Cooperative Study to Evaluate a Standard Test Method for the Speciation of Gasolines by Capillary Gas Chromatography

Schubert, A.; Johansen, N. G.

doi:10.4271/930144

Cited by 10 publications

(3 citation statements)

References 9 publications

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“…In other words, substances of less than 0.1 vol % concentration in a given mixture were considered too dilute to influence the overall solvation properties of that phase. Where specific characterizations of fuels were not given, we assumed average gasoline or diesel compositions found in surveys (5,30,32). Uncertainties in mixture compositions of the synthetic systems were generally estimated to be less than 1 vol %, whereas variabilities of the major component concentrations in real fuel mixtures were typically between 3 and 5 vol %, depending on the component and the type of mixture (5,30,32).…”

Section: Methodsmentioning

confidence: 99%

“…Liquid fuels are usually composed of mostly hydrocarbons, but they typically include additives or processing byproducts which contain heteroatoms (i.e., O, N, or S); such compounds may therefore affect the solvation properties of the fuel mixture (28,29). Conventional (not oxygenated) automotive retail gasolines contain C4-C12 alkanes (45% to 65% by mass), low molecular weight aromatic hydrocarbons (20% to 40% by mass), and low molecular weight olefins (5% to 15% by mass) (30). As of this writing, oxygenated gasolines in many regions are required to contain more than 10% MTBE or ethanol by volume, and these regulations are likely to change soon (31).…”

Section: Introductionmentioning

confidence: 99%

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Estimating Partition Coefficients for Fuel−Water Systems: Developing Linear Solvation Energy Relationships Using Linear Solvent Strength Theory To Handle Mixtures

Arey

Gschwend

2005

Environ. Sci. Technol.

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In many environmental transport problems, organic solutes partition between immiscible phases that consist of liquid mixtures. To estimate the corresponding partition coefficients, we evaluated the efficacy of combining linear solvation energy relationships (LSERs) developed for pure 1:1 systems via application of linear solvent strength theory. In this way, existing LSERs could be extended to treat solute partitioning from gasoline, diesel fuel, and similar mixtures into contacting aqueous mixtures. Unlike other approaches, this method allowed prediction of liquid-liquid partition coefficients in a variety of fuel-water systems for a broad range of dilute solutes. When applied to 37 polar and nonpolar solutes partitioning between an aqueous mixture and 12 different fuel-like mixtures (many including oxygenates), the root-mean-squared error was a factor of approximately 2.5 in the partition coefficient. This was considerably more accurate than application of Raoult's law for the same set of systems. Regulators and scientists could use this method to estimate fuel-water partition coefficients of novel additives in future fuel formulations and thereby provide key inputs for environmental transport assessments of these compounds.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Estimating Partition Coefficients for Fuel−Water Systems: Developing Linear Solvation Energy Relationships Using Linear Solvent Strength Theory To Handle Mixtures

Arey

Gschwend

2005

Environ. Sci. Technol.

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“…20 -23 The base gasoline composition was simulated from 17 major hydrocarbon components of a typical gasoline, based on a survey of several U.S. gasolines measured at several different laboratories. 24,25 UNIFACderived activity coefficients were combined with literature Antoine constants 26 and the oxygenated gasoline composition to estimate the simulated fuel mixture total vapor pressure and vapor-phase mass fraction of MTBE at several temperatures, using the standard approach. 27,28 These calculations indicated that the mass fraction of MTBE in fuel vapor is 10.5-11% by mass at temperatures ranging from Ϫ5 to 20°C.…”

Section: Modeling and Experimental Methods Estimation Of Regional Mtbmentioning

confidence: 99%

Emission and Fate Assessment of Methyl Tertiary Butyl Ether in the Boston Area Airshed Using a Simple Multimedia Box Model: Comparison with Urban Air Measurements

Kawamoto

Arey

Gschwend

2003

Journal of the Air & Waste Management Association

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Expected urban air concentrations of the gasoline additive methyl tertiary butyl ether (MTBE) were calculated using volatile emissions estimates and screening transport models, and these predictions were compared with Boston, MA, area urban air measurements. The total volatile flux of MTBE into the Boston primary metropolitan statistical area (PMSA) airshed was calculated based on estimated automobile nontailpipe emissions and the Universal Quasi-Chemical Functional-Group Activity Coefficient computed abundance of MTBE in gasoline vapor. The fate of MTBE in the Boston PMSA was assessed using both the European Union System for the Evaluation of Substances, which is a steady-state multimedia box model, and a simple airshed box model. Both models were parameterized based on the meteorological conditions observed during air sampling in the Boston area. Measured average urban air concentrations of 0.1 and 1 g/m 3 MTBE during February and September of 2000, respectively, were comparable to corresponding model predictions of 0.3 and 1 g/m 3 and could be essentially explained from estimated temperature-dependent volatile emissions rates, observed average wind speed (the airshed flushing rate), and reaction with ambient tropospheric hydroxyl radical (⅐OH), within model uncertainty. These findings support the proposition that one can estimate gasoline component source fluxes and use simple multimedia models to screen the potential impact of future proposed gasoline additives on urban airsheds. INTRODUCTIONNumerous investigators have found that liquid gasoline and gasoline vapor components constitute a substantial portion of tropospheric volatile organic pollutants in the United States. 1 We therefore anticipate that new gasoline additives that are both relatively volatile and abundant in fuel, such as methyl tertiary butyl ether (MTBE), accumulate in urban air to significant concentrations. As part of an effort to control toxic volatile compounds and urban air pollution precursors emitted from motor vehicles, the Clean Air Act Amendments of 1990 mandated 2% by weight oxygen (O 2 ) addition to fuels in areas affected by the federal Reformulated Gasoline Program (RFG). 2 To fulfill this requirement, MTBE has been added to gasoline in amounts of 10 -15% by volume in several metropolitan areas in the United States. 3 Gasolines in much of the New England region have been amended with at least 11% vol/vol MTBE year-round since 1995. 2 We expect MTBE to constitute a significant portion of fuel vapor, because it is a highly volatile, major fuel component. Therefore, relatively high MTBE concentrations in the urban air of RFG-affected areas and possibly also measurable ambient MTBE concentrations in more remote areas are expected. Tropospheric MTBE concentrations typically in the range of 5-25 g/m 3 have been

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A physical–chemical screening model for anticipating widespread contamination of community water supply wells by gasoline constituents

Arey¹,

Gschwend²

2005

Journal of Contaminant Hydrology

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Cooperative Study to Evaluate a Standard Test Method for the Speciation of Gasolines by Capillary Gas Chromatography

Cited by 10 publications

References 9 publications

Estimating Partition Coefficients for Fuel−Water Systems: Developing Linear Solvation Energy Relationships Using Linear Solvent Strength Theory To Handle Mixtures

Estimating Partition Coefficients for Fuel−Water Systems: Developing Linear Solvation Energy Relationships Using Linear Solvent Strength Theory To Handle Mixtures

Emission and Fate Assessment of Methyl Tertiary Butyl Ether in the Boston Area Airshed Using a Simple Multimedia Box Model: Comparison with Urban Air Measurements

A physical–chemical screening model for anticipating widespread contamination of community water supply wells by gasoline constituents

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