Hydrocarbon hydroaromatic

Different types of other coal liquefaction processes have been also developed to convert coals to liqnid hydrocarbon fnels. These include high-temperature solvent extraction processes in which no catalyst is added. The solvent is usually a hydroaromatic hydrogen donor, whereas molecnlar hydrogen is added as a secondary source of hydrogen. Similar but catalytic liquefaction processes use zinc chloride and other catalysts, usually under forceful conditions (375-425°C, 100-200 atm). In our own research, superacidic HF-BFo-induced hydroliquefaction of coals, which involves depolymerization-ionic hydrogenation, was found to be highly effective at relatively modest temperatnres (150-170°C). 

Dehydrogenation (the conversion of alicycllc or hydroaromatic compounds into their aromatic counterparts by removal of hydrogen and also, in some cases, of other atoms or groups) finds wide application in the determination of structure of natural products of complex hydroaromatic structure. Dehydrogenation is employed also for the s)mthesis of polycyclic hydrocarbons and their derivatives from the readily accessible synthetic hydroaromatic compounds. A very simple example is the formation of p-methylnaphthalene from a-tetra-lone (which is itself prepared from benzene—see Section IV, 143) ... 

Hydrogen donors are, however, not the only important components of solvents in short contact time reactions. We have shown (4,7,16) that condensed aromatic hydrocarbons also promote coal conversion. Figure 18 shows the results of a series of conversions of West Kentucky 9,14 coal in a variety of process-derived solvents, all of which contained only small amounts of hydroaromatic hydrocarbons. The concentration of di- and polyaromatic ring structures were obtained by a liquid chromatographic technique (4c). It is interesting to note that a number of these process-derived solvents were as effective or were more effective than a synthetic solvent which contained 40% tetralin. The balance between the concentration of H-donors and condensed aromatic hydrocarbons may be an important criterion in adjusting solvent effectiveness at short times. 

Coals are macromolecular, —i.e., low rank coals, at least, appear to be able to absorb certain molecules such as methanol and hydrocarbons. In low and medium rank coals the ultimate units are linked by chemical and physical forces, and in high rank coals physical forces predominate. The presence of hydroaromatic structures in low rank coals must lead to rather distorted frameworks. Although it is not difficult to visualize that spaces exist in which foreign... 

In geochemically reversible reactions, environmental conditions determine the final ratio of starting material to end product if conditions in the environment change, this ratio adjusts to the change. In cases of slow equilibration a molecular ratio of starting material to end product may be preserved, which is indicative of past environmental conditions. More data are needed to test this idea, but it is conceivable that analyses of aromatic and hydroaromatic hydrocarbons and pigments might be interpreted in terms of a fossil environment. 

Product distribution data (Table V) obtained in the hydrocracking of coal, coal oil, anthracene and phenanthrene over a physically mixed NIS-H-zeolon catalyst indicated similarities and differences between the products of coal and coal oil on the one hand and anthracene and phenanthrene on the other hand. There were differences in the conversions which varied in the order coal> anthracene>phenanthrene coal oil. The yield of alkylbenzenes also varied in the order anthracene >phenanthrene>coal oil >coal under the conditions used. The alkylbenzenes and C -C hydrocarbon products from anthracene were similar to the products of phenanthrene. The most predominant component of alkylbenzenes was toluene and xylenes were produced in very small quantities. Methane was the most and butanes the least predominant components of the gaseous product. The products of coal and coal oil were also found to be similar. The most predominant components of alkylbenzenes and gaseous product were benzene and propane respectively. The data also indicated distinct differences between products of coal origin and pure aromatic hydrocarbons. The alkyl-benzene products of coal and coal oil contained more benzene and xylenes and less toluene, ethylbenzene and higher benzenes when compared to the products from anthracene and phenanthrene. The gaseous products of coal and coal oil contained more propane and butanes and less methane and ethane when compared to the products of anthracene and phenanthrene. The differences in the hydrocracked products were obviously due to the differences in the nature of reactants. Coal and coal oil contain hydroaromatic, naphthenic, heterocyclic and aliphatic structures, in addition to polynuclear aromatic structures. Hydrocracking under severe conditions yielded more BTX as shown in Table VI. The yields of BTX obtained from coal, coal oil, anthracene and phenanthrene were respectively 18.5, 25.5, 36.0, and 32.5 percent. Benzene was the most... 

The compositional data for the aromatic hydrocarbons present in the upgraded anthracene oil are presented in Table XIII. Comparison of the data in Tables XII and XIII reveals significant increases and decreases in the amounts of hydroaromatic and aromatic hydrocarbons, respectively, under all reaction conditions. This is especially evident by the presence and absence of the hydroaromatic -10(H) series in the products and feeds, respectively, and by the large increase in the weight percentage of the -8(H) compounds in the products compared to the feeds. The presence of significant amounts of dihydro-, tetrahydro-, and octahydrophenanthrenes in the products is indicated by GC/MS, by the increase in the weight percents at C-14 in the -16(H) and -14(H) series, and by the presence of C- H g, -10(H). 

The previous assumptions probably produce upper limits to the weight percents of hydroaromatic hydrocarbons. However, comparison of the values in columns 3 and 5 of Table XIV reveals that the increased contribution of these compounds in the products compared to the feed must be quantitatively significant. Furthermore, the deficiencies associated with these necessary assumptions should be minimized by considering the ratio of aromatic to hydroaromatic hydrocarbons in the products relative to the corresponding ratio for the feed. Thus, the hydroaromatic to aromatic hydrocarbon ratio in the products relative to the feed is oa. 5 to 1. 

The amount of hydroaromatic hydrocarbons significantly increased upon hydrotreating. The ratio of aromatic to hydroaromatic hydrocarbons in the feed relative to the products is ca. 

Figure 4. Variation of yields with hydrocarbon type P = paraffin (n-undecane), N = naphthalene (cis/trans decalin), HA = hydroaromatic (tetralin), A = aromatic (mesitylene) cracking temperature, 1133 K vapor residence time, 1 s...

The polycyclic aromatic hydrocarbons (PAHs) in brown coal consist predominantly of pentacyclic angularly condensed hydroaromatic moieties. These compounds appear to be derived from C30 triterpenoid... 

Aliphatic hydrocarbon moieties are present in significant amounts within the Murchison macromolecular material and several pyrolysis studies have indicated that these entities exist within or around the aromatic network as hydroaromatic rings and short alkyl substituents or bridging groups (e.g., Hayatsu et al., 1977 Holtzer and Oro, 1977 Levy et al., 1973). 

From the table we see that no change in the H/C ratio took place in this time. Work at Mobil (1, 2), Exxon (7, 8), and Oak Ridge National Laboratory (9) indicate that none of the following reactions takes place under the liquefaction conditions described above hydrogenation of aromatic polycyclic hydrocarbons significant aromatization of the hydroaromatic structures or destruction or formation of polycyclic saturated structures. 

Multiple intramolecular ring closures of aryl-substituted unsaturated long chain alcohols, acids, acid chlorides and ethers in the presence of Friedel-Crafts catalysts have been extensively employed to synthesize polynuclear hydroaromatic hydrocarbons and polycyclic ketones. This is illustrated by two examples shown in equations (112) and (113). The application of stereospecific cycloalkylations in approaching the synthesis of complex organic molecules has been reviewed by Barclay. ... 

Pines found that potassium t-butoxide when heated to decomposition temperatures (250-300°) catalyzes the dehydrogenation of hydroaromatic hydrocarbons. For example, d-limonene and the alkoxide were sealed in an autoclave, the air was CH, ipHj... 

The Diels-Alder reaction (diene synthesis) is the addition of compounds containing double or triple bonds (dienophiles) to the 1,4 positions of conjugated dienes with the formation of six-membered hydroaromatic rings. Hydrocarbons most often used in the reaction are 1,3-butadiene, cyclopentadiene, and isoprene, and dienophiles used include maleic anhydride, acrolein, and acrylic acid. The literature on this process is thoroughly reviewed by Alder (1), Kloetzel (59), Holmes (48), and Norton (82). 

For the polycyclic aromatic and hydroaromatic compounds tested in this study, the energy yield from electric discharge hydrocracking for production of the lighter hydrocarbons was in the following order ... 

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