1、Designation: D 847 08Standard 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 () 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 Thi
3、s 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, r
4、esults shall berounded off in accordance with the rounding-off method ofPractice E29.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated
5、 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 Section 8.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specificati
6、on for Reagent WaterD 3437 Practice for Sampling and Handling Liquid CyclicProductsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 Other Documents:OSHA Regulations, 29CFR paragraphs 1910.1000 and1910.120033. Terminology3.1 Definitions:3.1.1 acidi
7、ty, nthe number of milligrams of sodium hy-droxide consumed when 100 mL of the specimen are titratedunder the conditions 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 meth
8、od.3.1.3 alkaline or basic reaction, na characteristic of thematerials producing the alkali-color of the indicator used 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 hydroxi
9、de titrationand a color change in a phenolphthalein indicator.5. Significance and Use5.1 This test method is suitable for 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 te
10、st method gives an indication ofresidual acidity and is a measure of the quality of the finishedproduct. It is an indication 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, sa
11、lts, or othercompounds derived from the atmosphere or apparatus. Thecontainer holding the specimen, and the apparatus, 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
12、are bleachedwith oxalic acid, it is advisable to rinse them thoroughly andcheck them for neutrality with the indicator used in the test.Glassware shall be of acid-resistant and alkali-resistant glass4and shall be rinsed with neutral distilled water before use. The1This test method is under the juris
13、diction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.01 on Benzene, Toluene, Xylenes, Cyclohexane and TheirDerivatives.Current edition approved Dec. 1, 2008. Published December 2008. Originallyapproved in 1945. Last previous
14、edition approved in 2004 as D 847 04.2For 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.3Available from U.S. Gov
15、ernment Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.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 A
16、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.room in which the test is performed shall be chosen so as toprevent undue contamination by carbon dioxide, ammonia, orother interfering substances that may be present in the atmo-sphere.6.2 The dis
17、tilled water used in the test shall not alter thecomposition of the specimen nor otherwise interfere with thepurpose of the work. Although inert impurities often may beneglected, care must be exercised to correct for impurities or toeliminate them entirely if they are likely to interfere. When thedi
18、stilled water does not show an acid or alkaline reaction, itmay be used without further adjustment to neutrality. However,if the water shows an 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
19、 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 subdivisions.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall c
20、onform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of
21、the determination.8.2 Phenolphthalein Indicator SolutionDissolve 0.5 g ofphenolphthalein in 100 mL of cp ethyl alcohol (95 %). Add0.01 N NaOH 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
22、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 vigor-ously for 30 min, 1 to 2 L of distilled water conforming to TypeIII of Specification D 1193. Insert a stopper carrying a guardtube of soda lime. Rinse a 20
23、0-mL flask with this distilledwater, add a 100-mLportion, and titrate in a closed system with0.01 N NaOH solution: or heat to boiling and titrate immedi-ately, taking care that the temperature does not fall below 80Cduring the titration. If more than 1 drop (0.05 mL) of 0.01 NNaOH solution is requir
24、ed to obtain an end point withphenolphthalein, adjust the pH of the water to be used byadding the calculated amount of NaOH solution. Repeat theblank 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.
25、 The distilled water now will beneutral or very slightly acid to the phenolphthalein indicator.9. Hazards9.1 Consult current OSHA regulations, suppliers MaterialSafety Data Sheets, and local regulations for all materials usedin this test method.10. Sampling10.1 Sample the material in accordance with
26、 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 2drops of phenolphthalein indicator solution. Stopper and shakethoroughly. Without separating the layers, titrate the acidity, ifany, with standard 0.1 N NaOH
27、 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 to produce a persistent pink end point, discard theresults of the test. While taking precautions to avoid contami-nation from the apparatus and atmosphere, p
28、roceed as follows:Rinse the 100-mL graduated cylinder and the 500-mL bottleand glass stopper with neutral distilled water. To the bottle, add100 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 temperatu
29、re to between 15 and18.5C.Add 1 drop of 0.1 N NaOH solution, stopper, and shakevigorously for 10 s. Repeat the addition of 1 drop of NaOHsolution, stoppering, and shaking for 10 s, until a sharp pinkend point is secured. Repeat this procedure on a blank run with100 mL of the neutral distilled water.
30、12. Interpretation of Results and Calculation12.1 Unless otherwise indicated in the applicable specifica-tions, the test results 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 prod
31、uces 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 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 a
32、s 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 = 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
33、 is currently available.14. Keywords14.1 acidity; aromatic hydrocarbons5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChe
34、micals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D847082SUMMARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue (D 847 - 04)that may
35、impact the use of this standard. (Approved December 1, 2008.)(1) The Fahrenheit equivalent temperatures were removedfrom 11.2.(2) The mandatory “Units” statement was added as 1.3.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item me
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38、ng 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 is copyrighted by ASTM International, 100 Barr Harbor Drive, PO
39、 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).D847083
