1、Designation: D 2340 09Standard Test Method forPeroxides in Styrene Monomer1This standard is issued under the fixed designation D 2340; 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 parenthes
2、es 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 perox-ide content of styrene monomer.1.2 This test method has been found applicable to thedetermination
3、of peroxides in styrene monomer in the range of1 to 60 mg/kg.1.3 In determining the conformance of the test results usingthis method to applicable specifications, results shall berounded off in accordance with the rounding-off method ofPractice E29.1.4 The values stated in SI units are to be regarde
4、d asstandard. No other units of measurement are included in thisstandard.1.5 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
5、the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 3437 Practice for Sampling and Handling Liquid CyclicProductsD 6809 Guide for Quality Control and Quality Assuran
6、ceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 Other Documents:OSHA Regulations, 29 CFR paragraphs 1910.1000 and1910.120033. Summary of Test Method3.1 A specimen of styrene monomer is
7、added to a solutionof isopropanol and acetic acid. A saturated solution of sodiumiodide in isopropanol is added and the solution refluxed. Theperoxides present liberate iodine from sodium iodide quantita-tively. The liberated iodine is then titrated with sodiumthiosulfate to a colorless end point.4.
8、 Significance and Use4.1 This test method is suitable for determining the quantityof peroxides in styrene monomer both for quality control andquality assurance of the product.5. Apparatus5.1 Erlenmeyer Flasks, glass-stoppered, 500-mL, equippedwith 300-mm Liebig condensers having inner and outer stan
9、-dard taper joints.5.2 Electric Hot Plate with totally enclosed heating unit.5.3 Boiling Chips.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Anal
10、ytical Reagents of the American Chemical Societywhere such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise i
11、ndicated, referencesto water shall be understood to mean reagent water as definedby Type III of Specification D 1193.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.07 on Styrene, Ethy
12、lbenzene and C9and C10Aromatic Hydro-carbons.Current edition approved June 15, 2009. Published July 2009. Originallyapproved in 1965. Last previous edition approved in 2003 as D 2340 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceas
13、tm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.4Reagent Chemicals, A
14、merican 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 the United States Pharmacopeiaand National Formul
15、ary, 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.6.3 Glacial Acetic Acid.6.4 Isopropyl Alcohol.6.5 Sodium
16、Iodide Isopropyl Alcohol SolutionPrepare asaturated solution of sodium iodide in isopropanol (approxi-mately 200 g NaI/L).6.6 Sodium Thiosulfate, Standard Solution (0.01 N)Dissolve 2.5 g of sodium thiosulfate (Na2S2O35H2O) and 0.1g of sodium carbonate (Na2CO3) in water and dilute to 1 L.Standardize
17、against primary standard potassium dichromate(K2Cr2O7).7. Hazards7.1 Consult the latest OSHAregulations, suppliers MaterialSafety Data Sheets, and local regulations regarding all mate-rials used in this test method.7.2 Styrene monomer is flammable and polymerizes exo-thermally on contact with peroxi
18、des, mineral acids, and alu-minum chloride.7.3 Isopropyl alcohol is flammable and should be kept awayfrom open flame and spark-producing apparatus. Use only ahot plate with totally enclosed heating unit in this analysis.8. Sampling8.1 Collect the sample as directed in Practice D 3437.9. Procedure9.1
19、 Add 200 mL of isopropyl alcohol into each of two500-mL Erlenmeyer flasks containing several boiling chips.Add 10 mL of glacial acetic acid to each flask. Into one flaskpipet 50 mL of the styrene monomer sample. Identify this flaskas “Sample” and the other flask as “Blank.” Fit the condenserin place
20、 (Warning: see 7.2 and 7.3). Heat the contents of theflasks to boiling and pipet 50 mL of the saturated NaI isopropylalcohol solution into each.9.2 Continue boiling gently for 10 min. At the end of theboiling period, remove the flasks from the heat source. Rinseeach condenser with two 10-mL portions
21、 of water, adding therinsings to the respective flasks. Cool the flasks to roomtemperature. Titrate the liberated iodine in each flask with 0.01N Na2S2O3solution to a light yellow color and continue totitrate slowly until the yellow color just disappears.10. Calculation10.1 Calculate the peroxide co
22、ntent of the specimens ashydrogen peroxide, in parts per million (mg/kg) as follows:Peroxides, mg/kg 5 A 2 B! 3 N 3 1.7 3 104# / 50 3 C!where:A = total millilitres of Na2S2O3solution required for titra-tion of the specimen,B = total millilitres of Na2S2O3solution required for titra-tion of the blank
23、,N = normality of Na2S2O3solution used, andC = density of styrene monomer at temperature pipetted (anapproximate density of 0.9 may be used to determinethe sample weight).11. Report11.1 Report the peroxide content to the nearest 1 mg/kg.12. Precision and Bias12.1 Intermediate Precision (formerly cal
24、ledRepeatability)Duplicate results by the same operator shouldnot be considered suspect (95 % confidence limit) unless theydiffer by more than the following:Peroxide Content,mg/kgRepeatability,mg/kg1to60 612.2 ReproducibilityThe averages of duplicate resultssubmitted by each of two laboratories shou
25、ld not be consideredsuspect (95 % confidence limit) unless they differ by more thanthe following:Peroxide Content,mg/kgReproducibility,mg/kg1to60 1312.3 BiasSince there is no accepted reference materialsuitable for determining the bias in this test method formeasuring peroxides in styrene monomer, b
26、ias has not beendetermined.13. Quality Guidelines13.1 Refer to Guide D 6809 for suggested QA/QC activitiesthat can be used as a part of this test method. It is recom-mended that the operator of this test method select and performrelevant QA/QC activities like the ones in Guide D 6809 tohelp ensure t
27、he quality of data generated by this test method.14. Keywords14.1 peroxide content; peroxide in styrene; styreneD2340092SUMMARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue(D 2340 - 03) that may impact the use of this standard. (Approv
28、ed June 15, 2009.)(1) A range was added to the Scope section.(2) The Quality Guidelines section was added to the method.(3) This method was editorially revised to update footnote 2.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item
29、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 responsibility.This standard is subject to revision at any time by the responsible technical commit
30、tee 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 addressed to ASTM International Headquarters. Your comments will receive careful consideration at a mee
31、ting 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 the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive,
32、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 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D2340093
