Tetracyclic Aromatic Hydrocarbons Research Articles

THE COMPOSITION OF STRUCTURAL FRAGMENTS BOUND VIA SULPHIDE AND ETHER/ESTER BRIDGES IN PETROLEUM AND NATURAL BITUMEN OILS

Selective chemical cleavage (chemolysis) of C-S and C-O bonds of sulphide and ether/ester bridges, respectively, are presented. The revealed difference in the structural-group and molecular composition of some types of compounds before and after chemolysis indicates that alkanes, alkyltrimethylbenzenes, naphthalenes, phenanthrenes, tetra- and pentacyclic aromatic hydrocarbons, and dibenzothiophenes are present in oils not only as molecular entities, but, partially, as structural fragments linked via sulphide and ether/ester bridges with other fragments in complex high-molecular entities. Ester-bound high-molecular С20-С30 homologues predominate among the bound alkanes. The proportion of C13-C16 homologues among alkyltrimethylbenzenes decreases after chemolysis. Chemolysis is accompanied by an increase in the proportion of С3-С4 naphthalenes in petroleum oils. The ratio of homologues among phenanthrenes changes after chemolysis: as a rule, the unsubstituted compound predominates over homologues. The ratio of fluoranthene and pyrene to benzanthracene and chrysene increases among tetracyclic aromatic hydrocarbons. The main trend in the changes in the composition of dibenzothiophenes after chemolysis is a sharp decrease in the proportion of unsubstituted homologue.

Photochemical investigation of aromatic hydrocarbons of Balakhani crude oil as petroleum luminophores

In this paper, the photochemical conversion process of aromatic hydrocarbons in Balakhani oil well (BO) as a case study was investigated. To study the composition of BO, first, it has been separated into the first, second, third, and fourth groups of aromatics using chromatography absorption column. It has been established that the composition of the separated groups is mainly composed of mono-, tri-, and tetracyclic aromatic hydrocarbons. It has been shown that the optical densities of the absorption bands corresponding to bi-, tri-, and polycyclic aromatic hydrocarbons decrease with increasing the photo-irradiation period, hence their maximum absorption band undergoes the hypsochromatic shift, which is characteristic for electron donor substances. It has been determined that the photochemical conversion process in the sample oil (BO) occurs with radical-chain and molecular mechanisms. As a result of the photochemical conversion process of arene-type aromatic hydrocarbons, the first difference during the photooxidation of endoperoxides, hydroxynones, quinones, and phenes is the formation of cyclic peroxides and quinones.

The Identification of Pollutants in the Ob River Near Oil Production Areas

The composition of organic component of water and bottom sediments of Ob River in the area from the mouth of Tom River to the mouth of Irtysh river was studied by using GCMC. Oil and biogenic compounds were found. The maximum content of biogenic compounds was obtained in water near the Vasyugan River mouth, which is starting and flowing through the area of peat bogs propagation. The latitudinal waters of Ob River are enriched with typical oil compounds, such as hopanes, steranes, secohopanes, cheilanthanes, tetracyclic aromatic hydrocarbons, polymethyl substituted naphthalene and phenanthrene. The bottom sediments near the inflow of Tom River are enriched with polycyclic aromatic hydrocarbons. It was shown, that the occurrence of n-alkanes with dual nature cannot be an indicator of water bodies pollution with crude oil. In addition to this, the composition of aromatic hydrocarbons and cyclic isoprenoids may be used to differentiate the pollutant sources

Change in the Hydrocarbon Composition of Ashal’chinskoe Crude Oil via Biodegradation by Indigenous Soil Microflora under Laboratory Conditions

It has been shown that deep biodegradation of the components of oils with the change in the molecular composition of aliphatic, naphthenic, and aromatic hydrocarbons (HCs) occurs upon the biodegradation of Ashal’chinskoe crude petroleum by indigenous soil microflora under laboratory conditions. It has been found that alkanes and tri- and tetracyclic aromatic HCs are present in the oils of the biodegraded petroleum not only in the molecular form but also in the form of structural fragments linked through ether or sulfide bridges in the composition of complex high-molecular-weight entities. The composition of O- and S-linked compounds of the aforementioned types is different in the oils of the petroleum subjected to biodegradation.

Effect of oxygen-rich combustion on soot formation in laminar co-flow propane diffusion flames

Oxygen-rich combustion is a new type of clean combustion technology with important application prospects. In this work, the effects of oxygen-rich combustion on soot formation in the propane/(O2+N2) laminar flow coaxial jets diffusion flame were numerically investigated by using the detailed gas-phase chemical reaction model with the mechanism of tetracyclic aromatic hydrocarbons and the complex thermodynamic properties and transport characteristics parameters. Soot surface growth follows the hydrogen-abstraction-carbon-addition (HACA) model. A hybrid gas-phase mechanism was adopted, which contains a DLR-based polycyclic aromatic hydrocarbons (PAHs) formation, growth model and a gas-phase model. Results show that the oxygen-rich combustion has a great influence on the flame temperature, especially the high temperature region. With the increase of oxygen concentration, the soot formation region of flame broadens and the maximum of soot volume fraction increase from 3.95 ppm to 10.87 ppm. The extra oxygen makes PAHs increased around the nozzle, leading to larger rate in early soot nucleation and surface growth, eventually more soot yield.

Composition of Hydrothermal–Catalytic Conversion Products of Asphaltite from the Spiridonovskoe Oilfield

It has been shown that the hydrothermal–catalytic conversion of solid natural asphaltite of the Spiridonovskoe oilfield (Republic of Tatarstan) at 250°C in the presence of hematite yields liquid products with a reduced amount of resins and asphaltenes. At the same time, a dispersed phase of insoluble carburized substances of the carbene and carboid types appears in the conversion products. The structural-group and molecular compositions of oils in the liquid products of conversion, which are enriched in aromatic, polycycloaromatic, and carbonyl-containing structural units and sulfoxides according to 1H NMR and IR data, have been determined. It has been established that the molecular composition of oils from the initial asphaltite and its conversion products is almost the same, but there are changes in the relative amount of various types of compounds. A low concentration of alkanes and an increased concentration of triterpanes characterize the initial Spiridonovskoe asphaltite as a biodegraded object. In the conversion products, the relative amount of alkanes has sharply increased and the concentrations of tri- and tetracyclic aromatic hydrocarbons (HC) and dibenzothiophenes have become greater. The proportion of phenanthrenes and tetracyclic aromatic hydrocarbons has increased by factors of 9.3 and 2.6, respectively, and alkylcyclohexanes have been identified, which are absent in the original asphaltite. But the relative amount of polycyclic naphthenes (pregnanes, steranes, cheilanthanes, and hopanes) significantly decreased. The revealed differences are apparently determined by the scale of generation of these compounds by the degradation of resins and asphaltenes, in which the compounds occur as structural units of molecules or in an adsorbed and/or occluded form.

Degradation of n-alkanes and PAHs from the heavy crude oil using salt-tolerant bacterial consortia and analysis of their catabolic genes.

In the present study, salt-tolerant strains, Dietzia sp. HRJ2, Corynebacterium variabile HRJ4, Dietzia cinnamea HRJ5 and Bacillus tequilensis HRJ6 were isolated from the Dagang oil field, China. These strains degraded n-alkanes and polycyclic aromatic hydrocarbons (PAHs) aerobically from heavy crude oil (HCO) in an experiment at 37°C and 140rpm. The GC/MS investigation for degradation of different chain lengths of n-alkanes (C8-C40) by individual strains showed the highest degradation of C8-C19 (HRJ5), C20-C30 (HRJ4) and C31-C40 (HRJ5), respectively. Moreover, degradation of 16 PAHs with individual strains demonstrated that the bicyclic and pentacyclic aromatic hydrocarbons (AHs) were mostly degraded by HRJ5, tricyclic and tetracyclic AHs by HRJ6 and hexacyclic AHs by HRJ2. However, the highest degradation of total petroleum hydrocarbons (TPHs), total saturated hydrocarbons (TSH), total aromatic hydrocarbons (TAH), n-alkanes (C8-C40) and 16 PAHs was achieved by a four-membered consortium (HRJ2+4+5+6) within 12days, with the predominance of HRJ4 and HRJ6 strains which was confirmed by denaturing gradient gel electrophoresis. The abundance of alkB and nah genes responsible for catabolism of n-alkanes and PAHs was quantified using the qPCR. Maximum copy numbers of genes were observed in HRJ2+4+5+6 consortium (gene copies l-1) 2.53×104 (alkB) and 3.47×103 (nah) at 12days, which corresponded to higher degradation rates of petroleum hydrocarbons. The superoxide dismutase (SOD) (total SOD (T-SOD), Cu2+Zn2+-SOD), catalase (CAT) and ascorbate peroxidase (APX) activities in Allium sativum and Triticum aestivum were lower in the HRJ2+4+5+6-treated HCO as compared to the plantlets exposed directly to HCO. The present results revealed the effective degradation of HCO-contaminated saline medium using the microbial consortium having greater metabolic diversity.

Analysis of aromatic hydrocarbons in cracking products of jet fuel by comprehensive two-dimensional gas chromatography-mass spectrometry

As coking precursors, aromatic hydrocarbons have an effect on the cracking stability of fuels. A method for identifying and quantitating aromatics in the supercritical cracking products of jet fuel was established by comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC×GC-MS). The effects of main chromatographic conditions such as initial oven temperature and modulation period on the separation of supercritical cracking products were studied. The method has good separation ability for polycyclic aromatic hydrocarbons (PAH) isomers. A total of 27 aromatics, including monocyclic aromatic hydrocarbons, bicyclic aromatic hydrocarbons, tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, etc., were identified based on standard mass spectra, the retention times of standards and literature reports. Moreover, the corresponding quantitative determination was achieved by external standard method of GC×GC-FID. The results showed that the contents of aromatics increased with the increase of gas yield. When gas yield reached 22%, the bicyclic aromatic hydrocarbons began to produce, and their contents increased exponentially with the increase of gas yield. Compared with the traditional GC-MS, the method has better separation and qualitative ability, and can be applied to the separation of complex samples and qualitative and quantitative analyses of cracking products.

The Marine Isolate Novosphingobium sp. PP1Y Shows Specific Adaptation to Use the Aromatic Fraction of Fuels as the Sole Carbon and Energy Source

Novosphingobium sp. PP1Y, isolated from a surface seawater sample collected from a closed bay in the harbour of Pozzuoli (Naples, Italy), uses fuels as its sole carbon and energy source. Like some other Sphingomonads, this strain can grow as either planktonic free cells or sessile-aggregated flocks. In addition, this strain was found to grow as biofilm on several types of solid and liquid hydrophobic surfaces including polystyrene, polypropylene and diesel oil. Strain PP1Y is not able to grow on pure alkanes or alkane mixtures but is able to grow on a surprisingly wide range of aromatic compounds including mono, bi, tri and tetracyclic aromatic hydrocarbons and heterocyclic compounds. During growth on diesel oil, the organic layer is emulsified resulting in the formation of small biofilm-coated drops, whereas during growth on aromatic hydrocarbons dissolved in paraffin the oil layer is emulsified but the drops are coated only if the mixtures contain selected aromatic compounds, like pyrene, propylbenzene, tetrahydronaphthalene and heterocyclic compounds. These peculiar characteristics suggest strain PP1Y has adapted to efficiently grow at the water/fuel interface using the aromatic fraction of fuels as the sole carbon and energy source.

Effect of water washing on hydrocarbon compositions of petroleum sandstone reservoir rocks in Tarim Basin, NW China

Gross compositions and distribution of saturated and aromatic hydrocarbons in Carboniferous sandstone reservoir rocks in oil and water zones for Tazhong-10 well of the Zhongyang Uplift in the Tarim Basin were studied in detail by means of Rock-Eval pyrolysis, thin-Chromatograph-flame ionization detection (TLC-FID), gas chromatography, gas chromatography-mass spectrometry. The results suggest that the gross composition of reservoir hydrocarbons between the oil zone and the water zone show significant differences. Water washing has a dramatic effect on saturated hydrocarbon biomarkers, especially drimane series compounds. Drimane series compounds in the water zone have been depleted completely. However, the contents of tricyclic diterpanes and pentacyclic triterpanes tend to decrease slightly, but the water-zone reservoir hydrocarbons contain a large amount of gammacerane. This suggests that gammacerane be more resistant to water washing than diterpanes and homohopanes. The contents of pregnane, homopregrane, diasteranes relatively decrease as a result of water washing. Water washing has a noticeable effect on polycyclic aromatic hydrocarbon compounds, especially aromatic sulfur compounds, and the contents of dibenzothiophene series compounds and benzonaphiothiophene decrease significantly as a result of water washing. However, the contents of bicyclic and tricyclic aromatic hydrocarbons decrease slightly and those of tetracyclic and pentacyclic aromatic hydrocarbons, especially benzofluoranthene and benzopyrenes, increase markedly owing to a decrease in light aromatic hydrocarbons as a result of water washing.

Degradation of polycyclic aromatic hydrocarbons by an immobilized mixed bacterial culture

The mixed bacterial culture MK1 was capable of degrading a wide spectrum of aromatic compounds both as free and as immobilized cells. By offering anthracene oil or a defined mixture of phenol, naphthalene, phenanthrene, anthracene and pyrene (in concentrations of 0.1–0.2 mm, respectively) as sources of carbon and energy, a specific degradation pattern correlating with the condensation degree was observed. Regarding the defined mixture of aromatic hydrocarbons, complete metabolism was reached for phenol (0.1 mm) after 1 day, for naphthalene (0.1 mm) after 2 days and for phenanthrene (0.1 mm) after 15 days of cultivation. The conversion of anthracene (0.1 mm) and pyrene (0.1 mm) resulted in minimal residual concentrations, analogous to fluoranthene and pyrene of the anthracene oil (0.1%). Maximal total degradation for the tricyclic compounds dibenzofurane, fluorene, dibenzothiophene, phenanthrene and anthracene of the anthracene oil (0.1%) occurred after 5 days. In general, a significant metabolisation of the tetracyclic aromatic hydrocarbons fluoranthene and pyrene was observed after the degradation of phenol, naphthalene and most of the tricyclic compounds. Doubling the start concentrations of the polycyclic aromatic hydrocarbons effected higher degradation rates. Cell growth occurred simultaneously with the conversion of phenol, naphthalene and the tricyclic compounds. The immobilized cells showed stable growth and, compared to freely suspended cells, the same degradation sequence as well as an equivalent degradation potential — even in a model soil system.

Determination of mono‐ to tetracyclic aromatic hydrocarbons in lubricating oil

AbstractLiquid – liquid extraction with N‐methyl‐2‐pyrrolidone, combined with solid‐phase extraction on silica gel using n‐pentane and dichloromethane as solvents, has been used for the isolation and concentration of the aromatic fraction from lubricating oil.The identification of individual compounds in this aromatic fraction was performed by capillary gas chromatography–mass spectrometry (CGC‐MS) and by determination of retention indices. Quantitative results were obtained by flame ionization detection (CGC‐FID). Eighty four compounds, predominantly naphthalenes, phenanthrenes, biphenyls, fluorenes, dibenzo‐thiophenes, and their alkylated derivatives, have been identified in a commercial lubricating oil. The total amount of the aromatic fraction did not exceed 0.04 % of the oil.

Aqueous chlorination of tetracyclic aromatic hydrocarbons: reactivity and product distribution

Reaction of tetracyclic aromatic hydrocarbons (TCAHs) with chlorine in water were investigated by means of a capillary GC equipped with flame ionization detector. TCAHs tested were benz(a)anthracene (B(a)A), benzo(c)phenanthrene (B(c)P), chrysene (Chy), pyrene (Py), and triphenylene (Tri). The reactivity of these TCAHs to chlorine in water were found to be dependent on their structures, indicating a increase in the reactivity with a decrease of their ionization potentials. Mono- and dichlorinated derivatives and oxygenated compounds were identified to be present in chlorine-treated TCAHs solutions under those conditions utilized for water treatment plant.

Mutagenicity of bi-, tri- and tetra-cyclic aromatic hydrocarbons in the “taped-plate assay” and in the conventional Salmonella mutagenicity assay

Aromatic hydrocarbons in the range of 1–4 nuclear rings were examined for mutagenicity in the so-called “taped-plate assay”. This modification of the Ames assay is particularly equipped for the detection of volatile mutagens. Of the many compounds tested only phenanthrene, pyrene, benzo[ c]phenanthrene and benzoacenaphthylene were positive in this assay. The present data underline the exceptional behaviour of fluoranthene by being a rather potent bacterial mutagen with a volatile nature (as found in a previous study).

Salmonella/microsome mutagenicity of monochloro derivatives of some di-, tri- and tetracyclic aromatic hydrocarbons

A series of 8 monochloroarenes have been tested for mutagenicity in the Salmonella/microsome assay. None of the compounds was detectably active in the absence of mammalian activation whereas, depending on structure, some of the compounds were mutagenic in its presence having responses higher than those reported for the parent compounds.

Sampling of tetracyclic aromatic hydrocarbons under atmospheric conditions

Sampling of tetracyclic aromatic hydrocarbons under atmospheric conditions

Formation of the Radical Cations of Some Tetracyclic Aromatic Hydrocarbons in Boric Acid Glass

The radical cations of tetracene, chrysene, 1,2-benzanthracene, and 3,4-benzphenanthrene have been produced in boric acid glass by u.v. irradiation. Their electronic spectra are recorded in the region 200–1400 nm and show a close resemblance to the available data for the cations reported earlier.

ChemInform Abstract: BOND DISTORTIONS AND RELATED PHENOMENA IN PERI‐CONDENSED TETRACYCLIC NONBENZENOID AROMATIC HYDROCARBONS

Chemischer InformationsdienstVolume 4, Issue 44 Physical Organic Chemistry ChemInform Abstract: BOND DISTORTIONS AND RELATED PHENOMENA IN PERI-CONDENSED TETRACYCLIC NONBENZENOID AROMATIC HYDROCARBONS AZUMAO TOYOTA, AZUMAO TOYOTASearch for more papers by this authorTAKESHI NAKAJIMA, TAKESHI NAKAJIMASearch for more papers by this author AZUMAO TOYOTA, AZUMAO TOYOTASearch for more papers by this authorTAKESHI NAKAJIMA, TAKESHI NAKAJIMASearch for more papers by this author First published: October 30, 1973 https://doi.org/10.1002/chin.197344083Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume4, Issue44October 30, 1973 RelatedInformation

Interpretation of pentacyclic aromatic hydrocarbon transitions in terms of composite system approximations

The observed electronic transitions and transition assignments of three pentacyclic aromatic hydrocarbons, benz(a)naphthacene, dibenz(a,c) anthracene, and 3,4-benzopyrene, are presented. The transitions of the pentacyclic aromatics are correlated with the transitions of tetracyclic aromatic hydrocarbons contained within the structure of the pentacyclic. The results of the experimental correlation are then compared with the results of a theoretical “molecules in molecule” interpretation of the pentacyclic transitions. The results of this comparison indicate that applying a theoretical composite system concept to the interpretation of pentacyclic spectra is justified for the lower energy transitions.

Use of gas-liquid and thin-layer chromatography in characterising air pollutants by fluorometry

Relatively large amounts of alkylated derivatives of the polynuclear aromatic hydrocarbons are present in some urban atmospheres. These compounds are believed to be derived from industrial sources. Because alkylation of the tetracyclic aromatic hydrocarbons can confer carcinogenic activity on the derivatives, the presence of substantial amounts of these alkylated compounds in the air needs thorough study. The RF value and the retention time, by themselves, are inadequate for characterisation of the polynuclear compounds. Gasliquid chromatography followed by fluorometric examination of the eluent bands, and mixed-adsorbent two-dimensional thin-layer chromatography followed by direct fluorometric examination are very useful in characterising all types of organic compound in the organic fractions of airborne particulates and effluents from air pollution sources.