ASTM D7347-07e1
(Test Method)Standard Test Method for Determination of Olefin Content in Denatured Ethanol by Supercritical Fluid Chromatography
Standard Test Method for Determination of Olefin Content in Denatured Ethanol by Supercritical Fluid Chromatography
SIGNIFICANCE AND USE
Olefinic hydrocarbons that may be present in denatured ethanol have been demonstrated to contribute to photochemical reactions in the atmosphere, and this can result in the formation of smog in susceptible urban areas.
The California Air Resources Board (CARB) has specified a maximum allowable limit of total olefins in spark ignition engine fuel. Denatured ethanol will be added at the terminals as an oxygenate additive and can contain olefinic species contributing to the total olefins present in spark ignition engine fuel. An analytical method is therefore necessary to determine total olefins in denatured ethanol intended for spark ignition engine fuel use. The test method is intended to be used by both regulators and producers.
The present test method is automated, does not require any sample preparation, and has a relatively short analysis time of approximately 20 min.
SCOPE
1.1 This test method covers the determination of the total amount of olefins in denatured ethanol to be used as an oxygenate additive in blended spark ignition engine fuels. The method of determination is supercritical fluid chromatography (SFC). The application range is from 0.1 to 1.0 mass percent total olefins. Results are expressed in terms of mass percent olefins.
1.2 This test method can be used for the analysis of denatured ethanol that is intended to be used as an oxygenate additive in commercial spark ignition engine fuels.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
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Designation:D7347 −07
StandardTest Method for
Determination of Olefin Content in Denatured Ethanol by
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Supercritical Fluid Chromatography
This standard is issued under the fixed designation D7347; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
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ε NOTE—Added research report footnote to Section 13 editorially in October 2008.
1. Scope 3. Terminology
1.1 This test method covers the determination of the total
3.1 Definitions:
amount of olefins in denatured ethanol to be used as an
3.1.1 critical pressure, n—that pressure needed to condense
oxygenate additive in blended spark ignition engine fuels. The
a gas at the critical temperature.
method of determination is supercritical fluid chromatography
3.1.2 critical temperature, n—highest temperature at which
(SFC). The application range is from 0.1 to 1.0 mass percent
a gaseous fluid can be converted to a liquid by means of
total olefins. Results are expressed in terms of mass percent
compression.
olefins.
3.1.3 supercritical fluid, n—fluid maintained in a thermody-
1.2 This test method can be used for the analysis of
namic state above its critical temperature and critical pressure.
denatured ethanol that is intended to be used as an oxygenate
additive in commercial spark ignition engine fuels.
3.1.4 supercritical fluid chromatography, n— class of chro-
matography that employs supercritical fluids as mobile phases.
1.3 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information
4. Summary of Test Method
only.
1.4 This standard does not purport to address all of the
4.1 A small aliquot of the denatured alcohol sample is
safety concerns, if any, associated with its use. It is the
injectedontoasetofthreeanalyticalchromatographiccolumns
responsibility of the user of this standard to establish appro-
connected in series. The sample is transported through the
priate safety and health practices and determine the applica-
columns using supercritical carbon dioxide (CO)asthe
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bility of regulatory limitations prior to use.
mobile phase. The first column is packed with polyvinyl
alcohol(PVA).Thesecondcolumnintheseriesisananalytical
2. Referenced Documents
column packed with high surface area silica gel particles, and
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the third column is packed with silica particles coated with
2.1 ASTM Standards:
strong cation exchange material loaded with silver ions.
D4052 Test Method for Density, Relative Density, and API
Gravity of Liquids by Digital Density Meter
4.2 Two six-port switching valves are used to direct the
D5186 Test Method for Determination of the Aromatic
different classes of components through the chromatographic
Content and Polynuclear Aromatic Content of Diesel
system to the detector. In a forward flow mode, saturates,
Fuels and Aviation Turbine Fuels By Supercritical Fluid
aromatics,andolefinspassontotheanalyticalsilicagelcolumn
Chromatography
whilethealcoholisretainedonthePVAcolumn.Thesaturates,
D6550 Test Method for Determination of Olefin Content of
aromatics, and olefins are maintained on the silica column,
Gasolines by Supercritical-Fluid Chromatography
whilethealcoholisback-flushedtothedetector.Thisstepfrees
the flow path of alcohol species allowing for the separation of
the olefins from saturates and aromatics. The forward flow
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This test method is under the jurisdiction of ASTM Committee D02 on
mode is resumed after the alcohol is eliminated and saturates
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
are carried to the detector, while the aromatics are retained on
Subcommittee D02.04.0C on Liquid Chromatography.
the silica column and the olefinic species are trapped on the
Current edition approved Aug. 1, 2007. Published September 2007. DOI:
10.1520/D7347-07E01.
silver-loaded column. The next step is to back-flush the olefins
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
from the silver-loaded column to the detector. Finally the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
aromatics are carried from the silica column to the detector in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. a forward flow mode, bypassing the silver-loaded column.
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D7347−07
TABLE 1 Typical Columns
4.3 A flame ionization detector (FID) is used for quantita-
tion. Calibration is based on the area of the chromatographic
...
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