Heavy Aromatic Hydrocarbons Research Articles

Chemical characterization and biological properties of airborne particulate matter

The presence of heavy metals and Polynuclear Aromatic Hydrocarbons (PAH) has been evidenced in airborne particulate matters samples collected in the atmosphere of a non-industrialized middle size Italian town (150.000 inhabitants). The PAH concentrations, higher in winter than in other seasons, was inversely correlated with some meteorological variables such as temperature (p<0.01) and wind speed (p<0.05). The positive correlation found (p<0.01) between lead and total PAH seems to indicate traffic as the most important source of pollution. All samples were mutagenic in the Ames test and the highest mutagenicity levels were obtained in winter samples. The positive correlation found between Benzo(a)Pyrene {B(a)P} concentration and the number of revertants/m3 air, suggests that B(a)P could be an index of mutagenic potential of the matrix considered. The airborne particulate matter extracts obtained by organic solvents were able to inhibit the phagocytosis of mice alveolar macrophages, giving further proof of the possibility of interaction between air-particulate chemical compounds and important biological functions.

Fluorescence spectroscopic studies of differential accumulation of aromatic hydrocarbons by Callianassa kraussi

The application of fluorescence spectroscopic techniques to the uptake of aromatic hydrocarbons into the sandprawn, Callianassa kraussi, was examined. Animals were exposed to the water-soluble fraction of Qatar crude oil for up to 12 weeks, then depurated in clean seawater for up to 4 weeks. Fixed wavelength measurements showed the extent and rapidity of aromatic hydrocarbon accumulation into the hepatopancreas of C. kraussi These measurements, along with synchronous spectra, were useful in demonstrating differential accumulation of light and heavy aromatic hydrocarbons.

Solubility and partial molar volumes of heavy aromatic hydrocarbons in super critical carbon dioxide

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolubility and partial molar volumes of heavy aromatic hydrocarbons in super critical carbon dioxideSomenath Mitra, Juh W. Chen, and Dabir S. ViswanathCite this: J. Chem. Eng. Data 1988, 33, 1, 35–37Publication Date (Print):January 1, 1988Publication History Published online1 May 2002Published inissue 1 January 1988https://doi.org/10.1021/je00051a012RIGHTS & PERMISSIONSArticle Views240Altmetric-Citations40LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (293 KB) Get e-Alerts Get e-Alerts

Changes in carbohydrate metabolism in tilapia, Oreochromis (Sarotherodon) mossambicus, during short-term exposure to different types of pollutants

During exposure of the freshwater fish, tilapia, Oreochromis (Sarotherodon) mossambicus, to heavy metals (mercury and copper), organochlorine insecticides (DDT and endosulfan) and aromatic hydrocarbons (napthalene and phenol) for up to 96 h, the lethal concentrations of all pollutants caused a substantial loss of liver and muscle glycogen. This was accompanied by a considerable rise in the plasma glucose levels. Although the sublethal concentrations generally failed to affect the tissue glycogen levels, the stress produced hyperglycaemia, especially towards the end of the exposure period. The most extensive effects were produced by the aromatic hydrocarbons which, at their lethal concentrations, also caused a reduction in the liver weight by 96 h exposure. The quantitative differences in effects of the three types of pollutants are discussed in relation to differences in the capacity of fish tissues to metabolise these hazardous chemicals and also the physical activity responses of the stressed fish.

Catalytic effects during cellulose liquefaction

Cellulose can be totally liquefied by heating to 350 °C in the presence of an aqueous phenolic solvent containing a catalyst. The main products are light aromatic hydrocarbons, benzofurans, heavier aromatic hydrocarbons such as substituted indanes and tetralin, and xanthenes. The variation of product distribution with catalyst was examined and it was found that in aqueous phenol, xanthene formation was enhanced by acidity. By substituting guaiacol for phenol, it was determined that most benzofuran formation involved the phenol solvent molecules, although a small proportion did not. This benzofuran may have arises from phenol generated from cellulose, the incorporation of phenol in the products being enhanced through a cage effect.

Stability of system against aggregation in coking a compounded feedstock

This article examines a vacuum resid from West Siberian crude and a 250/sup 0/C+ fraction of pyrolysis tar. The pyrolysis tar consists of heavy aromatic hydrocarbons and asphaltenes in approximately equal amounts of 46-48%. The vacuum resid is a conventional straight-run feedstock with a predominance of light and medium aromatic hydrocarbons (37.6%) and a moderate content of asphaltenes (10.2%). The vacuum resid and the pyrolysis tar were subjected to coking in a laboratory still, being coked separately and also in blends with a paraffin wax having a density of 739 kg/m/sup 3/ at 68/sup 0/C, melting point of 54/sup 0/C, and molecular weight of 356. The stability factor was determined for each blend. It is concluded that paraffin wax, like highly aromatic additives, when it is blended with residual stocks with low contents of paraffinic/naphthenic hydrocarbons or none of these hydrocarbons at all (such stocks have a low stability factor), may increase the stability of these residual stocks against phase separation to a significant degree.

Effects of aromatic hydrocarbon groups on properties of calcium sulfonates

This article examines 30% concentrates of hydrocarbons, prepared as solutions in white mineral oil, in order to evaluate the influence of the structure of the aromatic hydrocarbon groups in the original raw material (DS-14 oil) on the yield and composition of the sulfonic acids. Proposes that in order to improve the functional properties of the commercial PMS additive (an overbased calcium sulfonate), a specially prepared raw material must be used, free of the heavy aromatic hydrocarbons that are the main source of formation of oil-insoluble and water-soluble sulfonic acids. Recommends that a better process technology be used in order to increase the content of oil-soluble sulfonic acids in the additive composition through a more nearly complete utilization of the light and heavy aromatic hydrocarbons of the original raw material.

Influence of feedstock quality oh operation of 1a/1m commercial catalytic cracking unit

This article summarizes and correlates the results from the operation of the unit in 2-stage cracking, in which the fresh feed is cracked in the reactor with rising cocurrent flow of catalyst, and the bottom product from the distillation tower (cut distilling above 195/sup 0/C) is cracked in the reactor with rising semicocurrent flow of catalyst. The presence of heavy aromatic hydrocarbons in the feed has a significant effect on the yields of naphtha and stabilizer heat cut. With increasing amounts of the light cuts in the feed, the yield of desired products and the conversion level decreased.

Étude de la polarité d'un poly(oxy aryl sulfonyl arylène) utilisé comme phase stationnaire en chromatographie gaz-liquide

Polarity of a poly(oxy aryl sulfonyl arylene) used as a stationary phase in gas-liquid chromatography Retention indices of polynuclear hydrocarbons, phenols and aza-arenes on poly(oxy aryl sulfonyl arylene) were measured at different temperatures. Comparison between these data and the retention indices of the same compounds on SE-30, polyphenylether (6 rings), OV-17, Carbowax 20M, shows the polarity of this stationary phase (PS 179) to be similar to that of Carbowax 20M. The large polarity and the thermal stability of PS 179 permits the analysis of complex mixtures of heavy aromatic hydrocarbons and related compounds.

ChemInform Abstract: CHEMICAL REACTIVITY OF SINGLET OXYGEN PRODUCED IN THE GAS PHASE. II. ADDITION N OF O2(1ΔG) TO HEAVY AROMATIC HYDROCARBONS IN A HETEROGENEOUS GAS‐LIQUID SYSTEM

Chemischer InformationsdienstVolume 7, Issue 37 Isocyclic Compounds ChemInform Abstract: CHEMICAL REACTIVITY OF SINGLET OXYGEN PRODUCED IN THE GAS PHASE. II. ADDITION N OF O2(1ΔG) TO HEAVY AROMATIC HYDROCARBONS IN A HETEROGENEOUS GAS-LIQUID SYSTEM J. L. DUMAS, J. L. DUMASSearch for more papers by this author J. L. DUMAS, J. L. DUMASSearch for more papers by this author First published: September 14, 1976 https://doi.org/10.1002/chin.197637205Read 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 onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume7, Issue37September 14, 1976 RelatedInformation

Production of extender oil of the MINKh-1 type from hydrotreated deasphalted oil

1. An extender oil for SKD rubbers has been obtained from a deasphalted oil containing heavy aromatic hydrocarbons by hydrotreating followed by single-stage phenol treatment of the hydrotreated oil. The yield of extender oil is 25.0 to 27.4% by weight of the original deasphalted oil. 2. When this scheme is used for the production of extenders, it gives a simultaneous and very appreciable improvement in the viscosity-temperature properties of the dewaxed lube oils that are produced from the raffinates.

Chemical composition of lubricating oils in relation to protective properties

1. Polar and protective properties have been studied for three oil fractions of Sosnino crude and for a distillate, raffinate, extract, and dewaxed oil from Zhirnovsk crude. It has been shown that the most polar products are those containing maximum amounts of medium and heavy aromatic hydrocarbons. 2. The polar oil products have better protective properties, owing to the formation of adsorbed films on the metal. The protection efficiency of these films is still inadequate, so that corrosion inhibitors must be added to the oils.

Two-stage coking of sour feedstocks

1. It has been shown that one of the methods for producing cokes with lower sulfur contents from sour feedstocks is pretreatment or proper selection of feedstock. 2. Two-stage coking has been studied with two sour extracts of different origin. It has been shown that the coke/feedstock ratios of sulfur content are 1.24 and 0.98 for the first-stage coking of these extracts, but are reduced to 0.6 and 0.47 in the second-stage coking. 3. On the basis of the chemical group composition of the coker feedstocks, it can be postulated that the sulfur compounds present in the chromatogrpahic fractions of heavy aromatic hydrocarbons are less resistant to thermal breakdown than the sulfur compounds in the light and medium aromatic hydrocarbon fractions.

Rules for the distribution of sulfur among the products of Stag-Countercurrent Catalytic Cracking (SCCC)

1. Increasing the temperature increases the degree of decomposition of the sulfurous compounds in the crude stock, in which case the sulfur concentration in the liquid cracking products increases. 2. Decreasing the specific, gravimetric flow rate not only increases the degree of decomposition of the sulfurous compounds of the crude stock but also results in a decrease in the sulfur concentration in the liquid cracking products because of the occurrence of secondary desulfurization reactions. 3. Increasing the number of sections both for identical conditions and for the same degree of decomposition of the crude stock also increases the extent of decomposition of the sulfurous compounds and results in a desulfurization of the liquid cracking products. Upon increasing the number of sections, the amount of sulfur which is removed with the coke and gas also increases. 4. For the same conditions the greater the activity of the catalyst, the greater the extent of decomposition of the sulfurous compounds. Mainly, this takes place because of the more extensive decomposition of the crude stock itself. 5. For the same degree of decomposition of the crude stock and the same number of sections a different rule is observed. On the low-active, natural catalyst the decomposition of the sulfurous compounds of the crude stock takes place to a greater degree than on the synthetic catalyst but in this case a significant part of the decomposed sulfurous compounds is converted into the naphtha and light gas oil whereas on the synthetic catalyst the sulfur is removed more with the gas and coke than in the case for the natural catalyst. This indicates a smaller amount of secondary reactions for the cracking on the natural catalyst. 6. In cracking crude stock with a larger concentration of aromatic hydrocarbons (mainly heavy aromatic hydrocarbons) the sulfur which passes into the naphtha and light gas oil is greater than for the cracking of the less aromatic crude stock with predominantly light and medium aromatic hydrocarbons.

Polyisobutylene thickening of various hydrocarbon groups derived from the low-viscosity oily distillate of balakhanskii heavy crude petroleum

1. The thickening characteristics of various groups of hydrocarbons derived from the oily distillate (industrygrade “12”) of balakhanskii heavy crude petroleum have been investigated, using polyisobutylene as a thickening agent. 2. It was demonstrated that polyisobutylene of molecular weight 20,000 is practically insoluble in heavy aromatic hydrocarbons. 3. It was established that during thickening, the viscosity and the index of viscosity of aromatic hydrocarbons increase to a much greater degree than they do in the case of paraffin-naphthenic hydrocarbons.

Microbiological stability of petroleum oils

1. The microbiological stability of petroleum oils depends on their hydrocarbon composition; oils from highly aromatic petroleums prove to be the most stable. 2. Polycyclic (heavy) aromatic hydrocarbons play a basic role in microbiological stability. 3. The microbiological susceptibility of petroleum hydrocarbons, plus certain nitrogenous and sulfur-containing compounds, has been studied. 4. It has been established that n-alkanes are least stable to attack by microorganisms; the most stable are aromatic compounds of the benzene series. 5. It is necessary to take into account differences in stability of hydrocarbons toward microbiological damage in manufacturing petroleum products for use in tropical latitudes, choosing correctly the original raw material and the extent of product refining.

Production of Heavy Aromatic Hydrocarbons by Catalytic Reforming (Part 3)

Studies were carried out to investigate the composition of C6-C10 alkylbenzenes and C10-C12 alkylnaphthalenes in reformate and the yield of aromatics which were obtained by catalytic reforming of kerosene, using the commercial platinum-alumina reforming catalyst.1) Kerosene fractions having the boiling range of 210∼220°C, 220∼230°C, 230∼240°C, 240∼250°C and 250∼260°C obtained from Gach Saran crude oil were reformed.Kerosenes having boiling ranges of 210∼220°C, 230∼240°C and 250∼260°C gave higher yields (crude oil basis) of aromatics. Naphthalenes contents in reformates increased with raising of boiling point of the feed. However, compositions of C8, C9 and C10 aromatic isomers remained unchanged regardless of the boiling range of kerosene fractions.2) Gach Saran kerosene (180∼250°C) was reformed using the operating conditions as follows; the temperature 450∼530°C, the pressure 10∼50atm, the liquid hourly space velocity 0.6-8.4 and the mole ratio of hydrogen to hydrocarbon 5-15. From the data obtained, the relationship between the operating conditions and the yield, compositions of aromatics in reformates were investigated.3) Kerosenes of Gach Saran, North Sumatra, and Ekhabinskaya, having the boiling range of 180∼250°C and C10-C12 n-paraffins were reformed.The yields of reformates and the aromatics in reformates obtained from kerosenes varied with the kind of feed, but the compositions of aromatic isomers did not change with the feed.The yields of aromatics in reformates obtained from C10, C11 and C12 n-paraffins showed almost the same values, and compositions of aromatic isomers agreed with each other. Generally, C8-C10 aromatic isomers in the reformates obtained from C10-C12 n-paraffins contained more poly-methylbenzenes, and less mono-alkylbenzenes and alkylindanes than those obtained from kerosenes. From the above results, main pathway of dehydrocyclization of C10-C12 n-paraffins using the acidic platinum-alumina catalyst seems to be formed through iso-paraffin.

Production of Heavy Aromatic Hydrocarbons by Catalytic Reforming (2)

Studies were carried out for the purpose of production of C9, C10 aromatic hydrocarbons by catalytic reforming of heavy naphtha.1) Naphtha fraction with the boiling range from 100°C to 210°C, which was obtained from Gach Saran crude, was further fractionated into fractions, each having a 10°C boiling range. These naphtha fractions were then reformed, using a platinum-alumina commercial reforming catalyst. It was confirmed by the experiments that the fraction ranging from 130°C to 170°C and from 150°C to 205°C gave higher yields of C9, C10 aromatics, respectively. In addition, the relationship between the boiling range of naphtha and the yields of methylethybenzene (MEB), trimethylbenzene (TrMB), and tetramethylbenzene (TeMB) was also investigated. Components of these three isomers-i.e. MEB, TrMB, TeMB-in the reformed naphtha remained constant without regard to the boiling range of the feed naphtha.2) Straight run Gach Saran naphtha (125∼190°C) was reformed at the temperature 450∼530°C, the pressure 10∼50atm., the lipuid hourly space velocity 0.6∼4 and the mole ratio of hydrogen to hydrocarbon 5∼15. From the data obtained, the relationship between the operating condition and yields or compositions of C6∼C11 aromatic hydrocarbons, particularly MEB isomers, TrMB isomers, TeMB isomers and durene fraction in those reformates was investigated.

Production of Heavy Aromatic Hydrocarbons by Catalytic Reforming (1)

Production of Heavy Aromatic Hydrocarbons by Catalytic Reforming (1)

The lubricity characteristics of heavy aromatics

Heavy aromatic hydrocarbons are the most probable cause of the good lubricating characteristics of petroleum oils. As little as 2% can greatly reduce wear and friction and increase the load-carrying capacity of paraffins. These mixtures of heavy aromatics and paraffins are much better than either component alone. Condensed-ring heavy aromatics have a second unusual behavior: in the absence of water and oxygen they will scuff at very low loads. The unusual behavior of the heavy aromatics is attributed to a little-understood decomposition reaction at the rubbing surface and not to oxidation or reaction with the metal.