ASTM D2119-2003 Standard Test Method for Aldehydes in Styrene Monomer《苯乙烯单体中醛含量的标准试验方法》.pdf

1、Designation: D 2119 03Standard Test Method forAldehydes in Styrene Monomer1This standard is issued under the fixed designation D 2119; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This laboratory test method covers the wet chemicaldetermination of aldehydes in styrene monomer.Aldehydes arecalculated and reported as benzaldehyde. T

3、he range of concen-tration for this test method is 0.001 % to 0.030 %.1.2 For purposes of determining conformance with this testmethod, an observed value or a calculated value shall berounded off “to the nearest unit” in the last right-hand digitused in expressing the specification limit, in accorda

4、nce withthe rounding-off method of Practice E29.1.3 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 and determine the applica-bility of reg

5、ulatory limitations prior to use. For specific hazardstatements, see Section 8.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 3437 Practice for Sampling and Handling Liquid CyclicProducts3E29 Practice for Using Significant Digits in Test Data toDetermine Conforman

6、ce with Specifications42.2 Other Documents:OSHA Regulations, 29 CFR, paragraphs 1910.1000 and1910.120053. Summary of Test Method3.1 An alcoholic solution of hydroxylamine hydrochlorideis added to a specimen of styrene monomer. Active aldehydespresent react in accordance with the following equation:R

7、CHO 1 NH2OHHClRCHNOH 1 H2O 1 HClThe hydrochloric acid, which is equivalent to the aldehydepresent in the sample, is titrated with standard sodium hydrox-ide solution.4. Significance and Use4.1 This test method is suitable for determining the quantityof aldehydes, both for quality control and quality

8、 assurance ofthe product.5. Interferences5.1 Ketones, if present, interfere by partially reacting withthe reagent.6. Apparatus6.1 Erlenmeyer Flasks, glass-stoppered, 250-mL.6.2 Pipets, 25-mL.6.3 Volumetric Flasks, 100-mL.6.4 Burets, 10-mL. (Microburets are preferred.)6.5 Thermometers, capable of dif

9、ferentiating 1C at ambi-ent.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications a

10、re available.6Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as d

11、efinedby 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, Ethylbenzene, and C9and C10AromaticHydrocarbons.Current edition approved Aug. 1

12、0, 2003. Published August 2003. Originallyapproved in 1962. Last previous edition approved in 1996 as D 2119 96.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 06.04.4Annual Book of ASTM Standards, Vol 14.02.5Available from Standardization Documents Order Desk, DODSSP,

13、Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-50986Reagent 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,

14、 BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical 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,

15、PA 19428-2959, United States.7.3 Hydrochloric Acid, Standard (0.05 N)Prepare a 0.05N solution of hydrochloric acid (HCl) by diluting 4.15 mL ofconcentrated HCl (density 1.19 g/mL) to 1 L with water.7.4 Hydroxylamine Hydrochloride SolutionDissolve 20 gof hydroxylamine hydrochloride (NH2OHHCl) in 1 L

16、ofmethanol and neutralize to the red-yellow end point of thymolblue indicator.7.5 Methanol.7.6 Sodium Hydroxide, Standard Solution (0.05 N)Dissolve 2.00 g of low-carbonate sodium hydroxide (NaOH) inwater and dilute to 1 L. Standardize against primary standardbenzoic acid.7.7 Thymol Blue Indicator So

17、lutionDissolve 0.1 g ofthymol sulfonphthalein, sodium salt, in water and dilute to 100mL.8. Hazards8.1 Consult the latest OSHAregulations, suppliers MaterialSafety Data Sheets, and local regulations regarding all mate-rials used in this test method.8.2 Styrene monomer is flammable and polymerizes ex

18、o-thermally on contact with peroxides, mineral acids, and AlCl3.9. Sampling9.1 Collect the sample as directed in Practice D 3437.10. Procedure10.1 Pipet 25.0 mL of the sample (Warningsee 8.2) intoa 250-mL glass-stoppered Erlenmeyer flask containing 25 mLof methanol. Record the temperature of the sam

19、ple. Add 0.2mL of thymol blue indicator and, if necessary, neutralize with0.05 N NaOH solution or 0.05 N HCl to the red-yellow endpoint (do not record). Add 25 mL of the neutralized hydroxy-lamine hydrochloride solution and allow to stand 1 h, shakingthe flask occasionally. Titrate to the original r

20、ed-yellow endpoint with 0.05 N NaOH solution, dispensed from a 10-mLburet, and record the volume used. Let stand 1 h and againtitrate any acid that may have been liberated. Record the totalvolume of NaOH used.10.2 Since methanol may contain aldehydes, run a blankdetermination on 25 mL of methanol.11

21、. Calculation11.1 Calculate the percentage of aldehydes as benzaldehydeas follows:Aldehydes, % 5 A 2 B!N 3 0.106!/25C 3 100where:A = NaOH solution required for titration of the specimen,mL,B = NaOH solution required for titration of the methanolblank, mL,N = normality of NaOH solution used, andC = d

22、ensity of styrene monomer.12. Report12.1 Report the aldehydes content to the nearest 0.001 %.13. Precision and Bias13.1 Intermediate Precision (formerly calledRepeatability)Duplicate results by the same operator shouldnot be considered suspect (95 % confidence limit) unless theydiffer by more than t

23、he following:Aldehyde Content, % Repeatability, %0.004 0.000613.2 ReproducibilityThe averages of duplicate resultssubmitted by each of two laboratories should not be consideredsuspect (95 % confidence limit) unless they differ by more thanthe following:Aldehyde Content, % Reproducibility, %0.004 0.0

24、01613.3 BiasSince there is no accepted reference materialsuitable for determining the bias in this test method formeasuring aldehydes, bias has not been determined.14. Keywords14.1 aldehyde content; aldehydes in styrene; styreneSUMMARY OF CHANGESCommittee D16 has identified the location of selected

25、changes to this standard since the last issue(D 2119 96) that may impact the use of this standard.(1) A concentration range for the method was added to theScope paragraph 1.1. The value was calculated based on thetheoretical abilities of the method and typical range.(2) Section 5 Interferences was a

26、dded.(3) Editorial changes made to conform to D16 EditorialGuidelines.D2119032ASTM International takes 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 valid

27、ity 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 years andif not revised, either reapproved or withdrawn. Your comme

28、nts 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 committee, which you may attend. If you feel that your comments have n

29、ot 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 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).D2119033