1、Designation: D3703 13Standard Test Method forHydroperoxide Number of Aviation Turbine Fuels, Gasolineand Diesel Fuels1This standard is issued under the fixed designation D3703; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the de
3、termination of the hy-droperoxide content expressed as hydroperoxide number ofaviation turbine, gasoline and diesel fuels.1.2 The range of hydroperoxide number included in theprecision statement is 0 to 50 mg/kg active oxygen as hydrop-eroxide.1.3 The interlaboratory study to establish the precision
4、 ofthis test method consisted of spark-ignition engine fuels(regular, premium and California Cleaner-Burning gasoline),aviation gasoline, jet fuel, ultra low sulfur diesel, and biodiesel.However, biodiesel was not included in the precision calcula-tion because of the large differences in results wit
5、hin labs andbetween labs.1.4 This test method detects hydroperoxides such as t-butylhydroperoxide and cumene hydroperoxide. It does not detectsterically-hindered hydroperoxides such as dicumyl and di-t-butyl hydroperoxides1.5 Di-alkyl hydroperoxides added commercially to dieselfuels are not detected
6、 by this test method.1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.7 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 stan
7、dard to consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.For specific warning statements, see 7.3, 7.6, 9.2, and AnnexA1.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4057 Practice
8、for Manual Sampling of Petroleum andPetroleum ProductsD6447 Test Method for Hydroperoxide Number of AviationTurbine Fuels by Voltammetric Analysis2.2 Other Standards:CRC Report No. 559 Determination of the HydroperoxidePotential of Jet Fuels34500-C1 B. Iodometric Method IStandard Methods forthe Exam
9、ination of Water and Wastewater43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 hydroperoxide, norganic peroxide having the gener-alized formula ROOH.3.1.1.1 DiscussionThis test method detects hydroperox-ides such as t-butyl hydroperoxide (CH3)3COOH and cumenehydroperoxide C6H
10、5C(CH3)2OOH. It does not detectsterically-hindered hydroperoxides such as dicumyl and di-t-butyl hydroperoxides.3.1.2 hydroperoxide number, nan indication of the quan-tity of oxidizing constituents present in certain liquid fuels asdetermined by this test method.3.1.2.1 DiscussionThe higher the quan
11、tity of oxidizingconstituents in the fuels, the higher the hydroperoxide number.4. Summary of Test Method4.1 A quantity of sample dissolved in 2,2,4-trimethylpentane is contacted with aqueous potassium iodidesolution. The hydroperoxides present are reduced by the1This test method is under the jurisd
12、iction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved Oct. 1, 2013. Published October 2013. Originallyapproved in 1978. Last previous e
13、dition approved in 2012 as D3703 07 (2012).DOI: 10.1520/D3703-13.2For 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 webs
14、ite.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. Available from American Public HealthPublication Sales, P. O. Box 753, Waldorf, MD 20
15、6040753.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1potassium iodide. An equivalent amount of iodine is liberated,which is titrated with an aqueous sodium thiosulfat
16、e solution.The results are calculated as milligrams of hydroperoxide perkilogram of sample expressed as hydroperoxide number. (SeeNote 1.)NOTE 1The original standard D3703 was published in 1978 asStandard Test Method for Peroxide Number of Aviation Turbine Fuels.This test method originally used carb
17、on tetrachloride (CCl4), which wasdetermined to be carcinogenetic. CCl4was later replaced with 1,1,2-trichloro-1,2,2 trifluoroethane. 1,1,2-trichloro-1,2,2-trifluoroethane is anozone depleting substance. The use of an ozone depleting substanceprecludes its use by many operators.5. Significance and U
18、se5.1 The magnitude of the hydroperoxide number is anindication of the quantity of oxidizing constituents present.Deterioration of the fuels results in the formation of hydrop-eroxides and other oxygen-carrying compounds. The hydrop-eroxide number measures those compounds that will oxidizepotassium
19、iodide.5.2 The determination of the hydroperoxide number ofaviation turbine fuels, gasoline and diesel is significant becauseof the adverse effect of hydroperoxide upon certain elastomersin the fuel systems.5.3 The determination of hydroperoxide number of gasolineis significant because hydroperoxide
20、s have been demonstratedto decrease both Research and Motor Octane Numbers. Inaddition, hydroperoxides have adverse effects on certain fuelsystem components.5.4 The determination of hydroperoxide number of dieselfuel is significant because hydroperoxides have been demon-strated to increase the Cetan
21、e Number. In addition, hydroper-oxides have adverse effects on certain fuel system components.6. Apparatus6.1 Iodine Number Flask, 250 mL, glass-stoppered.6.2 Burettes, 10-mL, 25-mL, Class A with polytetrafluoro-ethylene (PTFE) stop cock.6.3 Volumetric Flasks, 100-mL and 1000-mL, 2000 mLClass A with
22、 PTFE stoppers.6.4 Mixing Cylinders, 100 mL and 500-mL, glass-stoppered.6.5 Microburet, 10-mL, Class A.6.6 Analytical Balance, capable of weighing to the nearestmilligram.6.7 Brown Bottles, 100-mL, 300-mL, 1000-mL with screwcaps with inert inserts.6.8 Measuring Cylinders, 25-mL and 100-mL.7. Reagent
23、s7.1 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.5Other grades ma
24、y beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.1.1 Commercially available solutions already preparedmay be used in place of laboratory preparations, if they meetthe method requirements.7
25、.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water that meetsthe requirement of Type I, II, or III of Specification D1193.7.3 Acetic Acid SolutionMix 4 mL of concentrated hydro-chloric acid (HCl, sp gr 1.19) with 996 mL of glacial aceticacid (C
26、H3COOH). (WarningPoison. Corrosive. Combus-tible. Can be fatal if swallowed. Causes severe burns. Harmfulif inhaled. See A1.2).7.4 Nitrogen Gas, 99.9995% Minimum purity7.5 Carbon Dioxide, 99.9995% Minimum purity7.6 2,2,4-trimethylpentane (iso-octane), (WarningFlammable, dangerous fire risk. Toxic by
27、 injection and inha-lation. See A1.1.)7.7 Potassium Dichromate Solution, Standard (0.1 N), ACSreagent grade. Dissolve 2.452 g of the dried potassium dichro-mate (K2Cr2O7) in water and dilute to 500 mL in a volumetricflask. This solution is 0.1 N. As an alterative, the lab may usecommercially prepare
28、d solution.7.8 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.)7.9 Potassium Iodate Solution, Standard (0.1 N)optional,ACS reagent grade, for use in
29、 standardizing the 0.1 N sodiumthiosulfate solution. Dissolve 3.567 g KIO3dried at 103 C6 2 C for 1 h, in distilled water and dilute to 1000 mL in avolumetric flask to yield a 0.1 N solution.As an alternative, thelab may use a commercially prepared solution.7.10 Potassium Iodide Solution, Dissolve 1
30、20 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. Protect the solution from sunlight bystoring in brown bottles and blanketed with nitrogen or carbondioxide. Discharge any color from this solution
31、by placing 1mL of KI solution, 50 mL of water, and 5 mL of starch solutionin a 300-mL flask and blanketing with nitrogen or carbondioxide. If a blue color develops, add 0.005 N Na2S2O3solution from a microburet until color just disappears. Add asufficient quantity of Na2S2O3solution, thus determined
32、, to themain KI solution to convert all free iodine to iodide. Whenproperly prepared, 1 mL of KI solution should not turn bluewhen starch solution is added, but with starch plus one drop of5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Sug
33、gestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D3703 1320.01 N K2Cr2O7solut
34、ion plus two drops of HCl, the blue colorshould develop. Store this solution under nitrogen or carbondioxide.7.11 Sodium Thiosulfate Solution, Standard (0.1 N), Dis-solve 12.5 g of sodium thiosulfate (Na2S2O35H2O) plus 0.1 gof sodium carbonate (Na2CO3) in 500 mL of water (theNa2CO3is added to stabil
35、ize the Na2S2O3solution). Let thissolution stand a week or more before using. Standardize usingany appropriate technique, such as the one indicated in4500-C1 B involving either a 0.1 N K2Cr2O7solution or a0.1 N KIO3solution. Standardize at intervals frequent enoughto detect changes of 0.0005 in norm
36、ality.7.12 Sodium Thiosulfate Solution, Standard (0.005 N), Pre-pare a twenty-fold dilution of the 0.1 N Na2S2O3solutionprepared in 7.11, using a volumetric flask. One way toaccomplish this is to dilute 100 mL of 0.1 N Na2S2O3solutionswith water to 2000 mL in a volumetric flask. Prepare thissolution
37、 fresh with restandardized 0.1 N Na2S2O3solutionwhen any change of 0.0005 or over in normality is detected.7.13 Starch Solution, Make a paste of6gofarrowrootstarch or soluble iodometric starch with cold water. Pour thepaste into 1 L of boiling water. Add 20 g of potassiumhydroxide (KOH), mix thoroug
38、hly, 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 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
39、.7.14 t-Butyl Hydroperoxide, (CH3)3COOH, 90% minimumpurity, Make working standards with iso-octane to cover therange of the expected results.8. Sampling8.1 Samples shall be taken in accordance with the proce-dures described in Practice D4057.8.2 If samples cannot be tested immediately, they should b
40、estored in a refrigerator at a temperature between 1 and 4C (35and 40F). Bring the sample to room temperature beforetesting.9. Procedure9.1 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 (Note 2) 1
41、081 to 100 5NOTE 2The precision statement was based up to 50 mg/kg oxygen.The precision might not apply for samples greater than 50 mg/kg.9.2 Weigh the sample, accurate to 1 mg, into a 250-mLiodine flask that has been flushed with nitrogen or carbondioxide. With a measuring cylinder, add 25 mL of 2,
42、2,4-trimethylpentane (WarningSee A1.1). Pass a vigorous flowof nitrogen or carbon dioxide through the solvent for at least 1min; then, without stopping the gas flow, add 20 mL of aceticacid solution and reduce the flow of gas so that the rate is onebubble per second. Add 2 mL of KI solution and mixv
43、igorously for 30 6 1 s. Set the flask aside to stand for 5 min6 3s.9.3 At the end of the reaction period, add 100 mL of waterand stop the gas flow. Add 5 mL of starch solution. Titrate with0.005N Na2S2O3solution to the disappearance of the bluecolor.9.4 Titrate a reagent blank just prior to each set
44、 of unknowndeterminations, following the same procedure as described in9.1 9.3. (See Note 3.)NOTE 3This end point is of the returning type. The end point intendedin this method is the disappearance of the blue color for 30 s or longer. Ifthere is no blue color upon the addition of the starch solutio
45、n, there is nodetectable hydroperoxide and therefore there is no need to titrate thesolution with Na2S2O3solution.10. Quality Control10.1 Confirm the performance of the test procedure byanalyzing a known hydroperoxide such ast-butylhydroperoxide or cumyl hydroperoxide.11. Calculation11.1 Calculate t
46、he peroxide number as follows:Hydroperoxide number, mg/kg 5 A 2 B!N 31000 38#/S (1)where:X = measured hydroperoxide number,A = millilitres of Na2S2O3solution required for titration ofthe sample,B = millilitres of Na2S2O3solution required for titration ofthe blank,N = normality of the Na2S2O3solution
47、,8 = milliequivalent of hydroperoxide number, andS = grams of sample used, accurate to 0.001 g.12. Report12.1 Report the result calculated in 11.1 to three (3) signifi-cant figures.12.2 If there is no detectable hydroperoxide (see Note 3),report “None Detected.”13. Precision and Bias613.1 PrecisionT
48、he precision of this method was deter-mined from an interlaboratory study (ILS). The study con-tained thirteen (13) fuel samples which were tested in nine (9)laboratories in duplicate. The fuel types in the study were:regular and premium gasoline, ultra low sulfur diesel, Jet A,and isooctane blank.
49、A biodiesel fuel was also included in thestudy but was not used in calculating the precision statementbecause of the variabilities between laboratories.13.1.1 RepeatabilityThe difference between two succes-sive test results, obtained by the same operator with the sameapparatus under constant operating conditions on identical testmaterial would, in the long run, in the normal and correct6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1630.D3703 133operation of the test metho
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