ASTM D1832-2004 Standard Test Method for Peroxide Number of Petroleum Wax《石油蜡过氧化值的标准测试方法》.pdf

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1、Designation: D 1832 04An American National StandardTechnical Association of Pulpand Paper Industry Standard Method T 659 su-67Standard Test Method forPeroxide Number of Petroleum Wax1This standard is issued under the fixed designation D 1832; the number immediately following the designation indicate

2、s the year oforiginal adoption or, in the case of revision, 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. Scope*1.1 This test method covers the determination of

3、 the perox-ide number of petroleum wax.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 l

4、imitations prior to use.2. Terminology2.1 Definitions:2.1.1 peroxide numberthe milliequivalents of constituentsper 1000 g of wax that will oxidize potassium iodide.3. Summary of Test Method3.1 A quantity of sample is dissolved in xylenes andacidified with acetic acid solution. A solution of potassiu

5、miodide is added and, after a reaction period, the solution istitrated with sodium thiosulfate solution to the end pointindicated by the color change of added starch solution.4. Significance and Use4.1 The magnitude of the peroxide number is an indicationof the quantity of oxidizing constituents pre

6、sent. Deteriorationof petroleum wax results in the formation of peroxides andother oxygen-carrying compounds. The peroxide number mea-sures those compounds that will oxidize potassium iodide.5. Apparatus5.1 Iodine Flask, borosilicate glass, 250-mL capacity, glass-stoppered.6. Reagents and Materials6

7、.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.2Other grades may

8、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 distilled water or water ofequal purity.6.3 Aceti

9、c Acid SolutionMix 4 mL of concentrated hydro-chloric acid (HCl, sp gr 1.19) with 996 mL of ACS specialreagent grade glacial acetic acid (CH3CO2H). The acetic acidmust pass the12-h test for substances reducing K2Cr2O7.6.4 Xylenes,(WarningFlammable liquid. Vapor harm-ful.) Treated to remove oxidizing

10、 impurities. One way to dothis is to pass the xylenes through an activated alumina columnshortly prior to use.6.5 Potassium Dichromate, Standard Solution (0.1 N)Recrystallize potassium dichromate (K2Cr2O7) twice from anaqueous solution and dry at about 325F (164C) to constantweight. Dissolve 2.452 g

11、 of the purified K2Cr2O7in water anddilute to 500 mL in a volumetric flask.6.6 Potassium Dichromate, Standard Solution (0.01 N)Dilute 100 mL of 0.1 N K2Cr2O7solution with water to 1000mL in a volumetric flask.6.7 Potassium Iodide SolutionDissolve 120 g of potas-sium iodide (KI) in 100 mL of water. D

12、ischarge any color fromthis solution as follows: put 1 mL of KI solution, 50 mL ofwater, and 5 mL of starch solution in a 300-mL flask andblanket with nitrogen or carbon dioxide. If a blue colordevelops, add 0.005 N Na2S2O3solution from a microburetuntil color just disappears. Calculate and add suff

13、icientNa2S2O3solution to the main KI solution to convert all freeiodine to iodide. When starch solution is added to 1 mL of KIsolution a blue color should not develop, but upon the additionof 1 drop of 0.01 N K2Cr2O7solution and 2 drops ofconcentrated hydrochloric acid (HCl, sp gr 1.19), a blue colo

14、r1This test method is under the jurisdiction of the ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.10 on Properties of Petroleum Wax.Current edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1961. Last previous e

15、dition approved in 1999 as D 183287(1999).2Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dors

16、et, U.K., and the United States Pharmacopeiaand National Formulary, 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 S

17、tates.should develop. Store this solution under chloroform by addinga few millilitres to the surface of the liquid.6.8 Sodium Thiosulfate, Standard Solution (0.1 N)Dissolve 12.5 g of sodium thiosulfate (Na2S2O35H2O) and 0.1g of sodium carbonate (Na2CO3) in 500 mL of water. Let standa week or more be

18、fore using. Standardize against 0.1 NK2Cr2O7solution. Restandardize at intervals frequent enoughto detect changes of 0.0005 in normality.6.9 Sodium Thiosulfate, Standard Solution (0.005 N)Dilute 100 mL of 0.1 N Na2S2O3solution with water to 2000mL in a volumetric flask. Standardize against 0.01 N K2

19、Cr2O7solution.6.10 Starch SolutionDissolve1gofsoluble starch plus afew milligrams of mercuric iodide (HgI2) in 100 mL of boilingwater.7. Procedure7.1 Melt a representative portion of wax sample on a waterbath or in an oven. Do not heat above 150F (65.6C) or morethan 20F (11C) above the congealing po

20、int as excessiveheating may change the peroxide content.7.2 Weigh, to the nearest 1 mg, 1 6 0.2 g of the wax into aweighed iodine flask. To the flask, add 25 mL of xylenes(treated to remove oxidizing impurities) and quickly dissolvethe sample, in an atmosphere of carbon dioxide (CO2)onasteam bath. (

21、WarningA hood is advised.) Do not heat above150F (65.5C) unless necessary to dissolve the sample. Withthe flask still on the steam bath, bubble a vigorous flow of CO2through the solution for 1 min. Reduce the flow of CO2so thatthe rate is 1 bubble per second, and add 20 mL of acetic acidsolution tha

22、t has been warmed sufficiently to prevent precipi-tation of the wax. Remove the flask from the steam bath, stillcontinuing the flow of CO2. Add 2 mL of KI solution and swirlvigorously for exactly 30 s. With the CO2bubbling through themixture, set the flask aside and let stand for 5 min 6 3 s. Stopth

23、e flow of gas, add 100 mL of water, and mix thoroughly for1 min. Titrate with 0.005 N Na2S2O3solution to a light yellowcolor. Add 5 mL of starch solution and continue the titrationuntil 1 drop of the thiosulfate solution causes the blue color todisappear and not reappear for at least 30 s.7.3 Make a

24、 blank determination on the reagents. Proceed asdirected in 7.1 and 7.2 except to omit the sample.8. Calculation8.1 Calculate the peroxide number as milliequivalents per1000 g of sample, as follows:Peroxide number 5 A 2 B!N 3 1000/S (1)where:A = millilitres of Na2S2O3solution required for titration

25、ofthe sample,B = millilitres of Na2S2O3solution required for titration ofthe blank,N = normality of the Na2S2O3solution, andS = grams of sample used.9. Precision and Bias9.1 The following criteria should be used for judging theacceptability of results (95 % confidence):9.1.1 RepeatabilityThe differe

26、nce between two test re-sults, obtained by the same operator with the same apparatusunder constant operating conditions on identical test material,would in the long run, in the normal and correct operation ofthe test method, exceed the following values only in one casein twenty:Range Repeatability0

27、to 15 peroxide number 1.59.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the following valu

28、es only in one case intwenty:Range Reproducibility0 to 15 peroxide number 3.3NOTE 1Precision limits have not been established for values above 15peroxide number.NOTE 2While the subcommittees solvent replacement study foundtreated xylenes to be essentially a direct replacement for carbon tetrachlo-ri

29、de in this test method, it should be noted that the precision limits in 9.1.1and 9.1.2 were determined using carbon tetrachloride rather than xylenes.9.2 BiasThe procedure in this test method has no biasbecause the value of peroxide number can be defined only interms of a test method.10. Keywords10.

30、1 peroxide number; petroleum wax; waxD1832042SUMMARY OF CHANGESSubcommittee D02.10 has identified the location of selected changes to this standard since the last issue(D 183287(1999) that may impact the use of this standard.(1) Carbon tetrachloride was replaced by xylenes treated toremove trace oxi

31、dants.(2) Added Note 2.(3) Corrected Keywords to read “peroxide number.”ASTM 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 validity of

32、 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 comments ar

33、e 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 not rec

34、eived 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).D1832043