1、Designation: D 464 05Standard Test Methods forSaponification Number of Naval Store Products IncludingTall Oil and Other Related Products1This standard is issued under the fixed designation D 464; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the determination of thesaponification number of tall oil and produ
3、cts obtained by thefractionation of tall oil such as rosin, fatty acids and distilledtall oil as defined in Terminology D 804. These test methodsare also applicable to gum and wood rosin. Two test methodsare covered as follows:1.1.1 Test method using a potentiometric method, and1.1.2 Test method usi
4、ng an internal indicator method.1.2 The potentiometric method is suitable for use with bothlight- and dark-colored test samples. It should be consideredthe referee method. The internal indicator method is suitablefor use only with light- and medium-colored test samples. Itshould be considered the al
5、ternate method.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 with its use. It is theresponsibility of the user of this standard to
6、 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 803 Test Methods for Testing Tall OilD 804 Terminology Relating to Naval Stores, Including TallOil and Related ProductsE70 Test Met
7、hod for pH of Aqueous Solutions With theGlass Electrode3. Significance and Use3.1 These test methods are designed to broaden the scope ofthe earlier editions of the test method by the inclusion of tall oiland tall oil derived products as test materials and is referencedin Test Methods D 803.3.2 The
8、saponification number is an important property oftall oil and the products obtained by the fractionation of tall oil.It is the test method widely used to determine the total acidcontent, both free and combined, of these products.3.3 The potentiometric test method should be used when themost reproduc
9、ible results are required.4. Preparation of Sample4.1 If the sample for analysis is rosin, it shall consist ofsmall pieces of rosin chipped from a freshly exposed part of alump or lumps, and thereafter crushed to facilitate weighingand dissolution. Prepare the sample the same day on which thetest is
10、 begun in order to avoid changes in properties due tosurface oxidation. Changes are very pronounced on groundrosin that has a large surface area exposed to air. Existing rosindust and powdered rosin must not be used.4.2 If the sample is a nonhomogeneous liquid, heat theentire sample in a closed cont
11、ainer fitted with a capillary ventor the equivalent. Some kind of agitation, even if doneoccasionally by hand, saves much time. Heat by immersion inopen steam or hot water bath to avoid overheating. Whendealing with crystallized rosin, a higher temperature of ap-proximately 160C may be needed. Remov
12、e samples fortesting only when the entire sample is homogeneous and hasbeen well stirred.5. Purity of Reagents and Water5.1 Unless otherwise indicated, it is intended that all re-agents shall conform to the specifications established by theCommittee on Analytical Reagents of the American Chemical1Th
13、ese test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D01.34 on Naval Stores.Current edition approved Dec. 1, 2005. Published January 2006. Originallyapproved in 1937. Last previous
14、 edition approved in 1999 as D 464 95 (1999).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.1Copyright ASTM
15、International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Society,3where such specifications are available. References towater shall be understood to mean distilled or deionized water.POTENTIOMETRIC TEST METHOD (Referee Method)6. Apparatus6.1 Erlenmeyer Flask
16、, 250-mL, of chemically resistantglass4with standard-taper glass joint.6.2 Hot Plates.6.3 Water-Cooled Reflux Condenser, with standard-taperjoint to fit the Erlenmeyer flask.6.4 Buret, with 0.1 mL divisions.6.5 Stirrer, variable-speed, with a polytetrafluoroethylene(PTFE) coated magnetic stir bar.6.
17、6 Delivery or Volumetric Pipet, 50-mL constant.6.7 PTFE Boiling Stones, or glass beads.6.8 Beaker, 400-mL tall-form.6.9 Glass Electrode pH Meter, conforming to the require-ments of Test Method E70. Use either standard or alkali-resistant electrodes for this test. Alternatively, an automaticpotentiom
18、etric titrator may be used.7. Reagents7.1 Ethyl Alcohol (95 %) denatured by Formula No. 3A orNo. 30 of the U.S. Bureau of Internal Revenue.57.2 Isopropyl Alcohol, Reagent grade.7.3 Toluene, Reagent grade.7.4 Alkali Solution, Standard Alcoholic (0.5 N)Dissolve33 g of potassium hydroxide (KOH), prefer
19、ably in pellet form,in ethyl alcohol conforming to 7.1 and dilute to 1 L with 3Aethyl alcohol. Standardize to 60.001 N by dissolving potas-sium acid phthalate (C6H4COOKCOOH) in 60 mL of waterfollowed by the addition of 40 mL of isopropyl alcohol. Oncethe potassium acid phthalate has dissolved, 2.553
20、 g of potas-sium acid phthalate will be neutralized by 25.0 mL of 0.5 NKOH solution. Protect the standardized solution against evapo-ration and absorption of carbon dioxide (CO2) from the air. Thesolution should be standardized either potentiometrically orcolorimetrically using either phenolphthalei
21、n or thymol blue asthe indicator. The standardization should use the same equip-ment and techniques as used in the actual saponificationnumber determination.7.5 Acid, Standard (0.5 N)Standardize a 0.5 N solution ofHCl to 60.001 N by any accepted procedure.7.6 Borax Buffer, Standard Solution (0.01 M,
22、 pH 9.18 at25C)Dissolve 3.81 6 0.01 g of disodium tetraborate(Na2B40710 H2O) in water and dilute to 1 L in a volumetricflask. Use the special grade6of borax prepared specifically foruse as a pH standard.As an alternative, commercially availablebuffer with a pH between 9 and 11 may be used.8. Procedu
23、re8.1 Transfer 2.95 to 3.05 g of the sample, weighed to thenearest 0.001 g, to the Erlenmeyer flask. If necessary, 10 mL ofisopropyl alcohol-toluene solution (1:1) can be added to theflask to predissolve the sample. Using a constant delivery pipetor volumetric pipet add 50.0 mL of the alkali solutio
24、n. Addseveral PTFE boiling stones or glass beads and connect theflask to the condenser.8.2 Place the flask on a hot plate and maintain the solutionat reflux for 1 h. At the end of the reflux time, while the sampleis still warm, transfer the contents of the Erlenmeyer flask intoa 400-mL tall-form bea
25、ker rinsing with 100 mL of isopropylalcohol in three washings. Place samples on a heated surfaceuntil they can be titrated. In order to avoid highly variableresults, make sure that the temperature of the samples isapproximately 60 to 70C when titrated.8.3 Titrate with 0.5 N acid, recording the buret
26、 and pH meterreadings. Sufficient acid may be added initially to bring the pHof the solution to about 12. Allow sufficient time for theelectrode system to reach equilibrium. Add acid in 1.0-mLportions until the change in pH per addition exceeds 0.3 pHunits. Reduce the additions of acid to 0.1 mL or
27、smaller untilthe end point has been passed, as indicated by a significantdecrease in pH units per 0.1 mL of acid added. Continue thetitration with 1.0-mLportions until it becomes apparent that theinflection point has been well defined.8.4 Determine the inflection point (point of maximumchange in pH
28、per millilitre of acid) to the nearest 0.05 mL. Thismay be found by inspection of a plot of pH against millilitresof acid added. For greater accuracy, a plot may be made of thechange in pH per millilitre of acid added, against the pH. Theinflection point is considered as the end point of the titrati
29、on.Alternatively if an automatic titrator is used, the endpoint iseither the inflection point from the plotted curve or the pHdetermined to coincide with the inflection point in the labora-tory performing the analysis. The value of 10.8 is the averagepH encountered at the inflection point by this pr
30、ocedure.8.5 BlankMake duplicate blank determinations using 50.0mL of the alkali solution. If 10 mL of isopropyl alcohol-toluenesolution (1:1) is used as a solvent in 8.1, then use the sameamount in the blank determination.9. Calculation and Report9.1 Calculate the saponification number, expressed as
31、 mil-ligrams of KOH per gram of sample as follows:Saponification number 5 B 2 A! N 3 56.1/Cwhere:B = acid required for titration of the blank, mL,A = acid required for titration of the sample, mL,N = normality of the acid, and3Reagent Chemicals, American Chemical Society Specifications, AmericanChem
32、ical Society, Washington, DC. For suggestions on the testing of reagents notlisted by 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), Rock
33、ville,MD.4Alkali-resistant glasses, or equivalent, are suitable for this purpose. Borosilicateflasks may be used, but they should either be new or be cleaned by rinsing with ahot solution of HF (2 or 3 %). This removes from the flasks the adhering partiallydisintegrated silicates that would interfer
34、e with the determination.5Available from the U.S. Bureau of Alcohol, Tobacco, and Firearms, DistilledSpirits and Tobacco Branch, 1200 Pennsylvania Ave., NW, Washington DC 20226.6The National Institute of Standards and Technology standard sample of boraxNo. 187 is satisfactory for this purpose.D46405
35、2C = sample weight, g.Report the saponification number to the nearest wholenumber.INTERNAL INDICATOR TEST METHOD (AlternativeMethod)10. Apparatus10.1 Same apparatus as 6.1-6.7.11. Reagents11.1 Phenolphthalein Indicator SolutionDissolve1gofphenolphthalein in 100 mL of methanol.11.2 Thymol Blue Indica
36、tor SolutionDissolve 0.1 g ofthymol blue in 100 mL of methanol.11.3 Same as 7.1-7.5.12. Procedure12.1 Transfer 2.95 to 3.05 g of the sample, weighed to thenearest 0.001 g to the Erlenmeyer flask. If necessary, 10 mL ofisopropyl alcohol-toluene (1:1) can be added to the flask topredissolve the sample
37、. Using a constant delivery pipet orvolumetric pipet, add 50.0 mL of the alkali solution. Addseveral PTFE boiling stones or glass beads, and connect theflask to the condenser.12.2 Place the flask on a hot plate and maintain the solutionat reflux for 1 h.At the end of the reflux time, place samples o
38、na heated surface until they can be titrated. In order to avoidhighly variable results, make sure that the temperature of thesamples is approximately 60 to 70C when titrated.12.3 Titrate with 0.5 N HCl using either 4 to 5 drops ofphenolphthalein indicator to a clear endpoint or 4 to 5 drops ofthymol
39、 blue indicator. With thymol blue, the end point isindicated when the color undergoes the first change from adistinct blue to a blue-green, just short of clear yellow. Ifneeded, more indicator may be used. Read the buret to0.05-mL titrant. If less than 20 mL of titrant is consumed,decrease the sampl
40、e size.12.4 BlankMake duplicate blank determinations using50.0 mL of the alkali solution and following the sameprocedure as for the sample. If 10 mL of isopropyl alcohol-toluene solution (1:1) was used as a solvent in 12.1, then usethe same amount in the blank determinations.13. Calculation and Repo
41、rt13.1 Calculate the saponification number as described inSection 9. Report the results to the nearest whole number.14. Precision and Bias714.1 PrecisionThe precision of these test methods wasdetermined through a multilaboratory round-robin testing pro-gram using two substances: tall oil fatty acid
42、and distilled talloil. The results were combined to give the conclusions givenbelow.14.1.1 Single operator precisionThe single operator stan-dard deviation was found to be 0.9 %. Therefore, results of twoproperly conducted tests by the same operator on the samesample should not differ by more than 2
43、.5 %.14.1.2 Multilaboratory precisionThe multilaboratorystandard deviation was found to be 2.2 %. Therefore, results oftwo properly conducted tests on the same sample from twolaboratories should not differ by more than 6.1 %.14.2 BiasThe procedure in this test method for measuringacid number has no
44、bias because the value of the acid numberis defined only in the terms of these test methods.15. Keywords15.1 rosin; saponification number; tall oil; tall oil fatty acidsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin
45、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 standard is subject to revision at any time by the responsible technical committee and must
46、 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 ther
47、esponsible 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,
48、 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).7Supporting data are available from ASTM International Headquarters. RequestRR: D011091.D464053
