ASTM D2426-23

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2426 − 19 D2426 − 23
Standard Test Method for
Butadiene Dimer and Styrene in Butadiene Concentrates by
Gas Chromatography
This standard is issued under the fixed designation D2426; 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*
1.1 This test method covers the determination of butadiene dimer (4-vinylcyclohexene-1) and styrene in butadiene concentrates,
both recycle and specification grade.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. For specific precautionary statements see Sections 6 and 8.
1.3 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. For specific precautionary statements see Sections 6 and 8.
1.3.1 The user is advised to obtain LPG safety training for the safe operation of this test method procedure and related activities.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1657 Test Method for Density or Relative Density of Light Hydrocarbons by Pressure Hydrometer
D1945 Test Method for Analysis of Natural Gas by Gas Chromatography
D2593 Test Method for Butadiene Purity and Hydrocarbon Impurities by Gas Chromatography
2.2 Other Documents:
STP 109A Physical Constants of Hydrocarbons C to C
1 10
3. Summary of Test Method
3.1 The sample is introduced into a gas-liquid partition column. The components of interest are separated as they are transported
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.D0.04 on C4 and C5 Hydrocarbons.
Current edition approved Dec. 1, 2019March 1, 2023. Published January 2020June 2023. Originally approved in 1965. Last previous edition approved in 20142019 as
D2426 – 93 (2014).D2426 – 19. DOI: 10.1520/D2426-19.10.1520/D2426-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 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.
*A Summary of Changes section appears at the end of this standard
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D2426 − 23
TABLE 1 Columns and Conditions Used Successfully
Carbowax
Dow Silicone Carbowax Carbowax Polyethylene Barecowax
Silicone SE-30 20M + Dow
200 1500 1540 Glycol-6000 1035
Corning Hi Vac
Column length, m 1.5 4.6 3.7 15.2 3.1 3.7 6.1
Column diameter, mm 3.2 4.8 6.4 0.5 6.4 4.8 6.4
Column temperature, °C 85 110 100 75 100–128 155 140
Liquid phase, wt % 10 15 16 . 0.75 each 30 20
Support material Chromosorb P TFE-fluorocarbon Chromosorb P (Coated) Silica Chromosorb P Chromosorb P
Mesh 80–100 40–60 100–120 . . 30–50 60–80
Carrier flow, mL/min 19 60 60 15 30 171 60
A B
Detector HFI T.C. HFI HFI T.C. T.C. T.C.
Sample size, μL 0.77 20 0.07 1.54 1.03 8.69 3.0
Peak measurement triangulation triangulation integrator triangulation triangulation peak height planimeter
A
HFI = hydrogen flame ionization.
B
T.C. = thermal conductivity.
through the column by a carrier gas, and their presence in the effluent is detected and recorded as a chromatogram. Packed columns
are used, and either thermal conductivity or ionization detectors are permissible. The quantity of the components of interest present
in the sample is determined from the chromatogram by comparing their peak areas or heights with those obtained from a synthetic
sample.
4. Significance and Use
4.1 Butadiene dimer and styrene may be present as impurities in commercial butadiene. This test method is suitable for use in
internal quality control and in establishing product specifications.
5. Apparatus
5.1 Chromatograph—Any chromatograph having either a thermal conductivity or flame ionization detector may be used. The
detector system shall have sufficient sensitivity to obtain a deflection of at least 2 mm at a signal-to-noise ratio of at least 5:1 for
0.01 % by mass of butadiene dimer and styrene under the operating conditions prescribed in this test method.
5.2 Recorder—A 0 mV to 1 mV, 0 mV to 5 mV, or 0 mV to 10 mV recorder with a full-scale response time of 2 s or less, and with
sufficient sensitivity to meet the requirements of 5.1.
5.3 Column—Any column may be used that is capable of resolving the butadiene dimer and styrene as discrete peaks,
quantitatively proportional to concentration and within an elapsed time sufficiently short to be practical.
5.4 Liquid Sampling Valve—Any liquid sampling valve may be used that will permit the reproducible introduction of the butadiene
concentrate as a liquid under its vapor pressure or higher and in a quantity sufficient to meet the sensitivity and resolution
requirements in 5.1 and 5.3, respectively.
NOTE 1—Suitable valves are commercially availableavailable.
6. Reagents and Materials
6.1 4-vinylcyclohexene-1 and Styrene, for calibration, purity of not less than 99 %.
6.2 Carrier Gas—Helium or hydrogen for use on thermal conductivity detector units; or nitrogen, helium, or argon for use on
ionization detector units. (Warning—Compressed gas. Hazardous pressure.) (Warning—Hydrogen gas is flammable. Hazardous
pressure.)
6.3 Liquid Phase, for column.
...