1、Designation: D 1240 02 (Reapproved 2006)Standard Test Methods forRosin Acids Content of Naval Stores, Including Rosin, TallOil, and Related Products1This standard is issued under the fixed designation D 1240; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case 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 rosinacids in tall oil, tall oil
3、fatty acid, tall oil rosin, and other navalstores products.1.2 These test methods may not be applicable to adducts orderivatives of rosin, fatty acid, or other naval stores products.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informati
4、ononly.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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Refer
5、enced Documents2.1 ASTM Standards:2D 1585 Test Methods for Fatty Acids Content of NavalStores, Including Rosin, Tall Oil, and Related ProductsE70 Test Method for pH of Aqueous Solutions With theGlass ElectrodeE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 691 Practice fo
6、r Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 The rosin acids content is determined by one of threeprocedures; by selective esterification of fatty acids to formmethyl esters followed by titration of the unreacted rosin acids,by selectiv
7、e esterification of fatty acids to form butyl estersfollowed by titration of the unreacted rosin acids, or byselective esterification of fatty acids to form methyl estersfollowed by extraction of the sulfuric acid catalyst and titrationof the unreacted rosin acids.4. Significance and Use4.1 This is
8、revision of the method for measuring rosin acidscontent combines the three major ways of determining therosin acids content of naval stores products into a singlemethod.4.1.1 For materials containing less than 15 % rosin, themodified Glidden procedure has gained acceptance over theHerrlinger-Compeau
9、. For materials containing more than 15 %rosin the modified Wolfe Method is preferred. The modifiedWolfe and modified Glidden procedures differ only in theirdetails. They have been combined here into a single procedure.This procedure can be run using either a potentiometer or aninternal indicator to
10、 determine the end point of the titration.Use of a potentiometer is preferred and is the referee method.Use of an internal indicator is the principal alternative method.They will be referred to as the Potentiometric Method and theInternal Indicator Method to distinguish them from theHerrlinger-Compe
11、au and Linder-Persson methods.4.1.2 The Herrlinger-Compeau Method is limited in appli-cation to materials containing less than 15 % rosin. It is littleused in the industry today. Much early work is based on thistest method so it is included here to provide a historical basisfor the overall test meth
12、od.4.1.3 The Linder-Persson Method is also little used in theindustry today. It is applicable for measuring the rosin acidscontent of naval stores products containing greater than 60 %rosin. Like the Herrlinger-Compeau, it is included here toprovide a historical basis for the test method. In those i
13、nstanceswhere they are used, the Herrlinger-Compeau and Linder-Persson methods are often in conjunction to cover the wholerange of rosin content.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibi
14、lity of Subcommittee D01.34 on Naval Stores.Current edition approved Nov. 1, 2006. Published November 2006. Originallyapproved in 1952. Last previous edition approved in 2002 as D 1240 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service
15、astm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Reagents5.1 Purity of ReagentsReagent grade chemicals s
16、hall 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 Chemical Societywhere such specifications are available.3Other grades may beused, provided it is first ascertained that t
17、he 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 mean deionized or distilled water.6. Preparation of Sample6.1 Homogeneous liquid materials may be used withoutfurthe
18、r preparation.6.2 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 from a freshly exposed surface of a
19、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 METHOD(Referee Method)7. Scope7.1 This tes
20、t method covers the determination of rosin acidscontent of tall oil rosin, tall oil fatty acid, and other naval storesproducts, where the most reproducible results are desired. Byusing the potentiometric inflection end points, the error due tocolorimetric end points is avoided.8. Summary of Test Met
21、hod8.1 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. Apparatus9.1 pH MeterAn indicating potentio
22、meter having a limitof error not greater than 60.1 pH over a range from pH 1 to pH13, 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 poten-tiometric titrator may be used.9.2 S
23、tirrer, 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-lime tubes against the absorption of CO2
24、from the air.9.4 Erlenmeyer Flask, 250-mL or larger of a chemicallyresistant 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, Standard Solution (0.5 N)Dissolve33 g of potass
25、ium 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 will be neutral-ized by 25.00 mL of 0.5 N KOH sol
26、ution. 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 acids containing low concentrations of rosinacid
27、s, 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 Sulfuric Acid SolutionSlowly pour 100 g ofconcentrat
28、ed 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. Store the methyl sulfuric acid in aglass-stopper
29、ed bottle.10.5 Toluene.11. Procedure11.1 Weigh the sample to the nearest 0.001 g in a 250-mLflask. Choose the amount of sample so that the second titrationwill consume between 10 and 30 mL of KOH solution. Forrosin acids, this will be about5gofmaterial. For fatty acidscontaining less than 15 % rosin
30、, this will 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.11.2 Dissolve the sample in 100 mL of methanol in a250-mL flask. If the sample has a high rosin content it m
31、ay behelpful first to dissolve it in 25 mL of toluene before adding the3Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryCh
32、emicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.TABLE 1 Sample Size and TitrantMaterialSample Size,gReflux Time,minKOHNormality,NRosin 5 2 0.5Fatty acid, 15 % rosin 40 20 0.5Fatty acid, 3 % ro
33、sin 40 20 0.1D 1240 02 (2006)2methanol. For material believed to contain less than 15 % fattyacid, that is, high in rosin, add 5 mL of methyl sulfuric acid,connect the flask assembly, and reflux the solution for 2 min.(Solid samples must be in solution before beginning reflux.)For materials believed
34、 to contain concentrations of fatty acidhigher than 15 %, that is, low in rosin, use 10 mL of methylsulfuric and reflux for 20 min. Measure reflux time from themoment the first drop of solvent returns to the flask from thecondenser. Cool and transfer to a 400-mL beaker, using a totalof 100 mL of met
35、hanol (Note 1) in three successive rinsings.NOTE 1Ethanol is preferable when an automatic 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 thoro
36、ughly with water and then with alcohol.11.4 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 KOH to a fixedpH of 4.0, the first end point. If it appears that the buret doesnot cont
37、ain 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 titration between the first andsecond end point. If an automatic titrator is used, the end po
38、intsshall 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, % 5 AN/B! 3 30.24 2 1.1 (1)where:A = KOH solution required for titration between thef
39、irst and second end points, mL,N = normality of the KOH solution,B = sample used, g, and30.24 = (mol weight of abietic acid 3 100)/100012.1.2 For materials containing greater than 15 % rosin:Rosin acids, % 5 AN/B! 3 30.24 (2)where:A = KOH solution required for titration between thefirst and second e
40、nd points, mL,N = normality of the KOH solution,B = sample used, g, and30.24 = (mol wt of abietic acid 3 100)/100012.2 Report the percentage of rosin acids calculated byeither 12.1.1 or 12.1.2 to the first decimal place.ROSIN ACIDS CONTENT BY THE INTERNALINDICATOR METHOD(Alternative Method)13. Scope
41、13.1 This test method covers the determination of rosinacids content of tall oil rosin, tall oil fatty acid, and other navalstores products, using an internal indicator for the determina-tion of the end point. It gives good results when routinelyapplied by a skilled analyst. However, where the most
42、repro-ducible results by different analysts and laboratories are de-sired, 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 fatty acids. The rosin acids and sulfuric acid arethen titrated in the presence
43、 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 consist of the flask, condenser, and buret de-scribed in Section 9.16. Reagents16.
44、1 Alcoholic Alkali, Standard SolutionSee 10.1.16.2 MethanolSee 10.316.3 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. Procedure17.1 Weigh the sample to the nearest 0.001 g in a 250-mLflask. Choose t
45、he amount of sample so that the titration willconsume between 10 and 30 mLof 0.5 N KOH. For rosin acids,this will be about5gofmaterial. For fatty acids containing lessthan 15 % rosin, this will be about 40 g of material. For fattyacids containing less than 3 % rosin acids, titrating with 0.1 NKOH ma
46、y give superior results. Table 1 gives suggestedamounts of material to use.17.2 Dissolve the sample in 100 mL of methanol in a250-mL flask. If the sample has a high-rosin content it may behelpful first to dissolve it in 25 mL of toluene before adding themethanol. For material believed to contain les
47、s than 15 % fattyacid, add 5 mL of methyl sulfuric acid, connect the flaskassembly, and reflux the solution for 2 min. (Solid samplesmust be in solution before beginning reflux.) For materialsbelieved to contain concentrations of fatty acid higher than15 %, use 10 mL of methyl sulfuric and reflux fo
48、r 20 min.Measure reflux time from the moment the first drop of solventreturns to the flask from the condenser. Cool, add 1 mL ofthymol 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 refil
49、l the buret. Continue thetitration 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.18. Calculation18.1 Calculate the percentage of rosin acids as described in12.1.D 1240 02 (2006)318.2 Report the percentage of rosin acids to the first decimalplace.19. Precision and Bias19.1 Interlaboratory Test ProgramAn interlaboratorys
