1、Designation: D 1839 91 (Reapproved 2005)An American National StandardStandard Test Method forAmyl Nitrate in Diesel Fuels1This standard is issued under the fixed designation D 1839; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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. Scope1.1 This test method covers the determination of 0.1 to 0.5volume % amyl nitrate in diesel fuels.1.2 The value
3、s stated in SI units are to be regarded as thestandard.1.3 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
4、 of regulatory limitations prior to use.NOTE 1This test method has been used for the determination of hexylnitrate in diesel fuels, but has not been cooperatively tested for suchsamples. For the determination of hexyl nitrate, use standards containingnitrate esters of primary hexanol. Use a density
5、of 0.97 in calculatingresults.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 4057 Practice for Manual Sampling of Petroleum andPetroleum Products3. Summary of Test Method3.1 This test method is based on the simultaneous hydroly-sis of the ester in 62.5 % sulfuric
6、acid and nitration ofm-xylenol by the nitric acid liberated. The nitroxylenol isdistilled from the reaction mixture and reacted with sodiumhydroxide to form the yellow sodium salt. Residual diesel fuelis removed by ether extraction. The color is measured spectro-photometrically at 452 nm, and the co
7、ncentration of amylnitrate is determined by reference to a standard curve.4. Significance and Use4.1 This test method can be used to determine the amount ofamyl nitrate that has been added to diesel fuels to improvecetane number. This test method is applicable as a basis forjudging compliance with s
8、pecifications covering amyl nitrate.5. Interferences5.1 Nitrate esters, inorganic nitrate ions, and nitrogen oxideswill interfere to give high results.6. Apparatus6.1 Absorption Cells, matched, having a 1.000- 6 0.002-cmlight path.6.2 Distillate Collector,3borosilicate glass with standardtaper joint
9、s and sealed-in funnel (Fig. 1).6.3 Electric Heating Mantle, to fit a 300-mL round-bottomflask, and having a variable transformer.6.4 Lunge-type Pipet, 2-mL capacity.NOTE 2A 2.5-mL hypodermic syringe, with scabbard, can be usedinstead of the Lunge pipet.6.5 Reflux Condenser (Allihn-type), borosilica
10、te glass, 300mm long, with standard-taper joints.6.6 Round-Bottom Flask, of borosilicate glass and having a300-mL capacity.6.7 Separatory Funnel, Squibb-type, 125-mL capacity.6.8 Shaking Machine, automatic, capable of 250oscillations/min.6.9 Spectrophotometer, capable of measuring absorption inthe r
11、egion of 452 nm.7. Reagents7.1 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
12、available.4Other grades may be1This method is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.03 onElemental Analysis.Current edition approved May 1, 2005. Published May 2005. Originallyapproved in 1961. Last previ
13、ous edition approved in 2000 as D 1839 91 (2000)e1.2For 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 website.3The sole
14、source of supply of the apparatus known to the committee at this timeis obtainable from Corning Glass Co., Corning, NY, Catalog No. 3320. If you areaware of alternative suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive careful consideration at
15、 a meetingof the responsible technical committee1, which you may attend.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryCh
16、emicals, 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 Conshohocken, PA 19428-2959, United States.used, provided it is first asc
17、ertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise specified, referencesto water shall be understood to mean reagent water as definedas Type II or III in Specification D 1193.7.3 Acetone (Wa
18、rningExtremely flammable. Vapors cancause flash fire. Harmful if inhaled.).7.4 Amyl NitrateAny mixture of nitrate esters of primaryamyl alcohol.7.5 Diethyl Ether (WarningExtremely flammable. Va-pors can cause flash fire. Harmful if inhaled.).7.6 Sodium Hydroxide Solution (20 g/L)Dissolve 20 g ofsodi
19、um hydroxide (NaOH) pellets in water and dilute to 1 L.7.7 Sulfuric Acid (5 + 3)Slowly add, with stirring, 500mL of nitrate-free concentrated sulfuric acid (H2SO4, rel dens1.84) to 300 mL of water. The m-xylenol solution must beadded before the H2SO4, otherwise low or negative results willbe obtaine
20、d. Cool before use.7.8 m-Xylenol SolutionDilute 4 mL of m-xylenol (2,4-dimethylphenol5) to 100 mL with acetone. Prepare fresh eachday.8. Sampling8.1 Samples shall be taken in accordance with the appropri-ate instructions in Practice D 4057.9. Preparation of Calibration Curve9.1 Prepare a series of s
21、tandard samples containing a knownamount of amyl nitrate in diesel fuel, covering the range of 0.2to 2.0 mg of amyl nitrate per gram (Note 3). Weigh 0.5-gportions of these standards, to the nearest 0.1 mg, into theSquibb-type separatory funnels and treat as described inSection 10. Calculate the mill
22、igrams of amyl nitrate in eachstandard by multiplying the weight of the standard taken by thecorresponding concentration of amyl nitrate. Construct a cali-bration curve by plotting absorbance values as the ordinate andcorresponding milligrams of amyl nitrate per 50 mL as theabscissa.NOTE 3Experience
23、 with the method indicates that different basestocks of diesel fuels do not cause variations in the results. If low resultsare obtained for a particular fuel, prepare standards using the fuel inquestion to check the reaction and recoveries.10. Procedure10.1 Weigh into a separatory funnel a sample of
24、 diesel fuelto the nearest 0.1 mg, not exceeding 2 mL (Note 4), and notcontaining more than 1.0 mg of amyl nitrate. Add 2 mL of them-xylenol solution and shake thoroughly. Add 50 mL ofH2SO4. Shake for 30 min on the automatic shaking machine.Transfer the contents of the separatory funnel to the round
25、-bottom flask and wash the funnel with 100 mL of water,combining this rinse with the solution in the flask.NOTE 4Incomplete reaction will take place if more than 2 mL ofsample is used.10.2 With the apparatus assembled as shown in Fig. 1, distillthe sample into a 50-mL volumetric flask containing 5 m
26、L ofNaOH solution. Collect 40 mL of distillate. Cool, and dilute tovolume with water, allowing any floating diesel fuel to beabove the mark.NOTE 5When the solution is not yellow, check the pH. When it is notalkaline, add additional NaOH solution.10.3 Transfer the solution to a separatory funnel and
27、extractwith several portions of ether to remove the diesel fuel thatotherwise would cause a turbid water layer.10.4 Filter the water layer through a coarse-texture paperinto an absorption cell and measure its absorbance at 452 nmwith respect to water (Note 6). Subtract a blank (Note 7) fromthe readi
28、ng and read the milligrams of amyl nitrate from thecalibration curve (Section 8).NOTE 6The color developed is stable for several hours. It obeysBeers law over the range from 0.2 to 2.0 mg of amyl nitrate.NOTE 7Obtain a blank by performing the analysis on the samples ofdiesel fuel and the reagents wi
29、thout the amyl nitrate present. A blank of0.019 absorbance can be used since it is the average obtained on a numberof representative diesel fuels.11. Calculation11.1 Calculate the amyl nitrate present in the sample asfollows:Amyl nitrate, mass % 5 100A/1000W 5 A/10W (1)Amyl nitrate, vol % 5 BD/C (2)
30、where:5The sole source of supply of the apparatus known to the committee at this timeis obtainable from Eastman Kodak Co., Rochester, NY, Reagent No. 1150. If you areaware of alternative suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive carefu
31、l consideration at a meetingof the responsible technical committee1, which you may attend.FIG. 1 Distillation ApparatusD 1839 91 (2005)2A = milligrams of amyl nitrate obtained from the calibra-tion curve,B = mass % of amyl nitrate obtained from Eq 1,C = density of amyl nitrate (0.998 at 20C),D = den
32、sity of diesel fuel sampled at 20C, andW = grams of sample used.12. Precision and Bias612.1 PrecisionThe precision of this test method as ob-tained by statistical analysis of interlaboratory test results is asfollows:12.1.1 RepeatabilityThe difference between successivetest results, obtained by the
33、same operator with the sameapparatus under constant operating conditions on identical testmaterial would, in the long run, in the normal and correctoperation of the test method exceed the following value only inone case in twenty:0.10 volume % (3)12.1.2 ReproducibilityThe difference between two sing
34、leand 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 values only in one case in twenty:0.10 volume % (4)12.2 BiasThe bias of this test m
35、ethod cannot be deter-mined since an appropriate standard reference material con-taining a known level of amyl nitrate in diesel fuel is notavailable.13. Keywords13.1 amyl nitrate; diesel fuel; nitroxylenol;spectrophotometricASTM International takes no position respecting the validity of any patent
36、rights asserted in connection 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
37、any time by the responsible technical 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
38、 will receive careful consideration 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
39、 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).6There is no existing research report for this test method.D 1839 91 (2005)3
