1、Designation: D5713 14 (Reapproved 2018)1Standard Test Method forAnalysis of High Purity Benzene for Cyclohexane Feedstockby Capillary Gas Chromatography1This standard is issued under the fixed designation D5713; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, 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.1NOTEEditorial corrections made in Footnote 1 and 8.1 in June 2018.1. Scope1.1 This test
3、method covers the determination of specificimpurities in, and the purity of benzene for cyclohexanefeedstock by gas chromatography.1.2 This test method has been found applicable to benzenein the range from 99 to 100 % purity and to impurities atconcentrations of 2 to 10 000 mg/kg.1.3 In determining
4、the conformance of the test results usingthis method to applicable specifications, results shall berounded off in accordance with the rounding-off method ofPractice E29.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 Thi
5、s standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For sp
6、ecific hazard statements, see 7.2 and Section 8.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by t
7、he World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3437 Practice for Sampling and Handling Liquid CyclicProductsD4790 Terminology of Aromatic Hydrocarbons and RelatedChemicalsD6809 Guide for Quality Control and Quality AssuranceProcedur
8、es for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE260 Practice for Packed Column Gas ChromatographyE355 Practice for Gas Chromatography Terms and Relation-shipsE1510 Practice for Installing Fused Sili
9、ca Open TubularCapillary Columns in Gas Chromatographs2.2 Other Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and1910.120033. Terminology3.1 Definitions:3.1.1 SeeTerminology D4790 for definition of terms used inthis test method.4. Summary of Test Method4.1 In this test method, the chromatog
10、ram peak area for eachimpurity is compared to the peak area of the internal standard(n-octane or other suitable known) added to the sample. Fromthe response factor of toluene relative to that of the internalstandard, and using a response factor of 1.00 for nonaromaticimpurities and the amount of int
11、ernal standard added, theconcentrations of the impurities are calculated. The benzenecontent is obtained by subtracting the total amount of allimpurities from 100.00.5. Significance and Use5.1 This test method is useful for benzene purity on thebasis of impurities normally present in benzene and may
12、 beused for final product inspections and process control.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic, Industrial, Specialty and Related Chemicals and is the direct responsi-bility of Subcommittee D16.01 on Benzene, Toluene, Xylenes, Cyclohexane andTheir Derivatives.
13、Current edition approved June 1, 2018. Published June 2018. Originallyapproved in 1995. Last previous edition approved in 2014 as D5713 14. DOI:10.1520/D5713-14R18E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
14、Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.Copyright ASTM International, 1
15、00 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and
16、Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15.2 This test method will detect the following impurities:toluene, methylcyclopentane, n-hexane, 2-methylhexane,cyclohexane, cyclopentane, 2-methylpentane, 2,3-dimethylpentane, 3-methylhexane, n-hepta
17、ne,methylcyclohexane, ethylcyclopentane, 2,4-dimethylhexane,trimethylpentane, and others where specific impurity standardsare available. Absolute purity cannot be accurately determinedif unknown impurities are present.6. Apparatus6.1 Gas ChromatographAny gas chromatograph having atemperature program
18、mable oven, flame ionization detector anda splitter injector suitable for use with a fused silica capillarycolumn may be used, provided the system has sufficientsensitivity that will give a minimum peak height of 3 times thebackground noise for 2 mg/kg of an impurity.6.2 ColumnFused silica capillary
19、 columns have beenfound to be satisfactory.An example is 50 m of 0.20-mm insidediameter fused silica capillary internally coated to a filmthickness of 0.50 m with polydimethylsiloxane (see Table 1for suggested instrument parameters). Other columns may beused after it has been established that such a
20、 column is capableof separating all major impurities (for example, compoundslisted in 5.2) and the internal standard from the benzene underoperating conditions appropriate for the column. The columnmust give satisfactory resolution (distance from the valleybetween the peaks is not greater than 50 %
21、of the peak heightsof the impurity) of cyclohexane from benzene as well as otherimpurity peaks. A poorly resolved peak, such as cyclohexane,will often require a tangent skim from the neighboring peak.6.3 Electronic Integration, with tangent skim capabilities isrecommended.6.4 Vial.6.5 Microsyringes,
22、 assorted volumes.6.6 Injector, the specimen must be precisely and repeatedlyinjected into the gas chromatograph. An automatic sampleinjection device is highly recommended. Manual injection canbe employed if the precision stated in Table 2 can be reliablyand consistently satisfied.7. Reagents and Ma
23、terials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical reagents of the American Chemical Society,where such specifications are available.4Other grad
24、es may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Carrier Gasa carrier gas (99.999 % minimum purity)appropriate to the type of detector used should be employed.(WarningIf hydrogen is
25、 used as the carrier gas, take specialsafety precautions to ensure that the system is free of leaks andthat the effluent is properly vented or burned.)7.3 Hydrogen, for the flame ionization detector (FID) mini-mum purity of 99.999 % and 0.5 ppm total hydrocarbons ispreferred.7.4 Air, for the flame i
26、onization detector, 0.1 ppm totalhydrocarbons is preferred.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BHD,
27、 Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.TABLE 1 Recommended Operating ConditionsCarrier gas hydrogenLinear velocity at 40C, cm/s 40Detector flame ionizationDetector temperature, C 250CInjection po
28、rt temperature, C 250CSplit ratio 40:1Split flow, mL/min 60Column 50mby0.20mmIDby0.5mbonded polydimethylsiloxanecapillary columnInitial column temperature, C 40Initial time, min 17Programming rate 10C/minFinal temperature, C 250CFinal time, min 10Sample size, L 1.2TABLE 2 Summary of Precision DataCo
29、mponentAverageConcentrationmg/kgIntermediatePrecisionReproducibilityBenzene (weight %) 99.9699.9799.960.0060.0070.0080.0220.0200.025Methylcyclopentane 10443548.312.22.527.919.415.1Toluene 6463285.13.01.822.016.69.1Methylcyclohexane 13243797.41.43.234.85.417.0Methylcyclohexane + 196 7.9 54.9Toluene 1
30、0610612.94.433.620.4n-Hexane 4322.21.51.83.72.22.5n-Heptane 616152.71.54.011.15.623.4Ethylcyclopentane 76111.81.91.53.711.06.1Total Other Impurities 9910718522.544.655.5163.0190.6233.0D5713 14 (2018)127.5 n-octane, 99.0 % minimum purity, or other internalstandard (99.0 % minimum purity), such as iso
31、-octane, previ-ously analyzed to be free of compounds coeluting withimpurities in the sample.NOTE 1It is highly recommended the carrier, make-up and detectorgases be purified to remove oxygen (to less than 1 ppm, less than 0.5 ppmis preferred), water and hydrocarbons. It is also recommended the air
32、bepurified to remove hydrocarbons and water.8. Hazards8.1 Consult current OSHA regulations, suppliers SafetyData Sheets, and local regulations for all materials used in thistest method.9. Sampling9.1 Sample in accordance with Practice D3437.10. Preparation of Apparatus10.1 Follow the manufacturers i
33、nstructions for mountingand conditioning the column into the chromatograph andadjusting the instrument to the desired conditions. Allowsufficient time for the equipment to reach equilibrium. SeePractices E260, E355 and E1510 for additional information ongas chromatography procedures, terminology, an
34、d columninstallation. The column and conditions in Table 1 were used todevelop this analysis. If there is a dispute, the column andconditions should be agreed upon between the parties or useTable 1 as a referee.11. Procedure11.1 Transfer approximately 10 g of the sample to beanalyzed to a tared vial
35、 and weigh to the nearest 0.1 mg. (Makesure that the sample is deposited in the center of the vial so thatthe liquid does not contact the neck.)11.2 Add approximately 0.1 g of internal standard (noctanewas used in Fig. 1) and quickly reweigh to the nearest 0.1 mg.(The internal standard is added to t
36、he vial while on the balancepan and deposited into the center of the liquidnot on the sideof the vial.)11.3 Cap the mixture and mix by inverting several times.11.4 Inject into the gas chromatograph an appropriateamount of the mixture as previously determined in accordancewith 6.1 and 6.2 and immedia
37、tely start the analysis. (1.2 Lwas used in Fig. 1.)11.5 Determine the areas of all the impurity peaks and theinternal standard. Identify the specific impurities by comparingthe chromatogram obtained to a typical chromatogram. (Un-identified impurities are summed and reported as a composite.)The chro
38、matogram shown in Fig. 1 can be used for the columnand conditions specified in Table 1.12. Calculation12.1 Measure the areas of all peaks, including the internalstandard, except the benzene peak.12.2 Calculate the weight to milligram per kilogrammg/kg of the individual impurities, Cias follows:Ci5 1
39、06BDFGH(1)where:B = peak area of a specific impurity or group of impuritiesD = response factor, (see 12.3)F = mass of internal standard added to the sample, gG = peak area of the internal standardH = weight of sample before addition of internal standard,g106= factor to convert to weight-mg/kgFIG. 1
40、High Purity BenzeneTypical Chromatogram(See Table 1 for Operating Conditions)D5713 14 (2018)1312.3 A response factor of 1.000 should be used for allhydrocarbon impurities except toluene which will be 0.935.12.4 Calculate the benzene content by subtracting the sumof the impurities from 100.000. Benze
41、ne weight% = 100.000 (sum of impurities in weight %). Total impuri-ties are converted from mg/kg to weight percent by multiplyingby 0.0001 %.13. Report13.1 Report the concentration of impurities to the nearestmg/kg and the benzene content to the nearest 0.01 %. Forconversion purposes, 1 mg/kg equals
42、 0.0001 %.14. Precision and Bias514.1 PrecisionThe criteria in Table 2 should be used tojudge the acceptability at the 95 % probability level of theresults obtained by this test method (95 % confidence level).The criteria were derived from an interlaboratory study of threesamples analyzed in duplica
43、te on two days between sixlaboratories. Details of the design and analysis of the data isgiven in ASTM Research Report RR: RR:D16-1018.14.1.1 Intermediate Precision (formerly Repeatability)Results in the same laboratory should not be consideredsuspect unless they differ by more than the amounts show
44、n inTable 2. Results differing by less than “r”havea95%probability of being correct.14.1.2 ReproducibilityResults submitted by each of twolaboratories should not be considered suspect unless they differby more than the amount shown in Table 2. Results differing byless than “R” have a 95 % probabilit
45、y of being correct.14.2 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this testmethod for measuring specific impurities, bias has not beendetermined.15. Quality Guidelines15.1 Laboratories shall have a quality control system inplace.15.2 Conf
46、irm the performance of the test instrument or testmethod by analyzing a quality control sample following theguidelines of standard statistical quality control practices.15.3 A quality control sample is a stable material isolatedfrom the production process and representative of the samplebeing analyz
47、ed.15.4 When QA/QC protocols are already established in thetesting facility, these protocols are acceptable when theyconfirm the validity of test results.15.5 When there are no QA/QC protocols established in thetesting facility, use the guidelines described in Guide D6809 orsimilar statistical quali
48、ty control practices.16. Keywords16.1 benzene; cyclohexane feedstock; impuritiesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the val
49、idity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which y
