Naphthalene , aromatic compound

The Huckel rule is strictly applicable only to monocyclic compounds, but the genera] concept of aromaticity can be extended beyond simple monocyclic compounds to include polycyclic aromatic compounds. Naphthalene, with two... 

Two or more benzene rings fused together form a number of polycyclic benzenoid aromatic compounds, naphthalene, anthracene and phenanthrene, and their derivatives. All these hydrocarbons are obtained from coal tar. Naphthalene is the most abundant (5%) of all constituents of coal tar. 

Aromaticity in the larger (4A+2) annulenes depends on whether the molecule can adopt the necessary planar conformation. In the all-cis [10]annulene, the planar conformation requires an excessive amount of angle strain. The [10]annulene isomer with two trans double bonds cannot adopt a planar conformation either, because two hydrogen atoms interfere with each other. Neither of these [10]annulene isomers is aromatic, even though each has (4/V+2) pi electrons, with N = 2. If the interfering hydrogen atoms in the partially trans isomer are removed, the molecule can be planar. When these hydrogen atoms are replaced with a bond, the aromatic compound naphthalene results. 

Using Py-GC/MS data and selecting the values of nine parameters for the pyrolysates (the content of long chain aliphatic compounds, content of benzene, toluene relative to total pyrolyzate, toluene relative to aromatic compounds, naphthalene relative to the content of benzene + naphthalene, cresol relative to aromatic compounds, cresols relative to toluene + cresols, and the level of o-cresol relative to total cresols), followed by the use of principal component analysis, it was possible to obtain the dendrogram shown in Figure 14.2.2. 

The Hiickel rule is strictly applicable only to monocyclic compounds, but the general concept of aromaticity can be extended beyond simple mono-cyclic compounds to include polycyclic aromatic compounds. Naphthalene, with two benzene-like rings fused together, anthracene, 1,2-benzpyrene, and coronene are all well-known compounds. Benzolalpyrene is particularly interesting because it is one of the cancer-causing substances that has been isolated from tobacco smoke,... 

Comparison of data in Tables 1 and 2 shows that the addition of 0.05% Bi to Pt-Re catalysts leads to an increase of n-hexane conversion and benzene yield from 82 to 93%, and from 47 to 68%, respectively. Maximum toluene yield decreases under these conditions from 29 to 21%. Ci-Cs hydrocarbons were not found in the products, but there were polycyclic aromatic compounds (naphthalene, anthracene, etc.). Their amounts were observed to increase with the increase in reaction temperature up to 650°C. The appearance of these products has been confirmed by ER-spectroscopy and chromatomassspectroscopy methods. 

The production of polysulfones was shown to be possible in Ref [ 181 ] by means of interaction of sulfuric acid, sulfur trioxide or their mixes with aromatic compounds (naphthalene, methylnaphthalene, methoxynaphtha-lene, dibenzyl ester, bisphenylcarbonate, bisphenyl, stilbene) if one used the anhydride of carbonic acid at 30-200 as the process activator. Obtained polymers could be reprocesses by means of pressing. 

In a typical experiment for CD-RTP analysis of PAHs an aliquot of the compovmd of interest is added to a flask and the solvent is evaporated gently on a hot plate. An aliquot of 1,2-dibromomethane or 2-bromoethanol (heavy-atom species) is then added, followed by an aliquot of 0.1 mol 1 sodium sulfite (oxygen scavenger), and final dilution with 0.01 mol 1 aqueous CD solution. The solution is shaken vigorously by hand. Some precipitation, usually due to inclusion of excess heavy atom by CD, may cause cloudiness in the solution, which does not affect the reproducibility and quality of phosphorescence spectra. Sample preparation time is less than 5 min in this method. Cline Love and colleagues reported RTP detection limits for several polynuclear aromatic compounds (naphthalene, biphenyl, phenanthrene, etc.) in CD solution in the range 10 -10 moll . ... 

The benzo-fiised counterparts of the simple heterocycles pyrrole, fiiran, and thiophene are indole, benzofuran, and benzothiophene. These compoimds are related to the two-ring, all-carbon aromatic compound naphthalene ... 

Carbonaceous materials are obtained via heat treatment from various sources, including coal, liquefied coal, coke, petroleum, resins, carbon blacks, paraffins, olefins, pitch, tar, polycyclic aromatic compounds (naphthalene, biphenyl, naphthalene sulfonic acid, anthracene sulfonic acid, phenanthrene sulfonic acid, etc.), polymers (polyethylene, polymethylacrylale, polyvinyl chloride, phenol resin, polyacrylonitrile, etc.) [99-101J. This kind of fluids is claimed to. show a strong ER effect, low electric power consumption and excellent durability [101]. Several publications addressed the ER effect and physical properties of carbonaceous ER fluids [102-104]. 

Ligroin, naphtha Ligroin is primarily used as a solvent in chemical manufacture and contains 55 % alkanes arxf 30 % cycloalkanes. Sometimes referred to as petroleum ether, but it is NOT an ether. Naphtha should not be confused with the solid aromatic compound naphthalene. 

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