1、Designation: D1240 14Standard Test Methods forRosin Acids Content of Pine Chemicals, Including Rosin,Tall Oil, and Related Products1This standard is issued under the fixed designation D1240; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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 rosinacids in tall oil, tall oil fatty acid, tall oi
3、l rosin, and other pinechemicals products.1.2 These test methods may not be applicable to adducts orderivatives of rosin, fatty acid, or other pine chemicals prod-ucts.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 Thi
4、s 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Document
5、s2.1 ASTM Standards:2D1585 Test Methods for Fatty Acids Content of NavalStores, Including Rosin, Tall Oil, and Related ProductsE70 Test Method for pH of Aqueous Solutions With theGlass ElectrodeE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an I
6、nterlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 The rosin acids content is determined by one of twoprocedures; by selective esterification of fatty acids to formmethyl esters followed by titration of the unreacted rosin acids,by selective esterification of
7、 fatty acids to form butyl estersfollowed by titration of the unreacted rosin acids.4. Significance and Use4.1 This is a revision of the method for measuring rosinacids content combines the three major ways of determiningthe rosin acids content of pine chemicals products into a singlemethod.4.1.1 Fo
8、r materials containing less than 15 % rosin, themodified Glidden procedure has gained acceptance. For mate-rials containing more than 15 % rosin the modified WolfeMethod is preferred.The modifiedWolfe and modified Gliddenprocedures differ only in their details. They have been com-bined here into a s
9、ingle procedure. This procedure can be runusing either a potentiometer or an internal indicator to deter-mine the end point of the titration. Use of a potentiometer ispreferred and is the referee method. Use of an internal indicatoris the principal alternative method. They will be referred to asthe
10、Potentiometric Method and the Internal Indicator Method.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemica
11、l Societywhere such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Unless otherwise indicated, references to water shall beunderstood to me
12、an deionized or distilled water.6. Preparation of Sample6.1 Homogeneous liquid materials may be used withoutfurther preparation.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommit
13、tee D01.34 on Pine Chemicals and HydrocarbonResins.Current edition approved July 1, 2014. Published August 2014. Originallyapproved in 1952. Last previous edition approved in 2012 as D1240 12. DOI:10.1520/D1240-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM C
14、ustomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents
15、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. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C70
16、0, West Conshohocken, PA 19428-2959. United States16.2 Nonhomogeneous liquid materials should be heateduntil they are homogeneous, then a portion taken for analysis.6.3 Solid samples are subject to surface oxidation whichmay affect the results. Prepare the sample for analysis bychipping small pieces
17、 from a freshly exposed surface of a lumpor lumps and crush to a coarse powder to facilitate weighingand solution. Prepare fresh on the same day, prior to weighing,in order to avoid changes due to surface oxidation of crushedrosin on exposure to the air.ROSIN ACIDS CONTENT BY THEPOTENTIOMETRIC METHO
18、D(Referee Method)7. Scope7.1 This test method covers the determination of rosin acidscontent of tall oil rosin, tall oil fatty acid, and other pinechemicals products, where the most reproducible results aredesired. By using the potentiometric inflection end points, theerror due to colorimetric end p
19、oints is avoided.8. Summary of Test Method8.1 Asample is refluxed with methyl sulfuric acid to esterifythe fatty acids. The rosin acids and sulfuric acid are thentitrated potentiometrically, and the rosin acids content calcu-lated from the difference between the two inflection pointsobtained.9. Appa
20、ratus9.1 pH MeterAn indicating potentiometer having a limitof error not greater than 60.1 pH over a range from pH 1 topH 13, using an alkali-resistant glass electrode and a saturatedcalomel half-cell. The pH meter shall conform to the require-ments of Test Method E70. Alternatively, an automatic pot
21、en-tiometric titrator may be used.9.2 Stirrer, magnetic, equipped withpoly(tetrafluoroethylene)-coated stir bar.9.3 Buret, 50-mL capacity, with 0.1-mL divisions. Theso-called automatic buret is preferable as its use minimizeserrors due to evaporation. The automatic buret should beguarded with soda-l
22、ime tubes against the absorption of CO2from the air.9.4 Erlenmeyer Flask, 250 mL, 500 mL, or larger of achemically resistant glass with a standard-taper 24/40 joint.9.5 Condenser, water-cooled, equipped with a joint fittingthe flask described in accordance with 9.4.10. Reagents10.1 Alcoholic Alkali,
23、 Standard Solution (0.5 N)Dissolve33 g of potassium hydroxide (KOH), preferably in pellet form,in methanol (CH3OH) and dilute to 1 L with methanol.Standardize to 60.001 N with potassium acid phthalate(C6H4COOKCOOH) in 60 mL of water followed by 40 mL ofmethanol; 2.553 g of potassium acid phthalate w
24、ill be neutral-ized by 25.00 mL of 0.5 N KOH solution. Protect thestandardized solution against evaporation and absorption ofcarbon dioxide (CO2) from the air. Restandardize the solutionfrequently, either potentiometrically or colorimetrically, usingphenolphthalein as the indicator.10.1.1 For fatty
25、acids containing low concentrations of rosinacids, 0.1 N alcoholic potassium hydroxide may give superiorresults.10.2 Ethanol (95 %)Denatured alcohol conforming toFormula No. 3A or No. 30 of the U.S. Bureau of InternalRevenue, neutralized by the addition of KOH.10.3 Methanol (99.5 %).10.4 Methyl Sulf
26、uric Acid SolutionSlowly pour 100 g ofconcentrated sulfuric acid (H2SO4sp gr 1.82 to 1.84), whilestirring constantly, into 400 g of methanol. Extreme cautionshould be taken while preparing the methyl sulfuric acid.Adding sulfuric acid too rapidly may cause the methanol toflash out of its container.
27、Store the methyl sulfuric acid in aglass-stoppered bottle.10.5 Toluene.11. Procedure11.1 Choose the amount of sample so that the secondtitration will consume between 10 and 30 mLof KOH solution.For rosin acids, this will be about5gofmaterial. For fattyacids containing less than 15 % rosin, this will
28、 be about 40 g ofmaterial. For fatty acids containing less than 3 % rosin acidstitrating with 0.1 N KOH may give superior results. Table 1gives suggested amounts of material to use. Weigh the sampleto the nearest 0.001 g in a 250-mL or 500-mL (15 % rosinsamples) flask.11.2 Dissolve the sample in 100
29、 mL of methanol in a250-mL flask (or 150 mL methanol for 500-mL flask with 40 gsample). If the sample has a high rosin content it may behelpful first to dissolve it in 25 mLof toluene before adding themethanol. For material believed to contain more than 15 %rosin acid, that is, high in rosin, add 5
30、mL of methyl sulfuricacid, connect the flask assembly, and reflux the solution for 2to 20 min. (Solid samples must be in solution before beginningreflux.) For materials believed to contain concentrations ofrosin acid less than 15 %, that is, low in rosin, one may use a250- or 500-mL flask, one must
31、use 10 mL of methyl sulfuricand reflux for 20 min. Measure reflux time from the momentthe first drop of solvent returns to the flask from the condenser.Cool and transfer to a 400-mL beaker, using a total of 100 mLof methanol (Note 1) in three successive rinsings.NOTE 1Ethanol is preferable when an a
32、utomatic titrator is used.11.3 Turn the pH meter on and allow a few minutes for it tocome to equilibrium. Balance the meter using a standard buffersolution as described in Test Method E70; then rinse theelectrodes thoroughly with water and then with alcohol.TABLE 1 Sample Size and TitrantMaterialSam
33、ple Size,gReflux Time,minKOHNormality,NRosin 5 2 0.5Fatty acid, 15 % rosin 40 20 0.5Fatty acid, 3 % rosin 40 20 0.1D1240 14211.4 Immerse the electrode in the sample solution. Start thestirrer and adjust its speed for vigorous stirring withoutsplattering.11.5 Titrate the sample solution with 0.5 N KO
34、H to a fixedpH of 4.0, the first end point. If it appears that the buret doesnot contain sufficient KOH to continue the titration to thesecond end point, refill the buret at this point. Continue thetitration to the fixed pH of 10.8, the second point. Record theamount of KOH required for the titratio
35、n between the first andsecond end point. If an automatic titrator is used, the end pointsshall be taken at the inflection points or at the fixed pH of 4.0and 10.8.12. Calculation12.1 Calculate the percentage of rosin acids as follows:12.1.1 For materials containing less than 15 % rosin:Rosin acids,
36、% 5 AN/B! 330.24# 2 1.1 (1)where:A = KOH solution required for titration between the firstand second end points, mL,N = normality of the KOH solution,B = sample used, g, and30.24 = (mol weight of abietic acid 100)100012.1.2 For materials containing greater than 15 % rosin:Rosin acids, % 5 AN/B! 330.
37、24 (2)where:A = KOH solution required for titration between the firstand second end points, mL,N = normality of the KOH solution,B = sample used, g, and30.24 = (mol wt of abietic acid 100)100012.2 Report the percentage of rosin acids calculated byeither 12.1.1 or 12.1.2 to the first decimal place.RO
38、SIN ACIDS CONTENT BY THE INTERNALINDICATOR METHOD(Alternative Method)13. Scope13.1 This test method covers the determination of rosinacids content of tall oil rosin, tall oil fatty acid, and other pinechemicals products, using an internal indicator for the deter-mination of the end point. It gives g
39、ood results when routinelyapplied by a skilled analyst. However, where the most repro-ducible results by different analysts and laboratories aredesired, the referee method (Sections 6 to 11) should be used.14. Summary of Test Method14.1 A sample is refluxed with methyl sulfuric acid toesterify the f
40、atty acids. The rosin acids and sulfuric acid arethen titrated in the presence of thymol blue indicator. The rosinacids content is then calculated from the difference between thetwo color end points obtained.15. Apparatus15.1 The apparatus for the esterification and titration of thesample shall cons
41、ist of the flask, condenser, and buret de-scribed in Section 9.16. Reagents16.1 Alcoholic Alkali, Standard SolutionSee 10.1.16.2 MethanolSee 10.3.16.3 Methyl Sulfuric Acid SolutionSee 10.4.16.4 Thymol Blue Indicator Solution (1 g/L)Dissolve 1 gof thymol blue in 1000 mL of methanol.16.5 Toluene.17. P
42、rocedure17.1 Choose the amount of sample so that the secondtitration will consume between 10 and 30 mLof KOH solution.For rosin acids, this will be about5gofmaterial. For fattyacids containing less than 15 % rosin, this will be about 40 g ofmaterial. For fatty acids containing less than 3 % rosin ac
43、ids,titrating with 0.1 N KOH may give superior results. Table 1gives suggested amounts of material to use. Weigh the sampleto the nearest 0.001 g in a 250-mL or 500-mL (15 % rosinsamples) flask.17.2 Dissolve the sample in 100 mL of methanol in a250-mL flask (or 150 mL methanol for 500 mL flask with
44、40 gsample). If the sample has a high rosin content it may behelpful first to dissolve it in 25 mLof toluene before adding themethanol. For material believed to contain more than 15 %rosin acid, that is, high in rosin, add 5 mL of methyl sulfuricacid, connect the flask assembly, and reflux the solut
45、ion for 2to 20 min. (Solid samples must be in solution before beginningreflux.) For materials believed to contain concentrations ofrosin acid less than 15 %, that is, low in rosin, one may use a250- or 500-mL flask, one must use 10 mL of methyl sulfuricand reflux for 20 min. Measure reflux time from
46、 the momentthe first drop of solvent returns to the flask from the condenser.Cool, add 1 mL of thymol blue indicator.17.3 Titrate with the KOH solution to the first end point,about pH 4.0, when the solution changes color from red toyellow. Record the reading or refill the buret. Continue thetitratio
47、n to the second end point, about pH 10.8, when thesolution changes color from yellow to blue. Record to thenearest 0.1 mL the millilitres of KOH solution required fortitration between the two end points.NOTE 2These end points approximate the inflection points under thenonaqueous conditions employed.
48、18. Calculation18.1 Calculate the percentage of rosin acids as described in12.1.18.2 Report the percentage of rosin acids to the first decimalplace.D1240 14319. Precision and Bias419.1 Interlaboratory Test ProgramAn interlaboratorystudy of the rosin acid content of three substances, tall oil fattyac
49、ids, distilled tall oil, and rosin, was run in 1994. Each of 14laboratories tested each of the three materials. The design ofthe experiment, similar to that of Practice E691 and a within-between analysis of the data are given in ASTM ResearchReport No. RR:D01-1087.19.2 Test ResultThe precision information given belowfor the rosin acid content of pine chemicals products is for thecomparison of two test results, each of which is the average ofthree test determinations as follows:19.2.1 Repeatability Limit95 % (within labora-tory) = 0.6 %.19.2.2 Reproducibility
