1、Designation: D 2712 91 (Reapproved 2003)e1An American National StandardStandard Test Method forHydrocarbon Traces in Propylene Concentrates by GasChromatography1This standard is issued under the fixed designation D 2712; the number immediately following the designation indicates the year oforiginal
2、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.e1NOTEWarning notes were editorially moved into the standard text in September
3、2003.1. Scope1.1 This test method covers the determination of 5 to 500ppm each of ethylene, total butylenes, acetylene, methylacetylene, propadiene, and butadiene in propylene concen-trates.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for i
4、nformationonly.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 of regulatory limitations prior to use.
5、2. Referenced Documents2.1 ASTM Standards:E 260 Practice for Packed Column Gas Chromatography2F 307 Practice for Sampling Pressurized Gas for Gas Analy-sis33. Summary of Test Method3.1 A relatively large volume of sample is charged to a gaspartition chromatography apparatus which has a column thatwi
6、ll separate the trace hydrocarbon constituents from the majorcomponents. Any column or combination of columns may beused provided they have the necessary resolution and thedetecting system has sufficient sensitivity. Several columns thathave been found satisfactory are given in 5.1.3.2 Calculation i
7、s performed by calculating the concentra-tion of the trace compound from its area relative to the area ofa standard compound of known concentration.4. Significance and Use4.1 The trace hydrocarbon compounds listed in Table 1 mayhave an effect in the commercial use of propylene concentrates,and infor
8、mation on their concentration is frequently necessary.5. Apparatus5.1 ColumnsAny column may be used provided it willresolve the trace compound peaks present in concentrations of20 ppm or more so that the resolution ratio, A/B, will not beless than 0.4, where A is the depth of the valley on either si
9、deof peak B and B is the height above the baseline of the smallerof any two adjacent peaks (see Fig. 1). For compounds presentin concentrations of less than 20 ppm the ratio A/B may be lessthan 0.4. In the case where the small-component peak isadjacent to a large one, it may be necessary to construc
10、t thebaseline of the small peak tangent to the curve as shown in Fig.2. Butylenes need not be resolved from each other. Columnsfound to be acceptable together with operating conditions usedare shown in Table 2. Table 3 shows typical retention times.5.1.1 Columns may be constructed of 3.2-mm (18-in.)
11、,6.4-mm (14-in.), or capillary tubing and usually need to be aminimum of 6 m (20 ft) in length. They usually have 20 to 40g of liquid substrate to 100 g of solid support. If packedcolumns are used, the liquid may be placed on the solid supportby any suitable method, provided the column has the desir
12、edresolution and sensitivity.NOTE 1Separation of all the desired compounds on a single columnhas been found by cooperators to be very difficult. Most laboratories havefound it necessary to use two or more columns. Typical instructions forpreparing such columns may be found in Practice E 260.5.2 Gas
13、ChromatographAny gas chromatography appa-ratus may be used provided the system has sufficient sensitivityto detect the trace compounds of interest. For calculationtechniques utilizing a recorder, the signal for 20 ppm concen-tration shall be at least 5 chart divisions above the noise levelona0to100s
14、cale chart. The noise level must be restricted to1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.D0 on Hydrocarbons for Chemical and Special Uses.Current edition approved Sept. 10, 2003. Publish
15、ed September 2003. Originallyapproved in 1968. Last previous edition approved in 1996 as D 271291(1996).2Annual Book of ASTM Standards, Vol 14.02.3Annual Book of ASTM Standards, Vol 15.03.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Stat
16、es.a maximum of 2 chart divisions. When electronic integration isemployed, the signal for 20-ppm concentration must be at leasttwice the noise level.NOTE 2A flame ionization detector is preferred. When using withrelatively volatile liquid phases, such as HMPA, an additional 0.31-m(1-ft) section of c
17、olumn containing uncoated solid support will aid inreducing noise.5.3 Sample IntroductionMeans shall be provided for in-troducing a measured quantity of sample into the apparatus.Pressure sampling devices may be used to inject a smallamount of the liquid directly into the carrier gas. Introductionma
18、y be by means of a gas valve to charge the vaporized liquid.6. Reagents and Materials6.1 Hydrocarbons, for peak identification, including propy-lene, ethylene, ethane, acetylene, methyl acetylene, propadi-ene, propane, 1,3-butadiene, isobutylene, 1-butene, cis andtrans 2-butene, iso- and normal buta
19、ne, and cyclopropane.(WarningLiquefied petroleum gas under pressure and flam-mable.) Mixtures of these hydrocarbons may be used forcalibration provided there is no uncertainty as to the identity ofthe desired compound.6.2 Propane or Propylene, for synthetic base stock contain-ing less than 2 ppm by
20、weight of acetylene or 1,3-butadiene.(WarningLiquefied petroleum gas under pressure and flam-mable.)6.3 Calibration CompoundsAcetylene and 1,3-butadiene99 % minimum purity. (WarningLiquefied petroleum gasunder pressure and flammable.)6.4 Carrier GasesHelium or Nitrogen.(WarningCompressed gas under p
21、ressure.)6.5 Hydrogen.(WarningCompressed gas under pressureand flammable.)6.6 Liquid Phase for ColumnSee Table 2. (WarningHexamethylphosphoramide is a potential carcinogen.)6.7 Solid SupportC22firebrick or diatomaceous earth,usually 40 to 60 or 60 to 80 mesh.6.8 Stainless Steel Sample Cylinder, 300
22、to 500-cm3capac-ity, capable of withstanding a minimum of 1723 kPa gage (250psig).6.9 Silicone Rubber Septum, with suitable fittings for attach-ment to sample cylinder.6.10 Gas Syringe, 10-cm3.6.11 Vacuum Pump, capable of evacuating sample cylinderto less than 2 mm Hg absolute pressure.6.12 Aluminum
23、 or Stainless Steel Tubing, 0.61 m (2 ft), 3.2mm (18 in.), or 1.6 mm (116 in.), outside diameter with fittingson one end to connect to butadiene cylinder and the other endmodified so as to have an opening with an inside diameter ofabout 0.5 mm larger than the outside diameter of the gassyringe needl
24、e.7. Sampling7.1 This section is to be followed on all samples includingunknown samples and the synthetic standards.7.2 Samples should be supplied to the laboratory in high-pressure sample cylinders, obtained using the proceduresdescribed in Practice F 307 or similar methods.7.3 Place the cylinder i
25、n a horizontal position in a safelocation such as a hood. Check to see that the container is atleast one-half full by slightly opening the valve. If liquid isemitted (a white cloud of vapors) the container is at leastone-half full. Do not analyze any samples or use any syntheticstandard if the liqui
26、d in the container is less than this amount.7.4 Place the cylinder in a vertical position and repressurizeto 1723 kPa gage (250 psig) with the chromatographic carriergas through the valve at the top of the cylinder, ensuring thatno air enters during the operation.7.5 Use either of the following two
27、procedures for obtaininga sample from the container:7.5.1 Using a Liquid ValveConnect the cylinder to theliquid valve on the chromatograph using a minimum length ofconnecting tubing, so that sample is withdrawn from thebottom of the cylinder and a liquid sample is obtained. Theliquid valve on the ch
28、romatograph must be designed in such amanner that full sample pressure can be maintained through thevalve without leaking and that means are provided for trappinga liquid sample in the chromatograph valve under staticconditions of flow. With the exit of the chromatograph valveclosed open the valve o
29、n the cylinder. Slowly open the exitfrom the chromatograph valve so that liquid flows through theTABLE 1 Molecular Weight and Specific GravityCompound Molecular Weight Specific Gravity, 60/60Propylene 42.08 0.5220Propane 44.09 0.5077FIG. 1 Illustration of A/B RatioFIG. 2 Illustration of A/B Ratio fo
30、r Small-Component PeakD 2712 91 (2003)e12connecting line and valve. Close the exits so that the liquidsample is trapped in the valve. Perform the necessary opera-tions to introduce the liquid sample into the chromatographcolumn.7.5.2 Vaporized SampleAssemble the apparatus similar tothat illustrated
31、in Fig. 3. Disconnect the 1700-cm3cylinder atE and evacuate. Close valve B and open valves C and D,allowing the liquid sample to flow into the small cylinder.Slowly open valve B and allow the sample to flow through untila steady slow stream of liquid emerges from B. Close valves B,C, and D in that o
32、rder, trapping a portion of the liquid samplein the pipe cylinder (Note 4). Attach the evacuated cylinderTABLE 2 Typical Column ConditionsColumn 1 2 345678 910 1Column: SeriesASeriesMixed20TCEPMixed80 MEEE SeriesLiquid DMS Squa DMS ODPN UCON DMS None 80 %SE-30 ODPN n C16HMPA8 DIDPNone DMS SquaWeight
33、, % 33 22 U 15 15 15 25 25 20 30 20 33 20Solid Chrom Chrom Chrom Chrom Chrom Chrom SiGel Chrom Chrom Chrom Chrom Chrom SiGel Chrom ChromMesh 60 to 80 60 to 80 100 80 to 100 U 60 to 80 U 30 to 60 30 to 60 60 to 80 60 to 80 60 to 80 40 to 60 60 to 80 60 to 80Treatment none none U U U U U AW AW AW AW n
34、one FeCl none noneLength, ft 4 30 22 20 8 16 3.5 50 50 20 20 25 15 8 35Inside diameter, 0.19 0.13 0.085 0.085 0.085 0.085 0.18 0.19 0.19 0.085 0.085 0.085 0.19 0.085 0.085in.Temperature:Inlet, C RT RT RT RT 160 70 RT RT RT RT RTDetector, C 150 RT 50 50 175 70 RT RT RT RT RTColumn, C RT RT 50 50 30 7
35、0 RT RT RT RT RTSample:InjectionGas, cm3SplitGV0.5GV0.2GV1GV0.7Syr3.0Syr1GV0.5GV540:1GV0.4GV0.4GV1Carrier:Gascm3/minHe50He22He24He42He40He40H217He60He30He30He52Detector:TypeVoltageFI TC8FI TC12FI TC70FI FI FI FI FIRecorder:Range, mV 1 1 511155 1 1 1in./h 30 60 30 30 30 30 30 30 60 60 30Measurement T
36、ri Plan Plan Plan PH PH PH PW/2 Tri Tri TriAbbreviations:AW Acid washed ODPN b,b8-oxydipropionitrileChrom “Chromosorb” P (trademark of Johns-Manville Products Corp.) PH Peak heightDIDP Diisodecyl phthalate Plan PlanimeterDMS 2,4-dimethyl sulfolane PW/2 Peak height 3 width at13 heightFeCl Ferric chlo
37、ride, modified RT Room temperatureFI Flame ionization SE-30 SE-30 gum rubberGV Gas valve SiGel Silica gelHe Helium Squa SqualaneH2Hydrogen Syr SyringeHMPA Hexamethyl phosphoramide TC Thermal conductivityMEEE Bis-2(methoxy ethoxy ethyl) ether TCEP 1,3-tris(2-cyano ethoxy)propanen C16Normal hexadecane
38、 Tri TriangulationU UnknownADetector bypassed during major peaks.TABLE 3 Typical Retention Time, MinColumn 1 23456 78 9 10 1Acetylene 10.1 . . . . 6.5 2.2 22.3 . . 8.01,3-Butadiene 39.4 24.9 . . 15.3 . . 20.8 17.4 . 35.1Isobutene 33.3 . 8.7 . . 15.7 . 11.0 10.9 . 29.71-Butene 33.3 . 9.5 . . 15.7 . 1
39、1.4 10.9 . 29.7trans-2-Butene 42.1 . 11.8 . . 18.1 . 13.1 12.9 . 38.0Acis-2-Butene 46.9 . 14.2 . . 20.5 . 15.1 14.8 . 42.8Cyclopropane 22.8 . . . . 12.0 7.2 8.3 . . .Ethylene 8.1 . . 5.1 . 5.8 2.3 . . 3.6 5.7Methyl acetylene 24.2 26.1 . . 18.3 . . 28.0 16.4 . 21.1Neopentane 34.3B. . . . . 15.4 8.8 .
40、 . .Propadiene 20.6 . 10.2 . . 11.3 . . 10.0 . 17.6ADMS portion only.BSqualane portion only.D 2712 91 (2003)e13(1700-cm3volume) at E. Open valve A and then valve B. Theliquid will expand, filling the larger cylinder and give a gagepressure of approximately 55 kPa (8 psi) for propyleneconcentrates. C
41、lose valve A and disconnect at E.NOTE 3To avoid possible rupture of the liquid-filled pipe cylinder, thesample cylinder and its contents should be at room temperature prior tosampling and the liquid should be allowed to remain in the pipe cylinderfor only a minimum amount of time.7.5.2.1 Connect the
42、 cylinder containing the vaporizedsample to the chromatograph gas valve. Evacuate the sampleloop and the lines up to the sample cylinder. Close the valve tothe vacuum source and allow the sample loop to fill withsample up to atmospheric pressure. Repeat the evacuation andfilling of the sample loop w
43、ith vaporized sample. Turn thevalve so that the vaporized sample is displaced with carrier gasinto the chromatograph.8. Calibration8.1 Select the conditions of column temperature and carriergas flow that will give the prescribed separation.8.2 Determine the retention time for each compound byinjecti
44、ng small amounts of the compound either separately orin a mixture using the same method of charging as is used forthe sample.9. Synthetic Standard9.1 Connect the silicone septum to a valve of the stainlesssteel sample cylinder in such a manner that the volumebetween the septum and the valve is less
45、than 1 % of the totalvolume of the cylinder. By means of suitable fittings connectthe other valve of the cylinder to a vacuum pump and evacuatethe cylinder and space between the cylinder valve and septum.Close the valves, disconnect the cylinder from the vacuumpump, and weigh the empty cylinder on a
46、 suitable platformbalance to the nearest 1 g.9.2 Connect the tubing to the 1,3-butadiene cylinder andcrack the valve on this cylinder so that there is a constant flowof vapors from the end of the tubing which must be at roomtemperature. Insert the syringe into the end of the tubing andslowly withdra
47、w 5 cm3of the butadiene vapors. Flush thesyringe three times with vapors and inject exactly 5 cm3of thevapor through the septum into the evacuated cylinder. Closethe valve between the cylinder and the septum. Inject 5 cm3ofacetylene to the evacuated cylinder in the same manner.9.3 Fill another cylin
48、der of the same size with propane orpropylene base stock. Establish outage in the base stockcylinder by removing 25 % of the liquid contents. Place thecylinder containing the blend stock in a vertical position so thatthe bottom valve is above the top of the cylinder containing thebutadiene. If the c
49、ylinder containing the base stock is equippedwith a dip pipe be sure that this valve is at the top. Connect thebottom valve of the base stock cylinder to the other cylinder bymeans of suitable tubing capable of withstanding 1723 kPa(250 psi) pressure. Flush the connecting line with base stockbefore tightening connections to the evacuated cylinder. Coolthe evacuated cylinder to a temperature of 11 to 17C (20 to30F) below that of the base stock. Open the valves betweenthe two cylinders and allow the base stock to flow into theFIG. 3 Sampling and Expansion Cy
