. 

Another variation of the preceding method is to apply HPLC to fractionate the cleaned-up aliphatic-aromatic fraction from flash colurim separation of soluble organic matter as it is performed in the Chevron laboratory, for example, as described in Reference 2. A Waters HPLC system equipped with a preparative Whatman Partisil 10 silica column (9.4 X 500 mm), a HPLC pump, and two detectors for separation monitoring (a UV and refractive index detector) are used, giving three fractions of aliphatic hydrocarbons, mono-, di-, and triaromatics and polar compounds. The hrst two fractions are eluted with hexane, whereas polar compounds are eluted with... 

Depending on activation and development conditions, the Rj values of three main separated fractions may change but their ranges are approximately as follows 0.40 to 1.00 (aliphatic hydrocarbons), 0.05 to 0.40 (aromatic compounds), and 0.00 to 0.05 (polar compounds fractions) [49,72,76]. 

Each oil-dispersant combination shows a unique threshold or onset of dispersion [589]. A statistic analysis showed that the principal factors involved are the oil composition, dispersant formulation, sea surface turbulence, and dispersant quantity [588]. The composition of the oil is very important. The effectiveness of the dispersant formulation correlates strongly with the amount of the saturate components in the oil. The other components of the oil (i.e., asphaltenes, resins, or polar substances and aromatic fractions) show a negative correlation with the dispersant effectiveness. The viscosity of the oil is determined by the composition of the oil. Therefore viscosity and composition are responsible for the effectiveness of a dispersant. The dispersant composition is significant and interacts with the oil composition. Sea turbulence strongly affects dispersant effectiveness. The effectiveness rises with increasing turbulence to a maximal value. The effectiveness for commercial dispersants is a Gaussian distribution around a certain salinity value. 

Boylan and Tripp [76] determined hydrocarbons in seawater extracts of crude oil and crude oil fractions. Samples of polluted seawater and the aqueous phases of simulated samples (prepared by agitation of oil-kerosene mixtures and unpolluted seawater to various degrees) were extracted with pentane. Each extract was subjected to gas chromatography on a column (8 ft x 0.06 in) packed with 0.2% of Apiezon L on glass beads (80-100 mesh) and temperatures programmed from 60 °C to 220 °C at 4°C per minute. The components were identified by means of ultraviolet and mass spectra. Polar aromatic compounds in the samples were extracted with methanol-dichlorome-thane (1 3). 

Whereas the relative amount of aromatics remained fairly constant as sulfur conversion level was increased to 92-94%, the relative amount of sulfur in the aromatic fraction decreased markedly. This also is depicted in Figure 3. Polar aromatics are intermediate to the aromatics and asphaltenes in regard to this behavior. 

The region of the map below the pentane-insoluble boundary corresponds to pentane-deasphalted oil from the original residuum. The saturate, aromatic, and polar fractions were separated by adsorption of the deasphalted oil over clay. The saturate fraction shows a zero carbon residue and the aromatic fraction is only a little higher at 0.7%. The coke-forming constituents in the deasphaltened oil are the polar aromatics that have a carbon residue of 15.4. The carbon residue balance shown in the insert table shows that almost all of the coke-forming mate-... 

The results in Figure 1 can be interpreted in terms of general ring structures with the hydrocarbon classes. The peak for the polypolar aromatic fraction at 160° C probably is caused by polar-monocyclic compounds and the peak at 240° C is probably the result of polar dicyclic compounds. The broad curve in the monoaromatics centering at 275°C is probably mainly caused by alkyl-substituted tetralins while the peaks... 

The carbon and hydrogen analyses, VPO molecular weights, and NMR results were used to calculate average molecular parameters for the >diaromatics and polar aromatics obtained from both the reduced crude and slurry oils. The average molecular parameters were calculated by the method of Williams,(5)(6) Typical results of the average molecular parameter calculations for >diaromatic and polar aromatic chromatographic fractions obtained from both the reduced crude and slurry oils are given in Tables II and III,... 

Table I summarizes the analytical results for deasphaltened Athabasca bitumen (without prior distillation) on a series of columns used in the USBM-API 60 procedure, and those obtained by the simplified silica and alumina class separation scheme. As seen, the results are comparable provided that the polyaromatic and polar fractions are combined. The total analyses of the separated fractions obtained by the two methods listed in Table II are also in good agreement, with the exception that sulfur values from the simplified procedure are somewhat higher in all aromatic fractions except the polyaromatic/polar fraction.

The oils and bitumen were separated chromatographically on silica gel into saturates, aromatics, polar aromatics, and asphaltenes fractions by the SAPA method of Barbour et al. (8). 

Results of the application of the SAPA chromatographic procedure are given in Table III. The light oils contain mostly saturate fractions. The bitumen contains 48% saturate fraction. The aromatic, polar aromatic, and asphaltene fractions of light oils are reduced greatly compared with bitumen. These data indicate that the light oils could be composed mainly of the lower boiling components in the bitumen or are cracked products from the bitumen. A combination of the two alternatives is also possible. 

Separation Techniques. The complexity of the organic composition of coal-derived liquids, shale oil, and their related effluents presents a formidable challenge to the analytical chemist. Our approach to this problem has been the classical separation technique based on acid-base-neutral polarity of the organic compounds. We further subdivide the neutral fraction into aromatic and non-aromatic fractions using dimethyl-sulfoxide (DMSO) extraction. DMSO effectively removes multiringed aromatic compounds with great eflBciency (85-95%) for these complex mixtures and thus allows a straightforward analysis for polynuclear... 

Limited experiments with the aromatic fraction from the vacuum distillate indicated this material resembled the polar fraction much more than the saturate in pyrolysis behavior. This would be consistent with the carbon-13 nmr results,... 

A summary of the JF-5 yield data for all fractions stressed for various times at 450°C is presented in Table V, The saturate fraction affords the highest yield of JF-5 but the polar fraction also gives good yields. The maximum yields for these two fractions came at 60 minutes stress but the overall effect of time on yield was moderate. The results for the aromatic fraction were inconclusive because of limited amount of starting material. The general pattern of JP-5 yield for the vacuum... 

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