scholarly journals The Role of Methyl Groups in the Early Stage of Thermal Polymerization of Polycyclic Aromatic Hydrocarbons Revealed by Molecular Imaging

2020 ◽  
Author(s):  
Pengcheng Chen ◽  
Shadi Fatayer ◽  
Bruno Schuler ◽  
Jordan N. Metz ◽  
Leo Gross ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Early Stage ◽  
Complex Mixture ◽  
Thermal Polymerization ◽  
Industrial Applications ◽  
Thermal Reactions ◽  
Force Microscopy ◽  
Wide Range ◽  
Polycyclic Aromatic

The initial thermal reactions of aromatic hydrocarbons are relevant to many industrial applications. However, tracking the growing number of heavy polycyclic aromatic hydrocarbon (PAH) products is extremely challenging because many reactions are unfolding in parallel from a mixture of molecules. Herein, we studied the reactions of 2,7-dimethylpyrene (DMPY) to decipher the roles of methyl substituents during mild thermal treatment. We found that the presence of methyl substituents is key for reducing the thermal severity required to initiate chemical reactions in natural molecular mixtures. A complex mixture of thermal products including monomers, dimers, and trimers were characterized by NMR, mass spectrometry and non-contact atomic force microscopy (nc-AFM). A wide range of structural transformations including methyl transfer and polymerization reactions were identified. A detailed mechanistic understanding was obtained on the roles of H radicals during the polymerization of polycyclic aromatic hydrocarbons.

scholarly journals The Role of Methyl Groups in the Early Stage of Thermal Polymerization of Polycyclic Aromatic Hydrocarbons Revealed by Molecular Imaging

2020 ◽  
Author(s):  
Pengcheng Chen ◽  
Shadi Fatayer ◽  
Bruno Schuler ◽  
Jordan N. Metz ◽  
Leo Gross ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Early Stage ◽  
Complex Mixture ◽  
Thermal Polymerization ◽  
Industrial Applications ◽  
Thermal Reactions ◽  
Force Microscopy ◽  
Wide Range ◽  
Polycyclic Aromatic

The initial thermal reactions of aromatic hydrocarbons are relevant to many industrial applications. However, tracking the growing number of heavy polycyclic aromatic hydrocarbon (PAH) products is extremely challenging because many reactions are unfolding in parallel from a mixture of molecules. Herein, we studied the reactions of 2,7-dimethylpyrene (DMPY) to decipher the roles of methyl substituents during mild thermal treatment. We found that the presence of methyl substituents is key for reducing the thermal severity required to initiate chemical reactions in natural molecular mixtures. A complex mixture of thermal products including monomers, dimers, and trimers were characterized by NMR, mass spectrometry and non-contact atomic force microscopy (nc-AFM). A wide range of structural transformations including methyl transfer and polymerization reactions were identified. A detailed mechanistic understanding was obtained on the roles of H radicals during the polymerization of polycyclic aromatic hydrocarbons.

scholarly journals The Role of Methyl Groups in the Early Stage of Thermal Polymerization of Polycyclic Aromatic Hydrocarbons Revealed by Molecular Imaging

2020 ◽  
Author(s):  
Pengcheng Chen ◽  
Shadi Fatayer ◽  
Bruno Schuler ◽  
Jordan N. Metz ◽  
Leo Gross ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Early Stage ◽  
Complex Mixture ◽  
Thermal Polymerization ◽  
Industrial Applications ◽  
Thermal Reactions ◽  
Force Microscopy ◽  
Wide Range ◽  
Polycyclic Aromatic

The initial thermal reactions of aromatic hydrocarbons are relevant to many industrial applications. However, tracking the growing number of heavy polycyclic aromatic hydrocarbon (PAH) products is extremely challenging because many reactions are unfolding in parallel from a mixture of molecules. Herein, we studied the reactions of 2,7-dimethylpyrene (DMPY) to decipher the roles of methyl substituents during mild thermal treatment. We found that the presence of methyl substituents is key for reducing the thermal severity required to initiate chemical reactions in natural molecular mixtures. A complex mixture of thermal products including monomers, dimers, and trimers were characterized by NMR, mass spectrometry and non-contact atomic force microscopy (nc-AFM). A wide range of structural transformations including methyl transfer and polymerization reactions were identified. A detailed mechanistic understanding was obtained on the roles of H radicals during the polymerization of polycyclic aromatic hydrocarbons.

scholarly journals The Most Important Methods for Depollution of Hydrocarbons Polluted Soils

1970 ◽  
Vol 66 (1) ◽  
Author(s):  
Laura DOBOS ◽  
Carmen PUIA
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Heterocyclic Compounds ◽  
Chemical Structure ◽  
Complex Mixture ◽  
Naphthenic Acids ◽  
International Agency ◽  
Polluted Soils ◽  
Polycyclic Aromatic

Crude oil is a highly complex mixture of hydrocarbons amounting to hundreds of individual compounds with different chemical structure and molecular weight plus a series of lower molecular weight compounds other than hydrocarbons (phenols, thiols, naphthenic acids, heterocyclic compounds with N (pyridines, pyrrole, indole, s.o.) compounds S (alkyl thiols, thiophene, etc.) (Zarnea, 1994). Mineral oil and polycyclic aromatic hydrocarbons (PAHs) creates larger environmental problems. They are considered particularly dangerous. In this regard, EPA Agency from U.S.A. includes a number of polycyclic aromatic hydrocarbons under 16 priority pollutants, which require special attention. IARC (International Agency for Research on Cancer) has identified 15 types of polycyclic aromatic hydrocarbons including six of the 16 types of PAHs, identifiable by the USEPA as having carcinogenic properties (Chauhan Archana et al., 2008).

Comparison of Polycyclic Aromatic Hydrocarbons Exposure Across Occupations Using Urinary Metabolite 1-Hydroxypyrene

2020 ◽  
Vol 64 (4) ◽  
pp. 445-454
Author(s):  
Dong-Hee Koh ◽  
Ju-Hyun Park ◽  
Sang-Gil Lee ◽  
Hwan-Cheol Kim ◽  
Sangjun Choi ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Coke Production ◽  
Geometric Standard Deviation ◽  
Occupational Groups ◽  
Skin Cancers ◽  
Wide Range ◽  
Polycyclic Aromatic ◽  
High Fraction ◽  
Pah Exposure

Abstract Objectives Polycyclic aromatic hydrocarbons (PAHs) are well-known carcinogens causing lung and skin cancers in exposed workers. Certain occupations, such as coke production, have been associated with high PAH exposure; however, the number of occupations tested to date remains small. Here, we sought to compare PAH exposure across a wide range of occupations based on levels of 1-hydroxypyrene (1-OHP), the urinary exposure surrogate of PAHs. Methods We collected urine 1-OHP data from the Korean National Environmental Health Survey (KoNEHS), a nationwide biomonitoring survey. We developed a linear regression model, controlling for sex, age, smoking, and survey cycle, and obtained resulting residuals. Then, we computed the fraction of exceeding the third quartile (Q3) level of residuals for each occupation, which is employed as a relative exposure indicator across occupations. Results A total of 15 125 measurements derived from three cycles of KoNEHS were used for analysis. The overall geometric means (GMs) and geometric standard deviation (GSD) of urine 1-OHP levels were 0.16 µg g−1 creatinine and 3.07, respectively. Among the sub-major occupational groups, ‘construction and mining related elementary occupations’ showed the highest fraction (0.45) of exceeding the Q3 level of residuals. Among the minor occupational groups, ‘deliverers’ showed a high fraction (0.42) of exceeding the Q3 level of residuals, which indicates rapidly growing occupations to be addressed. Conclusions Our results provide ancillary information regarding PAH exposure across occupations, especially for occupations for which PAH exposure has not been well characterized.

scholarly journals Efficiency of Polycyclic Aromatic Hydrocarbons (PAHs) Degrading Consortium in Resisting Heavy Metals During PAHs Degradation

2018 ◽  
Vol 7 (1) ◽  
pp. 14-27 ◽  
Author(s):  
Zubairu Darma Umar ◽  
Nor Azwady Abd ◽  
Syaizwan Zahmir Zulkifli ◽  
Muskhazli Mustafa
Keyword(s):  
Heavy Metals ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Inductively Coupled Plasma ◽  
Natural Habitat ◽  
Complex Mixture ◽  
Optical Emission ◽  
Inductively Coupled ◽  
Molecular Weights ◽  
Polycyclic Aromatic

Polycyclic aromatic hydrocarbons (PAHs) comprised of many dangerous organic pollutants which affect human cell. The choice of phenanthrene and pyrene as model substrates was based on their classification among the most hazardous PAHs group by the US EPA where they belonged to low and high molecular weights PAHs respectively. Biodegradation of these PAHs is the best strategy that completely removes such pollutants in an environmentally friendly manner. However, the bacteria involved are challenged degradation difficulties as a result of PAHs inhibitory effects to the organisms. This research is aimed at formulating phenanthrene and pyrene degrading consortium that effectively perform best even in complex mixture with hazardous heavy metals. Different bacteria consortia were formulated using the compatibility testing and mathematical permutation approach and the best consortium selected. This selected consortium was then subjected to the degradation of both phenanthrene and pyrene separately in a combined mixture with the selected heavy metals from the inductively coupled plasma optical emission spectrophotometer (ICP-OES) analysis. Consortium composition of C. sakazakii MM045 (2%, v/v) and Enterobacter sp. MM087 (2%, v/v) were found to be much effective during phenanthrene (500 mg/L) and pyrene (250 mg/L) degradation. This consortium also resisted more than 6 mg/L each of Nickel (Ni), Cadmium (Cd), Vanadium (V) and Lead (Pb) in such complex degradation which was found to be more than the concentration in the natural habitat the consortium exists prior to isolation. Such performance makes the selected consortium to be an extremely efficient tool for the PAHs degradation application as many biodegradation agents were reported to be less effective when significant concentration of Ni, Cd, V and Pb are present.

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