Aromatic Compounds In Gasoline Research Articles

Selective Detection of Aromatic Compounds with a Re-Designed Surface Acoustic Wave Sensor System Using a Short Packed Column

A self-developed and newly re-designed chemical SAW sensor system composed of four polymer-coated and four differently modified nano-diamond-coated SAW sensors was applied to measure aromatic compounds in gasoline in a low-cost, fast, and easy way. An additional short packed column at the system inlet improve the selectivity for various possible fuel applications. The column allows the direct sampling of liquid fuels and pre-separates the different components in groups (aromatic and aliphatic compounds) from a fuel sample. Since the sensors employed show linearity towards concentration, an easy quantification of single fuel components was possible even within the group of aromatic compounds.

Assessment of oxidative stress among refueling workers in an Egyptian setting.

Unlike developing countries, in Egypt, gasoline is dispensed at dedicated stations by gasoline filling workers. This leads to high levels of exposure to the aromatic compounds in gasoline [principally benzene, toluene, ethyl benzene, and xylene (BTEX)] with the consequences of adverse health effects including oxidative stress. To assess oxidative stress and trace metal levels among Egyptian gas filling workers. A cross-sectional study was conducted among 50 gasoline filling station workers (exposed group) and a matched group of 50 clerical workers (non-exposed group). Trace metal levels (Cu, Zn, Fe, and Mn) and the activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured in sera of all enrolled participants using atomic absorption spectroscopy. BTEX levels were assessed in the environment of the studied gas filling stations using the MIRAN IR system. All the measured trace metal levels and antioxidant enzyme activities were significantly lower among the exposed workers than among the non-exposed workers. All trace metals decreased significantly in relation to SOD activity among the exposed workers, whereas only Zn and Cu decreased in relation to SOD and GPx activity among the non-exposed workers. The exposed workers did not comply with the use of the required personal protective equipment (PPE) to avoid the dangerous effects of BTEX exposure. Among BTEX components, benzene exceeded the allowable Egyptian TLV in the studied gasoline stations (110.4mg/m3 versus 1.6mg/m3, respectively). The hygienic effect (HE) of the BTEX pollutant mixture exceeded the allowed borderline HE in Egypt although it did not show a significant correlation with different oxidative stress biomarkers and trace metals. Exposure to BTEX at gasoline filling stations lowers the levels of antioxidant enzyme activities and trace metals due to the strong hygienic effect of BTEX. Individual protection using the proper PPE should therefore be enforced. Research assessing the need of providing refueling workers with supplements of necessary trace metals and antioxidants is warranted.

Volatile organic compound analysis of accelerant detection canine distractor odours

Ignitable liquid detection dogs have been observed to falsely-respond to the pyrolysis products of common burned household items such as carpets and garden hoses, where ignitable liquids were not present. These responses from the canines are described as coming from distractor odours and decrease the reliability of detector dogs. The purpose of this research was to study the volatile organic compounds (VOCs) present in the odour profile of pyrolysed carpet and garden hose substrates, and determine whether a chemical similarity exists between these pyrolysis headspace profiles and target ignitable liquids, which may explain the false-positive behaviour of these detector dogs.Garden hose and carpet samples obtained from domestic settings were heated at a constant temperature for a specified time to produce pyrolysis products. A solid-phase microextraction (SPME) method was developed to extract the VOCs from burned substrates. The odours of the burned substrates were analysed by gas chromatography-mass spectrometry (GC/MS) and gas chromatography-tandem mass spectrometry (GC/MS/MS).A GC–MS/MS method was developed targeting the characteristic aromatic compounds in gasoline. Each pyrolysed substrate produced a complex and unresolved odour profile when analysed by GC- MS. GC–MS analysis failed to find any similarities between the odours of the burned substrates and ignitable liquids. GC–MS/MS analysis of pyrolysed garden hose and carpet substrate odours resolved and identified a wide range of aromatic target compounds – and these were present in high abundances in the hose samples. This indicates that there are significant chemical similarities between vapours of ignitable liquids and their distractor odours, which will have implications for the training of ignitable liquid detector dogs.

Production of aromatic compounds in the heavy naphtha and light cycle oil ranges: catalytic cracking of aromatics and C10 naphthenic‐aromatics

AbstractBACKGROUNDThe conversions of bicyclic compounds, both a naphthenic‐aromatic compound (tetralin) and an aromatic compound (naphthalene), as model reactants representative of the heavy gasoline and light cycle oil (LCO) cuts in fluid catalytic cracking (FCC), were studied to understand the formation of C10–C20 aromatic compounds in gasoline and middle distillates cuts, in view of their impact on the properties of the cuts. A commercial FCC catalyst was used in its fresh, hydrothermally de‐aluminated and equilibrium forms, at 450 °C in a fluidized bed CREC Riser Simulator reactor in the 2–8 s reaction time range.RESULTSProducts were C1–C14 hydrocarbons and coke. Based on the product distributions, reaction networks were proposed for both reactants. The reactions considered in the networks were hydrogen transfer, cracking, ring opening and contraction, alkylation and disproportionation.CONCLUSIONThe load of zeolite in the catalysts and their acidities have the strongest influences on reaction selectivities. In the case of tetralin, the prevalent reaction is hydrogen transfer, which becomes more important as the catalysts are less active, the hydrocarbons with highest yields being C10 aromatics. Cracking reactions predominate in naphthalene conversion over all the catalysts, a fact which favors mono‐aromatic C9− hydrocarbons. These results can help in the design of new FCC catalysts with better selectivity control. © 2014 Society of Chemical Industry

Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.

Catalytic Conversion of Biomass to Monofunctional Hydrocarbons and Targeted Liquid-Fuel Classes

It is imperative to develop more efficient processes for conversion of biomass to liquid fuels, such that the cost of these fuels would be competitive with the cost of fuels derived from petroleum. We report a catalytic approach for the conversion of carbohydrates to specific classes of hydrocarbons for use as liquid transportation fuels, based on the integration of several flow reactors operated in a cascade mode, where the effluent from the one reactor is simply fed to the next reactor. This approach can be tuned for production of branched hydrocarbons and aromatic compounds in gasoline, or longer-chain, less highly branched hydrocarbons in diesel and jet fuels. The liquid organic effluent from the first flow reactor contains monofunctional compounds, such as alcohols, ketones, carboxylic acids, and heterocycles, that can also be used to provide reactive intermediates for fine chemicals and polymers markets.

Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.

Analysis of aromatic compounds in gasoline with flow-switching comprehensive two-dimensional gas chromatography

A comprehensive two-dimensional gas chromatography (GC × GC) instrument has been created by coupling a flow-switching modulator and a standard gas chromatograph. The instrument was used to characterize the aromatic composition of gasoline. The high-resolution separation produced by flow-switching GC × GC allowed gasoline aromatics to be fully resolved from saturated components. The aromatic compounds were further separated into groups having the same carbon number. A standard gasoline sample was analyzed to evaluate the quantitative accuracy and precision of this technique. The data show that flow-switching GC × GC produces results that are comparable to gas chromatography–mass spectrometry (GC–MS) and thermal modulation GC × GC. The simple, low-cost, and robust nature of flow-switching GC × GC makes it an ideal technique for the routine analysis of aromatic compounds in gasoline.

Isolation and Characterization of Novel Strains of Pseudomonas aeruginosa and Serratia marcescens Possessing High Efficiency to Degrade Gasoline, Kerosene, Diesel Oil, and Lubricating Oil

Bacteria possessing high capacity to degrade gasoline, kerosene, diesel oil, and lubricating oil were screened from several areas of Hokkaido, Japan. Among isolates, two strains, WatG and HokM, which were identified as new strains of Pseudomonas aeruginosa and Serratia marcescens species, respectively, showed relatively high capacity and wide spectrum to degrade the hydrocarbons in gasoline, kerosene, diesel, and lubricating oil. About 90-95% of excess amount of total diesel oil and kerosene added to mineral salts media as a sole carbon source could be degraded by WatG within 2 and 3 weeks, respectively. The same amount of lubricating oil was 60% degraded within 2 weeks. Strain HokM was more capable than WatG in degrading aromatic compounds in gasoline. This strain could also degrade kerosene, diesel, and lubricating oil with a capacity of 50-60%. Thus, these two isolates have potential to be useful for bioremediation of sites highly contaminated with petroleum hydrocarbons.

Column switching–back flushing technique for the analysis of aromatic compounds in gasoline

A simple method, based on the technique of capillary column switching–back flushing, has been developed for the detailed analysis of aromatic compounds in gasoline. The sample was first separated on a 30-m long OV-2330 polar precolumn and then backflushed onto a nonpolar analytical column. The early eluting components from the precolumn and the components of interest (aromatic compounds plus heavier compounds) eluting from the analytical column are all directed to the same flame ionization detection system through a T piece, which permits the quantitative analysis of aromatic hydrocarbons in gasoline by a normalization method using correcting factors. The switching time window of the method is ±5 s, resulting in easier operation and higher reliability. The reproducibility of the quantitative analysis was ≤3% RSD for real gasoline samples.

Quantitative Determination of BTEX and Total Aromatic Compounds in Gasoline by Comprehensive Two-Dimensional Gas Chromatography (GC×GC)

Comprehensive two-dimensional gas chromatography (GC×GC) has been applied to the quantitative analysis of benzene, toluene, ethylbenzene, xylenes (BTEX), and all heavier aromatic compounds in gasoline. The two-dimensional chromatographic separation used volatility selection on the first-dimension column and polarity selection on the second-dimension column. In the resulting GC×GC chromatogram, aromatic species were resolved from other compound classes. Moreover, structurally related aromatics were grouped in a manner that facilitated identification and integration. The response of a flame ionization detector to each major aromatic group in gasoline was calibrated using internal standards. Quantitation produced results directly comparable with ASTM standard methods. The present GC×GC method can be expanded to analyze other gasoline components.