ASTM D2593-93(2014)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D2593 − 93 (Reapproved 2014)
Standard Test Method for
Butadiene Purity and Hydrocarbon Impurities by Gas
Chromatography
This standard is issued under the fixed designation D2593; 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.
1. Scope 2.2 Energy Institute Standards:
IP 194 Analysis of Butadiene-1,3 Polymerization Grade
1.1 This test method covers the determination of butadiene-
1,3 purity and impurities such as propane, propylene,
3. Summary of Test Method
isobutane, n-butane, butene-1, isobutylene, propadiene, trans-
3.1 A representative sample is introduced into a gas-liquid
butene-2, cis -butene-2, butadiene-1,2, pentadiene-1,4, and,
partition column. The butadiene and other components are
methyl, dimethyl, ethyl, and vinyl acetylene in polymerization
separated as they are transported through the column by an
grade butadiene by gas chromatography. Impurities including
inert carrier gas. Their presence in the effluent is measured by
butadienedimer,carbonyls,inhibitor,andresiduearemeasured
adetectorandrecordedasachromatogram.Thechromatogram
by appropriate ASTM procedures and the results used to
of the sample is interpreted by applying component attenuation
normalize the component distribution obtained by chromatog-
and detector response factors to the peak areas or peak heights
raphy.
and the relative concentration determined by relating indi-
NOTE 1—Other impurities present in commercial butadiene must be
vidual peak response to total peak response. Impurities includ-
calibrated and analyzed. Other impurities were not tested in the coopera-
ing butadiene dimer, carbonyls, inhibitor, and residue are
tive work on this test method.
NOTE 2—This test method can be used to check for pentadiene-1,4 and measured by appropriate ASTM procedures and the results
other C s instead of Test Method D1088.
5 used to normalize the distribution obtained by gas chromatog-
raphy.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
4. Significance and Use
standard.
4.1 The trace hydrocarbon compounds listed can have an
1.3 This standard does not purport to address all of the
effect in the commercial use of butadiene. This test method is
safety concerns, if any, associated with its use. It is the
suitable for use in process quality control and in setting
responsibility of the user of this standard to establish appro-
specifications.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific
5. Apparatus
warning statements, see 6.1 and 9.3.
5.1 Chromatograph—Any chromatograph having either a
2. Referenced Documents
thermal-conductivity or flame ionization detector can be used
2.1 ASTM Standards: provided the system has sufficient sensitivity and stability to
D1088 Method of Test for Boiling Point Range of obtain a recorder deflection of at least 2 mm at signal-to-noise
Polymerization-Grade Butadiene (Withdrawn 1983) ratio of at least 5:1 for 0.01 weight % of impurity.
5.2 Column—Any column can be used that is capable of
resolving the components listed in 1.1 with the exception of
This test method is under the jurisdiction of ASTM Committee D02 on
butene-1 and isobutylene, which can be eluted together. The
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.D0.04 on C4 Hydrocarbons.
componentsshouldberesolvedintodistinctpeakssuchthatthe
This test method was adopted as a joint ASTM-IP Standard, IP 194, in 1972.
ratio A/B will not be less than 0.5 where A is the depth of the
CurrenteditionapprovedMay1,2014.PublishedJuly2014.Originallyapproved
valley on either side of peak B and B is the height above the
in 1967. Last previous edition approved in 2009 as D2593–93(2009). DOI:
baseline of the smaller of any two adjacent peaks. In the case
10.1520/D2593-93R14.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
where the small component peak is adjacent to a large one, it
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
The last approved version of this historical standard is referenced on Obsolete. Contact Energy Institute, 61 New Cavendish St., London,WIG 7AR,
www.astm.org. U.K., http://www.energyinst.org.uk.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2593 − 93 (2014)
can be necessary to construct a baseline of the small peak optimum resolution and analysis time. Optimum size ranges
tangent to the curve as shown in Fig. 1. cannot be predicted on purely theoretical grounds. For some
5.2.1 A description of columns that meet the requirements systems it has been found that a ratio of average particle
of this test method is tabulated in theAppendix. Persons using diameter to column inside diameter of 1:25 will result in
other column materials must establish that the column gives minimum retention time and minimum band widths.
results that meet the precision requirements of Section 11. 6.2.3 Tubing Material—Copper, stainless steel, Monel,
aluminum, and various plastic materials have been found to be
5.3 Sample Inlet System—Means shall be provided for
satisfactory for column tubing. The material must be nonreac-
introducing a measured quantity of representative sample into
tive with respect to substrate, sample, and carrier gas and of
the column. Pressure-sampling devices can be used to inject a
uniform internal diameter.
small amount of liquid directly into the carrier gas. Introduc-
tion can also be accomplished by use of a gas valve to charge 6.3 Hydrocarbons for Calibration and Identification—
the vaporized liquid. Hydrocarbon standards for all components present are needed
for identification by retention time and for calibration for
5.4 Recorder—A recording potentiometer with a full-scale
quantitative measurements.
deflection of 10 mV or less is suitable for obtaining the
chromatographic data. Full-scale response time should be 2 s
NOTE 4—Mixtures of hydrocarbons can be used provided there is no
uncertainty as to the identity or concentration of the compounds involved.
or less, and with sufficient sensitivity to meet the requirements
of 5.1.
7. Preparation of Apparatus
NOTE3—Othermethodsofrecordingdetectoroutputsuchascomputer-
7.1 Column Preparation—Thetechniqueusedtopreparethe
teletype systems can be used instead of a recorder, provided precision
column is not critical as long as the finished column produces
requirements of Section 11 are met.
the desired separation. Preparation of the packing is not
6. Reagents and Materials difficult once the support, partitioning liquid, and loading level
have been determined. The following general directions have
6.1 Carrier Gas—A carrier gas appropriate to the type of
been found to produce columns of acceptable characteristics.
detectorusedshouldbeemployed.Heliumorhydrogenmaybe
7.1.1 Weigh out the desired quantity of support, usually
used with thermal conductivity detectors. Nitrogen, helium, or
twice that required to fill the column.
argon may be used with ionization detectors. The minimum
7.1.2 Calculate and weigh out the required quantity of
purity of any carrier should be 99.95 mol %. (Warning—
partitioning agent. Dissolve the partitioning agent in a volume
Compressed gas. Hazardous pressure.) (Warning—Hydrogen
ofchemicallyinert,low-boilingsolventequaltoapproximately
flammable gas. Hazardous pressure.)
twice the volume of support.
6.1.1 Ifhydrogenisused,specialsafetyprecautionsmustbe
7.1.3 Graduallyaddthesupportmaterialtothesolutionwith
taken to ensure that the system is free from leaks and that the
gentle stirring.
effluent is properly vented.
7.1.4 Slowly evaporate the solvent while gently agitating
6.2 Column Materials:
the mixture until the packing is nearly dry and no free liquid is
6.2.1 Liquid Phase—The materials that have been used
apparent.
successfully in cooperative work as liquid phases are listed in
7.1.4.1 Some stationary phases such as benzyl cyanide
Table X1.1.
silvernitratearesusceptibletooxidationandmustbeprotected
6.2.2 Solid Support—The support for use in the packed
from excessive exposure to air during the evaporation and
column is usually crushed firebrick or diatomaceous earth.
drying steps.
Sieve size will depend on the diameter of the column used and
7.1.5 Spread the packing in thin layers on a nonabsorbent
liquid-phase loading, and should be such as would give
surface and air- or oven-dry as required to remove all traces of
solvent.
7.1.6 Resieve the packing to remove fines and agglomerates
produced in the impregnation step.
7.1.7 Fill the column tubing with packing by plugging one
end with glass wool and pouring the packing into the other end
throughasmallfunnel.Vibratethetubingcontinuouslyoverits
entirelengthwhilefilling.Whenthepackingceasestoflow,tap
the column gently on the floor or bench-top while vibrating is
continued. Add packing as necessary until no further settling
occurs during a 2-min period. Remove a small amount of
packingfromtheopenend,plugwithglasswool,andshapethe
column to fit the chromatograph.
7.2 Chromatograph—Mount the column in the chromato-
graph and establish the operating conditions required to give
thedesiredseparation(AppendixX1).Allowsufficienttimefor
the instrument to reach equilibrium as indicated by a stable
FIG. 1 Illustration of A/B Ratio for Small-Component Peak base line. Control the oven temperature so that it is constant to
D2593 − 93 (2014)
within 0.5°C without thermostat cycling which causes an forpentadiene-1,4butadiene-1,2,dimethylacetylene,ethyland
uneven base line. Set the carrier-gas flow rate, measured with vinyl acetylene in this study to obtain the precision listed in
a soap film meter, so that it is constant to within 1 mL/min of Section 11. It is permissible to use the above established
the selected value. response factors instead of calibration when using thermal-
conductivity detectors with helium-carrier gas. With other
8. Calibration detectors or carrier gas, or both, it is necessary to calibrate
(Note 5).
8.1 Identification—Select the conditions of column tem-
8.2.2 Measurements can be made using peak heights as
perature and carrier gas flow that will give the necessary
criteria for calculations instead of peak areas. If peak heights
separation.Determinetheretentiontimeforeachcompoundby
are used, care must be taken so that chromatograph-operating
injecting small amounts of the compound either separately or
parameters such as column temperature and carrier-gas flow
in mixtures. Recommended sample sizes for retention data are
rate are kept at the same conditions as when the unit was
1 µL for liquids and 1 cm or less for gases.
calibrated. The chromatograph can be calibrated using known
8.2 Standardization—The area under the peak of the chro-
blends or by establishing relative-response data using peak
matogram is considered a quantitative measure of the amount
heights in the same manner as listed above.
of the corresponding compound. The relative area is propor-
NOTE 6—Use of a hydrogen-flame detector gives essentially equal
tional to the concentration if the detector responses of the
relative response to hydrocarbons. On a weight basis, the sensitivity of the
sample components are equal. The recommended procedure
flame detector for hydrocarbons is essentially independent of the hydro-
for quantitative calibration is as follows: with all equipment at
carbonsstructure.Onamolarbasis,thesensitivityappearstobeafunction
equilibrium at operating conditions, inject constant volume of the carbon content, giving essentially equal relative response to
hydrocarbons containing the same number of carbon atoms.
samples of high-purity components. Each compound should be
injected at least three times. The areas of the corresponding
8.2.3 Becausedetectororamplifieroutputneednotbelinear
peaks should agree within 1 %.When a recorder is used, adjust
with component concentration, this must be checked by inject-
the attenuation in all cases to keep the peak on-scale and with
ing constant volumes of pure butadiene at a series of decreas-
a height of at least 50 % of full scale. Measure the area of the
ing pressures from ambient down to 20 mm Hg (torr) or by
peaks by any reliable method (Note 7). To obtain component
using synthetic standards with vapor sample valves at ambient
weight % response data from the area response of the volume
or at decreasing pressures or by using synthetic standards with
injections, it is necessary to consider the density and purity of
liquid sample valves. If on plotting the results the response is
the compounds used for calibration. The average volume area
linear, then the calibration procedure given above is satisfac-
response of each component is divided by the density multi-
tory. If not, the relative responses of the minor components
pliedbytheweightpercentpurityofthecomponentasfollows:
must be determined in the linear response region.
Weight percent response of component (1)
9. Procedure
average component peak area
9.1 Attach the sample cylinder to the instrument-sampling
density 3weight percent purity of component
valve so that the sample is obtained from the liquid phase. If
introduction is through a liquid valve the sample cylinders
Component weight percent detector correction factors are
should be pressured with a suitable gas, such as helium, to a
then obtained by selecting a reference component such as
pressuresufficienttoensurethatsampleflashingdoesnotoccur
butadiene, and dividing the individual component weight
inthelinetothesamplingvalveorinthevalveitself.Ifavapor
responses into the reference weight response.
valve is used, care must be taken to completely vaporize a
8.2.1 Factors derived on a thermal-conductivity detector
small liquid sample, allowing the vapor to flow through the
using helium-carrier gas are as follows:
sample loop at a flow rate of 5 to 10 mL/min until at least ten
Component Mol wt Thermal Weight Factor Weight
times the volume of the sample loop has been flushed through.
Response Factor,
Butadiene-
If a vacuum-sampling system is used with a vapor valve, the
1,3=1.00
sampleloopshouldbefilledandevacuatedatleasttwicebefore
Butadiene-1,3 54 80 0.68 1.00
introduction of sample.
Propane 44 65 0.68 1.00
Propylene 42 63 0.67 0.98
9.2 Charge sufficient sample to ensure a
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