1、Designation: D 4755 95 (Reapproved 2004)Standard Test Method forFree Halogens in Halogenated Organic Solvents and TheirAdmixtures1This standard is issued under the fixed designation D 4755; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the evaluation of free halogensin halogenated organic solvents and their a
3、dmixtures.1.2 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 regulatory limitations prior to use.2. Re
4、ferenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent Water3. Summary of Test Method3.1 Any free halogens present in the halogenated solvent areextracted with water and reacted with potassium iodide testsolution containing starch indicator. A blue color indicates thatpresence of fre
5、e halogens.4. Significance and Use4.1 Free halogens will react with any residual moisture in asolvent to form acid. These acids can cause corrosion toprocess and storage equipment used for halogenated solvents.4.2 The presence of free halogens in halogenated solvents isoften an indication that the s
6、tabilizers in the solvent system arebreaking down.4.3 This test method provides a means of detecting thepresence of free halogens in halogenated solvents and theiradmixtures.5. Interferences5.1 The following materials interfere with this test giving afalse positive: ferric ion; phosgene; iodine; oxi
7、dizing agents;and strong acid (catalyze atmospheric oxidation of the KI).6. Apparatus6.1 Glass-Stoppered Graduate, 25-mL.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications
8、 of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other 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.7.2 Purity
9、 of Water Unless otherwise indicated, refer-ences to water shall be understood to mean reagent waterconforming to Type III of Specification D 1193.7.3 Potassium Iodide (KI) Test SolutionDissolve 16.5 g ofpotassium iodide in water to make 100 mL. Store in light-resistant containers.7.4 Starch Test So
10、lutionMix1gofsoluble starch4with 10mg of red mercuric iodide and sufficient cold water to make athin paste. Add 200 mL of boiling water, and boil for 1 minwith continuous stirring. Cool, and use only the clear solution.8. Procedure8.1 Transfer 10 mL of sample to a glass-stoppered graduateand add 10
11、mL of potassium iodide test solution and 1 mL ofstarch indicator solution. Shake vigorously for 2 min andobserve color of the aqueous layer. The presence of freehalogens is indicated by a blue coloration.NOTE 1The potassium iodide solution can generate free iodine via airoxidation. For this reason,
12、the test procedure should first be performed ona reagent blank (10 mL of potassium iodide and 1 mL of starch). If a faintblue color is observed in the blank, a fresh potassium iodide solutionshould be prepared and a reagent blank retested before proceeding withthe sample solution.1This test method i
13、s under the jurisdiction of ASTM Committee D26 onHalogenated Organic Solvents and Fire Extinguishing Agents and is the directresponsibility of Subcommittee D26.04 on Test Methods.Current edition approved March 15, 1995. Published May 1995. Originallypublished as D 4755 87. Last previous edition D 47
14、55 92.2For 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 Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifica
15、tions, 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 Formulary, U.S. Pharmacopeial Convention
16、, Inc. (USPC), Rockville,MD.4Commercially available, stabilized starch indicator solutions may be used.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.9. Report9.1 Report as either positive or negative.10. Precision and Bias10.1 This
17、 is a pass/fail test. It is not the intent of thisprocedure to provide a test method for determining theconcentration of free halogens.10.2 The lower limit of detection of this test method has notbeen documented by formal precision tests. Detection limit isbelow 1 ppm, by weight as Cl2based on repea
18、tability of avariety of standards.11. Keywords11.1 free halogens; halogenated organic solvent; halogens;solventASTM 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 advise
19、d 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 five years andif not revised, either re
20、approved 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 committee, which you may attend. If y
21、ou 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, 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).D 4755 95 (2004)2
