Aromatic structures oxygen-containing

Ethers are either aliphatic (chain-structure) or aromatic (ring-structure) hydrocarbons containing an oxygen atom connected to two carbon atoms by single bonds. In halogenated ethers, one or... 

The Thermal Decomposition of Aromatic Ethers. According to the results of Table I, the bond scission of oxygen containing polynucleus aromatic structure of coal at liquefaction temperature of 450°C seems to occur mainly at methylene or ether structures. Therefore, it will be very important to study the... 

The composition of crude oil may vary with the location and age of an oil field, and may even be depth dependent within an individual well or reservoir. Crudes are commonly classified according to their respective distillation residue, which reflects the relative contents of three basic hydrocarbon structural types paraffins, naphthenes, and aromatics. About 85% of all crude oils can be classified as either asphalt based, paraffin based, or mixed based. Asphalt-based crudes contain little paraffin wax and an asphaltic residue (predominantly condensed aromatics). Sulfur, oxygen, and nitrogen contents are often relatively higher in asphalt-based crude in comparison with paraffin-based crudes, which contain little to no asphaltic materials. Mixed-based crude contains considerable amounts of both wax and asphalt. Representative crude oils and their respective composition in respect to paraffins, naphthenes, and aromatics are shown in Figure 4.1. 

TABLE 10.4 Structures, Common Names, Empirical Formulas, and Molecular Weights for Selected Oxygen-Containing Polycyclic Aromatic Compounds (O-PACs) Identified in Ambient Air... 

In addition to the Bisphenol-A backbone epoxy resins, epoxies with substituted aromatic backbones and in the tri- and tetra- functional forms have been produced. Structure-property relationships exist so that an epoxy backbone chemistry can be selected for the desired end product property. Properties such as oxygen permeability, moisture vapor transmission and glass transition temperature have been related to the backbone structure of epoxy resins5). Whatever the backbone structure, resins containing only the pure monomeric form can be produced but usually a mixture of different molecular weight species are present with their distribution being dictated by the end-use of the resin. 

On the other hand, all the sulfur-containing heterocycles are located in the close vicinity of the model aromatic structure, the cyclopentadienyl anion 131. Thus, one can assign higher aromaticity to the sulfur-containing heterocycles relative to the oxygen-containing ones, not only on the basis of geometric criteria but also from the 2-D dimensional perspective. 

Figure 12.6 Dependence of polymer deposition rate on molecular weight of monomer. Group I (O)- triple-bond-containing, aromatic, and heteroaromatic compounds group II ( ) double-bond-containing and cyclic compounds group III (A) compounds without aforementioned structures group IV (x) oxygen-containing compounds.

Because of the high discriminating capacity of MAD for sterically and/or electronically similar ethers, Yamamoto and Maruoka examined the affinity of the compound toward other substrates with oxygen-containing functional groups, for example various carbonyl compounds, including both aliphatic and aromatic aldehydes, amides, esters, ethers, and ketones with similar structural substituents. Binding behavior was monitored by low-temperature NMR spectroscopy of these substrates and their... 

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