Designation: D 1240 – 02
Standard Test Methods for
Rosin Acids Content of Naval Stores, Including Rosin, Tall Oil, and Related Products1 This standard is issued under the fixed designation D 1240; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Scope
rosin rosin acids acids conten contentt of naval naval stores stores produc products ts into into a single single method. 4.1.1 4.1.1 For mater material ialss contai containin ning g less less than than 15 % rosin, rosin, the modified modified Glidden Glidden procedure procedure has gained gained acceptanc acceptancee over the Herrlinger-Compeau. For materials containing more than 15 % rosin the modified Wolfe Method is preferred. The modified Wolfe and modified modified Glidden Glidden procedure proceduress differ differ only in their their details. They have been combined here into a single procedure. This procedure can be run using either a potentiometer or an internal indicator to 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 the Inte Interna rnall Indic Indicat ator or Meth Method od to dist distin ingui guish sh them them from from the the Herrlinger-Compeau and Linder-Persson methods. 4.1.2 The HerrlingerHerrlinger-Comp Compeau eau Method is limited limited in appliapplication to materials containing less than 15 % rosin. It is little used in the industry today. Much early work is based on this test method so it is included here to provide a historical basis for the overall test method. 4.1.3 The Linder-Per Linder-Persson sson Method is also little little used in the industry today. It is applicable for measuring the rosin acids content of naval stores products containing greater than 60 % rosin. rosin. Like Like the Herrli Herrlinge ngerr-Com Compea peau, u, it is includ included ed here here to provide a historical basis for the test method. In those instances where where they they are used, used, the Herrli Herrlinge ngerr-Com Compea peau u and Linder Linder-Persson methods are often in conjunction to cover the whole range of rosin content.
1.1 These These test test metho methods ds cover cover the determ determina inatio tion n of rosin rosin acids in tall oil, tall oil fatty acid, tall oil rosin, and other naval stores products. 1.2 These test methods methods may not be applicable applicable to adducts adducts or derivatives of rosin, fatty acid, or other naval stores products. standard rd does not purport purport to addre address ss all of the 1.3 This standa safe safety ty conc concer erns ns,, if any any, asso associ ciat ated ed with with its its use. use. It is the the responsibility of the user of this standard to establish appro priate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: D 1585 1585 Test Method Methodss for Fatty Fatty Acids Acids Conten Contentt of Naval Naval Stores, Including Rosin, Tall Oil, and Related Products 2 E 70 70 Test Method Method for pH of Aqueous Aqueous Solution Solutionss with with the Glass Electrode 3 E 177 Practice Practice for the Use of the Terms Terms Precision Precision and Bias in ASTM Test Methods4 E 691 Practice Practice for Conductin Conducting g an Interlabo Interlaborato ratory ry Study to Determine the Precision of a Test Method 4 3. Summary Summary of Test Test Method 3.1 The rosin acids content content is determined determined by one of three procedures; by selective esterification of fatty acids to form methyl esters followed by titration of the unreacted rosin acids, by selective esterification of fatty acids to form butyl esters foll follow owed ed by titr titrat atio ion n of the the unre unreac acte ted d rosi rosin n acid acids, s, or by selectiv selectivee esterifica esterification tion of fatty fatty acids to form methyl esters followed by extraction of the sulfuric acid catalyst and titration of the unreacted rosin acids.
5. Reagents Reagents 5.1 Purity of Reagents —Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 5 Other grades may be used, used, provid provided ed it is first first ascert ascertain ained ed that that the reagent reagent is of sufficiently high purity to permit its use without lessening the
4. Significan Significance ce and Use 4.1 This is revision of the method method for measuring rosin rosin acids conten contentt combin combines es the three three major major ways ways of determ determini ining ng the 1
These test methods are under the jurisdiction of ASTM Committee D01 on Paint Paint and Related Related Coating Coatings, s, Material Materials, s, and Applicati Applications ons and are the direct direct responsibilit responsibility y of Subcommittee Subcommittee D01.34 on Naval Stores. Current Current edition edition approv approved ed May 10, 2002. 2002. Publish Published ed July July 2002. 2002. Origin Originally ally published published as D 1240 – 52 T. T. Last previous edition D 1240 – 96. 2 Annual Book of ASTM Standards Standards, Vol 06.03. 3 Annual Book of ASTM Standards Standards, Vol 15.05. 4 Annual Book of ASTM Standards Standards, Vol 14.02.
5 American Reagent Chemicals, American Chemical Society Specifications Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, Society, see see Analar Standards for Laboratory Chemicals, Chemicals , BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
D 1240 accuracy of the determination. 5.2 Unless otherwise indicated, indicated, references to water water shall be understood to mean deionized or distilled water.
(C6H4COOKCOOH) in 60 mL of water followed by 40 mL of methanol; 2.553 g of potassium acid phthalate will be neutralize zed d by 25 25.0 .00 0 mL of 0. 0.5 5 N KOH sol soluti ution. on. Pro Protec tectt the standardi stan dardized zed solu solution tion agai against nst evapo evaporati ration on and absor absorption ption of carbon dioxide (CO 2) from the air. Restandardize the solution frequently, either potentiometrically or colorimetrically, using phenolphthalein as the indicator. 10.1.1 For fatty acids containing low concentrations concentrations of rosin rosin acids, 0.1 N alcoholic potassium hydroxide may give superior results. Ethanol (95 %)—Dena 10.2 Ethanol —Denatured tured alco alcohol hol confo conformin rming g to Formul For mulaa No. 3A or No. 30 of the U.S. Bureau Bureau of Int Intern ernal al Revenue, neutralized by the addition of KOH. 10.3 Methanol (99.5 %). 10.4 Methyl Sulfuric Acid Solution —Slowly pour 100 g of concentrated sulfuric acid (H 2SO4 sp gr 1.82 to 1.84), while stirring constantly, into 400 g of methanol. Extreme caution should sho uld be tak taken en whi while le pre prepar paring ing the met methyl hyl sul sulfur furic ic aci acid. d. Adding sulfuric acid too rapidly may cause the methanol to flash out of its container. Store the methyl sulfuric acid in a glass-stoppered bottle. 10.5 Toluene.
6. Prep Preparati aration on of Sampl Samplee 6.1 Hom Homoge ogeneo neous us li liqui quid d mat materi erials als may be use used d wit withou houtt further preparation. 6.2 Non Nonhom homoge ogeneo neous us liq liquid uid mat materi erials als sho should uld be hea heated ted until they are homogeneous, then a portion taken for analysis. 6.3 Soli Solid d samp samples les are subj subject ect to surf surface ace oxidation oxidation which may af affec fectt the res result ults. s. Pre Prepar paree the sam sample ple for ana analys lysis is by chipping small pieces from a freshly exposed surface of a lump or lumps and crush to a coarse powder to facilitate weighing and solution. Prepare fresh on the same day, prior to weighing, in order to avoid changes due to surface oxidation of crushed rosin on exposure to the air. ROSIN ACIDS CONTENT BY THE POTENTIOMETRIC POTENTIO METRIC METHOD ( Referee Method ) 7. Sco Scope pe 7.1 This test method covers the determination determination of rosin acids content of tall oil rosin, tall oil fatty acid, and other naval stores products, where the most reproducible results are desired. By using the potentiometric inflection end points, the error due to colorimetric end points is avoided.
11. Procedure 11.1 Weigh the sample to the nearest 0.001 g in a 250-mL 11.1 flask. Choose the amount of sample so that the second titration will consume between 10 and 30 mL of KOH solution. For rosin acids, this will be about 5 g of material. For fatty acids containing less than 15 % rosin, this will be about 40 g of material. For fatty acids containing less than 3 % rosin acids titrating with 0.1 N KOH may give superior results. Table 1 gives suggested amounts of material to use. 11. 1.2 2 Di Diss ssol olve ve th thee sa samp mple le in 10 100 0 mL of me meth than anol ol in a 250-mL flask. If the sample has a high rosin content it may be helpful first to dissolve it in 25 mL of toluene before adding the methanol. For material believed to contain less than 15 % fatty acid, 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 to contain concentrations of fatty acid higher than 15 %, that is, low in rosin, use 10 mL of methyl sulfuric and reflux for 20 min. Measure reflux time from the moment the first drop of solvent returns to the flask from the condenser. Cool and transfer to a 400-mL beaker, using a total of 100 mL of methanol (Note 1) in three successive rinsings.
8. Summa Summary ry of Test Method 8.1 A sample is refluxed with methyl sulfuric sulfuric acid to esterify esterify the fatty acids. acids. The rosin acids and sul sulfur furic ic aci acid d are then titrated potentiometrically, and the rosin acids content calculated from the differenc differencee betwe between en the two infle inflection ction points obtained. 9. Appar Apparatus atus 9.1 pH Meter —An —An indicating potentiometer having a limit of error not greater than 60.1 pH over a range from pH 1 to pH 13, using an alka alkali-r li-resis esistant tant glass electrode electrode and a satur saturated ated calomel half-cell. The pH meter shall conform to the requirements of Test Method E 70. Alternatively, an automatic potentiometric titrator may be used. 9.2 Stirrer , m a g n e ti c , e q u ip p ed w i th poly(tetrafluoroethylene)-coated stir bar. 9.3 Buret , 5050-mL mL cap capaci acity ty,, wit with h 0.1 0.1-m -mL L div divisi isions ons.. The so-called so-ca lled automatic automatic buret is pref preferabl erablee as its use mini minimize mizess errors err ors due to eva evapor porati ation. on. The aut automa omatic tic bur buret et sho should uld be guarded with soda-lime tubes against the absorption of CO 2 from the air. Erlenmeyer Flask , 250 9.4 Erlenmeyer 250-m -mL L or lar larger ger of a che chemi mical cally ly resistant glass with a standard-taper 24/40 joint. 9.5 Condenser , water-cooled, equipped with a joint fitting the flask described in accordance with 9.4.
NOTE 1—Ethanol is preferable when an automatic titrator is used.
11.3 Tur 11.3 Turn n the pH meter on and allow a few minutes for it to come to equilibrium. Balance the meter using a standard buffer soluti sol ution on as des descri cribed bed in Test Met Method hod E 70; the then n rin rinse se the electrodes thoroughly with water and then with alcohol. TABLE 1 Sampl Sample e Size and Titrant
10. Reag Reagents ents
Material
10.1 Alcoholic Alkali, Standard Solution (0.5 N)—Dissolve 33 g of potassium hydroxide (KOH), preferably in pellet form, in me metha thanol nol (CH3OH OH)) an and d di dilu lute te to 1 L wi with th me meth than anol ol.. Standardize Standa rdize to 60.001 N with pot potass assium ium aci acid d pht phthal halate ate
Rosin Fatty acid, <15 % rosin Fatty acid, <3 % rosin
2
Sample Size, g
Reflux Time, min
KOH Normality, N
5 40 40
2 20 20
0 .5 0 .5 0 .1
D 1240 16. Reag Reagents ents
11.4 Immerse the electrode electrode in the sample solution. solution. Start the stirre sti rrerr and adj adjust ust its spe speed ed for vig vigoro orous us sti stirri rring ng wit withou houtt splattering. 11.5 Tit Titrate rate the sample solution solution with 0.5 N KOH to a fixed pH of 4.0, the first end point. If it appears that the buret does not con contai tain n suf sufffici icient ent KOH to con contin tinue ue the ti titra tratio tion n to the second end point, refill the buret at this point. Continue the titration to the fixed pH of 10.8, the second point. Record the amount of KOH required for the titration between the first and second end point. If an automatic titrator is used, the end points shall be taken at the inflection points or at the fixed pH of 4.0 and 10.8.
16.1 Alcoholic Alkali, Standard Solution —See 10.1. 16.2 Methanol—See 10.3 16.3 Methyl Sulfuric Acid Solution —See 10.4. 16.4 Thymol Blue Indicator Solution (1 g/L)—Dissolve 1 g of thymol blue in 1000 mL of methanol. 16.5 Toluene. 17. Proc Procedur eduree 17.1 Weigh the sample sample to the nearest nearest 0.001 g in a 250-m 250-mL L flask. Choose the amount of sample so that the titration will consume consu me between between 10 and 30 mL of 0.5 N KOH. KOH. For rosin acids, this will be about 5 g of material. For fatty acids containing less than 15 % rosin, this will be about 40 g of material. For fatty acids containing less than 3 % rosin acids, titrating with 0.1 N KOH ma may y giv givee sup superi erior or res result ults. s. Tabl ablee 1 giv gives es sug sugges gested ted amounts of material to use. 17.2 17 .2 Disso Dissolv lvee th thee sa samp mple le in 10 100 0 mL of me meth than anol ol in a 250-mL flask. If the sample has a high-rosin content it may be helpful first to dissolve it in 25 mL of toluene before adding the methanol. For material believed to contain less than 15 % fatty acid, aci d, add 5 mL of met methyl hyl sulfuric sulfuric acid, acid, con connec nectt the flask assembly asse mbly,, and reflux the solution for 2 min. (Solid samples samples must be in solut solution ion before begi beginning nning reflux.) For mate material rialss believed beli eved to conta contain in conce concentra ntrations tions of fatt fatty y acid higher than 15 %, use 10 mL of methyl sulfuric and reflux for 20 min. Measure reflux time from the moment the first drop of solvent returns to the flask from the condenser. Cool, add 1 mL of thymol blue indicator. 17.3 17. 3 Ti Titra trate te wit with h the KOH sol soluti ution on to the first end poi point, nt, about pH 4.0, when the solution changes color from red to yellow yell ow.. Recor Record d the reading or refill the buret. Conti Continue nue the titrat tit ration ion to the second second end point, point, abo about ut pH 10. 10.8, 8, whe when n the soluti sol ution on cha change ngess col color or fro from m yel yellow low to blu blue. e. Rec Record ord to the nearest near est 0.1 mL the mill millilit ilitres res of KOH solution required required for titration between the two end points.
12. Calculation 12.1 Calcu Calculate late the percentage percentage of rosi rosin n acid acidss as foll follows: ows: 12.1.1 For materials materials containing containing less than 15 % rosi rosin: n: Rosin acids, % 5 @~ AN / B! 3 30.24# 2 1.1
(1)
where: = KOH solut solution ion requ require ired d for titra titratio tion n between between the the A first and second end points, mL, N = norm normalit ality y of the KOH solut solution, ion, B = sam sample ple use used, d, g, and 30.24 30. 24 = (mo (moll weight weight of abie abietic tic acid acid 3 100)/1000 12.1.2 For materials materials containing containing greater than 15 % rosi rosin: n: Rosin acids, % 5 ~ AN / B! 3 30.24
(2)
where: = KOH solut solution ion requ require ired d for titra titratio tion n between between the the A first and second end points, mL, N = norm normalit ality y of the KOH solut solution, ion, B = sam sample ple use used, d, g, and 30.24 30. 24 = (mo (moll wt of of abiet abietic ic acid acid 3 100)/1000 12.2 12. 2 Rep Report ort the per percen centag tagee of ros rosin in aci acids ds cal calcul culate ated d by either 12.1.1 or 12.1.2 to the first decimal place. ROSIN ACIDS CONTENT BY THE INTERNAL INDICATOR METHOD ( Alternative Method )
NOTE 2—These end points approximate the inflection points under the nonaqueous conditions employed.
13. Scope
18. Calculation
13.1 Thi 13.1 Thiss tes testt met method hod cov covers ers the det determ ermina inatio tion n of ros rosin in acids content of tall oil rosin, tall oil fatty acid, and other naval stores products, using an internal indicator for the determination ti on of the end poi point. nt. It giv gives es goo good d res result ultss whe when n rou routin tinely ely applied by a skilled analyst. However, where the most reproducible results by different analysts and laboratories are desired, the referee method (Sections 6 to 11) should be used.
18.1 Calculate Calculate the percentage percentage of rosi rosin n acids as desc described ribed in 12.1. 18.2 Report the percentage of of rosin acids to the first first decimal place. 19. Pre Precisio cision n and Bias Interlaboratory boratory Test Progr Program am—An interlab 19.1 Interla interlaboratory oratory study of the rosin acid content of three substances, tall oil fatty acids, distilled tall oil, and rosin, was run in 1994. Each of 14 laboratories tested each of the three materials. The design of thee ex th expe peri rime ment nt,, si simi mila larr to th that at of Pr Prac acti tice ce E 69 691 1 an and d a with wi thin in-b -bet etwe ween en an anal alys ysis is of th thee da data ta ar aree gi give ven n in AS ASTM TM Research Report.6 Test Result —The 19.2 Test —The prec precision ision info informat rmation ion given below for the rosin acid content of naval stores products is for the
14. Summa Summary ry of Test Method 14.1 A sam 14.1 sample ple is refl refluxe uxed d wit with h met methyl hyl sul sulfur furic ic aci acid d to esterify the fatty acids. The rosin acids and sulfuric acid are then titrated in the presence of thymol blue indicator. The rosin acids content is then calculated from the difference between the two color end points obtained. 15. Appar Apparatus atus 15.1 The apparatus apparatus for the este esterific rification ation and titration titration of the sample sam ple sha shall ll con consis sistt of the flas flask, k, con conden denser ser,, and bur buret et described in Section 9.
6 Supporting data are available from ASTM International Headquarters. Request RR: D01 - 1087.
3
D 1240 Potassium ium Hydr Hydroxi oxide de Sta Standa ndard rd Alc Alcoho oholic lic Sol Soluu23.6 Potass tion (0.2 or 0.5 N )—Dissolve )—Dissolve 13.3 g of KOH (preferably in pellet form) for a 0.2- N solution solution or 33.3 g for a 0.5- N solution solution (see (s ee 24 24.3 .3)) in me meth than anol ol (9 (99. 9.5 5 %) an and d di dilu lute te to 1 L wi with th methanol. Standardize to 6 0.001 N . The standardized solution should be protected against evaporation and the absorption of CO2 from the air, and should be restandardized frequently. 23.7 Sodium Sulfate Solution—Dissolve 100 g Na 2SO4 in water and dilute to 1 L. The resulting solution should have a pH of 7.2 6 0.4 (Note 2).
comparison of two test results, each of which is the average of three test determinations as follows: 19.2.1 Rep ithin la bor a Repeat eatabi abilit lityy Lim Limit it , 9 5 % (w it tory) = 0.6 %. 19.2.2 Reproduc (betwe tween en lab labora oratotoReproducibility ibility Limit , 95 % (be ries) = 1.4 %. 19.3 These term termss (rep (repeata eatabili bility ty limi limitt and repr reproduci oducibilit bility y limit) are used as specified in Practice E 177. The respective standard stand ard deviations deviations among test resul results, ts, rela related ted to the above numbers by the factor of 2.8, are as follows: 19.3.1 Repeatability standard deviation = 0.2 %. 19.3.2 Reproducibility standard deviation = 0.5 %. 19.4 Bias—These test methods have no bias because rosin acid content is defined only in terms of these test methods.
NOTE 3—A suitable pH adjustment adjustment may be made made by adding dilute (5 %) NaOH solu NaOH solution tion to a fai faint nt pink pink-re -red d phe phenolp nolphtha hthalei lein n col color or,, the then n add adding ing dilute sulfuric acid (5 %) solution until the color is discharged.
23.8 Sulfuric Acid (sp gr 1.84) .
ROSIN ACIDS BY THE HERRLINGER-COMPEAU METHOD
24. Proc Procedur eduree 24.1 Dis 24.1 Dissol solve ve 40 60. 0.1 1 g of the sam ampl plee in 10 100 0 ml of methanol in a 250-mL flat-bottomed flask. Swirl the flask to dissolve the oil and add a clean boiling chip. Add slowly t mL of H2SO4, while swirling swirling the flask vigor vigorously ously.. Conne Connect ct the flask to the condenser, apply heat, and reflux the contents for 10 min. Cool the flask to room temperature with cold water. 24.2 24 .2 Ad Add d 25 250 0 mL of th thee Na2SO4 soluti solution on to a 500 500-mL -mL separatory funnel. Pour the contents of the flask into the funnel and complete the quantitative transfer of the flask contents with 100 mL of ether. Thoroughly shake the mixture in the funnel. Allow to settle, draw off the salt layer, and discard. Wash the contents of the funnel twice again with 250-mL portions of Na2SO4 solution. The last washing should not react pink to methyl orange indicator. 24.3 After removin removing g the last wash, wash, drain the contents contents of the separatory funnel into a 500-mL Erlenmeyer flask. Rinse the funnel with 20 mL of ether and add the rinsings to the flask. Add 20 mL of ethyl alcohol and 1 mL of the phenolphthalein indicator indi cator solution. solution. Tit Titrate rate to the appea appearanc rancee of the pinkpink-red red color using 0.2- N alcoholic alcoholic KOH solution if the rosin acids is less than 5 % or 0.5 N if if more than 5 %.
20. Scope 20.1 The Herrlinger Herrlinger-Com -Compeau peau Method given here has been largely superseded largely superseded by the methods described described in Sect Sections ions 1 through 18. 20.2 20. 2 Thi Thiss tes testt met method hod cov covers ers the det determ ermina inatio tion n of ros rosin in acids aci ds in fat fatty ty aci acids ds whe when n the rosin acids content content does not exceed 15 %. 21. Summ Summary ary of Test Test Method 21.1 The ros 21.1 rosin in aci acids ds are det determ ermine ined d by tit titrat ration ion,, aft after er esterification of the fatty acids with methanol in the presence of sulfuric acid as a catalyst, followed by separation of the acids. This test method requires use of an experimentally determined correction corre ction factor dependent dependent upon the amoun amountt of rosi rosin n acids 7 present. 22. Appar Apparatus atus 22.1 Flask , 250 250-mL -mL flat flat-bo -botto ttom, m, of che chemic micall ally y res resist istant ant glass with a standard-taper 24/40 neck. 22.2 Condenser , water-cooled, with a joint fitting the flask described in 22.1 22.3 Separatory Funnel, 500-mL, pear-shaped, fitted with a glass stopper. 22.4 Buret , 50-mL capacity, with 0.1-mL divisions.
25. Calculation 25.1 Calcu Calculate late the percentage percentage of rosin acids acids as foll follows: ows: Rosin acids, % 5 ~ 1.031 3 AN 3 S 2 3 30.2! / S 2 0.74
23. Reag Reagents ents
where: A = N = S = 0.74 0.7 4 =
23.1 Alcohol—Neutral methanol, neutral isopropanol (91 to 99 %), neu neutra trall 95 % eth ethano anol, l, or neu neutra trall den denatu atured red alc alcoho oholl conforming to formula No. 30 or No. 3A of the U.S. Bureau of Internal Revenue. 23.2 Ethyl Ether . 23.3 Methanol (99.5 %). 23.4 Methyl Orange Indicator Solution —Dissolve 0.1 g of methyl orange in 100 mL of water. 23.5 Phenolphthalein Indicator Solution —Dissolve 1 g of phenolphthalein in 100 mL of methanol.
(3)
KOH soluti solution on used used for for titrat titration ion of of the samp sample, le, mL, mL, normalit norm ality y of KOH solut solution, ion, sample sam ple use used, d, g, and correl cor relati ation on fac factor tor6 for a rosin acids content not over 15 %.
ROSIN ACIDS BY THE LINDER-PERSSON METHOD 8 26. Scope 26.1 26. 1 Thi Thiss tes testt met method hod cov covers ers the det determ ermina inatio tion n of ros rosin in acids content of rosin, unmodified by such materials as maleic
7
For information on the development of this test method and the establishment of the correction factor, see Herrlinger, R., and Compeau, G. M., “The Determination of Ros Rosin in in Fatt Fatty y Acids.” Acids.” Journal Journal of the American American Oil Chemists’ Chemists’ Soci Society ety,, August 1952, pp. 342–344.
8
Linder, A., and Persson, V., “Determination of Rosin Acids in Mixtures with Fatty Acids,” Journal Acids,” Journal of the American Oil Chemists’ Society , Vol XXXIV, No. 1, 1957, pp. 12–27.
4
D 1240 or fumaric acid, or phenols. Rosin acids determined by this method include free rosin.
used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 Other grades may be used, use d, pro provid vided ed it is firs firstt det determ ermine ined d tha thatt the reagent reagent is of sufficiently high purity to permit its use without lessening the accuracy of the test. 29.2 Cyclohexane. 29.3 n-Butyl Alcohol. Alcohol-S ol-Sulfur ulfuric ic Acid Este Esterifica rification tion Reage Reagent nt — 29.4 Butyl Alcoh Add 500 mL of n -butyl alcohol, 500 mL of cyclohexane, and 3.3 mL (6 g) of sulfuric acid (H 2SO4) in a 2 L round-bottom flask with ground glass joint, connect to a moisture trap and condenser, and reflux on a hot plate for 30 min to distill out the wate wa terr an and d fo form rm bu buty tyll-su sulf lfur uric ic ac acid id.. Co Cool ol an and d st stor oree in a glass-stoppered bottle. 0.25 N Potas Potassium sium Hydr Hydroxide oxide,, Meth Methanoli anolicc Stand Standar ard d 29.5 0.25 Solution—Dissolve 16.5 g of potassium hydroxide pellets in 1 L of methanol. Standardize against potassium acid phthalate primary standard. 29.6 Sulfuric Acid (sp gr 1.84) —Concentrated sulfuric acid (H2SO4). 29.7 Thymol Blue Indicator Solution (10 g /L) —Mix 1 g of thymol blue indicator with 100 mL of ethyl alcohol.
27. Summa Summary ry of Test Method 27.1 The rosin acids are determined determined by a selective selective esterification of fatty acids with n -butyl alcohol using sulfuric acid as a catalyst. The rosin acids content is then found by titration. 27.2 The method is applicable applicable for measuring measuring the rosin acids acids content of naval stores products containing greater than 60 % rosin. 28. Appar Apparatus atus 28.1 Condenser , wat water er-c -cool ooled, ed, equ equipp ipped ed wit with h a 24 24/40 /40 standard-taper joint. 28.2 Buret , as in 9.3. 28.3 Erlenmeyer Flask , 250–mL of a chemically resistant glass with a standard-taper 24/40 joint. 28.4 Moisture construct tructed ed acco according rding to Moisture Coll Collectio ection n Tr Trap ap, cons details deta ils shown in Fig. 1. Alte Alternati rnatively vely,, a comm commerci ercial al DeanStark trap with a minimal collection volume, preferably 5 mL, can be used. Wrap with insulation. 28.5 Pipet , 50 mL capacity 28.6 Stirrer , magnetic, equipped with a stir bar coated with poly(tetrafluorethylene). 29. Reage Reagents nts and Mate Material rialss 29.1 Purity of Reagents —Reagent grade chemicals shall be
30. Proc Procedur eduree 30.1 Tra Transfe nsferr 1 to 1.2 g of sample, sample, weighed to the nearest nearest 0.0001 g to a 250–mL Erlenmeyer flask. 30.2 Pipet exactly exactly 50 mL of the butyl sulfuric sulfuric acid esterification reagent into the flask. 30.3 30. 3 Connect Connect the flas flask k to the moi moistu sture re col collec lectio tion n tr trap, ap, having filled the collection arm with butanol. Connect the trap to a co cond nden ense serr an and d pl plac acee th thee fla flask sk on a ho hott pl plat ate. e. He Heat at to boiling and reflux for 20 min, measuring from the time the first drop dro p of con conden densat satee fal falls ls fro from m the condense condenserr. At the end of heating, allow the flask to cool somewhat, then remove and cool to room temperature. 30.4 Add 0.5 ml of thymol blue indicator indicator solution and titrate with wit h the alc alcoho oholic lic KOH sol soluti ution on to the second second end poi point, nt, yellow to blue, at about pH 10.8. 30.5 Make a blan blank k titration titration on 50 mL of the esterificat esterification ion solution, after refluxing it in the same manner. 31. Calculation 31.1 Calcu Calculate late the percent rosin rosin acid acidss in the samp sample le using the following equation. Rosin acids, % 5 ~ A2 B! 3 N 3 S 2 3 30.244 3 1.0184/ S 2 0.30
(4)
where: = alcoholic alcoholic KOH solu solution tion requi required red for titr titration ation of A the sample, mL, B = alco alcoholic holic KOH solu solution tion requi required red for titr titration ation of the blank, mL, N = norm normalit ality y of the KOH solut solution ion used used,, S = wei weight ght of the sam sample ple,, g, 30.244 = mol molecu ecular lar weight weight of abi abieti eticc aci acid d mul multip tiplie lied d by 100 and divided by 1000,
FIG. 1 Mositure Collection Trap
5
D 1240 should agr should agree ee wit within hin 0.8 0.81 1 %. Suc Such h val values ues are sui suitab table le for averaging. 32.1.1 32.1. 1 The betw betweeneen-labo laborato ratory ry stan standard dard devi deviatio ation n was found to be 0.43 %, absolute. Single determinations from two laboratories should agree within 1.2 %. 32.2 Bias—No bia biass can be det determ ermine ined d sin since ce no sta standa ndard rd naval stores products are available.
1.0184 = factor factor to cor correc rectt for the sli slight ght esterific esterificati ation on of rosin acids, and = facto factorr to corre correct ct for for unester unesterified ified fatt fatty y acids. acids. 0.30 31.2 Repor Reportt the resu results lts to one deci decimal mal place. place.
32. LinderLinder-Persson Persson Method Precision and Bias 32.1 Precision—The following information was developed by the laboratories of a single company. As such, it does not meett the req mee requir uireme ements nts nor normal mally ly exp expect ected ed for a pre precis cision ion statem sta tement ent.. How Howeve everr, the inf inform ormati ation on sho should uld be use useful ful for comparative purposes. The within-laboratory standard deviation of this method was found to be 0.29 %, at the 83.6 % rosin acid leve level. l. Dupli Duplicate cate determination determination from a sing single le labor laboratory atory
33. Keyw Keywords ords 33.1 fatty fatty acid acids; s; Gli Glidden dden met method; hod; Her Herrli rlinger nger-Co -Compea mpeau u method; rosin; tall oil; tall oil fatty acid; tall oil rosin; Wolfe Method
ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of 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 be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make 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, West Conshohocken, PA 19428-2959, United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address add ress or at 610 610-832 -832-95 -9585 85 (ph (phone one), ), 610 610-83 -832-95 2-9555 55 (fax (fax), ), or serv service ice@as @astm.o tm.org rg (e-m (e-mail ail); ); or thro through ugh the AST ASTM M web websit site e (www.astm.org).
6
