1、Designation: D1631 10Standard 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 revision, the year of l
2、ast 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 This test method covers the determina
3、tion of water inphenol and related materials such as cresols, xylenols, naph-thalene, pyridine, and quinoline.1.2 This test method has been found applicable to a varietyof materials varying in water content from 100 mg/kg tosolutions containing a relatively high percent of water.1.3 In determining t
4、he 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 regarded asstandard. No other units of measurement are included in thisstandard.1.5 This
5、 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 determine the applica-bility of regulatory limitations prior to use. For specific hazardsta
6、tements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D1364 Test Method for Water in Volatile Solvents (KarlFischer Reagent Titration Method)D3437 Practice for Sampling and Handling Liquid CyclicProductsD3852 Practice for Sampling and Handling Phenol,Cresols, and Cresylic AcidD4790 Termi
7、nology ofAromatic Hydrocarbons and RelatedChemicalsD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 Other Document:3OSHA Regulations, 2
8、9 CFR paragraphs 1910.1000 and1910.12003. Terminology3.1 See Terminology D4790 for 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:I21 SO21
9、H2O2HI 1 SO3(1)4.1.1 Sufficient pyridine is present in the reagent to consumethe hydriodic acid and sulfur trioxide:4.1.2 The pyridine sulfur trioxide salt reacts with the metha-nol, this preventing a second mole of water from beingconsumed:4.2 When the pyridine solution contains water and the sulfu
10、rdioxide is titrated with iodine in methanol solution, the1This 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 Jan. 1, 2010. Published Ja
11、nuary 2010. Originallyapproved in 1959. Last previous edition approved in 2004 as D1631 99 (2004).DOI: 10.1520/D1631-10.2For 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
12、 to the 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 20401.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Bar
13、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.platinum 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
14、This test method is particularly useful for determiningsmall 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. Interferen
15、ces6.1 This test method is not applicable in 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. Apparatus
16、7.1 The apparatus shall be assembled as shown 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
17、, it is intended that all reagents shallconform 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
18、its use without lessening the accuracy ofthe 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
19、 SolutionPlace 4000 mL of refined gradepyridine 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 g
20、lass tubing that extends almost to the bottom 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 co
21、ol. Fit the vent tube with a drying tube and 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.
22、3, and 8.4it is permissible to employ the single 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
23、 refer to PracticeD3437.9. Hazards9.1 Consult current OSHA regulations suppliers MaterialSafety Data Sheets and local regulations for all materials usedin this test method.9.2 Phenol, pyridine, and related materials are extremelytoxic when ingested and corrosive to the skin. Appropriateprecaution mu
24、st 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 be taken in sampling to preclude anypossibility of contamination with at
25、mospheric moisture adher-ing to the walls of the pipet.10.3 The sample size recommended, on the basis of watercontent expected is as follows:4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by
26、 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.FIG. 1 Titration AssemblyD1631 102Expected Water Content, % Size of Specimen
27、, g0.01 to 0.03 500.03 to 0.3 250.3to0.6 100.6to1.0 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
28、 automatic titration apparatusis used, a small 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
29、ammeter reads a maximumvalue, about 130 A. Remove 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 dryi
30、ng tube.11.2 Titrate with the iodine solution, 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 ofw
31、ater as follows: Accurately weigh a small aluminum 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
32、 so that the powder falls freely into the liquid 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 andweigh
33、t of tartrate used.11.3 Calculate the water equivalent 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 forstandard
34、izing:F 5 15.66S/B (3)where S = tartrate used, 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, f
35、urtheradditions of specimen and titration may 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
36、desiccator or attached to the buret to cool withthe 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 tit
37、ration.NOTE 3Visual observation of the end point 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 conf
38、used with the true end point, which is brown. 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 ofthe specimen,
39、 mLD = weight of specimen used, g14. Precision and Bias14.1 Intermediate Precision (formerly calledRepeatability)Duplicate results should be considered suspectif they differ by more than the following:Range, %Intermediate Precision(By Same Operator)Reproducibility(By Two Different Laboratories)0.01
40、to 0.12 0.0035 0.02114.1.1 Data on which these precision values are based aregiven in the 1959 Report of Committee D16, Proceedings,ASTM, Vol 59, 1959.14.2 BiasSince there is no accepted reference materialsuitable for determining the bias in this test method, bias hasnot been determined.15. Quality
41、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 statistical quality control practices.15.1.2 A quality control sample is a stable mate
42、rial 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 theyconfirm the validity of test results.15.1.4 When there are not QA/QC protocols established inthe
43、 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; quinoline; water; xylenolsD1631 103SUMMARY OF CHANGESCommittee D16 has identified the location of select
44、ed changes to this standard since the last issue(D1631 - 99 (2004) that may impact the use of this standard. (Approved January 1, 2010.)(1) Added Quality Guidelines Section 15.(2) Added a metric statement section 1.4.(3) Added Guide D6809 to list of Referenced Documents section 2.1.ASTM Internationa
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47、ddressed 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 on Standards,
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