The prebiotic molecules observed in the interstellar gas
... molecular weight, extending from the known interstellar molecules to the largest grains for which observational evidence exists: objects about 0.4 mm in size with the order of 1010 atoms. A crucial question then is how far the specific structures, which characterize all the known molecules, extend u ...
... molecular weight, extending from the known interstellar molecules to the largest grains for which observational evidence exists: objects about 0.4 mm in size with the order of 1010 atoms. A crucial question then is how far the specific structures, which characterize all the known molecules, extend u ...
SIDE GROUP ADDITION TO THE POLYCYCLIC AROMATIC
... Based on the evidence that aromatic compounds are commonly observed in interstellar space and in meteorites and should condense into interstellar grain mantles, we have investigated the energetic processing of PAHs in interstellar ice analogs to explore possible connections between interstellar and ...
... Based on the evidence that aromatic compounds are commonly observed in interstellar space and in meteorites and should condense into interstellar grain mantles, we have investigated the energetic processing of PAHs in interstellar ice analogs to explore possible connections between interstellar and ...
replacement of highly aromatic oils in tyres frequently asked
... legislators as a tool for classifying and labeling oils. Oils with an IP346 extract content below 3% are classified as non-carcinogenic 2. Highly aromatic oils Q1 - What are highly aromatic oils? What are they used for in tyres? Highly aromatic oils are derivatives of the petrochemical industry. Ar ...
... legislators as a tool for classifying and labeling oils. Oils with an IP346 extract content below 3% are classified as non-carcinogenic 2. Highly aromatic oils Q1 - What are highly aromatic oils? What are they used for in tyres? Highly aromatic oils are derivatives of the petrochemical industry. Ar ...
Setting the stage
... C10H8 to C130H28. Spectra of PAHs in neutral and singly charged (+/–) states. Spectra of a few multiply charged ...
... C10H8 to C130H28. Spectra of PAHs in neutral and singly charged (+/–) states. Spectra of a few multiply charged ...
Coal Tar Presentation - Fox River Ecosystem Partnership
... more toxic. In Lake-in-the-Hills, USGS researchers found that driveway dust was contaminated with extremely high levels of benzo[a]pyrene, one of the most toxic PAHs. The amount was 5,300 times higher than the level that triggers an EPA Superfund cleanup at polluted industrial sites. As Barbara Mahl ...
... more toxic. In Lake-in-the-Hills, USGS researchers found that driveway dust was contaminated with extremely high levels of benzo[a]pyrene, one of the most toxic PAHs. The amount was 5,300 times higher than the level that triggers an EPA Superfund cleanup at polluted industrial sites. As Barbara Mahl ...
POLYCYCLIC AROMATIC HYDROCARBON (PAH’S)
... PAHs are one of the most widespread organic pollutants. In addition to their presence in fossil fuels they are also formed by incomplete combustion of carbon-containing fuels such as wood, coal, diesel, fat, tobacco, and incense. ...
... PAHs are one of the most widespread organic pollutants. In addition to their presence in fossil fuels they are also formed by incomplete combustion of carbon-containing fuels such as wood, coal, diesel, fat, tobacco, and incense. ...
Polycyclic aromatic hydrocarbon
Polycyclic aromatic hydrocarbons (PAHs, also polyaromatic hydrocarbons) are hydrocarbons—organic compounds containing only carbon and hydrogen—that are composed of multiple aromatic rings (organic rings in which the electrons are delocalized). Formally, the class is further defined as lacking further branching substituents off of these ring structures. Polynuclear aromatic hydrocarbons (PNAs) are a subset of PAHs that have fused aromatic rings, that is, rings that share one or more sides. Though poly- in these cases literally means ""many"", there is precedence in nomenclature for beginning this class and subclass with the two ring cases, where naphthalene would therefore be considered a simple example; beginning at three rings, examples include anthracene and phenanthrene.PAHs are neutral, nonpolar molecules; they are found in fossil fuels (oil and coal) and in tar deposits, and are produced, generally, when insufficient oxygen or other factors result in incomplete combustion of organic matter (e.g., in engines and incinerators, when biomass burns in forest fires, etc.). PAHs can also be found at high levels in cooked foods, e.g., in meat cooked at high temperatures over open flame. Benzo[a]pyrene is a well-researched example of a coal tar PAH (see image) whose metabolites are mutagenic and highly carcinogenic; as a class, benzopyrenes, a ring fusion between monocyclic benzene and tetracyclic pyrene rings, result from incomplete combustion at temperatures between 300 °C (572 °F) and 600 °C (1,112 °F).PAHs may also be abundant in the universe, and are conjectured to have formed as early as the first couple of billion years after the Big Bang, in association with formation of new stars and exoplanets. Some studies suggest that PAHs account for a significant percentage of all carbon in the universe, and PAHs are discussed as possible starting materials for abiologic syntheses of materials required by the earliest forms of life.Critically, as noted, PAHs have been identified as carcinogenic and mutagenic (as well as teratogenic), and are considered pollutants of concern for the potency of potential adverse health impacts; the same holds true of their presence at significant levels over time in human diets.