Nitrogen polycyclic aromatic compounds

Later, D. W., Nitrogen Polycyclic Aromatic Compounds in Coal-Derived Materials, in Handbook of Polycyclic Aromatic Hydrocarbons (A. Bjprseth and T. Ramdahl, Eds.), Vol. 2, Dekker, New York, 1985. 

A schematic diagram of the column chromatographic separation method used to isolate APAH-rich fraction is shown in Figure 32.8. Briefly, the nitrogen polycyclic aromatic compounds (N-PACs) were eluted with chloroform from neutral aluminum oxide. Then, the APAHs were isolated from most of the other N-PAC by silicic acid adsorption chromatography. 

More detailed investigations will take some time polycyclic aromatic compounds have already been detected, some of which contain nitrogen and oxygen. Methylamine and ethylamine were also found. Contamination from the spacecraft seems unlikely. This first mission to return from the depths of the cosmos was a complete success (Brownlee et al 2006 Hoerz et al 2006). 

Hydroxylation may also take place at nitrogen atoms, resulting in hydroxyl-amines (e.g., acetaminophen). Benzene, polycyclic aromatic compounds (e.g., benzopyrene), and unsaturated cyclic carbohydrates can be converted by mono-oxygenases to epoxides, highly reactive electrophiles that are hepato-toxic and possibly carcinogenic. 

Asphaltenes These are complex high-molecular-weight polycyclic aromatic compounds which may contain oxygen, sulfur, or nitrogen heteroatoms. They are found in crude oil and in certain heavy fuel oils in micellar form. Their dispersion throughout oil can be stabilized by asphaltene precursors called resins and maltenes. 

TABLE 10.3 Structures, Common Names, Empirical Formulas, and Molecular Weights of Selected Nitrogen-Containing Mono- and Polycyclic Aromatic Compounds (N-PACs) Identified in Ambient Air... 

Later, D. W., C. W. Wright, K. L. Loening, and J. E. Merritt, Systematic Nomenclature of the Nitrogen, Oxygen, and Sulfur Functional Polycyclic Aromatic Compounds, in Polynuclear Aromatic Hydrocarbons Nomenclature Guide (K. Loening, J. Merritt, D. Later, and W. Wright, Eds.), pp. 27-47, Battelle Press, Columbus, OH, 1990. 

It is especially rewarding that the solutions of practical engineering problems, such as the reduction of emissions of nitrogen and sulfur oxides and polycyclic aromatic compounds from boilers, furnaces, and combustors, are amenable to the application of chemical engineering fundamentals. Guidance for preferred temperature-concentration history of the fuel may be given by reaction pathways and chemical kinetics, and elements of combustion physics, i.e., mixing and heat transfer may be used as tools to achieve the preferred temperature-concentration history in practical combustion systems. 

Similarly to the study on coal, of significant importance was the evaluation of polycyclic aromatic compounds generated from the pyrolysis of oil shale. This type of study included the evaluation of PAH in shale pyrolysates, and also of sulfur containing polycyclic aromatic compounds, and nitrogen containing polycyclic aromatic compounds [41 aj. 

Polycyclic aromatic compounds (PAC) are a significant environmental chemical group, with an associated health effect. PACs includes PAH (polycyclic aromatic hydrocarbon), PASH (polycyclic aromatic sulfur hydrocarbon), and PANH (polycyclic aromatic nitrogen hydrocarbon). The main PAHs are naphthalene, fluorene, phenanthrene, and their alkylated homologs PASHs are benzothiophene and diben-zothiophene PANHs are indole, carbazole, quinoline, and their alkylated derivatives (see Table 1). 

Polycyclic aromatic hydrocarbons Alkylated aromatic hydrocarbons Chlorinated aromatic compounds Chlorobenzenes Polychlorinated biphenyls Polychlorinated dibenzo[l,4]dioxins Chlorinated guaiacols and catechols Nitrogen-containing aromatic compounds Azaarenes and aromatic nitriles Oxygenated aromatic compounds 2,4-Dipentyl phenol Polycyclic quinones and ketones Aliphatic carboxylic acids Cs and C, dicarboxylic acids... 

Polycyclic aromatic compound Polycyclic aromatic hydrocarbon Polycyclic aromatic sulfur heterocycle Polycyclic aromatic oxygen heterocycle Nitrogen-containing polycyclic aromatic compound (both heterocyclic and nonheterocyclic compounds) Secondary-nitrogen polycyclic aromatic nitrogen heterocycles (nitrogen in a five-membered ring)... 

Recently, the application of short term bio-assays to a variety of emission and ambient particulate samples has demonstrated that other compounds than PAH, most likely PAH-derivatives, can be responsable for a major part of the observed biological activity of the extracts. These results have forced us to widen our interest to the field of particulate polycyclic organic matter (POM), which besides hetero-atomic PAH (polycyclic aromatic compounds, PAC, containing nitrogen or sulfur) may also contain oxidized, nitrated, or sulfonated derivatives of PAH, formed in exhausts, emission stacks, plumes or during transport through the atmosphere. 

FIGURE 32.8 Chemical class separation scheme for synthetic fuel products. HCs, hydrocarbons PACs, polycychc aromatic compounds N-PACs, nitrogen polycychc aromatic compounds 2 -PANHs, secondary nitrogen polycyclic aromatic heterocycles APAHs, amino polycyclic aromatic hydrocarbons 3 -PANHs, tertiary nitrogen polycyclic aromatic heterocycles. 

Another method for the analysis of nitrogen-containing compounds includes the formation of fluo-roamide derivatives for amino polycyclic aromatic compounds in coal liquids [28]. Quantitative analysis of amine-rich isolates of an SRC-II heavy distillate coal liquid with trifiuoroacetyl or pentafluoropropyl... 

Other kinds of molecules besides benzene-like compounds can also be aromatic. The cyclopentadienyl anion and cycloheptatrienyl cation, for instance, are aromatic ions. Pyridine and pyrimidine are srx-memhered, nitrogen-containing, aromatic heterocycles. Pyrrole and imidazole are five-membered, nitrogen-containing heterocycles. Naphthalene, quinoline, indole, and many others are polycyclic aromatic compounds. 

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