ASTM D890-1998(2008) Standard Test Method for Water in Liquid Naval Stores《液体松脂中水含量的标准试验方法》.pdf

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1、Designation: D 890 98 (Reapproved 2008)Standard Test Method forWater in Liquid Naval Stores1This standard is issued under the fixed designation D 890; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num

2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the quantitative determinationof dissolved or occluded water present in any proportion inliquid naval stores, suc

3、h as turpentine, pinene, dipentene, pineoil, tall oil, and tall oil fatty acids. Three methods of moisturetesting are included. The Karl Fisher titration method is thepreferred method for testing tall oil, Test Methods D 803.1.1.1 The Karl Fischer Titration method is based on thereaction between wat

4、er and a complex reagent2consisting ofiodine, sulfur dioxide, pyridine, and methanol, whereby theiodine is converted to a colorless compound. The appearanceof a persistent iodine color in the reaction mixture indicates thecomplete removal of free water by reaction with the reagent,and the endpoint m

5、ay be measured colorimetrically. Automatictitrators find this endpoint by the restoration of a currentstrength when the resistance provided by the presence of wateris eliminated. Amperometric automatic titrators find this end-point by detecting the current flow that occurs once water iseliminated.1.

6、1.2 The coulometric titration method determines watercontent by electronic integration of a current sufficient togenerate the precise amount of iodine from the required reagentto react with the water in the sample.1.1.3 The azeotropic method utilizes the relatively lowboiling point of water, as comp

7、ared with other sample con-stituents, in a toluene or xylene matrix so that water is collectedin a trap and measured.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesaf

8、ety 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.2. Referenced Documents2.1 ASTM Standards:3D 803 Test Methods for Testing

9、Tall OilD 1364 Test Method for Water in Volatile Solvents (KarlFischer Reagent Titration Method)3. Significance and Use3.1 Many naval stores products contain water as a result ofthe processes used for their production. Typically refinedproducts such as terpenes, pine oil, tall oil fatty acids, anddi

10、stilled tall oil contain only traces of water, but crude tall oilmight contain 0.5 to 2.5 % of water. Although the Karl Fischerand coulometric methods are most applicable to low levels ofmoisture, these can be and are used at higher levels. Theazeotropic distillation method is generally used at high

11、erlevels.Moisture By Karl Fischer Titration(Preferred method)4. Apparatus4.1 Titration Vessel, preferably closed, with stirring capa-bilities,4.2 Buret, capable of being read at 0.1 mL divisions, orautomatic buret, or4.3 Automatic Karl Fischer titrator.4.4 Balance, capable of weighing to the nearest

12、 0.0001 g.5. Reagents5.1 Karl Fischer Reagent, or Other Suitable Reagent, suchas Pyridine-free Adaptations of Karl Fischer Reagent. Re-agents vary in strength (titer). This test method is writtenassuming a titer of 5 mg water/mL reagent. Recommendedadditions of water in this test method may need to

13、be adjusteddepending on the titer of the reagent.5.2 MethanolACS grade.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.34 on Naval Stores.Current edition approved June 1, 2

14、008. Published June 2008. Originallyapproved in 1946. Last previous edition approved in 2003 as D 890 - 98 (2003).2This procedure has been adapted from the method of Karl Fischer published inZeitschrift fr Angewandte Chemie, Vol 48, 1935, p. 395; Chemical Abstracts,Vol29, 1935 p. 6532; as modified b

15、y Smith, Bryant, and Mitchell, Journal, Am.Chemical Soc., Vol. 61, 1939, p. 2407; and further modified by Axel Johansson,Svensk Papperstidning, Vol 50, No. 11B, 1947, p. 124; see also Publication 19 of theSwedish Wood Research Institute, Wood Chemistry and Paper Technique (Stock-holm) (1947). Karl F

16、ischer reagent is available from various laboratory supplies.Pyridine-free adaptations of the Karl Fischer reagent are available commercially.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards vol

17、ume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Standardization of Iodine Reagent6.1 Add methanol to the titration vessel, and titrate withreagent un

18、til the lemon-yellow color just changes to a red-brown color, or, if an automatic titrator is used, until thereadings indicate no free water present. The titration vessel isnow ready for titrating, and is considered conditioned.6.2 Add a drop of water, weighed to the nearest 0.0001 g, tothe titratio

19、n vessel by use of a transfer pipet, or a weighingpipet, weighing the pipet before and after the addition. Eachdrop will weigh approximately 0.03 g and will require roughly6 mL of titrant having a titer of 5 mg/mL. Alternatively, a25-L, or other volume syringe may be used to introduce exactvolumes.6

20、.3 Titrate with reagent until the lemon-yellow color justchanges to a red-brown color, or, if an automatic titrator isused, until the readings indicate no free water present. Recordthe mL of titrant used.6.4 Calculate the water equivalent of the iodine reagent, inmilligrams of water per millilitre o

21、f reagent, as follows:T 5W 3 1000V(1)where:T = water equivalent of the iodine reagent, mg/mL,W = weighed water added, in g, andV = iodine reagent, mL.7. Procedure7.1 Condition the titration vessel, as described in 6.1.7.2 Add an amount of sample which will contain 50 mg orless water to the titration

22、 vessel.7.3 Titrate to a red-brown color end point, as with previoustitrations, or, if an automatic titrator is used, titrate according tothe instruments operating instructions.8. Calculation8.1 Calculate the percentage of water as follows:Water, % 5V 3 TW 3 10(2)where:V = iodine reagent required fo

23、r the titration of the sample,in mL,T = (titer), water equivalent of the iodine reagent, andW = sample used, g.8.2 Report to the nearest 0.01 %.9. Precision and Bias9.1 The precision and bias of this test method for measuringwater content of the most highly refined naval stores productsare essential

24、ly as specified in Test Method D 1364.Itisnotpractical to measure the precision for moisture content ofNaval Stores products, since these test methods are applicableto many of these products that vary widely in purity, and theprecision would vary with the purity of each product.Moisture By Coulometr

25、ic Titration10. Apparatus10.1 Coulometric Karl Fischer Titrator.10.2 Sample Vials, 8-mL or 4-dram10.3 Medicine Dropper.10.4 Disposable Plastic Syringes, 1-cc with 16, 18 or 20gage needles.10.5 Syringe,10L11. Reagents11.1 See 5.1.12. Instrument Preparation12.1 Prepare and calibrate the instrument acc

26、ording to themanufacturers operating instructions. This generally includes:12.1.1 Clean and assemble the titration chamber.12.1.2 Pour titration solution into the chamber.12.1.3 Add the iodine generator solution to the generatorassembly.12.1.4 Put the instrument in the STANDBY position.12.1.5 Slowly

27、 add water, or a solution containing water,(normally by injection with a syringe).12.1.6 Continue the addition until the instrument indicatesthat excess water is present, usually by a light or liquid crystaldisplay (LCD) reading.12.1.7 Stop the addition of water.12.1.8 Let the instrument stabilize f

28、or1hintheSTANDBYposition.12.2 Verify the instrument by injecting a known amount ofwater, usually 1 L to 5 L, below the surface of the titrationsolution.12.3 Put the instrument in the TITRATE or RUN positionand record the reading when the END light comes on or amessage appears that the titration is c

29、omplete.12.4 Record the reading. This reading is usually in micro-grams or milligrams of water and should be within 65 % of theamount of water added. Example: for 5 L of water the readingshould be 5000 g 6 250 g.13. Procedure13.1 Some coulometric titrators require that the sample beinjected through

30、a septum. If this is the case proceed as follows(for instruments that do not require through-septum injections,go to 13.2):13.1.1 Draw approximately 0.5 mL of sample into a 1-ccdisposable syringe. Wipe the needle clean with a dry papertowel.13.1.2 Weigh the syringe with the sample to the nearest0.00

31、01 g. Record this weight.13.1.3 Inject about 0.1 to 0.2 mL of the sample into thetitrator. Withdraw the syringe.13.1.4 Weigh the syringe to the nearest 0.0001 g and recordthis weight.13.1.5 Proceed to 13.6.13.2 Add approximately 4 mL of sample in a small samplevial. Do not allow the sample to touch

32、the outside of the vial.D 890 98 (2008)213.3 Put a medicine dropper into the vial, and weigh thevial, sample, and medicine dropper together on an analyticalbalance to the nearest 0.0001 g. Record this weight.13.4 Using the medicine dropper, introduce one to twodrops of sample into the coulometric ti

33、trator.13.5 Put the medicine dropper back in the vial, and weigh tothe nearest 0.0001 g. Record this weight.13.6 Begin the titration.14. Calculation14.1 Calculate the percentage of water as follows:Water, % 5Water, gSample Weight, g 3 10 000(3)14.2 Report to the nearest 0.01 %.15. Precision and Bias

34、15.1 It is not possible to specify the precision of thiscoulometric titration procedure for measuring the water contentof naval stores products because the procedure is not widelyused and insufficient data could be generated to develop ameaningful precision and bias statement.Moisture By Azeotropic

35、Distillation16. Apparatus16.1 Flask, 1-L, short-neck, round-bottom glass flask orErlenmeyer flask. Use of smaller flasks should be accompaniedby reductions in sample size and solvent.16.2 Electric Mantle, with variable-resistance controller.16.3 Condenser, connected to the flask and discharging into

36、a trap.16.4 Trap, 5-mL, subdivided into 0.1 mL divisions, witheach 1 mL line numbered.17. Reagents17.1 Toluene or XyleneReagent grade, moisture free.18. Procedure18.1 Weigh 100 g of sample into the flask. Add a fewboiling stones. Fit the flask with a moisture trap and a refluxcondenser.18.2 Add 150

37、mL of toluene or xylene to the flask and fillthe moisture trap with the solvent.18.3 Heat gently until the solvent begins to reflux. Continuevigorous refluxing for 2 h. Wash the condenser down with5-mL portions of solvent from time to time during the refluxperiod, and with four 5-mL portions of solv

38、ent at the end. Adrop of water on the condenser may be dislodged with a finewire or a stirring rod wet with methanol.18.4 Record the volume of water in the trap.19. Calculation19.1 Calculate the percentage of water as follows:Water, % 5VW3 100 (4)where:V = volume of water, mLW = weight of sample, g.

39、19.2 Report to the nearest 0.1 %.20. Precision and Bias20.1 It is not possible to specify the precision of thisazeotropic distillation procedure for measuring the watercontent of naval stores products because this procedure is nolonger widely used and insufficient data could be generated todevelop a

40、 meaningful precision and bias statement.21. Keywords21.1 azeotropic; coulometric, Karl Fischer; moisture; navalstores; pine oil; tall oil; terpenes; turpentine; waterASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin th

41、is 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 standard is subject to revision at any time by the responsible technical committee and must b

42、e 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 theres

43、ponsible 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 Box C700, W

44、est 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 890 98 (2008)3