Paraffinic structures

During World War II, isopropyl benzene, more commonly and commercially known as cumene, was manufactured in large volumes for use in aviation gasoline. The combination of a benzene ring and an iso-paraffin structure made for a very high octane number at a relatively cheap cost. After the war, the primary interest in cumene was to manufacture cumene hydroperoxide. This compound was used in small amounts as a catalyst in an early process of polymerizing butadiene with styrene to make synthetic rubber. Only by accident did someone discover that mild treating of cumene hydroperoxide with phosphoric acid resulted in the formation of... 

The microcrystalline or amorphous waxes separated from the crude fractions boiling above paraffin distillate are predominantly of the naphthene-containing paraffin structure (62, 70). Thus urea adducting of 149° to 165° F. melting point wax (Superla of Indiana) isolated but 15% of adductive material assumed to be normal or terminally branched paraffins. The microcrystalline waxes consist mostly of hydrocarbon with 34 to 60 carbon atoms (70) and have a melting range from 140° to 200° F. (16). 

Van Westen and Van Nes8 12. It is based on the fact that there is a linear relationship between the percentage of carbon, %C (in either naphthenic, aromatic or paraffinic structure) and the refractive index, the density and the reciprocal molecular weight, according to the equation ... 

Fig. 88c.The change of the number of carbon atoms in naphthenic, aromatic and paraffinic structure during the coalification process, according to Meijs.

Table III shows elemental composition of typical sour petroleum, coal syncrudes or shale oils. Compared with typical sour petroleum, the coal syncrude is lower in sulfur content but significantly higher in nitrogen. Compared with shale oil, coal syncrude is lower boiling and contains only about one half the nitrogen. A major difference between the two liquids is the highly aromatic structure of coal liquids and the absence of long paraffinic structures. Shale oil is more aromatic than petroleum but significantly less aromatic than coal liquids. This is mirrored by the hydrogen contents which were shown in Table I.

In the first place, as already stated, when benzene is treated with bromine, substitution products are more readily formed than addition products, and the former are the stable compounds. While methane, because of its saturated character, does not form addition products, but only substitution products, benzene forms both, but the substitution products are the more stable. Evidently benzene is more like a saturated compound than an unsaturated one in spite of the fact that it has eight less hydrogen atoms than are sufficient to satisfy the six carbon atoms according to the open-chain structure, and six less than sufficient according to the cyclo-paraffin structure. 

Elastomer compounds can be plasticized by addition of organic compounds. Elastomer compounds are inherently flexible and selection of a base polymer on the basis of molecular weight characteristics, chemical composition, and degree of crystallinity serves as the basis for the properties of the compound from which an elastomer is made. Oils are the most common plasticizer for elastomers. Oils of paraffinic structure or aromatic structure can be used with elastomers in which they are compatible. Paraffin wax would also be included in this category. Other plasticizers include phthalic acid esters and adipic acid esters. Fatty acids can be used as plasticizers but these contribute to an increase in surface tack of elastomer compounds. Examples include stearic and palmitic acid. Plasticizer addition has the added benefit of aiding with incorporation of inorganic materials. 

NMR spectra of humin from three major types of depositional environments, aerobic soils, peats, and marine sediments, show significant variations that delineate structural compositions. In aerobic soils, the spectra of humin show the presence of polysaccharides and aromatic structures most likely derived from the lignin of vascular plants. However, another major component of humin is one that contains paraffinic carbons and is thought to be derived from algal or microbial sources. Hydrolysis of the humin effectively removes polysaccharides, but the paraffinic structures survive, indicating that they are not proteinaceous in nature. The spectra of humin differ dramatically from that of their respective humic acids, suggesting that humin is not a clay-humic acid complex. 

The other major components of peat are paraffinic structures (peak at 30 ppm) observed in NMR spectra and described by Hatcher et al. (1980c). These structures, which probably have the major fraction of the carboxyl or amide groups (peak at 175 ppm) associated with them, also appear to be selectively preserved with depth in the peat (see Fig. 2). Earlier studies have suggested that this paraffinic component of peat is derived from algal or microbial sources (Hatcher, 1980). This may explain why the Mangrove... 

Several factors lead us to believe that this paraffinic component of peat is macromolecular and nonproteinaceous. First, the peat was treated with a benzene/methanol mixture prior to isolation of humin. Thus, it is unlikely that the paraffinic structures have a significant contribution from lipids. Second, when hydrolyzed in refluxing 6N HCl, the humin lost some paraffinic carbons, but mostly its polysaccharides as demonstrated in Figure 4 which shows C NMR spectra of humin and its hydrolyzed residue. The paraffinic carbons survive the hydrolysis, demonstrating their resistance. It is unlikely that proteinaceous material would survive such a treatment as an insoluble residue. 

By examination of the spectra in Figure 5, it is clear that polysaccharides (holocellulose, peaks at 72 and 106 ppm) are dominant in the delignified humin in the upper layers of peat but diminish in relative concentration with depth. This trend was also observed in the spectra of humin in Figure 2. At depth, the polysaccharides are minor compared to the paraffinic carbons (peak at 30 ppm). Thus, the paraffinic structures in humin are resistant to sodium chlorite oxidation, and their relative increase in concentration with... 

It is strikingly apparent that all spectra of aquatic kerogen are predominantly aliphatic with a major peak centered at 30 ppm. This peak is also the most intense peak in the spectrum of humin from Mangrove Lake also shown in Figure 9. Paraffinic structures of the type shown to be present in... 

In peat, humin is also composed of the three structural entities mentioned above. The anaerobic nature of peat precludes the extensive decomposition that occurs in aerobic soils, and biomolecules are likely to be better preserved. Carbohydrates are major components of humin in near-surface intervals but are decomposed and lost with depth in the peat. Lignin and the paraffinic structures are selectively preserved with depth. When the humin of peat is delignified, the paraffinic structures remain. These components are likely to be derived from nonvascular plant contributors to the peat, namely, algae. 

In an algal sapropel and also in marine sediments, humin and the HF/ HCl-treated humin are predominantly composed of the paraffinic structures that evolve as a result of selective preservation with depth in the sediments. In this case as well, the paraffinic structures are most likely derived from algal or microbial sources and could very well be original biomolecular components of the algae. 

Humic acids. CPMAS NMR spectra of representative marine and estuarine humic acids are shown in Figure 2.Solution H and NMR and solid state NMR spectra of marine sedimentary humic acids have previously been described by Hatcher and others ( ) and Dereppe and others (13). These spectra showed that marine sedimentary humic acids are predominantly composed of paraffinic structures that have a relatively high degree of branching, compared to long-chain alkyl structures. Aromatic structures are generally depleted in marine humic acids whose source is predominantly from algal or microbial detritus. 

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