1、Designation: D 3703 99 (Reapproved 2004)An American National StandardStandard Test Method forPeroxide Number of Aviation Turbine Fuels1This standard is issued under the fixed designation D 3703; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test me
3、thod covers the determination of the perox-ide content of aviation turbine fuels.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 consult andestablish appropriate safety and health practi
4、ces and deter-mine the applicability of regulatory limitations prior to use.For specific warning statements, see 6.3, 6.6, 8.2, and AnnexA1.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 4057 Practice for Manual Sampling of Petroleum andPetroleum Products2.2 Other
5、 Standards:CRC Report No. 559 Determination of the HydroperoxidePotential of Jet Fuels34500-C1 B. Iodometric Method IStandard Methods forthe Examination of Water and Wastewater43. Summary of Test Method3.1 A quantity of sample dissolved in 1,1,2-trichloro-1,2,2-trifluoroethane is contacted with aque
6、ous potassium iodidesolution. The peroxides present are reduced by the potassiumiodide. An equivalent amount of iodine is liberated, which istitrated with sodium thiosulfate solution. The results arecalculated as milligrams per kilogram (ppm) of peroxide.4. Significance and Use4.1 The magnitude of t
7、he peroxide number is an indicationof the quantity of oxidizing constituents present. Deteriorationof turbine fuel results in the formation of peroxides and otheroxygen-carrying compounds. The peroxide number measuresthose compounds that will oxidize potassium iodide.4.2 The determination of the per
8、oxide number of aviationturbine fuels is significant because of the adverse effect ofperoxides upon certain elastomers in the fuel systems.5. Apparatus5.1 Iodine Number Flask, 250 mL, glass-stoppered.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise
9、 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.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity
10、to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193, Type II.6.3 Acetic Acid SolutionMix 4 mL of concentrated hydro-chloric acid (HCl, sp gr
11、1.19) with 996 mL of glacial aceticacid (CH3COOH). (WarningPoison Corrosive. Combustiblecan be fatal if swallowed. Causes severe burns. Harmful ifinhaled. See A1.2).6.4 1,1,2-Trichloro-1,2,2 Trifluoroethane. (WarningSee A1.1.)6.5 Potassium Dichromate Solution, Standard (0.1 N)ACS reagent grade. Diss
12、olve 2.452 g of the dried potassiumdichromate (K2Cr2O7) in water and dilute to 500 mL in a1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Mat
13、erial.Current edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1978. Last previous edition approved in 1999 as D 3703 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStand
14、ards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the Coordinating Research Council, Inc., 219 Perimeter CenterParkway, Atlanta, GA 30346.4Published by the American Health Assoc., the American Water Works Assoc.and Water Environment Federation.
15、Available from American Public HealthPublication Sales, P. O. Box 753, Waldorf, MD 206040753.5“Reagent Chemicals, American Chemical Society Specifications,” AmericanChemical Society, Washington, D.C. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar St
16、andards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockvelle,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.volume
17、tric flask. This solution is 0.1 N.As an alterative, the labmay use commercially prepared solution.6.6 Potassium Dichromate Solution, Standard (0.01 N)(WarningAvoid contact with eyes and skin and avoidbreathing of dust)Dilute 100 mL of 0.1 N K2Cr2O7solutionwith water to 1000 mL in a volumetric flask
18、.6.7 Potassium Iodide SolutionDissolve 120 g of potas-sium iodide (KI) in 100 mL of water. Larger quantities ofsolution may be prepared, provided the concentration of KI inwater is equivalent. Discharge any color from this solution byplacing 1 mL of KI solution, 50 mL of water, and 5 mL ofstarch sol
19、ution in a 300-mL flask and blanketing with nitrogenor carbon dioxide. If a blue color develops, add 0.005 NNa2S2O3solution from a microburet until color just disappears.Add a sufficient quantity of Na2S2O3solution, thus determined,to the main KI solution to convert all free iodine to iodide.When pr
20、operly prepared, 1 mL of KI solution should not turnblue when starch solution is added, but with starch plus onedrop of 0.01 N K2Cr2O7solution plus two drops of HCl, theblue color should develop. Store this solution under chloro-form.6.8 Sodium Thiosulfate Solution, Standard (0.1 N)Dissolve 12.5 g o
21、f sodium thiosulfate (Na2S2O35H2O) plus0.1 g of sodium carbonate (Na2CO3) in 500 mL of water (theNa2CO3is added to stabilize the Na2S2O3solution). Let thissolution stand a week or more before using. As an alternative,the lab may use a commercially prepared solution. Standardizeagainst 0.1 N K2Cr2O7s
22、olution, using any appropriate tech-nique, such as the one indicated in 4500-C1 B. Standardize atintervals frequent enough to detect changes of 0.0005 innormality.6.9 Sodium Thiosulfate Solution, Standard (0.005 N)Prepare a twenty-fold dilution of the 0.1 N Na2S2O3solutionprepared in 6.8, using a vo
23、lumetric flask. One way to accom-plish this is to dilute 100 mL of 0.1 N Na2S2O3solution withwater to 2000 mL in a volumetric flask. Prepare this solutionfresh with restandardized 0.1 N Na2S2O3solution when anychange of 0.0005 or over in normality is detected.6.10 Starch SolutionMake a paste of6gofa
24、rrowrootstarch or soluble iodometric starch with cold water. Pour thepaste into 1 L of boiling water. Add 20 g of potassiumhydroxide (KOH), mix thoroughly, and allow to stand forapproximately 2 h. Add 6 mL of glacial acetic acid. Mixthoroughly and then add sufficient HCl (sp gr 1.19) to adjustthe pH
25、 value of the solution to 4.0. Store in a glass-stopperedbottle. Starch solution prepared in this manner can remainchemically stable for up to one year. As an alternative, the labmay use a commercially prepared solution (some are preservedwith salicylic acid).7. Sampling7.1 Samples shall be taken in
26、 accordance with the proce-dures described in Practice D 4057.8. Procedure8.1 Select the appropriate weight of sample from the fol-lowing table:Estimated Peroxide Number,mg/kgSample Mass, g0to10 5011 to 30 3531 to 50 2551 to 80 1081 to 100 58.2 Weigh the sample into a 250-mL iodine flask that hasbee
27、n flushed with nitrogen or carbon dioxide. Add 25 mL of1,1,2-trichloro-1,2,2,trifluoroethane (WarningSee A1.1).Pass a vigorous flow of nitrogen or carbon dioxide through thesolvent for at least 1 min; then, without stopping the gas flow,add 20 mL of acetic acid solution and reduce the flow of gas so
28、that the rate is one bubble per second. Add 2 mL of KI solutionand mix vigorously for 30 6 1 s. Set the flask aside to stand for5 min 6 3s.8.3 At the end of the reaction period, add 100 mL of waterand stop the gas flow. Add 5 mL of starch solution. Titrate with0.005 N Na2S2O3solution to the disappea
29、rance of the bluecolor.NOTE 1This end point is of the returning type. The end point intendedin this test method is the disappearance of the blue color for 30 s or longer.8.4 Titrate a reagent blank just prior to each set of unknowndeterminations, following the same procedure as described in8.1-8.3.9
30、. Calculation9.1 Calculate the peroxide number as follows:Peroxide number, mg/kg 5 A 2 B!N 3 1000 3 8/S (1)where:A = millilitres of Na2S2O3solution required for titration ofthe sample,B = millilitres of Na2S2O3solution required for titration ofthe blank,N = normality of the Na2S2O3solution, andS = g
31、rams of sample used.10. Precision and Bias10.1 PrecisionThe precision of this test method, reportedin 10.1.1, was originally determined by dissolving the samplein carbon tetrachloride. The precision when using 1,1,2-trichloro 1,2,2-trifluoroethane has been shown to match that ofthe original work and
32、 is reported in CRC Report No. 559.NOTE 2Prior to 1983, the test method called for the use of carbontetrachloride and the precision was determined with carbon tetrachlorideas the sample solvent. It has become the policy of most laboratories toavoid the use of carbon tetrachloride wherever possible b
33、ecause it is acarcinogen. 1,1,2-trichloro-1,2,2-trifluoroethane should now be used asper the procedure in Section 8 of this test method.10.1.1 RepeatabilityThe difference between two succes-sive test results, obtained by the same operator with the sameD 3703 99 (2004)2apparatus under constant operat
34、ing conditions on identical testmaterial would, in the long run, in the normal and correctoperation of the test method, exceed the following values onlyin one case in twenty:r 5 0.15X (2)where:X = the average of two test results.10.1.2 ReproducibilityThe reproducibility of the testmethod has not bee
35、n determined because of the difficultyencountered in maintaining sample integrity when distributingthem to cooperative laboratories. Further work is being under-taken to come up with an acceptable reproducibility statement.10.2 BiasSince there is no accepted reference materialsuitable for determinin
36、g the bias for this test method measuringthe peroxide number of aviation turbines fuels, no statement onbias is being made.11. Keywords11.1 peroxide numberANNEX(Mandatory Information)A1. WARNING STATEMENTSA1.1 1,1,2-Trichloro-1,2,2-Trifluoroethane (Freon TF)A1.1.1 WarningInhalation of high concentra
37、tions maycause anaesthetic effects or asphyxiation. Repeated or pro-longed skin contact will cause defatting and possible dermati-tis. May produce toxic vapors if burned.A1.1.1.1 Use with adequate ventilation.A1.1.1.2 Keep container closed.A1.1.1.3 Avoid prolonged breathing of vapor or spray mist.A1
38、.1.1.4 Avoid prolonged or repeated contact with skin.A1.1.1.5 Can produce toxic vapors on contact with flames,hot glowing surfaces, or electric arcs.A1.2 Acetic Acid (Glacial)A1.2.1 WarningPoison. Corrosive. Combustible. May befatal if swallowed. Causes severe burns. Harmful if inhaled.A1.2.1.1 Do n
39、ot get in eyes, on skin, or on clothing.A1.2.1.2 Do not breathe vapor, spray, or mist.A1.2.1.3 Dilute by addition of acid to water.A1.2.1.4 Keep away from heat and open flame.A1.2.1.5 Keep in tightly closed container in approved acidstorage cabinet.A1.2.1.6 Keep cool.A1.2.1.7 Loosen closure carefull
40、y when opening.A1.2.1.8 Use with adequate ventilation.A1.2.1.9 Keep container closed when not in use.A1.2.1.10 Use protective clothing and goggles when han-dling.A1.2.1.11 Wash thoroughly after handling.A1.3 Potassium DichromateA1.3.1 WarningAvoid contact with eyes and skin andavoid breathing of dus
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44、ttee 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 3703 99 (2004)3
