1、Designation: D3703 13D3703 18Standard 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
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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test method
3、covers the determination of the hydroperoxide content expressed as hydroperoxide number of aviationturbine, gasoline and diesel fuels.1.2 The range of hydroperoxide number included in the precision statement is 00 mgkg to 5050 mg mg/kg kg active oxygenas hydroperoxide.1.3 The interlaboratory study t
4、o establish the precision of this 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 calculation because of the large
5、differences in results within labs and between labs.1.4 This test method detects hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide. It does not detectsterically-hindered hydroperoxides such as dicumyl and di-t-butyl hydroperoxides1.5 Di-alkyl hydroperoxides added commercially to
6、diesel fuels are not detected by this test method.1.6 The values stated in SI units are to be regarded as the standard.The values given in parentheses are for information only.afterSI units are provided for information only and are not considered standard.1.7 This standard does not purport to addres
7、s all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to consult and establish appropriate safety safety, health, and healthenvironmental practices anddetermine the applicability of regulatory limitations prior to use. For specific warnin
8、g statements, see 7.3, 7.6, 9.2, and AnnexA1.1.8 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the Worl
9、d Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD6447 Test Method for Hydroperoxide Number of Aviation Turbine Fuels by Voltammetric
10、Analysis2.2 Other Standards:CRC Report No. 559 Determination of the Hydroperoxide Potential of Jet Fuels34500-C1 B. Iodometric Method IStandard Methods for the Examination of Water and Wastewater43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 hydroperoxide, norganic peroxide
11、having the generalized formula ROOH.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved Oct. 1,
12、 2013April 1, 2018. Published October 2013April 2018. Originally approved in 1978. Last previous edition approved in 20122013 asD3703 07 (2012).D3703 13. DOI: 10.1520/D3703-13.10.1520/D3703-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at ser
13、viceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from the Coordinating Research Council, Inc., 219 Perimeter Center Parkway, Atlanta, GA 30346.5755 North Point Pkwy, Suite 265, Alpharetta, GA 30022,http:/w
14、ww.crcao.org.4 Published by the American Health Assoc., the American Water Works Assoc. and Water Environment Federation. Available from American Public Health PublicationSales, P. O. Box 753, Waldorf, MD 206040753.This document is not an ASTM standard and is intended only to provide the user of an
15、ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as publish
16、ed by ASTM is to be considered the official document.*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 States13.1.1.1 DiscussionThis test method detects hydroperoxides such as t-
17、butyl hydroperoxide (CH3)3COOH and cumene hydroperoxideC6H5C(CH3)2OOH. It does not detect sterically-hindered hydroperoxides such as dicumyl and di-t-butyl hydroperoxides.3.1.2 hydroperoxide number, nan indication of the quantity of oxidizing constituents present in certain liquid fuels asdetermined
18、 by this test method.3.1.2.1 DiscussionThe higher the quantity of oxidizing constituents 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 iodide solution. Thehydroperoxides pres
19、ent are reduced by the potassium iodide. An equivalent amount of iodine is liberated, which is titrated withan aqueous sodium thiosulfate solution. The results are calculated as milligrams of hydroperoxide per kilogram of sampleexpressed as hydroperoxide number. (See Note 1.)NOTE 1The original stand
20、ard D3703 was published in 1978 as Standard Test Method for Peroxide Number of Aviation Turbine Fuels. This testmethod originally used carbon tetrachloride (CCl4), which was determined to be carcinogenetic. CCl4 was later replaced with 1,1,2-trichloro-1,2,2trifluoroethane. 1,1,2-trichloro-1,2,2-trif
21、luoroethane is an ozone depleting substance. The use of an ozone depleting substance precludes its use by manyoperators.5. Significance and Use5.1 The magnitude of the hydroperoxide number is an indication of the quantity of oxidizing constituents present. Deteriorationof the fuels results in the fo
22、rmation of hydroperoxides and other oxygen-carrying compounds. The hydroperoxide numbermeasures those compounds that will oxidize potassium iodide.5.2 The determination of the hydroperoxide number of aviation turbine fuels, gasoline and diesel is significant because of theadverse effect of hydropero
23、xide upon certain elastomers in the fuel systems.5.3 The determination of hydroperoxide number of gasoline is significant because hydroperoxides have been demonstrated todecrease both Research and Motor Octane Numbers. In addition, hydroperoxides have adverse effects on certain fuel systemcomponents
24、.5.4 The determination of hydroperoxide number of diesel fuel is significant because hydroperoxides have been demonstratedto increase the Cetane Number. In addition, hydroperoxides have adverse effects on certain fuel system components.6. Apparatus6.1 Iodine Number Flask, 250 mL, 250 mL, glass-stopp
25、ered.6.2 Burettes, 10-mL, 25-mL,10 mL, 25 mL, Class A with polytetrafluoroethylene (PTFE) stop cock.6.3 Volumetric Flasks, 100-mL and 1000-mL, 2000 mL 100 mL and 1000 mL, 2000 mL Class A with PTFE stoppers.6.4 Mixing Cylinders, 100 mL 100 mL and 500-mL,500 mL, glass-stoppered.6.5 Microburet, 10-mL,1
26、0 mL, Class A.6.6 Analytical Balance, capable of weighing to the nearest milligram.6.7 Brown Bottles, 100-mL, 300-mL, 1000-mL100 mL, 300 mL, 1000 mL with screw caps with inert inserts.6.8 Measuring Cylinders, 25-mL25 mL and 100-mL.100 mL.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall
27、 be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.5 Other grades may be used, provided it is first ascertained that th
28、e reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.7.1.1 Commercially available solutions already prepared may be used in place of laboratory preparations, if they meet themethod requirements.5 Reagent Chemicals, American Chemical Society Sp
29、ecifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial C
30、onvention, Inc. (USPC), Rockville, MD.D3703 1827.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water that meets therequirement of Type I, II, or III of Specification D1193.7.3 Acetic Acid SolutionMix 4 mL of concentrated hydrochloric acid (HCl,
31、sp gr 1.19) with 996 mL of glacial acetic acid(CH3COOH). (WarningWarningPoison.Poison. Corrosive. Combustible. Can be fatal if swallowed. Causes severe burns.Harmful if inhaled. See A1.2).7.4 Nitrogen Gas, 99.9995% Minimum purity7.5 Carbon Dioxide, 99.9995% Minimum purity7.6 2,2,4-trimethylpentane (
32、iso-octane), (WarningFlammable, dangerous fire risk. Toxic by injection and inhalation. SeeA1.1A1.1)7.7 Potassium Dichromate Solution, Standard (0.1 N), (0.1 N), ACS reagent grade. Dissolve 2.452 g 2.452 g of the driedpotassium dichromate (K2Cr2O7) in water and dilute to 500 mL 500 mL in a volumetri
33、c flask. This solution is 0.1 0.1 N. As analterative, the lab may use commercially prepared solution.7.8 Potassium Dichromate Solution, Standard (0.01 N), (0.01 N), (WarningAvoid contact with eyes and skin and avoidbreathing of dust)Dilute 100 mL 100 mL of 0.1 0.1 N K2Cr2O7 solution with water to 10
34、00 mL 1000 mL in a volumetric flask.)7.9 Potassium Iodate Solution, Standard (0.1 N)optional, ACS reagent grade, for use in standardizing the 0.1 0.1 N sodiumthiosulfate solution. Dissolve 3.567 g 3.567 g KIO3 dried at 103 C 6 2 C for 1 h, in distilled water and dilute to 1000 mL ina volumetric flas
35、k to yield a 0.1 N solution. As an alternative, the lab may use a commercially prepared solution.7.10 Potassium Iodide Solution, Dissolve 120 g 120 g of potassium iodide (KI) in 100 mL 100 mL of water. Larger quantitiesof solution may be prepared, provided the concentration of KI in water is equival
36、ent. Protect the solution from sunlight by storingin brown bottles and blanketed with nitrogen or carbon dioxide. Discharge any color from this solution by placing 1 mL 1 mL ofKI solution, 50 mL 50 mL of water, and 5 mL 5 mL of starch solution in a 300-mL300 mL flask and blanketing with nitrogen orc
37、arbon dioxide. If a blue color develops, add 0.005 0.005 N Na2S2O3 solution from a microburet until color just disappears. Adda sufficient quantity of Na2S2O3 solution, thus determined, to the main KI solution to convert all free iodine to iodide. Whenproperly prepared, 1 mL 1 mL of KI solution shou
38、ld not turn blue when starch solution is added, but with starch plus one dropof 0.01 0.01 N K2Cr2O7 solution plus two drops of HCl, the blue color should develop. Store this solution under nitrogen or carbondioxide.7.11 Sodium Thiosulfate Solution, Standard (0.1 N), (0.1 N), Dissolve 12.5 g 12.5 g o
39、f sodium thiosulfate (Na2S2O35H2O) plus0.1 g 0.1 g of sodium carbonate (Na2CO3) in 500 mL 500 mL of water (the Na2CO3 is added to stabilize the Na2S2O3 solution).Let this solution stand a week or more before using. Standardize using any appropriate technique, such as the one indicated in4500-C1 B in
40、volving either a 0.1 N K2Cr2O7 solution or a 0.1 N KIO3 solution. Standardize at intervals frequent enough to detectchanges of 0.0005 in normality.7.12 Sodium Thiosulfate Solution, Standard (0.005 N), (0.005 N), Prepare a twenty-fold dilution of the 0.1 0.1 N Na2S2O3solution prepared in 7.11, using
41、a volumetric flask. One way to accomplish this is to dilute 100 mL 100 mL of 0.1 0.1 N Na2S2O3solutions with water to 2000 mL 2000 mL in a volumetric flask. Prepare this solution fresh with restandardized 0.1 0.1 N Na2S2O3solution when any change of 0.0005 or over in normality is detected.7.13 Starc
42、h Solution, Make a paste of 6 g 6 g of arrowroot starch or soluble iodometric starch with cold water. Pour the pasteinto 1 L 1 L of boiling water.Add 20 g 20 g of potassium hydroxide (KOH), mix thoroughly, and allow to stand for approximately2 h.Add 6 mL 2 h.Add 6 mL of glacial acetic acid. Mix thor
43、oughly and then add sufficient HCl (sp gr 1.19) to adjust the pH valueof the solution to 4.0. Store in a glass-stoppered bottle. Starch solution prepared in this manner can remain chemically stable forup to one year.7.14 t-Butyl Hydroperoxide, (CH3)3COOH, 90%90 % minimum purity, Make working standar
44、ds with iso-octane to cover therange of the expected results.8. Sampling8.1 Samples shall be taken in accordance with the procedures described in Practice D4057.8.2 If samples cannot be tested immediately, they should be stored in a refrigerator at a temperature between 11 C and 4C(354 C (35 F and 4
45、0F).40 F). Bring the sample to room temperature before testing.D3703 1839. Procedure9.1 Select the appropriate weight of sample from the following table:Estimated Peroxide Number,mg/kg Sample Mass, g0 to 10 5011 to 30 3531 to 50 2551 to 80 (Note 2) 1081 to 100 5NOTE 2The precision statement was base
46、d up to 5050 mg mg/kg kg oxygen. The precision might not apply for samples greater than 5050 mg mg/kg.kg.9.2 Weigh the sample, accurate to 1 mg, 1 mg, into a 250-mL250 mL iodine flask that has been flushed with nitrogen or carbondioxide. With a measuring cylinder, add 25 mL 25 mL of 2,2,4-trimethylp
47、entane (WarningSeeA1.1A1.1). Pass a vigorous flowof nitrogen or carbon dioxide through the solvent for at least 1 min; 1 min; then, without stopping the gas flow, add 20 mL 20 mLof acetic acid solution and reduce the flow of gas so that the rate is one bubble per second. Add 2 mL 2 mL of KI solution
48、 andmix vigorously for 3030 s 6 1 s. 1 s. Set the flask aside to stand for 5 min 6 3 s.5 min 6 3 s.9.3 At the end of the reaction period, add 100 mL 100 mL of water and stop the gas flow. Add 5 mL 5 mL of starch solution.Titrate with 0.005N0.005 N Na2S2O3 solution to the disappearance of the blue co
49、lor.9.4 Titrate a reagent blank just prior to each set of unknown determinations, following the same procedure as described in 9.1 9.3. (See Note 3.)NOTE 3This end point is of the returning type. The end point intended in this method is the disappearance of the blue color for 30 s 30 s or longer.If there is no blue color upon the addition of the starch solution, there is no detectable hydroperoxide and therefore there is no need to titrate the solutionwith Na2S2O3 solution.10. Quality Control10.1 Confirm the performance of the test procedu
