1、Designation: D2764 99 (Reapproved 2015)1Standard 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,
2、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.1NOTESI units formatting was corrected editorially in May 2015.1. Scope1.1 This test method covers the determination o
3、f 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 standard. The values given in parentheses are mathematicalconversions
4、to SI units that are provided for information onlyand are not considered 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 d
5、etermine the applica-bility of regulatory limitations prior to use. 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) Conten
6、t ofTar and PitchD4296 Practice for Sampling PitchE11 Specification 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 eval
7、uating and character-izing tars and pitches and as one element in 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 fin
8、e-porosity bottom,30 mL to 40 mL capacity, high form, maximum pore 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 F to 212 F (95 C to100 C).6. Rea
9、gents and Materials6.1 Dimethylformamide, reagent grade, boiling range 4 F(2 C) including 307 F (153 C). Store over a suitable desic-cant. Decant immediately before use. If necessary, filterthrough a plug of glass wool or absorbent cotton until opticallyclear.6.2 Acetone, meeting Specification D329.
10、(WarningFlammable. Health hazard.)6.3 Concentrated Hydrochloric Acid.6.4 Celite Analytical Filter Aid (CAFA)Dry to constantmass at 22 F (105 C) 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 s
11、hould be removed by means ofproper hoods from all working areas. The working area shouldbe kept free of sparks and flames. DMF fumes should not beinhaled, and prolonged contact of DMF with the skin should beavoided.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Product
12、s, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved April 1, 2015. Published May 2015. Originallyapproved in 1968. Last previous edition approved in 2009 as D2764 99 (2009).DOI: 10.
13、1520/D2764-99R15E01.2For referenced ASTM standards, 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.Copyright ASTM International, 100 Barr Ha
14、rbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17.2 Observe proper laboratory procedures for handling anddiluting hydrochloric acid.8. Bulk Sampling8.1 Samples from shipments shall be taken in accordancewith Practice D4296 and shall be free of foreign substances.The sample s
15、hall be thoroughly mixed immediately beforeremoving 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 at50 C.9.2 Soft PitchIf the presence of wate
16、r is indicated bysurface foam on heating, maintain a representative portion ofthe bulk sample at a temperature between 257 F and 302 F(125 C and 150 C) in an open container until the surface isfree of foam. Take care not to overheat, and remove heat sourceimmediately when foam subsides.9.3 TarDehydr
17、ate a representative portion of the bulksample in accordance with Test Method D370, but stop thedistillation when the temperature reaches 338 F (170 C).Separate any oil from the water that has distilled over (ifcrystals are present, warm sufficiently to ensure their solution),and thoroughly mix the
18、oil with the residual tar in the still afterthe latter 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
19、sample. The crushing can be done with a small jawcrusher and a mullite mortar and pestle. No particle in therepresentative sample shall be larger than 5 mm in any dimen-sion. Crush this sample so that all of it will pass the 250 m(No. 60) sieve but have a minimum of fine particles. Store thesieved w
20、orking sample in a tightly closed container and usewithin 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 exc
21、essive loss ofvolatile matter. Do not exceed 10 min for this 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 throu
22、gh this sieve to removeforeign matter.10.4 Preservation of 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 th
23、e crucible, after thorough cleaning (11.2), has beenused 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 for 1 h at about 1472 F(800 C). Cool the crucible slowly by placing it in a dryingoven for 1 h aft
24、er removal from the furnace to prevent crackingand place it in 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 t
25、o distilled water. Then boil thecrucible in distilled water, thoroughly 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 g to 0.55 g of Celite to a clean, filteringcrucible. Distribute the Celite evenly
26、 over the bottom. Dry inan oven at 221 F to 230 F (105 C to 110 C) for 30 min.Cool in a desiccator and weigh. Record the mass of crucibleplus Celite.12.3 Transfer 0.45 g to 0.55 g of previously dried Celite toa clean, dry, and tared 100 mL beaker and weigh. Record themass of Celite. Place 0.5 g of w
27、orking sample in the samebeaker and reweigh. Calculate and record the mass 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 was
28、h bottle contain-ing DMF in a water bath maintained at 203 F to 212 F (95 Cto 100 C). (A suitable mass can be used to keep the beakerfrom being 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 b
29、y inspectingthe bottom of the beaker for undigested pitch or tar.12.5 Insert 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 o
30、f evenlydistributed Celite. Maintain suction until filtration and subse-quent 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 success
31、ive portions into the crucible. Allow the con-tents to drain completely, 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 mL to 3 mL each) of DMF at203 F to 212 F (95 C to 10
32、0 C) from the wash bottle. Passall the washes through the filter. Allow each wash to passalmost completely through the filter before the next is added.Use a suitable policeman to sweep the insoluble particles intothe crucible. Repeat the DMF washes until the filtrate is thesame color as the DMF used
33、 for washing. Twelve washings areusually enough.D2764 99 (2015)1212.8 Discontinue the suction. Fill 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 fo
34、r a minimumof 5 min after the last acetone wash. Remove the crucible andwipe the outside with a clean, soft cloth or tissue moistenedwith acetone.12.9 Place the filtering crucible in the drying oven at 222 Fto 230 F (105 C to 110 C) and dry to constant mass(60.5 mg). When the hot crucible is removed
35、 from the dryingoven, it should have no odor of DMF (Note 1). Transfer thecrucible to the desiccator and cool for 25 min, then weigh andrecord the mass 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 evi
36、dence of insufficient washing.If odor of DMF is detectable, repeat the entire determination.13. Calculation13.1 Calculate the DMF-insoluble (DMF-I) content as fol-lows:DMF 2 I,% 5 A 2 B 2 C!/D# 3100where:A = total mass of the filtering crucible, Celite (added to thecrucible and to the sample), plus
37、DMF insoluble matter.B = initial mass of the filtering crucible containing driedCelite,C = mass of dry Celite added to the sample, andD = mass 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 %. Dup
38、licate runs thatagree within 1.0 % absolute are acceptable for averaging (95 %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 determ
39、inations), obtainedby the same analyst on different days, will approximate 0.4 %.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 determinati
40、ons),obtained by analysts in different laboratories, will approximate0.8 %. 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. Keywo
41、rds16.1 dimethylformamide; insoluble; insoluble matter; pitch;tarASTM International takes no position respecting the validity 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 su
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