1、Designation: D1839 11D1839 14Standard Test Method forAmyl Nitrate in Diesel Fuels1This standard is issued under the fixed designation D1839; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in par
2、entheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of 0.1 to 0.5 volume % amyl nitrate in diesel fuels.NOTE 1This test method has been used for the determin
3、ation of hexyl nitrate in diesel fuels, but has not been cooperatively tested for such samples.For the determination of hexyl nitrate, use standards containing nitrate esters of primary hexanol. Use a density of 0.97 in calculating results.1.2 The values stated in SI units are to be regarded as stan
4、dard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the app
5、licability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4057 Practice for Manual Sampling of Petroleum and Petroleum Products3. Summary of Test Method3.1 This test method is based on the simultaneous hydrolysis of the ester in
6、 62.5 % sulfuric acid and nitration of m-xylenol bythe nitric acid liberated. The nitroxylenol is distilled from the reaction mixture and reacted with sodium hydroxide to form theyellow sodium salt. Residual diesel fuel is removed by ether extraction. The color is measured spectrophotometrically at
7、452 nm,and the concentration of amyl nitrate is determined by reference to a standard curve.4. Significance and Use4.1 In diesel fuel, the presence of alkyl nitrates such as amyl nitrate, hexyl nitrate, or octyl nitrate causes a higher residue valuethan observed in untreated fuel, which can lead to
8、erroneous conclusions as to the coke forming propensity of the fuel. Thepresence of such alkyl nitrate in the fuel can be determined using this test method. This test method can be used to determine theamount of amyl nitrate that has been added to diesel fuels to improve cetane number. This test met
9、hod is applicable as a basis forjudging compliance with specifications covering amyl nitrate.5. Interferences5.1 Nitrate esters, inorganic nitrate ions, and nitrogen oxides will interfere to give high results.6. Apparatus6.1 Absorption Cells, matched, having a 1.000- 6 0.002-cm light path.6.2 Distil
10、late Collector,3borosilicate glass with standard taper joints and sealed-in funnel (Fig. 1).6.3 Electric Heating Mantle, to fit a 300-mL round-bottom flask, and having a variable transformer.1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fue
11、ls, and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved June 1, 2011June 1, 2014. Published July 2011July 2014. Originally approved in 1961. Last previous edition approved in 20052011 asD183991(2005).D1839 11. DOI: 10.1520/D1839-11.10.
12、1520/D1839-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The sole source of supply of the apparatus kn
13、own to the committee at this time is obtainable from Corning Glass Co., Corning, NY, Catalog No. 3320. If you are awareof alternative suppliers, please provide this information toASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical
14、 committee,1 which you may attend.This document is not an ASTM standard and is intended only to provide the user of an 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 recom
15、mends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published 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 C70
16、0, West Conshohocken, PA 19428-2959. United States16.4 Lunge-type Pipet, 2-mL capacity.NOTE 2A 2.5-mL hypodermic syringe, with scabbard, can be used instead of the Lunge pipet.6.5 Reflux Condenser (Allihn-type), borosilicate glass, 300 mm 300 mm long, with standard-taper joints.6.6 Round-Bottom Flas
17、k, of borosilicate glass and having a 300-mL capacity.6.7 Separatory Funnel, Squibb-type, 125-mL capacity.6.8 Shaking Machine, automatic, capable of 250 oscillations/min.6.9 Spectrophotometer, capable of measuring absorption in the region of 452 nm.7. Reagents7.1 Purity of ReagentsReagent grade chem
18、icals shall 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.4 Other grades may be used, provided it is first ascertai
19、ned that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.7.2 Purity of WaterUnless otherwise specified, references to water shall be understood to mean reagent water as defined asType II or III in Specification D1193.7.3 Acetone (Warnin
20、gExtremely flammable. Vapors can cause flash fire. Harmful if inhaled.).7.4 Amyl NitrateAny mixture of nitrate esters of primary amyl alcohol.7.5 Diethyl Ether (WarningExtremely flammable. Vapors can cause flash fire. Harmful if inhaled.).7.6 Sodium Hydroxide Solution (20 g/L)Dissolve 20 g of sodium
21、 hydroxide (NaOH) pellets in water and dilute to 1 L.7.7 Sulfuric Acid (5 + 3) Slowly add, with stirring, 500 mL500 mLof nitrate-free concentrated sulfuric acid (H2SO4, rel dens1.84) to 300 mL of water. The m-xylenol solution must be added before the H2SO4, otherwise low or negative results will beo
22、btained. Cool before use.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and
23、the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.FIG. 1 Distillation ApparatusD1839 1427.8 m-Xylenol SolutionDilute 4 mL of m-xylenol (2,4-dimethylphenol5) to 100 mL with acetone. Prepare fresh each day.8. Sampling8.1 Samples shall be ta
24、ken in accordance with the appropriate instructions in Practice D4057.9. Preparation of Calibration Curve9.1 Prepare a series of standard samples containing a known amount 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-g portions of th
25、ese standards, to the nearest 0.1 mg, into the Squibb-typeseparatory funnels and treat as described in Section 10. Calculate the milligrams of amyl nitrate in each standard by multiplyingthe weight of the standard taken by the corresponding concentration of amyl nitrate. Construct a calibration curv
26、e by plottingabsorbance values as the ordinate and corresponding milligrams of amyl nitrate per 50 mL as the abscissa.NOTE 3Experience with the method indicates that different base stocks of diesel fuels do not cause variations in the results. If low results are obtainedfor a particular fuel, prepar
27、e standards using the fuel in question to check the reaction and recoveries.10. Procedure10.1 Weigh into a separatory funnel a sample of diesel fuel to 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 the m-xylenol solution and shake th
28、oroughly. Add 50 mL of H2SO4.Shake for 30 min on the automatic shaking machine. Transfer the contents of the separatory funnel to the round-bottom flask andwash 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
29、 2 mL of sample is used.10.2 With the apparatus assembled as shown in Fig. 1, distill the sample into a 50-mL volumetric flask containing 5 mL ofNaOH solution. Collect 40 mL of distillate. Cool, and dilute to volume with water, allowing any floating diesel fuel to be abovethe mark.NOTE 5When the sol
30、ution is not yellow, check the pH. When it is not alkaline, add additional NaOH solution.10.3 Transfer the solution to a separatory funnel and extract with 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-
31、texture paper into an absorption cell and measure its absorbance at 452 nm withrespect to water (Note 6). Subtract a blank (Note 7) from the reading and read the milligrams of amyl nitrate from the calibrationcurve (Section 8).NOTE 6The color developed is stable for several hours. It obeys Beers law
32、 over the range from 0.2 to 2.0 mg of amyl nitrate.NOTE 7Obtain a blank by performing the analysis on the samples of diesel fuel and the reagents without the amyl nitrate present. A blank of 0.019absorbance can be used since it is the average obtained on a number of representative diesel fuels.11. C
33、alculation11.1 Calculate the amyl nitrate present in the sample as follows:Amyl nitrate,mass%5100A/1000W 5A/10W (1)Amyl nitrate,vol%5BD/C (2)where:A = milligrams of amyl nitrate obtained from the calibration curve,B = mass % of amyl nitrate obtained from Eq 1,C = density of amyl nitrate (0.998 at 20
34、C),D = density of diesel fuel sampled at 20C, andW = grams of sample used.12. Reporting12.1 Report the results to the nearest 0.1 m or v%, and indicate that they were obtained using Test Method D1839.13. Precision and Bias613.1 PrecisionThe precision of this test method as obtained by statistical an
35、alysis of interlaboratory test results is as follows:5 The sole source of supply of the apparatus known to the committee at this time is obtainable from Eastman Kodak Co., Rochester, NY, Reagent No. 1150. If you areaware of alternative suppliers, please provide this information to ASTM International
36、 Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1 which you may attend.6 There is no existing research report for this test method.D1839 14313.1.1 RepeatabilityThe difference between successive test results, obtained by the same oper
37、ator with the same apparatusunder constant operating conditions on identical test material would, in the long run, in the normal and correct operation of thetest method exceed the following value only in one case in twenty:0.10 volume% (3)13.1.2 ReproducibilityThe difference between two single and i
38、ndependent results obtained by different operators working indifferent laboratories on identical test material would in the long run, in the normal and correct operation of the test method exceedthe following values only in one case in twenty:0.10 volume% (4)13.2 BiasThe bias of this test method can
39、not be determined since an appropriate standard reference material containing aknown level of amyl nitrate in diesel fuel is not available.14. Keywords14.1 amyl nitrate; diesel fuel; nitroxylenol; spectrophotometricSUMMARY OF CHANGESSubcommittee D02.03 has identified the location of selected changes
40、 to this standard since the last issue(D183991(2005) that may impact the use of this standard. (Approved June 1, 2014.)(1) Added new Section Revised subsection 124.1 on reporting the results.to add more information to Significance and Use.ASTM International takes no position respecting the validity
41、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 any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject t
42、o 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 are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters.
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