1、Designation:D475595(Reapproved 2015)1Standard Test Method forFree Halogens in Halogenated Organic Solvents and TheirAdmixtures1This standard is issued under the fixed designation D4755;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,
2、the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEUnits statement was inserted in Section 1.2 editorially in June 2015.1.Scope1.1 This test method covers the evaluatio
3、n of free halogensin halogenated organic solvents and their admixtures.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It
4、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.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent Water3.Summary of Test Method3.1 Any free halogens
5、 present in the halogenated solvent areextracted with water and reacted with potassium iodide testsolution containing starch indicator.A blue color indicates thatpresence of free halogens.4.Significance and Use4.1 Free halogens will react with any residual moisture in asolvent to form acid.These aci
6、ds 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 stabilizers in the solvent system arebreaking down.4.3 This test method provides a means of detecting thepresence of free halo
7、gens in halogenated solvents and theiradmixtures.5.Interferences5.1 The following materials interfere with this test giving afalse positive:ferric ion;phosgene;iodine;oxidizing agents;and strong acid(catalyze atmospheric oxidation of the KI).6.Apparatus6.1 Glass-Stoppered Graduate,25-mL.7.Reagents7.
8、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 Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beu
9、sed,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 of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Type III of Specification D
10、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 SolutionMix 1 g of soluble starch4with 10mg of red mercuric iodide and sufficient cold water to make athin paste.Add 200 mL of boiling water,and bo
11、il for 1 minwith continuous stirring.Cool,and use only the clear solution.1This test method is 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 Jun
12、e 1,2015.Published June 2015.Originallyapproved in 1987.Last previous edition approved in 2010 as D4755 95(2010).DOI:10.1520/D4755-95R15E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume in
13、formation,refer to the standards Document Summary page onthe ASTM website.3Reagent 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 LaboratoryChemic
14、als,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.4Commercially available,stabilized starch indicator solutions may be used.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 1
15、9428-2959.United States1 8.Procedure8.1 Transfer 10 mL of sample to a glass-stoppered graduateand add 10 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 colo
16、ration.NOTE1The potassium iodide solution can generate free iodine via airoxidation.For this reason,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.9.Report9.1 Report the following information:9.1.1 Report as either positive or negative.10.Precision and Bias10.1 This is
