1、Designation: E1788 08E1788 16Standard Test Method forAcidity in Acrylonitrile1This standard is issued under the fixed designation E1788; 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 parenth
2、eses indicates 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 total acidity as acetic acid in concentrations below 500 g/g in acrylonitrile.1.2 The values stated in SI
3、units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health
4、 practices and determine the applicability of regulatorylimitations prior to use. Specific hazard statements are given in Section 8.1.4 Review the current Material Safety Data Sheets (MSDS)(SDS) for detailed information concerning toxicity, first aidprocedures, and safety precautions.2. Referenced D
5、ocuments2.1 ASTM Standards:2D1193 Specification for Reagent WaterE200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis3. Summary of Test Method3.1 The acrylonitrile sample is titrated with alcoholic sodium hydroxide solution to the visual
6、 end point.4. Significance and Use4.1 This test method is useful for determining low levels of acidity, below 500 g/g in acrylonitrile. The total acidity iscalculated as acetic acid.4.2 Acidity may be present as a result of contamination or decomposition during storage, distribution, or manufacture.
7、5. Apparatus5.1 Buret, 10 mL, graduated in 0.05 mL subdivision.6. Purity of Reagents6.1 Use reagent grade chemicals in all tests. Unless otherwise indicated, all reagents shall conform to the specifications of theCommittee on Analytical Reagents of the American Chemical Society, where such specifica
8、tions are available.3 Other grades maybe used provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracyof the determination.6.2 Unless otherwise indicated, references to water mean reagent water conforming to Type II or Type III
9、 of SpecificationD1193.1 This test method is under the jurisdiction of ASTM Committee E15 on Industrial and Specialty Chemicals and is the direct responsibility of Subcommittee E15.02 onProduct Standards.Current edition approved Dec. 15, 2008April 1, 2016. Published January 2009May 2016. Originally
10、approved in 1996. Last previous edition approved in 20032008 asE1788 96E1788 08.(2003). DOI: 10.1520/E1788-08.10.1520/E1788-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information,
11、 refer to the standards Document Summary page on the ASTM website.3 Reagent Chemicals, American Chemical Society Specifications, , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Che
12、micals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC),(USP), Rockville, MD.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been
13、made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*
14、A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. Reagents7.1 Bromthymol Blue Indicator Solution (1 g/L)Weigh 100 mg into a 150 mL beaker, add 1.5 mL of 0.1 meq/mL NaOH
15、toaid in dissolving, gradually add 100 mL of methanol. Neutralize to a deep green by dropwise addition of 0.02 meq/mL NaOH.7.2 Sodium Hydroxide Standard Solution (0.02 meq/mL)Dissolve 0.800 g NaOH in 500 mLof methanol and dilute to 1 Lwithmethanol. Standardize in accordance with the appropriate sect
16、ions of Test Method Practice E200.8. Hazards8.1 Acrylonitrile is potentially hazardous to human health if not properly handled. Acrylonitrile is a suspected humancarcinogen. Use acrylonitrile in a well ventilated hood.8.2 Acrylonitrile can contribute to a toxic condition in systems of the human body
17、 from inhalation, swallowing, or contact withthe eyes or skin. Direct contact with acrylonitrile can cause skin burns.8.3 Acrylonitrile liquid and vapor are absorbed readily into shoe leather and clothing and will penetrate most rubbers, barrierfabrics, or creams. Contact lenses should not be worn i
18、n areas where eye contact with acrylonitrile could occur. Impermeableprotective clothing must be used. Consult the current MSDSSDS for recommended materials.9. Procedure9.1 To a 250-mL Erlenmeyer flask, add 0.5 mL of bromthymol blue indicator solution.9.2 Pipet 100 mL of the sample into the 250-mL E
19、rlenmeyer flask. 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/gby wt.5A 3N 360000B 3D (1)where:A = NaOH solution required for titration of sample, mL,N = meq/mL of the NaOH so
20、lution,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 g/g.12. Precision and Bias412.1 PrecisionThe following criteria should be used for judging the acceptability of results (see Note 1):12.1.1 R
21、epeatability (Single Analyst)The standard deviation for a single determination has been estimated to be the absolutevalue in Table 1 at the indicated degrees of freedom. The 95 % limit for the difference between two such runs is given in Table1.12.1.2 Laboratory Precision (Within-Laboratory, Between
22、-Days Variability)The standard deviation of results (each theaverage of duplicates) obtained by the same analyst on different days has been estimated to be the absolute value in Table 1. The95 % limit for the difference between two such averages is given in Table 1.12.1.3 Reproducibility (Multilabor
23、atory)The standard deviation of results (each the average of duplicates) obtained byanalysts in different laboratories has been estimated to be the absolute value in Table 1 at the indicated degrees of freedom. The95 % limit for the difference between two such averages is given in Table 1.4 Supporti
24、ng data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:E15-1049. Contact ASTM CustomerService at serviceastm.org.TABLE 1 Precision for Total AcidityLevel,mg/kgRepeatability Laboratory Precision ReproducibilityStandardDeviation df95 %LimitStand
25、ardDeviation df95 %LimitStandardDeviation df95 %Limit2 0.0000 12 3A 0.2887 6 0.8 0.5323 5 1103 1.3229 10 4 0.7246 5 2 3.5532 4 10A Practical limit, based on reporting results to nearest 1 mg/kg.E1788 162NOTE 1The above precision estimates are based on an interlaboratory study of analyses performed i
26、n 1991 on two samples of acrylonitrile containingan average total acidity of 2 and 103 g/g, respectively. One analyst in each of seven laboratories performed duplicate determinations and repeated oneday later for a total of 56 determinations. Data from one laboratory, however, were excluded from the
27、 first sample and two laboratories were excludedfrom the second sample. Practice E180 was used in developing these precision estimates.12.2 BiasThe bias of this test method has not been determined because of the lack of acceptable reference material.13. Keywords13.1 acidity; acrylonitrile; alcoholic
28、 sodium hydroxide; end point; indicator; titratedSUMMARY OF CHANGESSubcommittee E15.02 has identified the location of selected changes to this standard since the last issue(E1178-97(2002)E1178-08 that may impact the use of this standard.(1) Updated units of measure to comply with the International S
29、ystemChanged “Material Safety Data Sheets (MSDS)” to “SafetyData Sheets (SDS)” in 1.4of Units (SI)(2) Added numbered paragraph in Scope stating that the SI units are to be considered standard.(3) Added Summary of Changes section.ASTM International takes no position respecting the validity of any pat
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