1、Designation: D2549 02 (Reapproved 2012)Standard Test Method forSeparation of Representative Aromatics and NonaromaticsFractions of High-Boiling Oils by Elution Chromatography1This standard is issued under the fixed designation D2549; the number immediately following the designation indicates the yea
2、r 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the separation and determina-ti
3、on of representative aromatics and nonaromatics fractionsfrom hydrocarbon mixtures that boil between 232 and 538C(450 and 1000F). Alternative procedures are provided for theseparation of2gor10gofhydrocarbon mixture.NOTE 1Some components may not be eluted from the chromato-graphic column for some typ
4、es of samples under the conditions used inthis method.NOTE 2Test Method D2007 is an alternative method of separatinghigh-boiling oils into polar compounds, aromatics, and saturates fractions.1.2 An alternative procedure is provided to handle samplesboiling below 232C (450F), but whose 5 % point is a
5、bove178C (350F) as determined by Test Method D2887. Thisprocedure is given in Appendix X1.1.3 The values stated in acceptable SI units are to beregarded as the standard. The values given in parentheses areprovided for information purposes only.1.4 This standard does not purport to address all of the
6、safety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and heal practices and determine the applicabilityof regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2007 Test Method for Characteri
7、stic Groups in RubberExtender and Processing Oils and Other Petroleum-Derived Oils by the Clay-Gel Absorption Chromato-graphic MethodD2425 Test Method for Hydrocarbon Types in MiddleDistillates by Mass SpectrometryD2786 Test Method for Hydrocarbon Types Analysis ofGas-Oil Saturates Fractions by High
8、 Ionizing VoltageMass SpectrometryD2887 Test Method for Boiling Range Distribution ofPetroleum Fractions by Gas ChromatographyD3239 Test Method for Aromatic Types Analysis of Gas-Oil Aromatic Fractions by High Ionizing Voltage MassSpectrometry3. Terminology3.1 Definitions of Terms Specific to This S
9、tandard:3.1.1 aromatics fractionthe portion of the sample des-orbed with the polar eluants. The aromatics fraction maycontain aromatics, condensed naphthenic-aromatics, aromaticolefins, and compounds containing sulfur, nitrogen, and oxy-gen atoms.3.1.2 nonaromatics fractionthe portion of the samplee
10、luted with n-pentane. The nonaromatics fraction is a mixtureof paraffinic and naphthenic hydrocarbons if the sample is astraight-run material. If the sample is a cracked stock, thenonaromatics fraction will also contain aliphatic and cyclicolefins.4. Summary of Test Method4.1 A weighed amount of sam
11、ple is charged to the top of aglass chromatographic column packed with activated bauxiteand silica gel. n-Pentane is added to the column to elute thenonaromatics. When all of the nonaromatics are eluted, thearomatics fraction is eluted by additions of diethyl ether,chloroform, and ethyl alcohol.4.2
12、The solvents are completely removed by evaporation,and the residues are weighed and calculated as the aromaticsand nonaromatics fractions of the sample.5. Significance and Use5.1 The determination of compound types by mass spec-trometry requires, in some instances, a preliminary separationof the pet
13、roleum sample into representative aromatics andnonaromatics fractions, as in Test Methods D2425, D2786, and1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0C on Liquid Chromatography.Current
14、edition approved April 15, 2012. Published April 2012. Originallyapproved in 1966. Last previous edition approved in 2007 as D254902(2007).DOI: 10.1520/D2549-02R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Boo
15、k of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D3239. This test method provides a suitable separation tech-nique for this applica
16、tion.6. Apparatus6.1 Chromatographic Columns, as shown in Fig. 1. Differ-ent chromatographic columns are provided for the analysis of2 and 10-g samples.6.2 Beakers, 100, 250, and 600-mL, inverted-rim type.36.3 Steam Bath.6.4 Electric Vibrator, for packing column.6.5 Weighing Bottles or Erlenmeyer Fl
17、asks, 25 and 50 mL.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in this test. 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 sp
18、ecifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Bauxite,520 to 60-mesh. Before use, activate thebauxite by heating at 538C (1000F) for 16 h. T
19、ransfer theactivated material to an airtight container while still hot andprotect thereafter from atmospheric moisture.7.3 Chloroform.(WarningToxic. May be fatal if swal-lowed.)3The sole source of supply of the beakers known to the committee at this timeis Kontes Glass Co., Vineland, NJ; order “Anti
20、-Creep” beakers and refer to DrawingNo. 9413-A. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee1, whichyou may attend.4Reagent Chemicals,
21、American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions 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 Formu
22、lary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5The sole source of supply of the bauxite known to the committee at this timeis Porocel Corp., Little Rock, AR. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your comments w
23、illreceive careful consideration at a meeting of the responsible technical committee1,which you may attend.FIG. 1 Chromatographic ColumnsD2549 02 (2012)27.4 Cleaning SolutionChromic-sulfuric acid.(WarningCauses severe burns.Arecognized carcinogen, strong oxidizer,contact with organic material may ca
24、use fire.)7.5 Diethyl Ether, anhydrous. (WarningExtremely flam-mable.) The ethyl ether used in this test method should be freeof peroxides as determined by the procedure in “ReagentChemical, American Chemical Society Specifications.”7.6 Ethyl Alcohol, denatured, conforming to Formula 2B ofthe U.S. B
25、ureau of Internal Revenue. (WarningFlammable.)7.7 Pressuring Gas, dry air or nitrogen, delivered to the topof the column at a regulated gage pressure of 0 to 2 psi (13.8kPa). (WarningCompressed gas.)7.8 n-Pentane, commercial grade, aromatic-free. Somesamples of waxy stocks may not dissolve completel
26、y inn-pentane, in which case cyclohexane, commercial grade,aromatic-free, may be substituted for n-pentane. (WarningExtremely flammable liquid.)7.9 Silica Gel,6100 to 200-mesh.8. ProcedureNOTE 3The procedural details differ depending on the initial boilingpoint of the sample. If the 5 % point is abo
27、ve 178C (350F), but below232C (450F), use procedure described in Appendix X1. If above 232C,continue as written depending on amount of sample to be analyzed.Instructions specific for 2-g samples are given in 8.4.1-8.4.13, andinstructions specific for 10-g samples are given in 8.5.1 and 8.5.8.8.1 Sel
28、ect the appropriate column, depending on whether 2or 10 g of sample are to be analyzed. Clean the column withchromic-sulfuric acid (WarningCauses severe burns), fol-lowed by distilled or demineralized water, acetone, and dry airor nitrogen.8.2 Introduce a small plug of glass wool into the column,pre
29、ssing it firmly into the lower end to prevent the flow of silicagel from the column.8.3 Clamp the column in a vertical position. Add smallincrements of silica gel, while vibrating the column along itslength, until the tightly packed silica gel extends to the lowermark on the chromatographic column.
30、Continue to vibrate thecolumn and add bauxite until the bauxite layer extends to theupper mark on the chromatographic column. Vibrate thecolumn for an additional 3 min after filling is completed.8.4 If2gofsample are to be analyzed, continue as in 8.4.1,otherwise continue as in 8.5.8.4.1 If the sampl
31、e is viscous, warm it with intermittentmixing or shaking until it is completely fluid. Transfer arepresentative sample (approximately 2 g) to a 25-mL weigh-ing bottle or flask. Determine the weight of the sample to thenearest 1 mg by weighing the flask before and after sampletransfer. Add 10 mL of n
32、-pentane (WarningExtremelyflammable liquid), to the flask and dissolve the sample. If thesample does not dissolve completely in cold n-pentane, warmit in warm water or over a steam bath. If the sample does notdissolve in warm n-pentane, take a fresh sample and substitutecyclohexane for the n-pentane
33、.8.4.2 Add 10 mL of n-pentane to the top of the column toprewet the adsorbent. When the liquid level reaches the top ofthe bauxite bed, transfer the sample solution from the weighingflask to the top of the column. Rinse the flask with threesuccessive 3-mL washes of n-pentane. Add each wash to thetop
34、 of the column. Then rinse the walls of the column bulb withtwo 3-mL portions of n-pentane, allowing the liquid level toreach the top of the bauxite bed before adding the next portion.Finally add 35 mL of n-pentane to the column bulb.8.4.3 Place a 50-mL graduate beneath the column to collectthe elua
35、te. The elution rate should be approximately 1 mL/min.NOTE 4Gas pressure (WarningCompressed gas) can be applied tothe top of the column as necessary to maintain the elution rate atapproximately 1 mL/min. If the correct pressure setting is known fromprevious runs, gas pressure may be applied after ad
36、dition of the lastincrement of n-pentane. Otherwise, gas pressure should be applied whenn-pentane begins to elute from the column and should be adjusted to givea flow rate of approximately 1 mL/min.8.4.4 When the n-pentane level reaches the top of thebauxite bed, add 80 mL of diethyl ether (WarningE
37、xtremelyflammable). Connect the pressuring gas to the top of thecolumn and adjust the pressure to maintain an elution rate of 1to 2 mL/min.8.4.5 Collect 50 mL of n-pentane eluate in the graduate.Rinse the tip of the column with 1 to 2 mLof n-pentane, addingthis to the 50 mL in the graduate (Note 5).
38、 Label the 50-mLgraduate as n-pentane eluate.NOTE 5The n-pentane will have reached the adsorbent bed before therequired volume of eluate has been collected in the 50-mL receiver.Continue collection in this receiver after the addition of ether until theproper volume has been collected before changing
39、 to the 100-mLgraduate.8.4.6 When the ether level reaches the top of the bauxitebed, release the gas pressure and add 100 mL of chloroform(WarningToxic. May be fatal if swallowed) to the top of thecolumn. Reconnect the gas pressuring system and continue theelution. When 80 mL of eluate have been col
40、lected in thegraduate, rinse the column tip with 1 mL of ether and add therinse to the 100-mL graduate. Change the receiver to a 250-mLgraduate. Label the 100-mL graduate as ether-eluted fraction.8.4.7 When the chloroform level reaches the top of thebauxite bed, release the gas pressure and add 75 m
41、L of ethylalcohol (WarningFlammable liquid). Reconnect the gaspressuring system and continue the elution until the alcohollevel reaches the top of the bauxite bed. Release the gaspressure. Rinse the column tip with 1 mL of chloroform addingthis to the graduate. Label the 250-mL graduate as chlorofor
42、m-alcohol-eluted fraction.8.4.8 Weigh a 100-mL inverted-rim beaker to the nearest 1mg. Quantitatively transfer the n-pentane eluate to this beakerand allow the n-pentane to evaporate at room temperature.Cyclohexane, if used as the elution solvent, is evaporated on asteam bath. Evaporation is acceler
43、ated in both cases bydirecting a controlled stream of dry nitrogen downward ontothe surface of the liquid.6The sole source of supply of the silica gel known to the committee at this timeis W.R. Grace and Co., Davison Chemical Div., Baltimore, MD 21203, byspecifying Code 923. If you are aware of alte
44、rnative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee1, whichyou may attend.D2549 02 (2012)38.4.9 When all the solvent appears to be evaporated, stopthe nitrogen flow,
45、allow the beaker to come to room tempera-ture, and dry the outside of the beaker to remove anycondensed moisture. Reweigh the beaker to the nearest 1 mg.NOTE 6Complete solvent evaporation is indicated by a tendency ofthe oil to creep up the side of the beaker.8.4.10 Repeat the evaporation step for 5
46、-min periods untilthe weight loss between successive evaporations is less than 20mg. Heat from a steam bath is generally required during thefinal evaporation steps to remove completely the elutionsolvent. The weight of the residue in the beaker is the quantityof the nonaromatics fraction.8.4.11 Weig
47、h a 250-mL inverted-rim beaker to the nearest 1mg. Quantitatively transfer the chloroform-alcohol-eluted frac-tion to this beaker and evaporate on a steam bath with acontrolled stream of dry nitrogen directed downward onto thesurface of the liquid. When the solvent is evaporated, removethe beaker fr
48、om the steam bath, cool to room temperature, andadd quantitatively the ether-eluted fraction. Evaporate the etherat room temperature as described in 8.4.8-8.4.10. Determinethe weight of the residue (aromatics fraction) to the nearest 1mg.8.4.12 The weight of the aromatics plus the nonaromaticsfracti
49、on recovered must equal at least 95 % of the samplecharged. If 95 % recovery is not obtained, repeat the test.Recoveries greater than 100 % indicates incomplete removal ofsolvent or the condensation of moisture in the beakers.8.4.13 Transfer the aromatics and nonaromatics fractionsinto suitable size vials for storage pending further analysis.8.5 If 10 g of sample are to be analyzed, continue as in8.5.1.8.5.1 Warm the sample with intermittent mixing or shakinguntil it is completely fluid. Transfer a representative sample(approximately 8 to 10 g) to
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