1、Designation: D1631 10 (Reapproved 2018)1Standard Test Method forWater in Phenol and Related Materials by the IodineReagent Method1This standard is issued under the fixed designation D1631; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, 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 U.S. Department of Defense.1NOTESection 14 was editor
3、ially corrected in February 2018.1. Scope*1.1 This test method covers the determination of water inphenol and related materials such as cresols, xylenols,naphthalene, pyridine, and quinoline.1.2 This test method has been found applicable to a varietyof materials varying in water content from 100 mg/
4、kg tosolutions containing a relatively high percent of water.1.3 In determining the conformance of the test results usingthis method to applicable specifications, results shall berounded off in accordance with the rounding-off method ofPractice E29.1.4 The values stated in SI units are to be regarde
5、d asstandard. No other units of measurement are included in thisstandard.1.5 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, health, and environmental practice
6、s and deter-mine the applicability of regulatory limitations prior to use.For specific hazard statements, see Section 9.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelop
7、ment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1364 Test Method for Water in Volatile Solvents (KarlFischer Reagent Titration Method)D3437 Practice for Sampling
8、 and Handling Liquid CyclicProductsD3852 Practice for Sampling and Handling Phenol, Cresols,and Cresylic AcidD4790 Terminology of Aromatic Hydrocarbons and RelatedChemicalsD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for
9、 Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Other Document:3OSHA Regulations, 29 CFR paragraphs 1910.1000 and1910.12003. Terminology3.1 See Terminology D4790 for
10、definition of terms used inthis test method.4. Summary of Test Method4.1 When solutions of iodine in methanol and of sulfurdioxide in pyridine are mixed in the presence of water, thefollowing reaction occurs:I21SO21H2O2HI1SO3(1)4.1.1 Sufficient pyridine is present in the reagent to consumethe hydrio
11、dic acid and sulfur trioxide:1This test method is under the jurisdiction of ASTM Committee D16 onAromatic, Industrial, Specialty and Related Chemicals and is the direct responsi-bility of Subcommittee D16.02 on Oxygenated Aromatics.Current edition approved Feb. 15, 2018. Published February 2018. Ori
12、ginallyapproved in 1959. Last previous edition approved in 2010 as D1631 10. DOI:10.1520/D1631-10R18E01.2For 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 standard
13、s Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office, Superintendent ofDocuments, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:/www.access.gpo.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr
14、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommen
15、dations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14.1.2 The pyridine sulfur trioxide salt reacts with themethanol, this preventing a second mole of water from beingconsumed:4.2 When the pyridine solution contains water and the sulfurdioxide is titrated with
16、iodine in methanol solution, theplatinum electrodes remain polarized until all the water reacts.A slight excess of iodine depolarizes the electrodes, allowingcurrent to flow through the microammeter which indicates theend point.5. Significance and Use5.1 This test method is particularly useful for d
17、eterminingsmall amounts of water in hygroscopic materials. This testmethod is suitable for setting specifications on materialsreferenced in the scope. It may also be used as an internalquality control tool and in development or research work.6. Interferences6.1 This test method is not applicable in
18、the presence ofmercaptans, peroxides, or appreciable quantities of aldehydesor amines.6.2 If ketones are present in the sample, interference fromthem can be avoided by employing the glycol-pyridine samplesolvent specified in Test Method D1364.7. Apparatus7.1 The apparatus shall be assembled as shown
19、 in Fig. 1.Any suitable modification permitting equal facility and accu-racy may be used. Automatic titration equipment is commer-cially available and may be used.8. Reagents8.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, it is intended that all reagents shallconfo
20、rm to the specifications of the Committee on AnalyticalReagents of the American Chemical Society, where suchspecifications are available.4Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe
21、determination.8.2 Iodine SolutionDissolve 150 g of iodine (I2) crystalsin 3 L of anhydrous methanol. Place the solution in the reagentbottle connected to the buret as shown in Fig. 1.8.3 Methanol, anhydrous, containing less than 0.05 % wa-ter.8.4 Pyridine SolutionPlace 4000 mL of refined gradepyridi
22、ne in a 5000-mL distilling flask. Distill over and discard400 mL of forecut at atmospheric pressure. Distill off 3400 mLof center cut and transfer to a suitable glass bottle fitted with atwo-hole stopper. Through one hole of the stopper insert apiece of glass tubing that extends almost to the bottom
23、 of thebottle; through the other hole insert a short piece of glasstubing to serve as a vent. Through the long tube add 400 g ofrefrigerant-grade sulfur dioxide (SO2) dried through concen-trated sulfuric acid (H2SO4sp gr 1.84), and allow the solutionto cool. Fit the vent tube with a drying tube and
24、an aspiratorbulb; connect the long tube with an adapter suitable forintroducing the reagent into the titration flask. For conveniencein measuring, a suitable reservoir may be placed in the system.NOTE 1In place of the divided reagents described in 8.2, 8.3, and 8.4it is permissible to employ the sin
25、gle solution reagent specified in TestMethod D1364 or commercial Karl Fischer reagents. Pyridine-free re-agents are available from various laboratory suppliers and may be used ifsuitable for the material being tested.8.5 When handling Karl Fischer reagent refer to PracticeD3437.9. Hazards9.1 Consult
26、 current OSHA regulations suppliers SafetyData Sheets and local regulations for all materials used in thistest method.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical
27、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.FIG. 1 Titration AssemblyD1631 10 (2018)129.2 Phenol, pyridine, and related materials are extremely
28、toxic when ingested and corrosive to the skin. Appropriateprecaution must be exercised when handling them.10. Sampling10.1 Sample in accordance with Practice D3852 for propersampling and handling of phenol and related materials ana-lyzed by this test method (see 9.1 and 9.2.).10.2 Precautions must b
29、e taken in sampling to preclude anypossibility of contamination with atmospheric moisture adher-ing to the walls of the pipet.10.3 The sample size recommended, on the basis of watercontent expected is as follows:Expected Water Content, % Size of Specimen, g0.01 to 0.03 500.03 to 0.3 250.3to0.6 100.6
30、to1.0 51.0to5.0 25.0 to 10.0 110.0 to 20.0 0.511. Standardization of Sulfur DioxideIodine Reagent11.1 By means of pressure from the aspirator bulb, transfersufficient pyridine solution (Warningsee 9.2) to the titrationflask to cover the electrodes. If an automatic titration apparatusis used, a small
31、 amount of methanol may be added to thepyridine to improve the response of the titrator. Turn on themagnetic stirrer and turn the “zero-set” knob until a reading of70 A is obtained on the ammeter. Add the iodine solutiondropwise from the buret until the ammeter reads a maximumvalue, about 130 A. Rem
32、ove the drying tube from the sidearmand quickly introduce an amount of distilled water, or water ofequivalent purity, at least equal to that to be determined,weighed to the nearest 0.1 mg by means of a suitable weighingpipet. Immediately replace the drying tube.11.2 Titrate with the iodine solution,
33、 approaching the endpoint dropwise until the maximum value, about 130 A, isobtained on the ammeter. The standardization should berepeated daily. If desired, a suitable accurately weighed amountof sodium tartrate dihydrate reagent may be used in place ofwater as follows: Accurately weigh a small alum
34、inum weigh-ing dish containing about 0.20 to 0.22 g of powdered sodiumtartrate dihydrate (Na2C4H4O62H2O) to the nearest 0.1 mg.Remove the stopper from the titration flask and introduce thetartrate by inserting the spout into the opening and gentlytapping so that the powder falls freely into the liqu
35、id withoutcontacting the side walls. Do not brush out the dish: accuratelyreweigh it and calculate the weight of tartrate used bydifference. Quickly reseal the flask, turn on the stirrer, andtitrate to the end point. Record the volume of reagent andweight of tartrate used.11.3 Calculate the water eq
36、uivalent of the sulfur dioxide-iodine reagent as follows:F 5 100A/B (2)where:F = water equivalent of the reagent, g/100 mLA = water added, gB = volume of reagent used for the titration, mLIf sodium tartrate dihydrate is used in place of water forstandardizing:F 5 15.66S/B (3)where S = tartrate used,
37、 g.12. Procedure12.1 Repeat the procedure described in Section 11 adding,instead of water, an amount of specimen selected according toSection 10. Record all weighings to the nearest 0.1 mg.As longas an excess of pyridine remains in the titration flask, furtheradditions of specimen and titration may
38、be made. (WarningSee 9.2.)NOTE 2The titration flask may be removed and cleaned betweenspecimens. Washing should be followed by an alcohol or acetone rinse anddrying in a ventilated oven at 100 to 130C for several hours. The cleanflask may be cooled in a desiccator or attached to the buret to cool wi
39、ththe openings closed with drying tubes. If a series of specimens is to betested, it is preferable to continue additions of specimens and titration (andaddition of pyridine if necessary) until the volume of liquid in the flask istoo great for further titration.NOTE 3Visual observation of the end poi
40、nt may be used in place ofthe more precise electrometric method described if the solution is verylightcolored. During the titration the solution turns yellow after theaddition of the first few millilitres of the reagent. This color change mustnot be confused with the true end point, which is brown.
41、The transitionfrom yellow to brown is quite sharp and easily reproducible.13. Calculation13.1 Calculate the amount of water in the specimen asfollows:Water, weight% 5 CF/D (4)where:C = sulfur dioxide-iodine reagent required for titration of thespecimen, mLD = weight of specimen used, g14. Precision
42、and Bias14.1 Intermediate PrecisionTwo results, each the mean ofduplicate determinations, obtained by the same analyst shouldbe considered suspect if they differ by more than 0.0035 %.14.2 ReproducibilityTwo results, each the mean of dupli-cate determinations, obtained by analysts in different labor
43、ato-ries should be considered suspect if they differ by more than0.021 %.14.3 Data on which these precision values are based aregiven in the 1959 Report of Committee D16, Proceedings,ASTM, Vol 59, 1959.14.4 BiasSince there is no accepted reference materialsuitable for determining the bias in this te
44、st method formeasuring water in phenol, bias has not been determined.15. Quality Guidelines15.1 Laboratories shall have a quality control system inplace.15.1.1 Confirm the performance of the test instrument ortest method by analyzing a quality control sample followingthe guidelines of standard stati
45、stical quality control practices.D1631 10 (2018)1315.1.2 A quality control sample is a stable material isolatedfrom the production process and representative of the samplebeing analyzed.15.1.3 When QA/QC protocols are already established inthe testing facility, these protocols are acceptable when th
46、eyconfirm the validity of test results.15.1.4 When there are not QA/QC protocols established inthe testing facility, use the guidelines described in GuideD6809 or similar statistical quality control practices.16. Keywords16.1 cresols; iodine; Karl Fischer method; naphthalene;phenol; pyridine; quinol
47、ine; water; xylenolsSUMMARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue(D1631 10) that may impact the use of this standard. (Approved February 15, 2018.)(1) Added Practice E691 to section 2.1.ASTM International takes no position respe
48、cting 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 riskof infringement of such rights, are entirely their own responsibility.This st
49、andard 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 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 hearing you shouldmake your views known to the ASTM Committee
