1、Designation: D2764 99 (Reapproved 2009)Standard Test Method forDimethylformamide-Insoluble (DMF-I) Content of Tar andPitch1This standard is issued under the fixed designation D2764; 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of thedimethylformamide-insoluble matter (DMF-I) in tar and pitch
3、.1.2 Since this test method is empirical, strict adherence toall details of the procedure is necessary.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not co
4、nsidered standard.1.4 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 u
5、se. For specific hazardinformation, see Sections 6 and 7.2. Referenced Documents2.1 ASTM Standards:2D329 Specification for AcetoneD370 Practice for Dehydration of Oil-Type PreservativesD4072 Test Method for Toluene-Insoluble (TI) Content ofTar and PitchD4296 Practice for Sampling PitchE11 Specificat
6、ion for Woven Wire Test Sieve Cloth and TestSieves3. Summary of Test Method3.1 A sample is digested in hot DMF and filtered. Anyinsoluble matter is washed, dried, and weighed.4. Significance and Use4.1 This test method is useful in evaluating and character-izing tars and pitches and as one element i
7、n establishing theuniformity of shipments or sources of supply. It is a rapid andreasonably accurate measure of the toluene insoluble (TI)content of tar and pitch Test Method D4072.5. Apparatus5.1 Filtering Crucible, porcelain, with fine-porosity bottom,30 to 40-mL capacity, high form, maximum pore
8、diameter7 m.5.2 Filter ApparatusFilter flask and tube with crucibleadapter.5.3 Sieves, U.S. Standard 600-m (No. 30) and 250-m (No.60), conforming to Specification E11.5.4 Water Bath, maintained at 203 to 212F (95 to 100C).6. Reagents and Materials6.1 Dimethylformamide, reagent grade, boiling range 4
9、F(2C) including 307F (153C). Store over a suitable desiccant.Decant immediately before use. If necessary, filter through aplug of glass wool or absorbent cotton until optically clear.6.2 Acetone, meeting Specification D329.(WarningFlammable. Health hazard.)6.3 Concentrated Hydrochloric Acid.6.4 Celi
10、te Analytical Filter Aid (CAFA)Dry to constantweight at 22F (105C) and store in tightly stoppered container.NOTE 1Do not use any other grade of filtering medium becauseporosities differ.7. Hazards7.1 Fumes of the solvents should be removed by means ofproper hoods from all working areas. The working
11、area shouldbe kept free of sparks and flames. DMF fumes should not beinhaled, and prolonged contact of DMF with the skin should beavoided.7.2 Observe proper laboratory procedures for handling anddiluting hydrochloric acid.8. Bulk Sampling8.1 Samples from shipments shall be taken in accordancewith Pr
12、actice D4296 and shall be free of foreign substances.The sample shall be thoroughly mixed immediately beforeremoving a representative portion for the determination or fordehydration.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direc
13、t responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved Oct. 1, 2009. Published November 2009. Originallyapproved in 1968. Last previous edition approved in 2004 as D276499(2004)1.DOI: 10.1520/D2764-99R09.2For referenced ASTM standar
14、ds, 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
15、19428-2959, United States.9. Dehydration of Sample9.1 Hard PitchIf the solid bulk sample contains freewater, air-dry a representative portion in a forced draft oven at50C.9.2 Soft PitchIf the presence of water is indicated bysurface foam on heating, maintain a representative portion ofthe bulk sampl
16、e at a temperature between 257 and 302F (125and 150C) in an open container until the surface is free offoam. Take care not to overheat, and remove heat sourceimmediately when foam subsides.9.3 TarDehydrate a representative portion of the bulksample in accordance with Test Method D370, but stop thedi
17、stillation when the temperature reaches 338F (170C).Separate any oil from the water that has distilled over (ifcrystals are present, warm sufficiently to ensure their solution),and thoroughly mix the oil with the residual tar in the still afterthe latter has cooled to a moderate temperature.10. Prep
18、aration of Working Sample10.1 Hard PitchIf the pitch can be crushed at roomtemperature, prepare a 20-g working sample by suitablecrushing, mixing, and quartering of a representative portion ofthe dry sample. The crushing can be done with a small jawcrusher and a mullite mortar and pestle. No particl
19、e in therepresentative sample shall be larger than 5 mm in anydimension. Crush this sample so that all of it will pass the250-m (No. 60) sieve but have a minimum of fine particles.Store the sieved working sample in a tightly closed containerand use within 24 h (see 10.4).10.2 Soft PitchIf the pitch
20、is too soft to grind and toosticky to mix, heat a representative portion of the dry sample tothe lowest temperature that will permit passage through the600-m (No. 30) sieve, taking care to avoid excessive loss ofvolatile matter. Do not exceed 10 min for this melting period.Pass the heated sample thr
21、ough the 600-m sieve to removeforeign matter.10.3 TarHeat a representative portion of the dry tar to thelowest temperature that will permit passage through the600-m (No. 30) sieve, then filter through this sieve to removeforeign matter.10.4 Preservation of Working SamplesStore samples aslarge lumps
22、or as solidified melts in closed containers. Discardworking samples 24 h after crushing and sieving since changesin composition sometimes occur in pulverized pitch.11. Crucible Preparation11.1 If the crucible, after thorough cleaning (11.2), has beenused for less than six determinations, clean it as
23、 follows.Remove the mat, wash the crucible with distilled water, dry,and ignite in a muffle furnace for1hatabout 1472F (800C).Cool the crucible slowly by placing it in a drying oven for 1 hafter removal from the furnace to prevent cracking and place itin a desiccator while still warm.11.2 After the
24、crucible has been used for six determinations,remove any residual ash from pores in the filtering area byboiling in 1 + 1 hydrochloric acid. Add equal volume ofconcentrated hydrochloric acid to distilled water. Then boil thecrucible in distilled water, thoroughly back wash with distilledwater, dry,
25、and ignite as in 11.1.12. Procedure12.1 Make and record all weighings to the nearest 0.5 mg.12.2 Transfer 0.45 to 0.55 g of Celite to a clean, filteringcrucible. Distribute the Celite evenly over the bottom. Dry inan oven at 22 to 230F (105 to 110C) for 30 min. Cool in adesiccator and weigh. Record
26、the weight of crucible plusCelite.12.3 Transfer 0.45 to 0.55 g of previously dried Celite to aclean, dry, and tared 100-mL beaker and weigh. Record theweight of Celite. Place 0.5 g of working sample in the samebeaker and reweigh. Calculate and record the weight of thesample.12.4 Add 25 mL of dry dim
27、ethylformamide (DMF) to thebeaker while stirring the mixture with a stirring rod orthermometer to break up lumps, then cover the beaker with asmall watch glass. Place the beaker and a wash bottle contain-ing DMF in a water bath maintained at 203 to 212F (95 to100C). (Asuitable weight can be used to
28、keep the beaker frombeing upset in the water bath.) Digest for at least 30 min.Occasionally stir the contents of the beaker to promotedigestion. Check for completeness of digestion by inspectingthe bottom of the beaker for undigested pitch or tar.12.5 Insert the filter tube with adapter into the fil
29、ter flaskand place the previously prepared and tared crucible in theadapter. Carefully add sufficient DMF to the crucible to wet theCelite thoroughly. Apply suction, and form a mat of evenlydistributed Celite. Maintain suction until filtration and subse-quent washing with DMF are completed.12.6 Pour
30、 the hot DMF-pitch mixture into the crucible,while the Celite in the crucible is still wet without disturbingthe mat. Stir the mixture in the beaker immediately beforepouring successive portions into the crucible. Allow the con-tents to drain completely, but not to the extent that the insolublemater
31、ial on the filter appears substantially dry.12.7 Wash the beaker, thermometer or stirring rod, andcrucible with small portions (2 to 3 mL each) of DMF at 203to 212F (95 to 100C) from the wash bottle. Pass all thewashes through the filter. Allow each wash to pass almostcompletely through the filter b
32、efore the next is added. Use asuitable policeman to sweep the insoluble particles into thecrucible. Repeat the DMF washes until the filtrate is the samecolor as the DMF used for washing. Twelve washings areusually enough.12.8 Discontinue the suction. Fill the crucible with acetone;reapply suction un
33、til the solvent has passed through the filter,then discontinue suction and repeat the operation with freshacetone three more times. Maintain full suction for a minimumof 5 min after the last acetone wash. Remove the crucible andwipe the outside with a clean, soft cloth or tissue moistenedwith aceton
34、e.12.9 Place the filtering crucible in the drying oven at 222 to230F (105 to 110C) and dry to constant weight (60.5 mg).When the hot crucible is removed from the drying oven, itshould have no odor of DMF (Note 1). Transfer the crucible tothe desiccator and cool for 25 min, then weigh and record thew
35、eight of the filtering crucible and its contents.D2764 99 (2009)2NOTE 2Insoluble matter on the filter, after washing with acetone,should have no odor of DMF, which is evidence of insufficient washing.If odor of DMF is detectable, repeat the entire determination.13. Calculation13.1 Calculate the DMF-
36、insoluble (DMF-I) content as fol-lows:DMF2I, % 5 A 2 B 2 C!/D 3 100where:A = total weight of the filtering crucible, Celite (added tothe crucible and to the sample), plus DMF insolublematter.B = initial weight of the filtering crucible containing driedCelite,C = weight of dry Celite added to the sam
37、ple, andD = weight of working sample used for the determination.14. Report14.1 Report the percentage of matter insoluble in dimethyl-formamide (DMF-I) to the nearest 0.1 %. Duplicate runs thatagree within 1.0 % absolute are acceptable for averaging (95 %confidence level).15. Precision and Bias15.1 T
38、he following criteria should be used for judging theacceptability of results.15.1.1 RepeatabilityThe average difference between tworesults (each the average of duplicate determinations), obtainedby the same analyst on different days, will approximate 0.4 %.Two such values should be considered suspec
39、t (95 % confi-dence level) if they differ by more than 1.0 % absolute.15.1.2 ReproducibilityThe average difference betweentwo results (each the average of duplicate determinations),obtained by analysts in different laboratories, will approximate0.8 %. Two such values should be considered suspect (95
40、 %confidence level) if they differ by more than 2.5 % absolute.15.2 BiasThis test method has no bias because the valueof DMF-1 is defined in terms of this test method.16. Keywords16.1 dimethylformamide; insoluble; insoluble matter; pitch;tarASTM International takes no position respecting the validit
41、y 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
42、 to 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 Headquarter
43、s. Your comments 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 i
44、s copyrighted by 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).D2764 99 (2009)3
