ASTM D5845-2001(2006) Standard Test Method for Determination of MTBE ETBE TAME DIPE Methanol Ethanol and tert-Butanol in Gasoline by Infrared Spectroscopy《用红外线光谱法测定汽油中MTBE、ETBE、TAM.pdf

1、Designation: D 5845 01 (Reapproved 2006)An American National StandardStandard Test Method forDetermination of MTBE, ETBE, TAME, DIPE, Methanol,Ethanol and tert-Butanol in Gasoline by InfraredSpectroscopy1This standard is issued under the fixed designation D 5845; the number immediately following the

2、 designation indicates the year oforiginal adoption or, in the case of 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.1. Scope1.1 This test method covers

3、the determination of methanol,ethanol, tert-butanol, methyl tert-butyl ether (MTBE), ethyltert-butyl ether (ETBE), tert-amyl methyl ether (TAME), anddiisopropyl ether (DIPE) in gasoline by infrared spectroscopy.The test method is suitable for determining methanol from 0.1to 6 mass %, ethanol from 0.

4、1 to 11 mass %, tert-butanol from0.1 to 14 mass %, and DIPE, MTBE, ETBE and TAME from0.1 to 20 mass %.1.2 SI units of measurement are preferred and used through-out this standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespon

5、sibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1298 Test Method for Density, Relative Density (SpecificGravity), or API Gravity of Crude P

6、etroleum and LiquidPetroleum Products by Hydrometer MethodD 4052 Test Method for Density and Relative Density ofLiquids by Digital Density MeterD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD 4815

7、Test Method for Determination of MTBE, ETBE,TAME, DIPE, tertiary-Amyl Alcohol and C1to C4Alco-hols in Gasoline by Gas ChromatographyD 5599 Test Method for Determination of Oxygenates inGasoline by Gas Chromatography and Oxygen SelectiveFlame Ionization DetectionE 1655 Practices for Infrared Multivar

8、iate QuantitativeAnalysis2.2 Other Standard:3GC/OFID EPA Test MethodOxygen and Oxygenate Con-tent Analysis (by way of gas chromatography withoxygen-selective flame ionization detection)3. Terminology3.1 Definitions:3.1.1 oxygenate, nan oxygen-containing organic com-pound, which may be used as a fuel

9、 or fuel supplement, forexample, various alcohols or ethers.3.1.2 multivariate calibration, na process for creating acalibration model in which multivariate mathematics is appliedto correlate the absorbances measured for a set of calibrationsamples to reference component concentrations or propertyva

10、lues for the set of samples. The resultant multivariatecalibration model is applied to the analysis of spectra ofunknown samples to provide an estimate of the componentconcentration or property values for the unknown sample.4. Summary of Test Method4.1 A sample of gasoline is introduced into a liqui

11、d samplecell. A beam of infrared light is imaged through the sampleonto a detector, and the detector response is determined.Regions of the infrared spectrum are selected for use in theanalysis by either placing highly selective bandpass filtersbefore or after the sample or mathematically selecting t

12、heregions after the whole spectrum is obtained. A multivariatemathematical analysis is carried out which converts the detec-tor response for the selected regions in the spectrum of anunknown to a concentration for each component.5. Significance and Use5.1 Alcohols and ethers are added to gasoline to

13、 produce areformulated lower emissions gasoline. Alcohols and ethersmay also be added to gasoline to increase the octane number.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0F on Absorptio

14、n Spectroscopic Methods.Current edition approved Dec. 1, 2006. Published January 2007. Originallyapproved in 1995. Last previous edition approved in 2001 as D 5845 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual

15、Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Code of Federal Regulations, Part 80 of Title 40, Section 80.46(g); alsopublished in the Federal Register, Volume 59, No. 32, February 16, 1994, p 7828.1Copyright ASTM International, 100 Barr H

16、arbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Type and concentration of various oxygenates are specified andregulated to ensure acceptable commercial gasoline quality.Driveability, vapor pressure, phase separation, and evaporativeemissions are some of the concerns associa

17、ted with oxygenatedfuels.5.2 This test method is faster, simpler, less expensive andmore portable than current methods.5.3 This test method may be applicable for quality control inthe production of gasoline.5.4 This test method is not suitable for testing for compli-ance with federal regulations.35.

18、5 False positive readings for some of the samples tested inthe round robin were sometimes observed. As only extremebase gasolines were tested in the round robin, no definitivestatement can be made as to the expected frequency ormagnitude of false positives expected in a wider range of basegasolines.

19、6. Apparatus6.1 Mid-IR Spectrometric Analyzer, of one of the followingtypes:6.1.1 Filter-based Mid-IR Test ApparatusThe type ofapparatus suitable for use in this test method minimallyemploys an IR source, an infrared transmission cell or a liquidattenuated total internal reflection cell, wavelength

20、discrimi-nating filters, a chopper wheel, a detector, an A-D converter, amicroprocessor, and a sample introduction system.6.1.2 Fourier Transform Mid-IR Test ApparatusThe typeof apparatus suitable for use in this test method employs an IRsource, an infrared transmission cell or a liquid attenuated t

21、otalinternal reflection cell, a scanning interferometer, a detector, anA-D converter, a microprocessor and a sample introductionsystem.6.1.3 Dispersive Mid-IR Test ApparatusThe type of appa-ratus suitable for use in this test method minimally employs anIR source, an infrared transmission cell or a l

22、iquid attenuatedtotal internal reflection cell, a wavelength dispersive elementsuch as a grating or prism, a chopper wheel, a detector, an A-Dconverter, a microprocessor and a sample introduction system.7. Reagents and Materials7.1 Samples for Calibration and Quality Control CheckSolutionsUse of che

23、micals of at least 99 % purity is highlyrecommended when preparing calibration and quality controlcheck samples. If reagents of high purity are not available, anaccurate assay of the reagent must be performed using aproperly calibrated GC or other techniques (for example, waterdetermination).7.1.1 B

24、ase gasolines containing no oxygenates,7.1.2 Methanol,7.1.3 Ethanol,7.1.4 tert-Butanol,7.1.5 Methyl tert-butyl ether, MTBE,7.1.6 Ethyl tert-butyl ether, ETBE,7.1.7 tert-Amyl methyl ether, TAME, and7.1.8 Diisopropyl ether, DIPE.7.2 WarningThese materials are flammable and may beharmful if ingested or

25、 inhaled.8. Sampling and Sample Handling8.1 General Requirements:8.1.1 Gasoline samples must be handled with meticulouscare to prevent evaporative loss and composition changes.8.1.2 Gasoline samples to be analyzed by the test methodshall be obtained using method(s) specified by governmentalregulator

26、y agencies or by the procedures outlined in PracticeD 4057 (or equivalent). Do not use the “Sampling by WaterDisplacement” method as some alcohols or ethers might beextracted into the water phase.8.1.3 Protect samples from excessive temperatures prior totesting. This can be accomplished by storage i

27、n an appropriateice bath or refrigerator at 0 to 5C.8.1.4 Do not test samples stored in leaky containers. Discardand obtain a new sample if leaks are detected.8.1.5 Perform the oxygenate determination on fresh samplesfrom containers that are at least 80 % full. If sample containersare less than 80 %

28、 full or have been opened and sampledmultiple times, a new sample shall be obtained.8.2 Sample Handling During Analysis:8.2.1 Prior to the analysis of samples by infrared spectros-copy, the samples should be allowed to equilibrate to thetemperature at which they should be analyzed (15 to 38C).8.2.2

29、After withdrawing the sample, reseal the container,and store the sample in an ice bath or a refrigerator at 0 to 5C.9. Preparation, Calibration, and Qualification of theInfrared Test Apparatus9.1 PreparationPrepare the instrument for operation inaccordance with the manufacturers instructions.9.2 Cal

30、ibrationEach instrument must be calibrated by themanufacturer or user in accordance with Practice E 1655. Thispractice serves as a guide for the multivariate calibration ofinfrared spectrometers used in determining the physical char-acteristics of petroleum and petrochemical products. Theprocedures

31、describe treatment of the data, development of thecalibration, and qualification of the instrument. Note that biasand slope adjustments are specifically not recommended toimprove calibration or prediction statistics for IR multivariatemodels.9.3 Qualification of InstrumentThe instrument must bequali

32、fied according to the procedure inAnnexA1 to ensure thatthe instrument accurately and precisely measures each oxygen-ate in the presence of typical gasoline compounds or otheroxygenates that, in typical concentrations, present spectralinterferences. General classes of compounds that will causeinterf

33、erences include aromatics, branched aliphatic hydrocar-bons, and other oxygenates.10. Quality Control Standards10.1 Confirm the proper operation of the instrument eachday it is used by analyzing at least one quality control standardof known oxygenate content for each oxygenate to be deter-mined. The

34、se standards should be made up by mass accordingto Practice D 4307 and should be at the expected concentrationlevel for that oxygenate. The recommended quality controlstandard concentrations are found in Table 1.10.2 The individual oxygenate values obtained must agreewithin 6 5 % relative of the val

35、ues in the prepared qualityD 5845 01 (2006)2control standard (for example, MTBE 14.0 6 0.7 mass %) orto within 6 0.3 mass % absolute, whichever is greater (forexample, methanol 4.0 6 0.3 mass % ). If the individual valuesare outside the specified range, recalibrate the instrumentaccording to the pro

36、cedures in 9.2. The quality control stan-dards should not be used for the calibration or recalibration ofthe instrument. Do not analyze samples without meeting thequality control specifications.11. Procedure11.1 Equilibrate the samples to between 15 and 38C beforeanalysis.11.2 Follow the manufacture

37、rs instructions for establishinga baseline for the instrument, introducing a sample into thesample cell and operating the instrument. If the instructionscall for a non-oxygenated gasoline to be used in establishingthe baseline, use a non-oxygenated gasoline that is differentfrom the non-oxygenated g

38、asolines used in the preparation ofeither calibration standards, validation of qualification samples,or quality control standards.11.3 Thoroughly clean the sample cell by introducingenough sample to the cell to ensure the cell is washed aminimum of three times with the test solution.11.4 Establish t

39、hat the equipment is running properly byrunning the quality control standards prior to the analysis ofunknown test samples (see Section 10).11.5 Introduce the sample in the manner established by themanufacturer. Obtain the concentration reading produced bythe instrument.12. Calculation12.1 Conversio

40、n to Mass Concentration of OxygenatesIfthe instrument readings are in volume % for each component,convert the results to mass % according to Eq 1:mi5 ViDi/Df! (1)where:mi= mass % for each oxygenate to be determined,Vi= volume % of each oxygenate,Di= relative density at 15.56C of the individual oxyge

41、n-ate as found in Table 2,Df= relative density of the fuel at 15.56C under study asdetermined by Practice D 1298 or Test MethodD 4052. If the density has not been measured, anassumed density of 0.742 should be used.12.2 Total Mass % OxygenTo determine the total oxygencontent of the fuel, sum the mas

42、s % oxygen contents of alloxygenate components determined above according to Eq 2:Wtot5 ( mi3 16.0 3 Ni!/Mi# (2)where:Wtot= total mass % oxygen in the fuel,mi= mass % for each oxygenate,16.0 = atomic mass of oxygen,Ni= number of oxygen atoms in the oxygenate mol-ecule, andMi= molecular mass of the o

43、xygenate molecule as givenin Table 2.13. Report13.1 Report results of each oxygenate and the total oxygento the nearest 0.1 mass %.14. Precision and Bias414.1 The precision of the method as obtained by statisticalexamination of interlaboratory results is as follows:14.2 RepeatabilityThe difference b

44、etween successive testresults, obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialwould, in the long run, in the normal and correct operation ofthe test method exceed the following values only in one case intwenty:Oxygenate Repeatabilit

45、y (mass %)MTBE 0.13TAME 0.13ETBE 0.15Ethanol 0.13Methanol 0.07t-Butanol 0.10DIPE 0.14Total Oxygen Content 0.0514.3 ReproducibilityThe difference between two singleand independent results, obtained by different operators work-ing in different laboratories on identical test materials would, inthe long

46、 run, exceed the following values only in one case intwenty:Oxygenate Reproducibility (mass %)MTBE 0.98TAME 1.36ETBE 0.77Ethanol 0.59Methanol 0.37t-Butanol 0.59DIPE 0.79Total Oxygen Content 0.304Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Resea

47、rch Report RR: D02-1374.TABLE 1 Recommended Concentrations for Individual QualityControl StandardsOxygenateConcentration to Attain2.0 mass % O 2.7 mass % O 3.5 mass % OMethanol 4.00 mass % 5.41 mass %Ethanol 5.76 mass % 7.77 mass % 10.1 mass %tert-Butanol 9.26 mass % 12.5 mass %MTBE 11.0 mass % 14.9

48、 mass %TAME 12.8 mass % 17.2 mass %DIPE 12.8 mass % 17.2 mass %ETBE 12.8 mass % 17.2 mass %TABLE 2 Pertinent Physical ConstantsComponent CAS Number Molecular MassRelative Density,15.56CMethanol 67-56-1 32.04 0.7963Ethanol 64-17-5 46.07 0.7939tert-Butanol 75-65-0 74.12 0.7922MTBE 1634-04-4 88.15 0.74

49、60DIPE 108-20-3 102.18 0.7300ETBE 637-92-3 102.18 0.7452TAME 994-05-8 102.18 0.7758D 5845 01 (2006)314.4 BiasNo consistent bias was observed with thesamples tested in the round robin and since a wide range ofbase gasolines was not tested, it is not possible to offer adefinitive statement of bias except to note that biases wereobserved in the round robin.15. Keywords15.1 alcohols; diisopropyl ether; ethanol; ethers; ethyl tert-butyl ether; methanol; methyl tert-butyl ether; motor gasoline;oxygenate;tert-amyl methyl ether;tert-butanolANNEX(Mandatory Inform