1、Designation: E 1788 08Standard 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 number in parentheses i
2、ndicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of totalacidity as acetic acid in concentrations below 500 g/g inacrylonitrile.1.2 The values stated in SI units ar
3、e 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 any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices
4、 and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 8.1.4 Review the current Material Safety Data Sheets (MSDS)for detailed information concerning toxicity, first aid proce-dures, and safety precautions.2. Referenced Documents2.1 A
5、STM Standards:2D 1193 Specification for Reagent WaterE 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis3. Summary of Test Method3.1 The acrylonitrile sample is titrated with alcoholic so-dium hydroxide solution to the visual end point
6、.4. Significance and Use4.1 This test method is useful for determining low levels ofacidity, below 500 g/g 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. Apparatus
7、5.1 Buret, 10 mL, graduated in 0.05 mL subdivision.6. Purity of Reagents6.1 Use reagent grade chemicals in 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 av
8、ailable.3Other grades may be used provided it is first ascertained thatthe reagent is of sufficiently high 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-
9、tion D 1193.7. Reagents7.1 Bromthymol Blue Indicator Solution (1 g/L)Weigh100 mg into a 150 mL beaker, add 1.5 mL of 0.1 meq/mLNaOH to aid in dissolving, gradually add 100 mL of methanol.Neutralize to a deep green by dropwise addition of 0.02meq/mL NaOH.7.2 Sodium Hydroxide Standard Solution (0.02 m
10、eq/mL)Dissolve 0.800 g NaOH in 500 mL of methanol and dilute to1 L with methanol. Standardize in accordance with the 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. U
11、se acrylonitrile in a well ventilated hood.8.2 Acrylonitrile 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.8.3 Acrylonitrile liquid and vapor are absorbed readily int
12、oshoe leather and clothing and will penetrate most rubbers,1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and is the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved Dec. 15, 2008. Published January 2009
13、. Originallyapproved in 1996. Last previous edition approved in 2003 as E 1788 96(2003).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 Summa
14、ry page onthe ASTM website.3Reagent 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, BDH Ltd., Poole, Dorset, U.K., and
15、the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.barrier
16、fabrics, or creams. Contact lenses should not be worn inareas 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 solu
17、tion.9.2 Pipet 100 mL of the sample into the 250-mL Erlenmeyerflask. Titrate with the 0.02 meq/mL NaOH solution to the firstperceptible blue color.10. Calculation10.1 Calculate the acidity of the sample as follows:Acidity as Acetic Acid, g/g by wt. 5A 3 N 3 60 000B 3 D(1)where:A = NaOH solution requ
18、ired for titration of sample, mL,N = meq/mL of the NaOH 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 nearestg/g.12. Precision and Bias412.1 PrecisionThe following criteria should be used forju
19、dging the acceptability of results (see 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
20、.12.1.2 Laboratory Precision (Within-Laboratory, 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
21、is given in Table 1.12.1.3 Reproducibility (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 be
22、tween two such averages isgiven in Table 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 g/g, respectively. Oneanalyst in each of seven laboratories performed dupl
23、icate determinationsand repeated one day 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 te
24、st method has not beendetermined because of the lack of acceptable reference mate-rial.13. Keywords13.1 acidity; acrylonitrile; alcoholic sodium hydroxide; endpoint; indicator; titratedSUMMARY OF CHANGESSubcommittee E15.02 has identified the location of selected changes to this standard since the la
25、st issue(E 1178-97(2002) that may impact the use of this standard.(1) Updated units of measure to comply with the InternationalSystem of Units (SI).(2) Added numbered paragraph in Scope stating that the SIunits are to be considered standard.(3) Added Summary of Changes section.ASTM International tak
26、es 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 validity of any such patent rights, and the riskof infringement of such rights, are entirely their own re
27、sponsibility.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 addres
28、sed to ASTM International Headquarters. Your comments 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 th
29、e address shown below.This standard is copyrighted 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 (ph
30、one), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: E151049.TABLE 1 Precision for Total AcidityLevel,mg/kgRepeatability 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 mg/kg.E1788082
