Polynuclear aromatic compounds pyrolysis studies

Primary Conversions and Influence of Mobile Phase Yields for the various H-donor and non-donor solvent extractions of Linby coal at 400% are summarised in Table III the conversions for the THF-extracted coal include the extracted material. Surprisingly, pre-extraction with THF significantly increases primary conversions in the polynuclear aromatic compounds (PACs) investigated. These findings appear to be contrary to those of other liquefaction (16) and pyrolysis (17) studies where prior removal of chloroform-extractable material significantly reduced conversions. However, Rincon and Cruz (18) have reported recently that pre-swelling coals in THF increases conversions for both anthracene oil and tetralin. The fact that Point of Ayr (87% dmmf C) coal yielded over 80% pyridine-solubles in pyrene (C.E. Snape, unpublished data) without pre-extraction is consistent with the earlier results of Qarke et al (19) for anthracene oil extraction where UK coals... 

Many studies of the pyrolysis of individual polynuclear aromatic compounds, particularly polynuclear aromatic hydrocarbons, have been published. The... 

Other studies on coal were performed using pyrolysis, such as the measurement of the level of sulfur containing compounds in coal [27,28], or evaluation of polynuclear aromatic hydrocarbons (PAH) in coal [29]. The generation of PAH in coal pyrolysis is an important issue, as some of these compounds are known to have carcinogenic properties. A list of PAHs identified in coal pyrolysates is given in Table 14.2.2. The yield of PAH in coal pyrolysate depends to some extent on the coal type but mainly on the pyrolysis temperature. The variation of PAH levels as a function of temperature for several bituminous coals is shown in Figure 14.2.3. The yields of other pyrolysis products of coal were also shown to be temperature dependent [30]. 

The origin of most compounds with effects on human health in cigarette smoke and in other types of smoke is not well understood. Studies on pyrolysis of pure substances were performed to find the origin of some of these undesirable compounds [39]. For example for the generation of polynuclear aromatic hydrocarbons (PAH), selected... 

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