Aromatic hydrocarbons complexes with oxygen

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. Physically, they are usually viscous liquids or semi-solids that are black or dark brown with a naphthalene-like odor. The coal tars are complex combinations of polycyclic aromatic hydrocarbons, phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. By comparison, coal tar creosotes are distillation products of coal tar. They have an oily liquid consistency and range in color from yellowish-dark green to brown. The coal tar creosotes consist of aromatic hydrocarbons, anthracene, naphthalene, and phenanthrene derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, dark brown to black residue which contains polycyclic aromatic hydrocarbons and their methyl and polymethyl derivatives, as well as heteronuclear compounds... 

As the reaction temperature is increased, chemiluminescence is observed in the reactions of ozone with aromatic hydrocarbons and even alkanes. Variation of temperature has been used to control the selectivity in a gas chromatography (GC) detector [35], At room temperature, only olefins are detected at a temperature of 150°C, aromatic compounds begin to exhibit a chemiluminescent response and at 250°C alkanes respond, giving the detector a nearly universal response similar to a flame ionization detector (FID). The mechanisms of these reactions are complex and unknown. However, it seems likely that oxygen atoms produced in the thermal decomposition of ozone may play a significant role, as may surface reactions with 03 and O atoms. 

Many PSPs are composed of probe dyes, such as polycyclic aromatic hydrocarbons (e.g., pyrene) and coordination compounds (e.g., platinum por-phryins and ruthenium(II) polypyridyl complexes) immobilized in various gas permeable polymer films such as silicon polymer, organic glassy polymers (e.g., poly(methylmethacrylate), polystyrene), fluorinated polymers, or cellulose derivatives such as ethyl cellulose [9,10]. As probe molecules interact with polymer matrices directly, the properties of PSPs strongly depend on the properties of polymer matrices. The oxygen permeability of polymer matrix is an especially important factor for highly sensitive PSP. 

Phthalic thioanhydride forms charge-transfer complexes with A.A-diethylaniline and various aromatic hydrocarbons (e.g., a 1 1 complex with naphthalene).131 When oxygen and sulfur are members... 

The narrow fluorine resonance of "Ci BF " is quite in contrast to the fluorine absorption found for the product of Illinois 6 coal with BF3. At room temperature, we observe a 0.25 mT (=2.5 G) wide, dipolar-broadened, spectrum not indicative of translation freedom. In contrast to the weakly bound complexes of BF3 with aromatic hydrocarbons, we anticipate BF3 to react strongly with oxygen functionality in the coal, through hydration with water, hydrolysis with acids (13), and ether complex formation (14), to give fluorine absorption lines which are in the rigid lattice condition. 

Triplet quantum yields (high rate of intersystem crossing (much faster than for typical aromatic hydrocarbons) and the inefficient fluorescence. These values were determined by photothermal and spectroscopic methods and agree with lower limits determined from singlet oxygen quantum yields [9,10]. (see below). A cyclodextrin complex also produces the triplet state efficiently in water [39]. 

Creosote. The major portion of creosote is derived from coal and is a complex mixture of aromatic hydrocarbons with condensed ring systems. The remaining components are tar acids, which are phenolic derivatives of these compounds, and tar bases, which are heterocyclic compounds containing nitrogen plus some neutral oxygenated compounds. At least 200 chemical compounds have been identified in coal-tar creosote, but many of these are present in small amounts. The chemical composition is variable, but some idea of a typical creosote is given in Table I (2). 

Usually, coal tars are viscous liquids or semisolids that are black or dark brown with a naphthalene-like odor. Coal tars are complex combinations of polycyclic aromatic hydrocarbons (PAHs), phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. PAH composition of coal tars is variable. 

Photocyanation of aromatic compounds is dealt with in several papers this year. In the presence of an electron acceptor such as p-dicyanobenzene, aromatic hydrocarbons such as naphthalene (81), substituted naphthalenes, phenanthrene, or anthracene give mixtures of products on irradiation with sodium cyanide. The major products involve substitution of hydrogen by cyanide or addition of hydrogen cyanide to the aromatic hydrocarbon. When oxygen is present, the product mixture is less complex, and a good yield of cyano-substituted compound is obtained. It is proposed that the aromatic radical cation is involved in the... 

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