1、Designation: D2340 13D2340 18Standard Test Method forPeroxides in Styrene Monomer1This standard is issued under the fixed designation D2340; 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 par
2、entheses 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 the peroxide content of styrene monomer.monomer reported as hydrogenperoxide.1.2 This test method has
3、been found applicable to the determination of peroxides in styrene monomer in the range of 1 to 60mg/kg.1.3 In determining the conformance of the test results using this method to applicable specifications, results shall be roundedoff in accordance with the rounding-off method of Practice E29.1.4 Un
4、itsThe values stated in SI units are to be regarded as standard. No other units of measurement are included in thisstandard.1.5 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 app
5、ropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.1.6 This international standard was developed in accordance with internationally recognized principles on standardiza
6、tionestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD3437 Practice fo
7、r Sampling and Handling Liquid Cyclic ProductsD6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related MaterialsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications2.2 Other Documents:OSHA Regulations, 29 CF
8、R paragraphs 1910.1000 and 1910.120033. Summary of Test Method3.1 Aspecimen of styrene monomer is added to a solution of isopropanol and acetic acid.Asaturated solution of sodium iodidein isopropanol is added and the solution refluxed. The peroxides present liberate iodine from sodium iodide quantit
9、atively. Theliberated iodine is then titrated with sodium thiosulfate to a colorless end point.4. Significance and Use4.1 This test method is suitable for determining the quantity of peroxides in styrene monomer both for quality control andquality assurance of the product.1 This test method is under
10、 the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Related Chemicals and is the directresponsibility of Subcommittee D16.07 on Styrene, Ethylbenzene and C9 and C10 Aromatic Hydrocarbons.Current edition approved July 1, 2013Jan. 1, 2018. Published Aug
11、ust 2013January 2018. Originally approved in 1965. Last previous edition approved in 20092013 asD2340 09.D2340 13. DOI: 10.1520/D2340-13.10.1520/D2340-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM S
12、tandardsvolume information, refer to the standardsstandards Document Summary page on the ASTM website.3 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, PA19111-5098, http:/www.dodssp.daps.mil.19111-
13、5094, http:/quicksearch.dla.mil.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 made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recomme
14、nds 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
15、 West Conshohocken, PA 19428-2959. United States15. Apparatus5.1 Erlenmeyer Flasks, glass-stoppered, 500-mL, equipped with 300-mm Liebig condensers having inner and outer standardtaper joints.5.2 Electric Hot Plate with totally enclosed heating unit.5.3 Boiling Chips.6. Reagents6.1 Purity of Reagent
16、sReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society wheresuch specifications are available.4 Other grades may be used, provided it
17、 is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water as defined byType III of Specification D1193.6.3 Gla
18、cial Acetic Acid.6.4 Isopropyl Alcohol.6.5 Sodium Iodide IsopropylAlcohol SolutionPrepare a saturated solution of sodium iodide in isopropanol (approximately 200g NaI/L).6.6 Sodium Thiosulfate, Standard Solution (0.01 N)Dissolve 2.5 g of sodium thiosulfate (Na2S2O3 5H2O) and 0.1 g ofsodium carbonate
19、 (Na2CO3) in water and dilute to 1 L. Standardize against primary standard potassium dichromate (K2Cr2O7).6.7 Alternate volumes of solutions may be prepared so long as the preparation meets the concentration specified.7. Hazards7.1 Consult the latest OSHA regulations, suppliers Material suppliers Sa
20、fety Data Sheets, and local regulations regarding allmaterials used in this test method.7.2 Styrene monomer is flammable and polymerizes exothermally on contact with peroxides, mineral acids, and aluminumchloride.7.3 Isopropyl alcohol is flammable and should be kept away from open flame and spark-pr
21、oducing apparatus. Use only a hotplate with totally enclosed heating unit in this analysis.8. Sampling8.1 Collect the sample as directed in Practice D3437.9. Procedure9.1 Add 200 mL of isopropyl alcohol into each of two 500-mL Erlenmeyer flasks containing several boiling chips. Add 10 mLof glacial a
22、cetic acid to each flask. Into one flask pipet 50 mL of the styrene monomer sample. Identify this flask as “Sample” andthe other flask as “Blank.” Fit the condenser in place (Warning: see 7.2 and 7.3). Heat the contents of the flasks to boiling andpipet 50 mL of the saturated NaI isopropyl alcohol s
23、olution into each.9.2 Continue boiling gently for 10 min. At the end of the boiling period, remove the flasks from the heat source. Rinse eachcondenser with two 10-mL portions of water, adding the rinsings to the respective flasks. Cool the flasks to room temperature.Titrate the liberated iodine in
24、each flask with 0.01 N Na2S2O3 solution to a light yellow color and continue to titrate slowly untilthe yellow color just disappears.10. Calculation10.1 Calculate the peroxide content of the specimens as hydrogen peroxide, in parts per million (mg/kg) as follows:Peroxides,mg/kg5A 2B! 3N 31.7310 4#/5
25、03C!where:A = total millilitres of Na2S2O3 solution required for titration of the specimen,A = total milliliters of Na2S2O3 solution required for titration of the specimen,B = total millilitres of Na2S2O3 solution required for titration of the blank,4 Reagent Chemicals, American Chemical Society Spe
26、cifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Co
27、nvention, Inc. (USPC), Rockville, MD.D2340 182B = total milliliters of Na2S2O3 solution required for titration of the blank,N = normality of Na2S2O3 solution used, andC = density of styrene monomer at temperature pipetted (an approximate density of 0.9 may be used to determine the sampleweight).11.
28、Report11.1 Report the peroxide content to the nearest 1 mg/kg.12. Precision and Bias12.1 Intermediate Precision (formerly called Repeatability)Duplicate results by the same operator should not be consideredsuspect (95 % confidence limit) unless they differ by more than the following:Peroxide Content
29、,mg/kgRepeatability,mg/kg1 to 60 612.2 ReproducibilityThe averages of duplicate results submitted by each of two laboratories should not be considered suspect(95 % confidence limit) unless they differ by more than the following:Peroxide Content,mg/kgReproducibility,mg/kg1 to 60 1312.3 BiasSince ther
30、e is no accepted reference material suitable for determining the bias in this test method for measuringperoxides in styrene monomer, bias has not been determined.13. Quality Guidelines13.1 Laboratories shall have a quality control system in place.13.1.1 Confirm the performance of the test instrument
31、 or test method by analyzing a quality control sample following theguidelines of standard statistical quality control practices.13.1.2 Aquality control sample is a stable material isolated from the production process and representative of the sample beinganalyzed.13.1.3 When QA/QC protocols are alre
32、ady established in the testing facility, these protocols are acceptable when they confirmthe validity of test results.13.1.4 When there are no QA/QC protocols established in the testing facility, use the guidelines described in Guide D6809 orsimilar statistical quality control practices.14. Keywords
33、14.1 peroxide content; peroxide in styrene; styreneSUMMARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue(D2340-09)-13) that may impact the use of this standard. (Approved JulyJanuary 1, 2013.)2018.)(1) Quality guidelines were updated.Mi
34、nor tweaks to Scope, 1.1, and 1.4.(2) Section 6.7 added to reagents.(3) Section 7.1, MSDS updated to SDS.(4) Spelling tweaks to “millilitres” in 10.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. User
35、s 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 at any time by the responsible technical committee and must be reviewed every
36、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 comments will receive careful consideration at a meeting of theresponsible technical
37、 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 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
38、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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 183
