1、Designation: D464 05 (Reapproved 2010)D464 15Standard Test Methods forSaponification Number of Naval StorePine ChemicalProducts Including Tall Oil and Other Related Products1This standard is issued under the fixed designation D464; the number immediately following the designation indicates the year
2、oforiginal adoption 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 the saponif
3、ication number of tall oil and products obtained by thefractionation of tall oil such as rosin, fatty acids and distilled tall oil as defined in Terminology D804. These test methods are alsoapplicable to gum and wood rosin. Two test methods are covered as follows:1.1.1 Test method using a potentiome
4、tric method, and1.1.2 Test method using an internal indicator method.1.2 The potentiometric method is suitable for use with both light- and dark-colored test samples. It should be considered thereferee method. The internal indicator method is suitable for use only with light- and medium-colored test
5、 samples. It should beconsidered the alternate method.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the res
6、ponsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D803 Test Methods for Testing Tall OilD804 Terminology Relating to Pine Chemicals, Including T
7、all Oil and Related ProductsE70 Test Method for pH of Aqueous Solutions With the Glass Electrode3. Significance and Use3.1 These test methods are designed to broaden the scope of the earlier editions of the test method by the inclusion of tall oiland tall oil derived products as test materials and i
8、s referenced in Test Methods D803.3.2 The saponification number is an important property of tall oil and the products obtained by the fractionation of tall oil. Itis the test method widely used to determine the total acid content, both free and combined, of these products.3.3 The potentiometric test
9、 method should be used when the most reproducible results are required.4. Preparation of Sample4.1 If the sample for analysis is rosin, it shall consist of small pieces of rosin chipped from a freshly exposed part of a lumpor lumps, and thereafter crushed to facilitate weighing and dissolution. Prep
10、are the sample the same day on which the test is begunin order to avoid changes in properties due to surface oxidation. Changes are very pronounced on ground rosin that has a largesurface area exposed to air. Existing rosin dust and powdered rosin must not be used.4.2 If the sample is a nonhomogeneo
11、us liquid, heat the entire sample in a closed container fitted with a capillary vent or theequivalent. Some kind of agitation, even if done occasionally by hand, saves much time. Heat by immersion in open steam or hot1 These test methods are under the jurisdiction of ASTM Committee D01 on Paint and
12、Related Coatings, Materials, and Applications and are the direct responsibility ofSubcommittee D01.34 on Pine Chemicals and Hydrocarbon Resins.Current edition approved June 1, 2010Dec. 1, 2015. Published June 2010December 2015. Originally approved in 1937. Last previous edition approved in 20052010
13、asD464 05.D464 05 (2010). DOI: 10.1520/D0464-05R10.10.1520/D0464-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standardsstandards Document Summary page on t
14、he ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users c
15、onsult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1water bath to avoid overheating.
16、 When dealing with crystallized rosin, a higher temperature of approximately 160C may beneeded. Remove samples for testing only when the entire sample is homogeneous and has been well stirred.5. Purity of Reagents and Water5.1 Unless otherwise indicated, it is intended that all reagents shall confor
17、m to the specifications established by the Committeeon Analytical Reagents of the American Chemical Society,3 where such specifications are available. References to water shall beunderstood to mean distilled or deionized water.POTENTIOMETRIC TEST METHOD (Referee Method)6. Apparatus6.1 Erlenmeyer Fla
18、sk, 250-mL, of chemically resistant glass4 with standard-taper glass joint.6.2 Hot Plates.6.3 Water-Cooled Reflux Condenser, with standard-taper joint 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
19、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 requirements of Test Method E70. Use either standard or alkali-resistantelectrodes for this test. Alternatively, an automatic pote
20、ntiometric titrator may be used.7. Reagents7.1 Ethyl AlcoholEthyl Alcohol(95 %) denatured by Formula No. 3A or No. 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)Dissolve 33 g of potassium hydr
21、oxide (KOH), preferably in pellet form, inethyl alcohol conforming to 7.1 and dilute to 1 L with 3A ethyl alcohol. Standardize to 60.001 N by dissolving potassium acidphthalate (C6H4 COOKCOOH) in 60 mL of water followed by the addition of 40 mL of isopropyl alcohol. Once the potassiumacid phthalate
22、has dissolved, 2.553 g of potassium acid phthalate will be neutralized by 25.0 mL of 0.5 N KOH solution. Protectthe standardized solution against evaporation and absorption of carbon dioxide (CO2) from the air. The solution should bestandardized either potentiometrically or colorimetrically using ei
23、ther phenolphthalein or thymol blue as the indicator. Thestandardization should use the same equipment and techniques as used in the actual saponification number determination.7.5 Acid, Standard (0.5 N)Standardize a 0.5 N solution of HCl to 60.001 N by any accepted procedure.7.6 Borax Buffer, Standa
24、rd Solution (0.01 M, pH 9.18 at 25C)Dissolve 3.81 6 0.01 g of disodium tetraborate (Na2B40710H2O) in water and dilute to 1 Lin a volumetric flask. Use the special grade6 of borax prepared specifically for use as a pH standard.As an alternative, commercially available buffer with a pH between 9 and 1
25、1 may be used.8. Procedure8.1 Transfer 2.95 to 3.05 g of the sample, weighed to the nearest 0.001 g, to the Erlenmeyer flask. If necessary, 10 mL ofisopropyl alcohol-toluene solution (1:1) can be added to the flask to predissolvepre-dissolve the sample. Using a constant deliverypipet or volumetric p
26、ipet add 50.0 mL of the alkali solution. Add several PTFE boiling stones or glass beads and connect the flaskto the condenser.8.2 Place the flask on a hot plate and maintain the solution at reflux for 1 h. At the end of the reflux time, while the sample isstill warm, transfer the contents of the Erl
27、enmeyer flask into a 400-mL tall-form beaker rinsing with 100 mL of isopropyl alcohol3 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards f
28、or Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.4 Alkali-resistant glasses, or equivalent, are suitable for this purpose. Borosilicate flasks may be used, but they should eithe
29、r be new or be cleaned by rinsing with a hotsolution of HF (2 or 3 %). This removes from the flasks the adhering partially disintegrated silicates that would interfere with the determination.5 Available from the U.S. Bureau of Alcohol, Tobacco, and Firearms, Distilled Spirits and Tobacco Branch, 120
30、0 Pennsylvania Ave., NW, Washington DC 20226,http:/www.atf.gov.6 The National Institute of Standards and Technology standard sample of borax No. 187 is satisfactory for this purpose.D464 152in three washings. Place samples on a heated surface until they can be titrated. In order to avoid highly vari
31、able results, make surethat the temperature of the samples is approximately 60 to 70C when titrated.8.3 Titrate with 0.5 N acid, recording the buret and pH meter readings. Sufficient acid may be added initially to bring the pHof the solution to about 12. Allow sufficient time for the electrode syste
32、m to reach equilibrium. Add acid in 1.0-mL portions untilthe change in pH per addition exceeds 0.3 pH units. Reduce the additions of acid to 0.1 mL or smaller until the end point has beenpassed, as indicated by a significant decrease in pH units per 0.1 mL of acid added. Continue the titration with
33、1.0-mL portionsuntil it becomes apparent that the inflection point has been well defined.8.4 Determine the inflection point (point of maximum change in pH per millilitre of acid) to the nearest 0.05 mL. This may befound by inspection of a plot of pH against millilitres of acid added. For greater acc
34、uracy, a plot may be made of the change inpH per millilitre of acid added, against the pH. The inflection point is considered as the end point of the titration. Alternativelyif an automatic titrator is used, the endpoint is either the inflection point from the plotted curve or the pH determined to c
35、oincidewith the inflection point in the laboratory performing the analysis. The value of 10.8 is the average pH encountered at the inflectionpoint by this procedure.8.5 BlankMake duplicate blank determinations using 50.0 mL of the alkali solution. If 10 mL of isopropyl alcohol-toluenesolution (1:1)
36、is used as a solvent in 8.1, then use the same amount in the blank determination.9. Calculation and Report9.1 Calculate the saponification number, expressed as milligrams of KOH per gram of sample as follows:Saponification number5B 2A! N 356.1#/Cwhere:B = acid required for titration of the blank, mL
37、,A = acid required for titration of the sample, mL,N = normality of the acid, andC = sample weight, g.Report the saponification number to the nearest whole number.INTERNAL INDICATOR TEST METHOD (Alternative Method)10. Apparatus10.1 Same apparatus as 6.1 6.7.11. Reagents11.1 Phenolphthalein Indicator
38、 SolutionDissolve 1 g of phenolphthalein in 100 mL of methanol.11.2 Thymol Blue Indicator SolutionDissolve 0.1 g of thymol 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 the nearest 0.001 g to the Erlenmeyer flask. If necessary, 10
39、 mL ofisopropyl alcohol-toluene (1:1) can be added to the flask to predissolvepre-dissolve the sample. Using a constant delivery pipet orvolumetric pipet, add 50.0 mL of the alkali solution. Add several PTFE boiling stones or glass beads, and connect the flask to thecondenser.12.2 Place the flask on
40、 a hot plate and maintain the solution at reflux for 1 h. At the end of the reflux time, place samples ona heated surface until they can be titrated. In order to avoid highly variable results, make sure that the temperature of the samplesis approximately 60 to 70C when titrated.12.3 Titrate with 0.5
41、 N HCl using either 4 to 5 drops of phenolphthalein indicator to a clear endpoint or 4 to 5 drops of thymolblue indicator. With thymol blue, the end point is indicated when the color undergoes the first change from a distinct blue to ablue-green, just short of clear yellow. If needed, more indicator
42、 may be used. Read the buret to 0.05-mL titrant. If less than 20 mLof titrant is consumed, decrease the sample size.12.4 BlankMake duplicate blank determinations using 50.0 mL of the alkali solution and following the same procedure as forthe sample. If 10 mL of isopropyl alcohol-toluene solution (1:
43、1) was used as a solvent in 12.1, then use the same amount in theblank determinations.13. Calculation and Report13.1 Calculate the saponification number as described in Section 9. Report the results to the nearest whole number.D464 15314. Precision and Bias714.1 PrecisionThe precision of these test
44、methods was determined through a multilaboratory round-robin testing programusing two substances: tall oil fatty acid and distilled tall oil. The results were combined to give the conclusions given below.14.1.1 Single operator precisionThe single operator standard deviation was found to be 0.9 %. Th
45、erefore, results of twoproperly conducted tests by the same operator on the same sample should not differ by more than 2.5 %.14.1.2 Multilaboratory precisionThe multilaboratory standard deviation was found to be 2.2 %. Therefore, results of twoproperly conducted tests on the same sample from two lab
46、oratories should not differ by more than 6.1 %.14.2 BiasThe procedure in this test method for measuring acid number has no bias because the value of the acid number isdefined only in the terms of these test methods.15. Keywords15.1 rosin; saponification number; tall oil; tall oil fatty acidsASTM Int
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