1、Designation: D 3760 02e1Standard Test Method forAnalysis of Isopropylbenzene (Cumene) by GasChromatography1This standard is issued under the fixed designation D 3760; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEResearch report was added editorially in September 2004.1. Scope1.1 This test method covers the determination of the purityof i
3、sopropylbenzene (cumene) by gas chromatography.1.2 This test method has been found applicable to themeasurement of impurities such as nonaromatic hydrocarbons,benzene, ethylbenzene, t-butylbenzene, n-propylbenzene,alpha-methylstyrene, sec-butylbenzene, and diisopropylben-zene, which are common to th
4、e manufacturing process ofisopropylbenzene. Limit of detection for these impurities is 10mg/kg (see 5.1).1.3 The following applies to all specified limits in thisstandard: for purposes of determining conformance with thisstandard, an observed value or a calculated value shall berounded off “to the n
5、earest unit” in the last right-hand digitused in expressing the specification limit, in accordance withthe rounding-off method of Practice E 29.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standa
6、rd to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2D 3437 Practice for Sampling and Handling Liquid CyclicProductsE 29 Practice for U
7、sing Significant Digits in Test Data toDetermine Conformance with SpecificationsE 260 Practice for Packed Gas ChromatographyE 355 Practice for Gas Chromatography Terms and Rela-tionships2.2 Other Document:OSHA Regulations, 29CFR, paragraphs 1910.1000 and1910.120033. Summary of Test Method3.1 A known
8、 amount of internal standard is added to asample of isopropylbenzene. The prepared sample is mixedand analyzed by a gas chromatograph equipped with a flameionization detector (FID). The peak area of each impurity andthe internal standard is measured and the amount of eachimpurity is calculated from
9、the ratio of the peak area of theinternal standard versus the peak area of the impurity. Purity byGC (the isopropylbenzene content) is calculated by subtractingthe sum of the impurities found from 100.00. Results arereported in weight percent.4. Significance and Use4.1 This test method is suitable f
10、or setting specifications onthe materials referenced in 1.2 and for use as an internal qualitycontrol tool where isopropylbenzene is produced or is used ina manufacturing process. It may also be used in developmentor research work involving isopropylbenzene.4.2 This test method is useful in determin
11、ing the purity ofisopropylbenzene with normal impurities present includingdiisopropylbenzenes. If extremely high boiling or unusualimpurities are present in the isopropylbenzene, this test methodwould not necessarily detect them and the purity calculationwould be erroneous.4.3 Cumene hydroperoxide,
12、if present, will yield decompo-sition products that will elute in the chromatogram therebygiving incorrect results.4.4 The nonaromatic hydrocarbons commonly present fromthe isopropylbenzene manufacturing process will interfere withthe determination of benzene when Column A in Table 1 isused.1This te
13、st method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.07 on Styrene, Ethylbenzene, and C9and C10Aromatic Hydro-carbons.Current edition approved Jan. 10, 2002. Published March 2002. Originallypublish
14、ed as D 3760 79. Last previous edition D 3760 98.2For referenced ASTM standards, visit the 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.3Available f
15、rom U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.5 The internal standard must be sufficiently resolved from
16、any impurity and the isopropylbenzene peak.5. Apparatus5.1 Gas ChromatographAny instrument having a flameionization detector that can be operated at the conditions givenin Table 1. The system should have sufficient sensitivity toobtain a minimum peak height response for 10 mg/kgn-butylbenzene of twi
17、ce the height of the signal backgroundnoise.5.2 ColumnsThe choice of column is based on resolutionrequirements. Any column may be used that is capable ofresolving all significant impurities from isopropylbenzene andfrom the internal standard. The columns described in Table 1have been used successful
18、ly.5.3 RecorderElectronic integration is recommended.6. Reagents and Materials6.1 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 Ameri
19、can Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.1.1 Internal StandardNormal Butylbenzene (nBB) isthe recommend
20、ed internal standard of choice. Other com-pounds may be found acceptable provided they meet thecriteria as defined in 4.5 and 6.1.6.2 Carrier GasChromatographic grade helium or hydro-gen is recommended.6.3 Compressed AirChromatographic grade.6.4 HydrogenHigh purity.7. Hazards7.1 Consult current OSHA
21、 regulations and suppliers Mate-rial Safety Data Sheets on handling materials listed in this testmethod.8. Sampling and Handling8.1 Sample the material in accordance with PracticeD 3437.9. Preparation of Apparatus9.1 Follow manufacturers instructions for mounting andconditioning the column into the
22、chromatograph and adjustingthe instrument to the conditions described in Table 1 allowingsufficient time for the equipment to reach equilibrium. SeePractices E 260 and E 355 for additional information on gaschromatography practices and terminology.10. Procedure10.1 Into a 100-mL volumetric flask, ad
23、d 100 L of nBB to99.90 mL of cumene. Mix well. Assuming a density of 0.856for nBB and 0.857 for cumene, the resulting nBB concentrationwill be 0.1000 weight %.10.2 Inject into the gas chromatography an appropriateamount of sample as previously determined according to 6.1and start the analysis.10.3 O
24、btain a chromatograph and peak integration report.Fig. 1 and Fig. 2 illustrate a typical analysis of cumene forColumns A and B, respectively.11. Calculations11.1 Determine the area defined by each peak in thechromatogram.11.2 Calculate the percent concentration of the total nonaro-matics and each im
25、purity as follows:Ci5Ai!C2!A2!(1)where:Ci= concentration of component i, weight%,Ai= peak area of component i,A2= peak area of nBB,C2= concentration of nBB, weight %.11.3 Calculate the total concentration of all impurities asfollows:Ct5 (Ci(2)where:Ct= total concentration of all impurities.11.4 Calc
26、ulate the purity of isopropylbenzene as follows:isopropylbenzene, weight % 5 100.000 2 Ct(3)12. Report12.1 Report the individual impurities to the nearest0.0001 %.12.2 Report the purity of isopropylbenzene to the nearest0.001 weight%.4Reagent Chemicals, American Chemical Society Specifications, Amer
27、icanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USP
28、C), Rockville,MD.TABLE 1 Instrumental ParametersColumn A Column BDetector Flame Ionization Flame IonizationColumn:Tubing fused silica fused silicaStationary phase polyethylene glycol methyl siliconeSolid support crosslinked crosslinkedFilm thickness 0.25 0.5 Length, m 50 50Diameter, mm 0.32 mm ID 0.
29、32 mm IDTemperatures:Injector, C 275 275Detector, C 300 300Oven:Initial, C 60 35Time 1, min 10 10Final, C 175 275Rate, C/min 10 5Time 2, min 10 0Carrier gas hydrogen heliumFlow rate, mL/min 1.0 1.0Split ratio 100:1 100:1Sample size, L 1.0 1.0D376002e1213. Precision and Bias513.1 PrecisionThe criteri
30、a in Table 2 should be used tojudge the acceptability of results obtained by this test method.The criteria were derived from round robin testing of foursamples. Table 3 illustrates equations for repeatability andreproducibility.13.2 BiasSince there is no accepted reference materialsuitable for deter
31、mining the bias for the procedure in this testmethod for measuring isopropylbenzene purity, bias has notbeen determined.14. Keywords14.1 alpha methylstyrene; analysis by gas chromatography;benzene; butylbenzene; cumene; ethylbenzene; isopropylben-zene; nonaromatic hydrocarbons; propylbenzene5Support
32、ing data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D161032.FIG. 1 Typical Chromatogram using Conditions for Column AD376002e13FIG. 2 Typical Chromatogram using Conditions for Column BD376002e14TABLE 2 Typical Values for Repeatability and
33、Reproducibility forSelected Cumene ComponentsComponentConcentration,wt %Repeatability Reproducibilitya-Methylstyrene 0.0065 0.00048 0.000720.0083 0.00048 0.000740.0104 0.00131 0.00151Benzene 0.0024 0.00023 0.00088Ethylbenzene 0.0042 0.00046 0.003500.0080 0.00050 0.002980.0099 0.00111 0.00519Nonaroma
34、tics 0.0163 0.00231 0.004820.0571 0.00635 0.00635n-Propylbenzene 0.0192 0.00170 0.001690.0218 0.00113 0.001450.0246 0.00006 0.00088s-Butylbenzene 0.0024 0.00014 0.000820.0037 0.00030 0.000630.0059 0.00034 0.00071t-Butylbenzene 0.0067 0.00041 0.001100.0106 0.00031 0.001060.0283 0.00102 0.00353Cumene
35、99.8443 0.00237 0.0972099.8657 0.01050 0.0622099.9221 0.01300 0.0429099.9386 0.01060 0.02750TABLE 3 Repeatability and ReproducibilityCumeneRepeatability = 0.07801 (3 ) 7.7843Reproducibility = 0.63789(3) + 63.7785t-ButylbenzeneRepeatability = 0.031894(3 ) + 0.00009Reproducibility = 0.120596(3) + 0.00
36、00648s-ButylbenzeneRepeatability = 0.054069(3 ) + 0.0000437Reproducibility = 9.60703(3) + 0.000817n-PropylbenzeneRepeatability = 0.30407(3 ) + 0.007613Reproducibility = 0.14927(3) + 0.004605a-MethylstyreneRepeatability = 0.21785(3 ) 0.0010752Reproducibility= 0.20833(3) 0.000761BenzeneRepeatability =
37、 0.095(3 )Reproducibility = 0.367175(3)NonaromaticsRepeatability = 0.098932(3 ) 0.000697Reproducibility = 0.03733(3) + 0.004214EthylbenzeneRepeatability = 0.099441(3 ) 0.000045Reproducibility = 0.208332(3) + 0.0021557D376002e15ASTM International takes no position respecting the validity of any paten
38、t rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision a
39、t 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 commen
40、ts will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted
41、by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D376002e16
