1、Designation: D 2764 99 (Reapproved 2004)e1An American National StandardStandard Test Method forDimethylformamide-Insoluble (DMF-I) Content of Tar andPitch1This standard is issued under the fixed designation D 2764; the number immediately following the designation indicates the year oforiginal adopti
2、on 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 moved into the text editorially in November 2004.1. Scope1.1 This
3、 test method covers the determination of thedimethylformamide-insoluble matter (DMF-I) in tar and pitch.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 the standard.1.4 This standard
4、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. For specificprecautionary inform
5、ation, see Section 7.2. Referenced Documents2.1 ASTM Standards:2D 329 Specification for AcetoneD 370 Test Method for Dehydration of Oil-Type Preserva-tivesD 4072 Test Method for Toluene-Insoluble (TI) Content ofTar and PitchD 4296 Practice for Sampling PitchE11 Specification for Wire Cloth and Sieve
6、s for TestingPurposes3. 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 in establishing theuniformity
7、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 D 4072.5. Apparatus5.1 Filtering Crucible, porcelain, with fine-porosity bottom,30 to 40-mL capacity, high form, maximum pore diameter7m.35.2 Filter Appar
8、atusFilter 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 4F(2C) including 307F (153C).
9、 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 D 329.(WarningFlammable. Health hazard.)6.3 Concentrated Hydrochloric Acid.6.4 Celite Analytical Filter Aid (C
10、AFA)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 area shouldbe kept free of
11、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.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and
12、 is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved Nov. 16, 2004. Published November 2004. Originallyapproved in 1968. Last previous edition approved in 1999 as D 2764 99.2For referenced ASTM standards, visit the AS
13、TM 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.3Selas Grade 01, Size No. FC30 or FC40, or equivalent, has been foundsatisfactory for this purpose.1Copyr
14、ight ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8. Bulk Sampling8.1 Samples from shipments shall be taken in accordancewith Practice D 4296 and shall be free of foreign substances.The sample shall be thoroughly mixed immediately beforeremo
15、ving a representative portion for the determination or fordehydration.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, mainta
16、in a representative portion ofthe bulk sample 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 acco
17、rdance with Test Method D 370, but stop thedistillation 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
18、has cooled to a moderate temperature.10. Preparation 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 jawcrushe
19、r and a mullite mortar and pestle. No particle 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
20、 24 h (see 10.4).10.2 Soft PitchIf the pitch 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 t
21、his melting period.Pass the heated sample through 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 o
22、f Working SamplesStore samples aslarge lumps 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
23、for less than six determinations, clean it as 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
24、a desiccator while still warm.11.2 After the 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, th
25、oroughly back wash with distilledwater, dry, 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 3
26、0 min. Cool in adesiccator and weigh. Record 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
27、weight of thesample.12.4 Add 25 mL of dry dimethylformamide (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 (
28、95 to100C). (Asuitable weight can be used to 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 Ins
29、ert the filter tube with adapter into the filter 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-q
30、uent washing with DMF are completed.12.6 Pour 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,
31、but not to the extent that the insolublematerial 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
32、to pass almostcompletely through the filter before 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
33、 the crucible with acetone;reapply suction until 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 cle
34、an, soft cloth or tissue moistenedwith acetone.D 2764 99 (2004)e1212.9 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
35、tothe desiccator and cool for 25 min, then weigh and record theweight of the filtering crucible and its contents.NOTE 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 dete
36、rmination.13. Calculation13.1 Calculate the DMF-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 dried
37、Celite,C = weight of dry Celite added to the sample, 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
38、 %confidence level).15. Precision and Bias15.1 The 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
39、.4 %.Two such values should be considered suspect (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 %.
40、Two such values should be considered suspect (95 %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 Intern
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44、ards, at the address shown below.This standard is 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).D 2764 99 (2004)e13
