1、Designation: D464 05 (Reapproved 2010)Standard Test Methods forSaponification Number of Naval Store Products IncludingTall Oil and Other Related Products1This standard is issued under the fixed designation D464; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, 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.1. Scope1.1 These test methods cover the determination of thesaponification number of tal
3、l oil and products obtained by thefractionation of tall oil such as rosin, fatty acids and distilledtall oil as defined in Terminology D804. These test methods arealso applicable to gum and wood rosin. Two test methods arecovered as follows:1.1.1 Test method using a potentiometric method, and1.1.2 T
4、est method using 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 con
5、sidered the alternate 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 th
6、is 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:2D803 Test Methods for Testing Tall OilD804 Terminology Relating to Naval Stores, Including TallOil and Related Products
7、E70 Test Method 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 D8
8、03.3.2 The 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 themo
9、st reproducible 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
10、 thetest is 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
11、closed container 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 ne
12、eded. Remove 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
13、Chemical1These 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 Pine Chemicals and HydrocarbonResins.Current edition approved June 1, 2010. Published June 2010. Originall
14、yapproved in 1937. Last previous edition approved in 2005 as D464 05. DOI:10.1520/D0464-05R10.2For 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
15、 Summary page onthe ASTM website.1Copyright ASTM 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
16、 (Referee Method)6. Apparatus6.1 Erlenmeyer Flask, 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 polytetr
17、afluoroethylene(PTFE) coated magnetic stir bar.6.6 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 fo
18、r this test. Alternatively, an automaticpotentiometric 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)
19、Dissolve33 g of potassium hydroxide (KOH), preferably 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. Once
20、the potassium acid phthalate has dissolved, 2.553 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 potentiometrical
21、ly orcolorimetrically using either phenolphthalein 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 proce
22、dure.7.6 Borax Buffer, Standard Solution (0.01 M, 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
23、with a pH between 9 and 11 may be used.8. Procedure8.1 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 v
24、olumetric pipet add 50.0 mL of the alkali solution. 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 o
25、f the Erlenmeyer flask intoa 400-mL tall-form beaker 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
26、.8.3 Titrate with 0.5 N acid, recording the buret 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 pH
27、units. Reduce the additions of acid to 0.1 mL or 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 th
28、e inflection point (point of maximumchange in pH 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 po
29、int is considered as the end point of the titration.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 average
30、pH encountered at the inflection point by this procedure.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
31、Calculate the saponification number, expressed as mil-ligrams of KOH per gram of sample as follows:Saponification number 5 B 2 A! N 3 56.1/C3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by
32、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.4Alkali-resistant glasses, or equivalent, are suitable for this purpose. Boro
33、silicateflasks 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 interfere with the determination.5Available from the U.S. Bureau of Alcohol, Tobacco, and Fire
34、arms, DistilledSpirits and Tobacco Branch, 1200 Pennsylvania Ave., NW, Washington DC 20226,http:/www.atf.gov.6The National Institute of Standards and Technology standard sample of boraxNo. 187 is satisfactory for this purpose.D464 05 (2010)2where:B = acid required for titration of the blank, mL,A =
35、acid required for titration of the sample, mL,N = normality of the acid, andC = 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 Soluti
36、onDissolve1gofphenolphthalein in 100 mL of methanol.11.2 Thymol Blue Indicator 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 ofisoprop
37、yl alcohol-toluene (1:1) can be added to the flask topredissolve the sample. 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 t
38、he solutionat reflux for 1 h.At the end of the reflux time, place samples ona 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 dro
39、ps ofphenolphthalein indicator to a clear endpoint or 4 to 5 drops ofthymol 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.
40、05-mL titrant. If less than 20 mL of titrant is consumed,decrease the sample 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, t
41、hen usethe same amount in the blank determinations.13. Calculation and Report13.1 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 multilaborat
42、ory round-robin testing pro-gram using two substances: tall oil fatty acid 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 te
43、sts by the same operator on the samesample should not differ by more than 2.5 %.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 %.
44、14.2 BiasThe procedure in this test method for measuringacid number has no 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 vali
45、dity 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 standard is subj
46、ect 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 Headquar
47、ters. 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, at the address shown below.This standar
48、d is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, 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 servi
49、ceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).7Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1091.D464 05 (2010)3
