ASTM E1178-1997(2002) Standard Test Methods for Analysis of Acrylonitrile《丙烯腈分析的测试法》.pdf

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1、Designation: E 1178 97 (Reapproved 2002)Standard Test Methods forAnalysis of Acrylonitrile1This standard is issued under the fixed designation E 1178; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num

2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the analysis of acrylonitrile.1.2 The analytical procedures appear in the following order:SectionsColor 7 to 9Hy

3、drogen Cyanide 10 to 18p-Methoxyphenol 19 to 28Water 29 to 321.3 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 standard to establish appro-priate safety and health practices and determine the applica-

4、bility of regulatory limitations prior to use. See Section 5 forspecific hazards statements.1.4 Review the current Material Safety Data Sheets (MSDS)for detailed information concerning toxicity, first aid proce-dures, and safety precautions.2. Referenced Documents2.1 ASTM Standards:D 1193 Specificat

5、ion for Reagent Water2D 1209 Test Method for Color of Clear Liquids (Platinum-Cobalt Scale)3E 60 Practice for Analysis of Metals, Ores, and RelatedMaterials by Molecular Absorption Spectrometry4E 180 Practice for Determining Precision of ASTM Meth-ods for Analysis and Testing of Industrial Chemicals

6、5E 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis5E 203 Test Method for Water Using Karl Fischer Reagent53. Significance and Use3.1 These test methods provide for the determination ofcolor and various impurities in acrylonitrile. Co

7、lor and impu-rity levels are important factors in many uses of acrylonitrile.4. Purity of Reagents4.1 Purity of ReagentsUse reagent grade chemicals in alltests. Unless otherwise indicated, it is intended that all reagentsshall conform to the specifications of the Committee onAnalytical Reagents of t

8、he American Chemical Society,6wheresuch specifications are available. Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.4.2 Purity of WaterUnless otherwise indicated, reference

9、sto water shall be understood to mean Type II or Type IIIreagent water conforming to Specification D 1193.5. Hazards5.1 Acrylonitrile is potentially hazardous to human health ifnot properly handled. Acrylonitrile is a suspected humancarcinogen. Use acrylonitrile in a well ventilated hood.5.2 Acrylon

10、itrile can contribute to a toxic condition insystems of the human body, from inhalation, swallowing, orcontact with the eyes or skin. Direct contact with acrylonitrilecan cause skin burns as well.5.3 Acrylonitrile liquid and vapor are absorbed readily intoshoe leather and clothing and will penetrate

11、 most rubbers,barrier fabrics, or creams. Contact lenses should not be worn inareas where eye contact with acrylonitrile could occur. Useimpermeable protective clothing and consult the current MSDSfor recommended materials.6. Photometers and Photometric Practice6.1 The photometers and photometric pr

12、actice described inthese test methods shall conform to Practice E 60.COLOR7. Procedure7.1 Determine the color of the acrylonitrile in accordancewith Test Method D 1209.1This specification is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and is the direct responsib

13、ility of SubcommitteeE15.02 on Product Standards.Current edition approved Oct. 10, 2002. Published February 2003. Originallyapproved ijn 1987. Last previous edition approved in 1997 as E 1178 97.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 06.04.4Annual Book of ASTM

14、Standards, Vol 03.05.5Annual Book of ASTM Standards, Vol 15.05.6Reagent 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,

15、BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8. Report8.1 Estimate and report the co

16、lor of the acrylonitrile to thenearest 1 Pt-Co unit, absolute.9. Precision and Bias9.1 The precision and bias of this test method have not beendetermined.7HYDROGEN CYANIDE10. Scope10.1 This test method covers the determination of HCNover the concentration of 0.5 to 10 ppm in acrylonitrile.11. Summar

17、y of Test Method11.1 Hydrogen cyanide (HCN) is extracted from the sampleas a water soluble salt by means of a solution containingsodium hydroxide, ammonium hydroxide, and potassium io-dide. The aqueous extract is then titrated with standard silvernitrate until all the cyanide is complexed as soluble

18、 Ag(CN)2.The first excess of silver, the end point, is indicated visuallywith the formation of insoluble silver iodide (turbidity). TheHCN content is calculated from the quantity of silver nitrateconsumed.12. Significance and Use12.1 The level of HCN in product acrylonitrile is anindication of produ

19、ct quality and stability. Knowledge of theHCN content can be used in judging quality and monitoringstability.13. Apparatus13.1 Buret, micro, 10-mL capacity, graduated in 0.02 mLsubdivisions.13.2 Separatory funnels, 250-mL capacity.14. Reagents14.1 Potassium Iodide (KI), crystal.14.2 Ammonium Hydroxi

20、de (NH4OH), concentrated.14.3 Sodium Hydroxide (NaOH), pellets.14.4 Caustic Iodide ReagentDissolve 3.6 g of potassiumiodide crystals and 44.1 g of sodium hydroxide pellets inapproximately 700 mL of water contained in a 1-L volumetricflask. Add 180 mL of concentrated NH4OH and swirl to mix.Dilute to

21、volume with water, mix thoroughly, and store in aplastic screw-capped bottle. This solution is stable for at least6 months.14.5 Standard Silver Nitrate Solution, 0.1 NPrepare andstandardize as described in Practice E 200.814.6 Standard Silver Nitrate Solution, 0.01 NPipet 50.0mL of standard 0.1 N Ag

22、NO3solution into a 500-mL volumet-ric flask. Dilute to volume with water and mix thoroughly.15. Procedure15.1 Add 100 mL of caustic iodide to each of three 125-mLErlenmeyer flasks using a graduated cylinder.15.2 Slowly titrate each solution with standard 0.01 NAgNO3to the same slight persistent opal

23、escence.15.3 Transfer the contents of two of the flasks into glass-stoppered 250-mL separatory funnels. Retain the third flask forreference. Add 100 mL of sample to each separatory funnelusing a graduated cylinder.15.4 Stopper and shake the separatory funnels for 1 min610 s, then allow the layers to

24、 separate.15.5 Drain the lower aqueous layers into the original125-mL Erlenmeyer flasks.15.6 Titrate each solution with standard 0.01 N AgNO3untilan opalescence is obtained that matches the reference solution.Record the volume of 0.01 N AgNO3required for each titrationand calculate the duplicate val

25、ues for HCN content.16. Calculation16.1 Calculate the HCN content of the sample as follows:HCN, ppm w/w!5mL AgNO3!N AgNO3!0.054!3106mL sample!0.806!(1)where:0.054 = meq weight of HCN, and0.806 = density acrylonitrile, g/mL.or HCN, ppm w/w!5mL AgNO3!N AgNO3!66914!mL sample!(2)17. Report17.1 Report th

26、e parts per million of HCN to two significantfigures.18. Precision and Bias18.1 The following criteria should be used for judging theacceptability of results (Note 1):18.1.1 Repeatability (Single Analyst)The coefficient ofvariation for a single determination has been estimated to be17.6 % relative a

27、t 12 df. The 95 % limit for the differencebetween two such runs is 49 % relative.18.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability (formerly called repeatability)The coeffi-cient of variation of results (each the average of duplicates),obtained by the same analyst on different

28、 days, has beenestimated to be 12.4 % relative at 4 df. The 95 % limit for thedifference between two such averages is 35 % relative.18.1.3 Reproducibility (multilaboratory)The coefficientof variation of results (each the average of duplicates), ob-tained by analysts in different laboratories, has be

29、en estimatedto be 39.1 % relative at 3 df. The 95 % limit for the differencebetween two such averages is 109 % relative.NOTE 1The above precision estimates are based on an interlaboratorystudy of analyses performed in 1986 on one sample of acrylonitrilecontaining approximately 0.81 ppn HCN. One anal

30、yst in each of 5laboratories performed duplicate determinations and repeated one daylater, for a total of 20 determinations. One outlying laboratory (four7A round-robin test was conducted with acrylonitrile for color. In each case thevalue reported was 5 Pt-Co units which is typical for industrial g

31、rade acrylonitrile.8This solution may be purchased from Fisher Scientific Co., No. 5572, or anequivalent.E 1178 97 (2002)2determinations) was excluded from the calculations.9Practice E 180 wasused in developing these precision estimates.18.2 BiasThe bias of this test method has not beendetermined be

32、cause of the lack of acceptable reference mate-rial.p-METHOXYPHENOL19. Scope19.1 This test method covers the determination ofp-methoxyphenol (MEHQ) in acrylonitrile. MEHQ is added toacrylonitrile to prevent polymerization during storage andshipment.20. Summary of Test Method20.1 The absorbance of ME

33、HQ is measured directly inacrylonitrile at 295 nm using UV spectrophotometry. The ppmMEHQ is determined from the absorbance by use of a standardcurve prepared from known concentrations of MEHQ in pureacrylonitrile.21. Significance and Use21.1 Knowledge of the inhibitor content of product acry-lonitr

34、ile is essential for proper stability during storage andshipment of this material. The MEHQ prevents prematurepolymerization of the monomer.22. Interferences22.1 Any impurity which absorbs at 295 nm will interfere.Experience has shown that some impurities produced in agedacrylonitrile absorb in this

35、 region. The test method should,therefore, be applied only to acrylonitrile which is within thecolor specification.23. Apparatus23.1 UV Spectrophotometer.23.2 Absorption Cells, 1 cm, matched, silica, with caps.23.3 Buret, 25-mL capacity, graduated in 0.1 mL subdivi-sions.23.4 Separatory Funnel, 500-

36、mL capacity.24. Reagents24.1 p-Methoxyphenol (monomethyl ether hydroquinone,MEHQ).24.2 Sodium Hydroxide (1 N)Dissolve 40 g of NaOH inabout 500 mL of water. Cool, then dilute to 1-L with water andmix.1025. Standardization and Calibration25.1 Prepare inhibitor-free acrylonitrile as follows:25.1.1 Shak

37、e 200 mL of 1 N NaOH with 100 mL ofacrylonitrile in a 500-mL separatory funnel. Draw off andreserve the acrylonitrile layer. Repeat the extraction until 500mL of inhibitor-free acrylonitrile has been accumulated.25.1.2 Alternately, distill 750 mL of acrylonitrile retainingthe 500 mL heart-cut.25.2 P

38、repare calibration curve as follows:25.2.1 Quantitatively transfer 0.160 g of MEHQ to a100-mL volumetric flask. Add 50 mL inhibitor-free acryloni-trile and swirl to dissolve. Dilute to volume with inhibitor-freeacrylonitrile and mix well. This solution contains 2000 ppmMEHQ.25.2.2 Pipet 10 ml of thi

39、s solution (25.2.1) into a second100-mL volumetric flask, dilute to volume with inhibitor-freeacrylonitrile and mix well. This solution contains 200 ppmMEHQ.25.2.3 Using a buret, deliver 5.0, 7.5, 10.0, and 12.5 mL ofthe 200 ppm standard solution into separate 50.0 mL volumet-ric flasks. Dilute each

40、 to the mark with inhibitor-free acryloni-trile and mix well. These solutions contain 20, 30, 40, and 50ppm MEHQ respectively.25.2.4 Measure the absorbance of each of the standards at295 nm using 1-cm cells and inhibitor-free acrylonitrile as thereference.25.2.5 Construct a calibration curve by plot

41、ting the absor-bance of each standard (ordinate) versus the ppm MEHQ(abscissa). Draw the best straight line through the plottedprints.25.2.6 Reinhibit any remaining inhibitor-free acrylonitrileby adding at least 35 ppm MEHQ to prevent prematurepolymerization of the monomer.26. Procedure26.1 Measure

42、the absorbance of the product acrylonitrilesample at 295 nm using 1-cm cells and inhibitor-free acryloni-trile as a reference.NOTE 2Air can be used as the reference in place of inhibitor-freeacrylonitrile.26.2 Determine the ppm MEHQ present in the sample byreference to the standard calibration curve

43、.27. Report27.1 Report the parts per million of p-methoxyphenol to twosignificant figures.28. Precision and Bias28.1 The following criteria should be used for judging theacceptability of results (Note 3):28.1.1 Repeatability (Single Analyst)The coefficient ofvariation for a single determination has

44、been estimated to be0.91 % relative at 12 df. The 95 % limit for the differencebetween two such runs is 2.5 % relative.28.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability (formerly called repeatability)The coeffi-cient of variation of results (each the average of duplicates),obt

45、ained by the same analyst on different days, has beenestimated to be 1.02 % relative at 6 df. The 95 % limit for thedifference between two such averages is 2.9 % relative.28.1.3 Reproducibility (Multilaboratory)The coefficientof variation of results (each the average of duplicates), ob-tained by ana

46、lysts in different laboratories, has been estimated9Supporting data are available from ASTM International Headquarters. RequestRR: E15 1038.10This solution may be purchased from Fisher Scientific Co., No. 55266, or theequivalent.E 1178 97 (2002)3to be 2.79 % relative at 5 df. The 95 % limit for the

47、differencebetween two such averages is 7.8 % relative.NOTE 3The above precision estimates are based on an interlaboratorystudy of analyses performed in 1986 on one sample of acrylonitrilecontaining approximately 44.9 ppm p-methoxyphenol. One analyst ineach of six laboratories performed duplicate det

48、erminations and repeatedone day later, for a total of 24 determinations.9Practice E 180 was used indeveloping these precision estimates.28.2 BiasThe bias of this test method has not beendetermined because of the lack of acceptable reference mate-rial.WATER29. Scope29.1 This test method covers the de

49、termination of water inthe concentration of 0.05 to 3.0 weight percent in productacrylonitrile.30. Procedure30.1 Determine the water in the acrylonitrile sample asdescribed in Test Method E 203.1131. Report31.1 Report the percentage of water to two significantfigures.32. Precision and Bias32.1 The following criteria should be used for judging theacceptability of results (Note 4):32.1.1 Repeatability (Single Analyst)The coefficient ofvariation for a single determination has been estimated to be3.07 % relative at 12 df. The 95 % limit for the differenc