1、Designation: D 1686 96 (Reapproved 2004)Standard Test Method forColor of Solid Aromatic Hydrocarbons and Related Materialsin the Molten State (Platinum-Cobalt Scale)1This standard is issued under the fixed designation D 1686; the number immediately following the designation indicates the year oforig
2、inal 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.1. Scope1.1 This test method covers the visual measurement of thecolor of
3、thermally stable solids melting below 150C. It isapplicable only to materials in which the color-producingbodies present have light absorption characteristics quite simi-lar to those of the standards used.1.2 The following applies to all specified limits in this testmethod: for purposes of determini
4、ng conformance with thistest method, an observed value or a calculated value shall berounded off “to the nearest unit” in the last right-hand digitused in expressing the specification limit, in accordance withthe rounding-off method of Practice E 29.1.3 This standard does not purport to address all
5、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 specific hazardstatements see Sections 7 and 9.2. Referenced
6、 Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 3438 Practice for Sampling and Handling Naphthalene,Maleic Anhydride, and Phthalic AnhydrideD 3852 Practice for Sampling and Handling Phenol,Cresols, and Cresylic AcidE 29 Practice for Using Significant Digits in Test Data toDeter
7、mine Conformance with Specifications2.2 Other Document:OSHA Regulations, 29 CFR, paragraphs 1910.1000 and1910.120033. Significance and Use3.1 Color by this test method is a measure of color-producing impurities present in the thermally stable solids.This test method is suitable for setting specifica
8、tions and foruse as an internal quality control tool.4. Apparatus4.1 Color Comparison TubesMatched 100-mL, tall-formNessler tubes, provided with ground-on, optically clear, glasscaps. Tubes should be selected so that the height of the 100-mLgraduation mark is 300 6 3 mm above the bottom of the tube.
9、The use of heat-resistant tubes is preferred for safety reasons.4.2 Color ComparatorA color comparator constructed topermit visual comparison of light transmitted through tall-form, 100-mL Nessler tubes in the direction of their longitu-dinal axes. The comparator should be constructed so that whitel
10、ight is reflected off a white plate and directed with equalintensity through the tubes, and should be shielded so that nolight enters the tubes from the side.4.3 OvenAn oven, preferably of the forced draft type andcapable of maintaining a constant temperature 61C in therange up to 150C. Alternativel
11、y, the use of an aluminumheating block provided with proper temperature control orother similar equipment is permissible.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications
12、 of the Commit-tee on Analytical Reagents of the American Chemical Society,1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.02 on Oxygenated Aromatics.Current edition approved June 1, 2
13、004. Published June 2004. Originallyapproved in 1959. Last previous edition approved in 2000 as D 1686 96 (2000).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
14、 standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Sta
15、tes.where such specifications 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.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be unders
16、tood to mean Type IV reagent waterconforming to Specification D 1193.5.3 Cobalt Chloride (CoCl26H2O).5.4 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).5.5 Potassium Chloroplatinate (K2PtCl6).6. Standards6.1 Platinum-Cobalt Stock Solution Dissolve 1.245 g ofK2PtCl6and 1.000 g of
17、 CoCl26H2O in water. Add 100 mL ofHCl and dilute to 1 L with water. This solution has a color of500.56.2 Platinum-Cobalt Standards6From the stock solution,prepare color standards, as given in Table 1, by diluting therequired volumes to 100 mL with water in the Nessler tubes. Ifdesired, these standar
18、ds may be made permanent by sealing onthe caps with a suitable colorless cement.7. Hazards7.1 Consult OSHA regulations, suppliers Material SafetyData Sheets, and local regulations for all materials used in thistest method.7.2 Warning: When handling molten solids in open tubes,adequate ventilation mu
19、st be provided and proper protectionshould be used to prevent thermal burns.8. Sampling8.1 Sample the material in accordance with PracticesD 3438 or D 3852.9. Procedure9.1 Melt approximately 150 g of the sample and simulta-neously preheat a Nessler tube and cap in an oven maintainedat constant tempe
20、rature at 10 to 20C above the solidificationpoint of the sample. The sample must not be heated to morethan 20C above its solidification point.9.2 As soon as the sample is completely liquid, mix bystirring with a clean dry glass rod, then quickly fill thepreheated Nessler tube to the 100-mL mark with
21、 the sampleand cap the tube. Place the tube in the comparator andimmediately compare with the standards.NOTE 1A variation of more than 2 to 3 mm in depth can affect the testresults.9.3 When measuring the color of solids that sublime, somedifficulty may be encountered due to condensation of solid ont
22、he cap. In such a case, the Nessler tube may be reheated in theoven after first loosening the cap, or, the color may bemeasured using an open Nessler tube without a cap (Warning,see 9.3.1). In this latter case the caps should also be removedfrom the standards.9.3.1 Warning: Make sure to provide adeq
23、uate ventilationif open tubes are used.9.4 In no case shall this test method be applied if the moltensample contains any visible turbidity.10. Report10.1 Report as the color, the number of the standard thatmost nearly matches the sample. In the event that the color liesmidway between two standards,
24、report the darker of the two.10.2 If, owing to small differences in hue between thesample and the standards, an exact match cannot be obtained,but an estimate is possible, report the range over which anapproximate match is obtained, and report the sample as “offhue.”10.3 If, owing to large differenc
25、es in hue between thesample and the standards, no estimate is possible, report thesample as “no match.”11. Precision and Bias11.1 Intermediate Precision (formerly calledRepeatability)Results in the same laboratory should not beconsidered suspect unless they differ by more than the follow-ing amounts
26、:Platinum-Cobalt Color Intermediate PrecisionUnder No. 50 2.5No. 50 to No. 100 5Over No. 100 1011.2 ReproducibilityResults submitted by two laborato-ries should not be considered suspect unless they differ bymore than the following amounts:Platinum-Cobalt Color ReproducibilityUnder No. 50 5No. 50 to
27、 No. 100 10Over No. 100 1511.3 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this testmethod, bias has not been determined.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions
28、 on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5The stock solution with color No. 5
29、00 may be purchased as such from chemicalsupply firms. Use of the purchased standard is satisfactory.6The preparation of these platinum-cobalt standards was originally described byA. Hazen, American Chemical Journal, Vol 14, p. 300 (1892). The description givenin Test Method D 1686 is identical with
30、 that given in the “Standard Methods for theExamination of Water and Sewage,” American Public Health Assn., Tenth Edition,1955, p. 88. A description is also given by W. W. Scott, “Standard Methods ofChemical Analysis,” D. Van Nostrand Co., Inc., Fifth Ed., Vol 2, p. 2048.TABLE 1 Platinum-Cobalt Colo
31、r StandardsAColorStandardNo.StockSolution,mLColorStandardNo.StockSolution,mL5 1 35 710 2 40 815 3 50 1020 4 60 1225 5 70 1430 6 100 20AOther color standards may be prepared by proportional dilution.D 1686 96 (2004)212. Keywords12.1 color; cresylic acid; maleic anhydride; naphthalene;phenol; phthalic
32、 anhydride; platinum-cobalt; solid aromatichydrocarbonsASTM 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 such patent
33、rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject 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
34、for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. 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 hear
35、ing you shouldmake your views known to the ASTM Committee on Standards, 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 1686 96 (2004)3
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