1、Designation: D890 12 (Reapproved 2016)Standard Test Method forWater in Liquid Pine Chemicals1This standard is issued under the fixed designation D890; 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 pine chemicals, s
3、uch as turpentine, pinene, dipentene,pine oil, tall oil, and tall oil fatty acids. Three methods ofmoisture testing are included. The Karl Fisher titration methodis the preferred method for testing tall oil, Test Methods D803.1.1.1 The Karl Fischer Titration method is based on thereaction between wa
4、ter 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
5、may 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 com
7、pared with other sampleconstituents, in a toluene or xylene matrix so that water iscollected in 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 thesafe
8、ty 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:3D803 Test Methods for Testing Ta
9、ll OilD1364 Test Method for Water in Volatile Solvents (KarlFischer Reagent Titration Method)3. Significance and Use3.1 Many pine chemical products contain water as a resultof the processes used for their production. Typically refinedproducts such as terpenes, pine oil, tall oil fatty acids, anddist
10、illed 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 higher
11、levels.Moisture By Karl Fischer Titration(Preferred method)4. Apparatus4.1 Titration Vessel, preferably closed, with stirringcapabilities,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 0.0
12、001 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 written1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, an
13、d Applications and is the direct responsibility ofSubcommittee D01.34 on Pine Chemicals and Hydrocarbon Resins.Current edition approved Dec. 1, 2016. Published December 2016. Originallyapproved in 1946. Last previous edition approved in 2012 as D890 12. DOI:10.1520/D0890-12R16.2This procedure has be
14、en 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 by Smith, Bryant, and Mitchell, Journal, Am.Chemical Soc., Vol 61, 1939, p. 2407; and further modified by Axel Johansson,Svensk Pappersti
15、dning, 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 Fischer reagent is available from various laboratory supplies.Pyridine-free adaptations of the Karl Fischer reagent are available commerci
16、ally.3For 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.Copyright ASTM International, 100 Barr Harbor Drive, PO
17、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 Recommendations issued by
18、 the World Trade Organization Technical Barriers to Trade (TBT) Committee.1assuming a titer of 5 mg water/mL reagent. Recommendedadditions of water in this test method may need to be adjusteddepending on the titer of the reagent.5.2 MethanolACS grade.6. Standardization of Iodine Reagent6.1 Add metha
19、nol to the titration vessel, and titrate withreagent until 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
20、 water, weighed to the nearest 0.0001 g, tothe titration 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
21、 volume syringe may be used to introduce exactvolumes.6.3 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
22、 iodine reagent, inmilligrams of water per millilitre of reagent, as follows:T 5W 31000V(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
23、which will contain 50 mg orless water to the titration 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,
24、 % 5V 3TW 310(2)where:V = iodine reagent required for 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 mo
25、st highly refined pine chemical prod-ucts are essentially as specified in Test Method D1364.Itisnotpractical to measure the precision for moisture content of pinechemical products, since these test methods are applicable tomany of these products that vary widely in purity, and theprecision would var
26、y with the purity of each product.Moisture By Coulometric Titration10. Apparatus10.1 Coulometric Karl Fischer Titrator.10.2 Sample Vials, 8-mL or 4-dram.10.3 Medicine Dropper.10.4 Disposable Plastic Syringes, 1-cc with 16, 18 or 20gage needles.10.5 Syringe, 10 L.11. Reagents11.1 See 5.1.12. Instrume
27、nt Preparation12.1 Prepare and calibrate the instrument according 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
28、.4 Put the instrument in the STANDBY position.12.1.5 Slowly 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
29、the addition of water.12.1.8 Let the instrument stabilize for1hintheSTANDBYposition.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
30、 light comes on or amessage appears that the titration is complete.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 coulom
31、etric titrators require that the sample beinjected through 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.
32、13.1.2 Weigh the syringe with the sample to the nearest0.0001 g. Record this weight.D890 12 (2016)213.1.3 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 approximate
33、ly 4 mL of sample in a small samplevial. Do not allow the sample to touch the outside of the vial.13.3 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, i
34、ntroduce one to twodrops of sample into the coulometric titrator.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 310 000(3
35、)14.2 Report to the nearest 0.01 %.15. Precision and Bias15.1 It is not possible to specify the precision of thiscoulometric titration procedure for measuring the water contentof pine chemical products because the procedure is not widelyused and insufficient data could be generated to develop ameani
36、ngful precision and bias statement.Moisture By Azeotropic 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.1
37、6.3 Condenser, connected to the flask and discharging intoa 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 flas
38、k with a moisture trap and a refluxcondenser.18.2 Add 150 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 du
39、ring the refluxperiod, and with four 5-mL portions of solvent 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, % 5VW3100
40、 (4)where:V = volume of water, mLW = weight of sample, g.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 pine chemical products because this procedure is nolonger widely
41、 used and insufficient data could be generated todevelop a meaningful precision and bias statement.21. Keywords21.1 azeotropic; coulometric, Karl Fischer; moisture; navalstores; pine chemicals; pine oil; tall oil; terpenes; turpentine;waterASTM International takes no position respecting the validity
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