1、Designation: D2593 93 (Reapproved 2014)Standard Test Method forButadiene Purity and Hydrocarbon Impurities by GasChromatography1This standard is issued under the fixed designation D2593; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of butadiene-1,3 purity and impurities such as propane, prop
3、ylene,isobutane, n-butane, butene-1, isobutylene, propadiene, trans-butene-2, cis -butene-2, butadiene-1,2, pentadiene-1,4, and,methyl, dimethyl, ethyl, and vinyl acetylene in polymerizationgrade butadiene by gas chromatography. Impurities includingbutadiene dimer, carbonyls, inhibitor, and residue
4、are measuredby appropriate ASTM procedures and the results used tonormalize the component distribution obtained by chromatog-raphy.NOTE 1Other impurities present in commercial butadiene must becalibrated and analyzed. Other impurities were not tested in the coopera-tive work on this test method.NOTE
5、 2This test method can be used to check for pentadiene-1,4 andother C5s instead of Test Method D1088.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if
6、 any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificwarning statements, see 6.1 and 9.3.2. Referenced Documents2.1 ASTM Standards
7、:2D1088 Method of Test for Boiling Point Range ofPolymerization-Grade Butadiene (Withdrawn 1983)32.2 Energy Institute Standards:4IP 194 Analysis of Butadiene-1,3 Polymerization Grade3. Summary of Test Method3.1 A representative sample is introduced into a gas-liquidpartition column. The butadiene an
8、d other components areseparated as they are transported through the column by aninert carrier gas. Their presence in the effluent is measured bya detector and recorded as a chromatogram. The chromatogramof the sample is interpreted by applying component attenuationand detector response factors to th
9、e peak areas or peak heightsand the relative concentration determined by relating indi-vidual peak response to total peak response. Impurities includ-ing butadiene dimer, carbonyls, inhibitor, and residue aremeasured by appropriate ASTM procedures and the resultsused to normalize the distribution ob
10、tained by gas chromatog-raphy.4. Significance and Use4.1 The trace hydrocarbon compounds listed can have aneffect in the commercial use of butadiene. This test method issuitable for use in process quality control and in settingspecifications.5. Apparatus5.1 ChromatographAny chromatograph having eith
11、er athermal-conductivity or flame ionization detector can be usedprovided the system has sufficient sensitivity and stability toobtain a recorder deflection of at least 2 mm at signal-to-noiseratio of at least 5:1 for 0.01 weight % of impurity.5.2 ColumnAny column can be used that is capable ofresol
12、ving the components listed in 1.1 with the exception ofbutene-1 and isobutylene, which can be eluted together. Thecomponents should be resolved into distinct peaks such that theratio A/B will not be less than 0.5 where A is the depth of thevalley on either side of peak B and B is the height above th
13、ebaseline of the smaller of any two adjacent peaks. In the casewhere the small component peak is adjacent to a large one, it1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.D0.04 o
14、n C4 Hydrocarbons.This test method was adopted as a joint ASTM-IP Standard, IP 194, in 1972.Current edition approved May 1, 2014. Published July 2014. Originally approvedin 1967. Last previous edition approved in 2009 as D259393(2009). DOI:10.1520/D2593-93R14.2For referenced ASTM standards, visit th
15、e ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Obsolete. Contac
16、t Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.uk.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1can be necessary to construct a baseline of the small peaktangent to the curve as shown in Fig
17、. 1.5.2.1 A description of columns that meet the requirementsof this test method is tabulated in the Appendix. Persons usingother column materials must establish that the column givesresults that meet the precision requirements of Section 11.5.3 Sample Inlet SystemMeans shall be provided forintroduc
18、ing a measured quantity of representative sample intothe column. Pressure-sampling devices can be used to inject asmall amount of liquid directly into the carrier gas. Introduc-tion can also be accomplished by use of a gas valve to chargethe vaporized liquid.5.4 RecorderA recording potentiometer wit
19、h a full-scaledeflection of 10 mV or less is suitable for obtaining thechromatographic data. Full-scale response time should be 2 sor less, and with sufficient sensitivity to meet the requirementsof 5.1.NOTE 3Other methods of recording detector output such as computer-teletype systems can be used in
20、stead of a recorder, provided precisionrequirements of Section 11 are met.6. Reagents and Materials6.1 Carrier GasA carrier gas appropriate to the type ofdetector used should be employed. Helium or hydrogen may beused with thermal conductivity detectors. Nitrogen, helium, orargon may be used with io
21、nization detectors. The minimumpurity of any carrier should be 99.95 mol %. (WarningCompressed gas. Hazardous pressure.) (WarningHydrogenflammable gas. Hazardous pressure.)6.1.1 If hydrogen is used, special safety precautions must betaken to ensure that the system is free from leaks and that theeffl
22、uent is properly vented.6.2 Column Materials:6.2.1 Liquid PhaseThe materials that have been usedsuccessfully in cooperative work as liquid phases are listed inTable X1.1.6.2.2 Solid SupportThe support for use in the packedcolumn is usually crushed firebrick or diatomaceous earth.Sieve size will depe
23、nd on the diameter of the column used andliquid-phase loading, and should be such as would giveoptimum resolution and analysis time. Optimum size rangescannot be predicted on purely theoretical grounds. For somesystems it has been found that a ratio of average particlediameter to column inside diame
24、ter of 1:25 will result inminimum retention time and minimum band widths.6.2.3 Tubing MaterialCopper, stainless steel, Monel,aluminum, and various plastic materials have been found to besatisfactory for column tubing. The material must be nonreac-tive with respect to substrate, sample, and carrier g
25、as and ofuniform internal diameter.6.3 Hydrocarbons for Calibration and IdentificationHydrocarbon standards for all components present are neededfor identification by retention time and for calibration forquantitative measurements.NOTE 4Mixtures of hydrocarbons can be used provided there is nouncert
26、ainty as to the identity or concentration of the compounds involved.7. Preparation of Apparatus7.1 Column PreparationThe technique used to prepare thecolumn is not critical as long as the finished column producesthe desired separation. Preparation of the packing is notdifficult once the support, par
27、titioning liquid, and loading levelhave been determined. The following general directions havebeen found to produce columns of acceptable characteristics.7.1.1 Weigh out the desired quantity of support, usuallytwice that required to fill the column.7.1.2 Calculate and weigh out the required quantity
28、 ofpartitioning agent. Dissolve the partitioning agent in a volumeof chemically inert, low-boiling solvent equal to approximatelytwice the volume of support.7.1.3 Gradually add the support material to the solution withgentle stirring.7.1.4 Slowly evaporate the solvent while gently agitatingthe mixtu
29、re until the packing is nearly dry and no free liquid isapparent.7.1.4.1 Some stationary phases such as benzyl cyanidesilver nitrate are susceptible to oxidation and must be protectedfrom excessive exposure to air during the evaporation anddrying steps.7.1.5 Spread the packing in thin layers on a no
30、nabsorbentsurface and air- or oven-dry as required to remove all traces ofsolvent.7.1.6 Resieve the packing to remove fines and agglomeratesproduced in the impregnation step.7.1.7 Fill the column tubing with packing by plugging oneend with glass wool and pouring the packing into the other endthrough
31、 a small funnel. Vibrate the tubing continuously over itsentire length while filling. When the packing ceases to flow, tapthe column gently on the floor or bench-top while vibrating iscontinued. Add packing as necessary until no further settlingoccurs during a 2-min period. Remove a small amount ofp
32、acking from the open end, plug with glass wool, and shape thecolumn to fit the chromatograph.7.2 ChromatographMount the column in the chromato-graph and establish the operating conditions required to givethe desired separation (Appendix X1).Allow sufficient time forthe instrument to reach equilibriu
33、m as indicated by a stablebase line. Control the oven temperature so that it is constant toFIG. 1 Illustration of A/B Ratio for Small-Component PeakD2593 93 (2014)2within 0.5C without thermostat cycling which causes anuneven base line. Set the carrier-gas flow rate, measured witha soap film meter, s
34、o that it is constant to within 1 mL/min ofthe selected value.8. Calibration8.1 IdentificationSelect the conditions of column tem-perature and carrier gas flow that will give the necessaryseparation. Determine the retention time for each compound byinjecting small amounts of the compound either sepa
35、rately orin mixtures. Recommended sample sizes for retention data are1 L for liquids and 1 cm3or less for gases.8.2 StandardizationThe area under the peak of the chro-matogram is considered a quantitative measure of the amountof the corresponding compound. The relative area is propor-tional to the c
36、oncentration if the detector responses of thesample components are equal. The recommended procedurefor quantitative calibration is as follows: with all equipment atequilibrium at operating conditions, inject constant volumesamples of high-purity components. Each compound should beinjected at least t
37、hree times. The areas of the correspondingpeaks should agree within 1 %. When a recorder is used, adjustthe attenuation in all cases to keep the peak on-scale and witha height of at least 50 % of full scale. Measure the area of thepeaks by any reliable method (Note 7). To obtain componentweight % re
38、sponse data from the area response of the volumeinjections, it is necessary to consider the density and purity ofthe compounds used for calibration. The average volume arearesponse of each component is divided by the density multi-plied by the weight percent purity of the component as follows:Weight
39、 percent response of component (1)5average component peak areadensity 3weight percent purity of componentComponent weight percent detector correction factors arethen obtained by selecting a reference component such asbutadiene, and dividing the individual component weightresponses into the reference
40、 weight response.8.2.1 Factors derived on a thermal-conductivity detectorusing helium-carrier gas are as follows:Component Mol wt ThermalResponseWeight Factor WeightFactor,Butadiene-1,3=1.00Butadiene-1,3 54 80 0.68 1.00Propane 44 65 0.68 1.00Propylene 42 63 0.67 0.98Isobutane 58 82 0.71 1.04n-Butane
41、 58 85 0.68 1.00Butene-1 56 81 0.69 1.01Isobutylene 56 82 0.68 1.00trans-Butene-2 56 85 0.66 0.97cis-Butene-2 56 87 0.64 0.94Propadiene 40 53 0.75 1.10Methyl acetylene 40 58 0.69 1.01NOTE 5Response based on data represented by Messner,A. E., Rosie,D. M., and Argabright, P. A., Analytical Chemistry,
42、Vol 31, 1959, pp.230233, and Dietz, W. A., Journal of Gas Chromatography, Vol 5, No.2, 1967, pp. 6871.8.2.1.1 Although not determined with standards, weightfactors of 1.00 (compared to butadiene 1,3 as 1.00) were usedfor pentadiene-1,4 butadiene-1,2, dimethyl acetylene, ethyl andvinyl acetylene in t
43、his study to obtain the precision listed inSection 11. It is permissible to use the above establishedresponse factors instead of calibration when using thermal-conductivity detectors with helium-carrier gas. With otherdetectors or carrier gas, or both, it is necessary to calibrate(Note 5).8.2.2 Meas
44、urements can be made using peak heights ascriteria for calculations instead of peak areas. If peak heightsare used, care must be taken so that chromatograph-operatingparameters such as column temperature and carrier-gas flowrate are kept at the same conditions as when the unit wascalibrated. The chr
45、omatograph can be calibrated using knownblends or by establishing relative-response data using peakheights in the same manner as listed above.NOTE 6Use of a hydrogen-flame detector gives essentially equalrelative response to hydrocarbons. On a weight basis, the sensitivity of theflame detector for h
46、ydrocarbons is essentially independent of the hydro-carbons structure. On a molar basis, the sensitivity appears to be a functionof the carbon content, giving essentially equal relative response tohydrocarbons containing the same number of carbon atoms.8.2.3 Because detector or amplifier output need
47、 not be linearwith component concentration, this must be checked by inject-ing constant volumes of pure butadiene at a series of decreas-ing pressures from ambient down to 20 mm Hg (torr) or byusing synthetic standards with vapor sample valves at ambientor at decreasing pressures or by using synthet
48、ic standards withliquid sample valves. If on plotting the results the response islinear, then the calibration procedure given above is satisfac-tory. If not, the relative responses of the minor componentsmust be determined in the linear response region.9. Procedure9.1 Attach the sample cylinder to t
49、he instrument-samplingvalve so that the sample is obtained from the liquid phase. Ifintroduction is through a liquid valve the sample cylindersshould be pressured with a suitable gas, such as helium, to apressure sufficient to ensure that sample flashing does not occurin the line to the sampling valve or in the valve itself. If a vaporvalve is used, care must be taken to completely vaporize asmall liquid sample, allowing the vapor to flow through thesample loop at a flow rate of 5 to 10 mL/min until at least tentimes the volume of the sample loop has been fl
