1、Designation: D 2180 89 (Reapproved 2003)Standard Test Method forActive Oxygen in Bleaching Compounds1This standard is issued under the fixed designation D 2180; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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 determination of inorganic“active oxygen” in bleaching compounds such as perborates,percarbonates,
3、and peroxides but not in persulfates or monop-ersulfates.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-bili
4、ty of regulatory limitations prior to use. Material SafetyData Sheets are available for reagents and materials. Reviewthem for hazards prior to usage.2. Referenced Documents2.1 ASTM Standards:D 459 Terminology Relating to Soaps and Other Deter-gents2D 1193 Specification for Reagent Water33. Terminol
5、ogy3.1 Definition:3.1.1 active oxygenthe measure of the oxidizing power ofcompounds such as inorganic perborates, percarbonates, orperoxides which, in effect, release hydrogen peroxide in acidsolutions. It is expressed in terms of oxygen (O) with gram-equivalent weight of 8.00.4. Summary of Test Met
6、hod4.1 Active oxygen is determined by titration of an acidifiedaqueous solution of the compound with a standard solution ofpotassium permanganate.NOTE 1Use of a molybdate-catalyzed iodometric method for thispurpose has been suggested, but the possible reaction of the liberatediodine on organics pres
7、ent must be considered. It is believed there is lesslikelihood of reaction with permanganate, provided the titration isperformed in such a manner as to avoid any considerable excess ofpermanganate.5. Interferences5.1 The possibility of interference from organic constitu-ents, which may react with pe
8、rmanganate, must be consideredwith each compound encountered. A sluggish reaction or vagueend point, will suggest interference. Inorganic builders ordetergents, such as silicates, phosphates, or carbonates, do notinterfere. Organic detergents or wetting agents may interfere.EDTA-type sequestrants do
9、 interfere (see Terminology D 459).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 Analytical Reagents of the American Chemical Society,where such
10、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 indicated, referencesto water shall be understood to mean re
11、agent water conformingto Specification D 1193.6.3 Potassium Permanganate, Standard Solution (0.1 N)Dissolve 3.2 g of potassium permanganate (KMnO4)in100mL of water and dilute the solution with water to 1 L. Allowthe solution to stand in the dark for two weeks and then filterthrough a fine-porosity s
12、intered-glass crucible. Do not wash thefilter. Store the solution in glass-stoppered, amber-colored glassbottles.NOTE 2Do not permit the filtered solution to come into contact withpaper, rubber, or other organic material.6.3.1 Weigh accurately to the nearest 0.1 mg about 0.3 gstandard sodium oxalate
13、 (Na2C2O4, previously dried at 105C).Transfer to a 400-mL beaker. Add 250 mL of H2SO4(5+95),freshly boiled for at least 10 min and cooled to 27 6 3C. Stiruntil the oxalate has dissolved. Add 0.1 N KMnO4solutionrapidly from a buret (25 to 30 mL/min) while stirring slowlybut constantly until about 40
14、mL have been added. Let stand1This test method is under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergents, and is the direct responsibility of Subcommittee D12.12 onAnalysis of Soaps and Synthetic Detergents.Current edition approved May 26, 1989. Published July 1989. Originallypubl
15、ished as D 2180 63T. Last previous edition D 2180 81 (1987).2Annual Book of ASTM Standards, Vol 15.04.3Annual Book of ASTM Standards, Vol 11.01.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted
16、 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, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
17、onshohocken, PA 19428-2959, United States.until the pink color disappears. Heat the solution from 55 to60C and complete the titration promptly, adding the last 0.5 to1 mL dropwise, with particular care to let the color disappearbefore adding the next drop. Continue until a faint pink colorpersists f
18、or 30 s. Determine the amount of KMnO4solutionrequired to produce the same color in a blank of an equalamount of special dilute acid at the same temperature. Calcu-late the normality of the KMnO4solution, N as follows:N 5 W/V 2 B! 3 0.0670# (1)where:W = grams of Na2C2O4used,V = millilitres of KMnO4s
19、olution required for the titrationof the standard, andB = millilitres of KMnO4solution required for titration ofthe blank.6.4 Sodium Oxalate,5,6primary standard grade.6.5 Sulfuric Acid (1+9)To 900 mL of cool water, carefullyadd 100 mL of concentrated sulfuric acid (H2SO4, sp gr 1.84).Mix well and co
20、ol.6.6 Sulfuric Acid (5+95)To 950 mL of cool water, care-fully add 50 mL of concentrated H2SO4. Mix well and cool.7. Sampling7.1 The material shall be well mixed just prior to samplingto ensure a representative sample for analysis, especially withcommercial products compounded of several ingredients
21、. Ifsufficient product is available, a relatively large sample shouldbe weighed and put into solution. An aliquot should then beused for the titration. See Section 8 for the recommendedamount.8. Procedure8.1 From a well mixed sample, weigh to the nearest 0.1 mg,a sample of sufficient size so that a1
22、20 aliquot will require atitration of at least 10 mL of 0.1 N KMnO4solution. Forexample, use 3.5 to 4.0 g of a sample containing 5 % activeoxygen. Transfer this sample quantitatively to a 500-mLvolumetric flask, using 250 mL of water. Swirl the flask gentlyto dissolve the sample and avoid producing
23、a foam should thesample contain foam-producing ingredients. Dilute to volumewith H2SO4(1+9) and mix thoroughly (Note 3). Immediatelypipet a 25-mL aliquot and titrate (Note 4) with standard 0.1 NKMnO4solution to a faint pink color. Prepare a blank anddetermine the amount of KMnO4solution necessary to
24、 producethe same pink color. Record the volume of titrant required forsample and blank. Replicate samples are advisable.NOTE 3Caution: When the dilute, H2SO4, is added, there is apossibility of vigorous CO2evolution from carbonates or bicarbonates inthe sample.NOTE 4Titrate slowly so as to avoid any
25、 considerable temporaryexcess of permanganate.9. Calculation9.1 Calculate the weight percentage of active oxygen asfollows:Active oxygen as O, weight % 5 V 2 B!NA 3 0.008/W# 3 100(2)where:V = millilitres of KMnO4solution required for titration ofthe sample,B = millilitres of KMnO4solution required f
26、or titration ofthe blank,N = normality of the KMnO4solution,A = aliquot factor (500/25 = 20), andW = grams of sample used.10. Keywords10.1 active oxygen; bleaches; perborate; percarborate;peroxideASTM International takes no position respecting the validity of any patent rights asserted in connection
27、 with any item 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 t
28、echnical committee 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 conside
29、ration at a meeting 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
30、 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).5This reagent is used for standardization purposes only.6National Institute of Standards and Technology Standard Sample 40C has beenfound satisfactory for this purpose.D 2180 89 (2003)2
