1、Designation: D 847 04Standard Test Method forAcidity of Benzene, Toluene, Xylenes, Solvent Naphthas,and Similar Industrial Aromatic Hydrocarbons1This standard is issued under the fixed designation D 847; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 Th
3、is test method is intended for the detection of acidityand for the quantitative determination of acidity of benzene,toluene, xylenes, solvent naphthas, and similar industrial aro-matic hydrocarbons.1.2 In determining the conformance of the test results usingthis method to applicable specifications,
4、results shall berounded off in accordance with the rounding-off method ofPractice E 29.1.3 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
5、and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements see Section 8.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 3437 Practice for Sampling and Handling Liquid CyclicProductsE 29 Practice for Using Significant Dig
6、its in Test Data toDetermine Conformance with Specifications2.2 Other Documents:OSHA Regulations, 29 CFR, Paragraphs 1910.1000 and1910.120033. Terminology3.1 Definitions:3.1.1 acidity, nthe number of milligrams of sodium hy-droxide consumed when 100 mL of the specimen are titratedunder the condition
7、s prescribed in this test method.3.1.2 acid reaction, na characteristic of materials produc-ing the acid-color of the indicator used under the conditionsprescribed in this test method.3.1.3 alkaline or basic reaction, na characteristic of thematerials producing the alkali-color of the indicator used
8、 underthe conditions prescribed in this test method.4. Summary of Test Method4.1 The acidity of aromatic hydrocarbons is detected anddetermined quantitatively using a sodium hydroxide titrationand a color change in a phenolphthalein indicator.5. Significance and Use5.1 This test method is suitable f
9、or setting specifications, foruse as an internal quality control tool, and for use in develop-ment or research work on industrial aromatic hydrocarbons andrelated materials. This test method gives an indication ofresidual acidity and is a measure of the quality of the finishedproduct. It is an indic
10、ation of the tendency of the product tocorrode equipment.6. Interferences6.1 Tests for acidity are not applicable in the presence ofcontaminating acidic or alkaline gases, soaps, salts, or othercompounds derived from the atmosphere or apparatus. Thecontainer holding the specimen, and the apparatus,
11、water,indicator, and other materials used in the test shall be chosen sothat they themselves shall not appreciably affect the results.Since new corks used in specimen bottles often are bleachedwith oxalic acid, it is advisable to rinse them thoroughly andcheck them for neutrality with the indicator
12、used in the test.Glassware shall be of acid-resistant and alkali-resistant glass4and shall be rinsed with neutral distilled water before use. Theroom in which the test is performed shall be chosen so as to1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and R
13、elated Chemicals and is the direct responsibility ofSubcommittee D16.01 on Benzene, Toluene, Xylenes, Cyclohexane and TheirDerivatives.Current edition approved June 1, 2004. Published July 2004. Originally approvedin 1945. Last previous edition approved in 1996 as D 847 96 (2000).2For referenced AST
14、M 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.3Available from U.S. Government Printing Office Superintendent of Documents,732
15、N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.4Borosilicate glass or the equivalent has been found satisfactory for this purpose.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
16、-2959, United States.prevent undue contamination by carbon dioxide, ammonia, orother interfering substances that may be present in the atmo-sphere.6.2 The distilled water used in the test shall not alter thecomposition of the specimen nor otherwise interfere with thepurpose of the work. Although ine
17、rt impurities often may beneglected, care must be exercised to correct for impurities or toeliminate them entirely if they are likely to interfere. When thedistilled water does not show an acid or alkaline reaction, itmay be used without further adjustment to neutrality. However,if the water shows a
18、n acid or alkaline reaction, it shall bebrought to a persistent pink end point before use by titrationwith standard 0.01 N NaOH solution (see 8.5) or standard 0.01N H2SO4, respectively.7. Apparatus7.1 Graduate, 100-mL.47.2 Bottle, 500-mL glass-stoppered.47.3 Buret, 10-mL, graduated in 0.05-mL subdiv
19、isions.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available
20、.5Other 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.8.2 Phenolphthalein Indicator Solution Dissolve 0.5 g ofphenolphthalein in 100 mL of cp ethyl alcohol (95 %). Add0.01 N NaOH
21、 solution cautiously until a faint pink colorappears; then just remove the color with a drop or two of 0.01N acid.8.3 Sodium Hydroxide, Standard Solution (0.1 N).8.4 Sodium Hydroxide, Standard Solution (0.01 N).8.5 Sulfuric Acid, Standard (0.01 N).8.6 Purity of Water: Distilled Water, NeutralBoil vi
22、g-orously for 30 min, 1 to 2 L of distilled water conforming toType III of Specification D 1193. Insert a stopper carrying aguard tube of soda lime. Rinse a 200-mL flask with thisdistilled water, add a 100-mL portion, and titrate in a closedsystem with 0.01 N NaOH solution: or heat to boiling andtit
23、rate immediately, taking care that the temperature does notfall below 80C during the titration. If more than 1 drop (0.05mL) of 0.01 N NaOH solution is required to obtain an end pointwith phenolphthalein, adjust the pH of the water to be used byadding the calculated amount of NaOH solution. Repeat t
24、heblank titration, and readjust if necessary until the blank titrationon 100 mL of the distilled water is 1 drop (0.05 mL) or less ofthe 0.01 N NaOH solution. The distilled water now will beneutral or very slightly acid to the phenolphthalein indicator.9. Hazards9.1 Consult current OSHA regulations,
25、 suppliers MaterialSafety Data Sheets, and local regulations for all materials usedin this test method.10. Sampling10.1 Sample the material in accordance with PracticeD 3437.11. Procedure11.1 Measure out 100 mL of the sample into the 500-mLbottle. Add 100 mL of neutral distilled water (see 8.2) and
26、2drops of phenolphthalein indicator solution. Stopper and shakethoroughly. Without separating the layers, titrate the acidity, ifany, with standard 0.1 N NaOH solution to the first persistentshade of pink, while shaking thoroughly.11.2 If more than 2 drops (0.10 mL) of 0.1 N NaOH solutionis required
27、 to produce a persistent pink end point, discard theresults of the test. While taking precautions to avoid contami-nation from the apparatus and atmosphere, proceed as follows:Rinse the 100-mL graduated cylinder and the 500-mL bottleand glass stopper with neutral distilled water. To the bottle, add1
28、00 mL of the sample and 100 mL of neutral distilled water.Add 2 drops of phenolphthalein indicator solution, and shakevigorously for 10 s. Bring the temperature to between 15 and18.5C (60 and 65F). Add 1 drop of 0.1 N NaOH solution,stopper, and shake vigorously for 10 s. Repeat the addition of1 drop
29、 of NaOH solution, stoppering, and shaking for 10 s,until a sharp pink end point is secured. Repeat this procedureon a blank run with 100 mL of the neutral distilled water.12. Interpretation of Results and Calculation12.1 Unless otherwise indicated in the applicable specifica-tions, the test results
30、 shall be interpreted as follows:12.1.1 A specimen shall be said to contain no free acid, thatis, show no evidence of acidity, if 2 drops or less of 0.1 NNaOH solution produces a persistent pink end point in the testbottle.12.1.2 When more than 2 drops (0.10 mL) of 0.1 N NaOHsolution is required to
31、produce a persistent pink end point in thetest bottle, the acidity shall be reported in terms of milligramsof NaOH required for 100 mL of specimen, and shall becalculated as follows:Acidity, mg NaOH per 100 mL 5 4 A 2 B! (1)where:A = 0.1 N NaOH solution required for titration of thesample, mL, andB
32、= 0.1 N NaOH solution required for titration of the blank,mL.13. Precision and Bias13.1 In the case of pass/fail data, no generally acceptedmethod for determining precision is currently available.14. Keywords14.1 acidity; aromatic hydrocarbons5Reagent Chemicals, American Chemical Society Specificati
33、ons, AmericanChemical Society, Washington, DC. For suggestions 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,
34、Inc. (USPC), Rockville,MD.D847042SUMMARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue(D 847 96 (2000) that may impact the use of this standard.(1) The rounding statement in 1.2 was updated.(2) Aromatic hydrocarbons was added to Keyword
35、s.(3) Summary of changes was added.ASTM 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 rights, and the risk
36、of 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 for revision of this
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38、our 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).D847043
