ASTM E1788-1996(2003) Standard Test Method for Acidity in Acrylonitrile《丙烯腈中酸度的标准测试方法》.pdf

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1、Designation: E 1788 96 (Reapproved 2003)Standard Test Method forAcidity in Acrylonitrile1This standard is issued under the fixed designation E 1788; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe

2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of totalacidity as acetic acid in concentrations below 500 ppm inacrylonitrile.1.2 This standard

3、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-bility of regulatory limitations prior to use. Specific hazardstatements are gi

4、ven in Section 8.1.3 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 Specification for Reagent Water2E 200 Practice for Preparation, Standardization, and

5、Stor-age of Standard and Reagent Solutions for ChemicalAnalysis33. Summary of Test Method3.1 The acrylonitrile sample is titrated with alcoholic so-dium hydroxide solution to the visual end point.4. Significance and Use4.1 This test method is useful for determining low levels ofacidity, below 500 pp

6、m in acrylonitrile. The total acidity iscalculated as acetic acid.4.2 Acidity may be present as a result of contamination ordecomposition during storage, distribution, or manufacture.5. Apparatus5.1 Buret, 10 mL, graduated in 0.05 mL subdivision.6. Purity of Reagents6.1 Use reagent grade chemicals i

7、n all tests. Unless other-wise indicated, all reagents shall conform to the specificationsof the Committee on Analytical Reagents of the AmericanChemical Society, where such specifications are available.4Other grades may be used provided it is first ascertained thatthe reagent is of sufficiently hig

8、h purity to permit its usewithout lessening the accuracy of the determination.6.2 Unless otherwise indicated, references to water meanreagent water conforming to Type II or Type III of Specifica-tion D 1193.7. Reagents7.1 Bromthymol Blue Indicator Solution (1 g/L)Weigh100 mg into a 150 mL beaker, ad

9、d 1.5 mL of 0.1 N NaOH toaid in dissolving, gradually add 100 mL of methanol. Neutral-ize to a deep green by dropwise addition of 0.02 N NaOH.7.2 Sodium Hydroxide Standard Solution (0.02 N)Dissolve 0.800 g NaOH in 500 mL of methanol and dilute to1 L with methanol. Standardize in accordance with the

10、appro-priate sections of Test Method E 200.8. Hazards8.1 Acrylonitrile is potentially hazardous to human health ifnot properly handled. Acrylonitrile is a suspected humancarcinogen. Use acrylonitrile in a well ventilated hood.8.2 Acrylonitrile can contribute to a toxic condition insystems of the hum

11、an body from inhalation, swallowing, orcontact with the eyes or skin. Direct contact with acrylonitrilecan cause skin burns.8.3 Acrylonitrile liquid and vapor are absorbed readily intoshoe leather and clothing and will penetrate most rubbers,barrier fabrics, or creams. Contact lenses should not be w

12、orn in1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicalsand is the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved Apr. 10, 2003. Published May 2003. Originallyapproved in 1996. Last previous edition approv

13、ed in 1996 as E 1788 96.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 15.05.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, s

14、ee Analar Standards for LaboratoryChemicals, 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 S

15、tates.areas where eye contact with acrylonitrile could occur. Imper-meable protective clothing must be used. Consult the currentMSDS for recommended materials.9. Procedure9.1 To a 250-mL Erlenmeyer flask, add 0.5 mL of bromthy-mol blue indicator solution.9.2 Pipet 100 mL of the sample into the 250-m

16、L Erlenmeyerflask. Titrate with the 0.02 N NaOH solution to the firstperceptible blue color.10. Calculation10.1 Calculate the acidity of the sample as follows:Acidity as Acetic Acid, ppm by wt. 5A 3 N 3 60 000B 3 D(1)where:A = NaOH solution required for titration of sample, mL,N = normality of the N

17、aOH solution,B = volume of sample used, mL, andD = Sp Gr of the sample at the test temperature.11. Report11.1 Report the total acidity as acetic acid to the nearest partper million.12. Precision and Bias512.1 PrecisionThe following criteria should be used forjudging the acceptability of results (see

18、 Note 1):12.1.1 Repeatability (Single Analyst)The standard devia-tion for a single determination has been estimated to be theabsolute value in Table 1 at the indicated degrees of freedom.The 95 % limit for the difference between two such runs isgiven in Table 1.12.1.2 Laboratory Precision (Within-La

19、boratory, Between-Days Variability)The standard deviation of results (each theaverage of duplicates) obtained by the same analyst ondifferent days has been estimated to be the absolute value inTable 1. The 95 % limit for the difference between two suchaverages is given in Table 1.12.1.3 Reproducibil

20、ity (Multilaboratory)The standard de-viation of results (each the average of duplicates) obtained byanalysts in different laboratories has been estimated to be theabsolute value in Table 1 at the indicated degrees of freedom.The 95 % limit for the difference between two such averages isgiven in Tabl

21、e 1.NOTE 1The above precision estimates are based on an interlaboratorystudy of analyses performed in 1991 on two samples of acrylonitrilecontaining an average total acidity of 2 and 103 ppm, respectively. Oneanalyst in each of seven laboratories performed duplicate determinationsand repeated one da

22、y later for a total of 56 determinations. Data from onelaboratory, however, were excluded from the first sample and twolaboratories were excluded from the second sample. Practice E 180 wasused in developing these precision estimates.12.2 BiasThe bias of this test method has not beendetermined becaus

23、e of the lack of acceptable reference mate-rial.13. Keywords13.1 acidity; acrylonitrile; alcoholic sodium hydroxide; endpoint; indicator; titratedASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of

24、 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 at any time by the responsible technical committee and must be reviewed every five

25、 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 co

26、mmittee, 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 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA

27、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).5Supporting data have been filed at

28、 ASTM International Headquarters and maybe obtained by requesting Research Report RR: E151049.TABLE 1 Precision for Total AcidityLevel,ppmRepeatability Laboratory Precision ReproducibilityStandardDeviationdf95 %LimitStandardDeviationdf95 %LimitStandardDeviationdf95 %Limit2 0.0000 12 3A0.2887 6 0.8 0.5323 5 1103 1.3229 10 4 0.7246 5 2 3.5532 4 10APractical limit, based on reporting results to nearest 1 ppm.E 1788 96 (2003)2