1、Designation: D 3049 89 (Reapproved 2003)Standard Test Method forSynthetic Anionic Ingredient by Cationic Titration1This standard is issued under the fixed designation D 3049; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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 This test method covers the determination of the amountof synthetic anionic ingredient in a surfactant by direct
3、titrationwith a standardized cationic reagent. The test method is asimple and convenient means for the quantitative estimation ofthe anionic material. The end point is detected by the transferof a colored complex from an organic solvent phase to anaqueous phase. The colored complex is formed by the
4、additionof a solution of dye to a solution of the anionic surfactant. Thiscomplex is soluble in the organic-solvent phase and insolublein the aqueous phase. When this solution is titrated with astandardized solution of a cationic reagent, the dye is displacedfrom the colored complex and, being water
5、-soluble, migrates tothe aqueous phase. Therefore, a cationic titrating solution thathas been standardized against a characterized anionic agent canbe used to analyze for other anionics of known molecular mass.1.2 This test method is applicable to alkylaryl sulfonates,alkyl sulfonates, alkyl sulfate
6、s and hydroxy-sulfates,alkylphenol- and fatty alcohol ethoxy-sulfates and dialkylsul-fosuccinates. It applies to active materials containing onehydrophilic group per molecule.1.3 The analytical procedures appear in the following order:SectionsReagents 6Primary Standard 8Purity 8.2Alcohols 8.3Free Ac
7、id or Alkali 8.4Preparation of Mixed Indicator Solution 9Preparation of Hyamine Solution 10Standardization of Hyamine Solution 11General Procedure for Anionic-Active Material 121.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsi
8、bility 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. A precautionarystatement appears in Section 7. Material Safety Data Sheets areavailable for reagents and materials. Review them for hazar
9、dsprior to usage.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water23. Summary of Test Method3.1 An aqueous solution of an anionic-type detergent, towhich is added a small amount of mixed indicator (dimidiumbromide and disulphine blue), is shaken with aqueous Hyaminesol
10、ution and chloroform. The pink complex which is formed bythe reaction between the anionic detergent and the cationic dye,dimidium bromide, is extracted into the chloroform. Incre-ments of additional Hyamine solution are added with athorough mixing after each addition. At first the reaction takesplac
11、e between the Hyamine and the excess anionic-typedetergent, during which there is no noticeable change in thecolor (pink) of the chloroform phase. As the equivalence pointbetween the anionic and cationic materials is approached, thedimidium bromide portion of the anionic detergent active-dimidium br
12、omide complex (pink) is gradually released andtransferred to the aqueous layer. As excess Hyamine is added itreacts with the anionic dye, disulphine blue, to form achloroform-soluble blue complex. During the transition at theend point the chloroform layer, therefore, changes from pink togray, to blu
13、e. The gray color is taken as the end point.4. Significance and Use4.1 This test method offers a means of determining anionicdetergents commonly found in laundry, dishwashing, and othercleaning materials. Accurate determination of the anionicactive substance is highly important in assessing the cost
14、 andeffectiveness of such cleaning substances.4.2 This test method is not affected by low molecular weightsulfonates, such as those of toluene and xylene commonlyfound in detergent formulations, when these substances arepresent up to 15 weight % of active material.5. Interferences5.1 Normal inorgani
15、c components of detergent formula-tions, such as chloride, sulfate, borate, phosphates, perborate,and silicates do not interfere. Soaps, urea, and ethylenedi-aminetetraacetic acid salts do not interfere. Bleaching agentsother than perborate should be destroyed prior to performing1This test method is
16、 under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergents and is the direct responsibility of Subcommittee D12.12 onAnalysis of Soaps and Synthetic Detergents.Current edition approved May 26, 1989. Published July 1989. Originallypublished as D 3049 72 T. Last previous edition D 3049
17、 88.2Annual Book of ASTM Standards, Vol 11.01.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.this analysis. Low molecular weight sulfonates, such as thoseof toluene and xylene, do not interfere when present up to 15 %(w) of active m
18、aterial. Since the titration is performed underacidic conditions (about pH 2.0), care should be exercisedwhen using this procedure on products containing significantamounts of alkaline materials, such as carbonates and silicates,to ensure that the final solution is being titrated in the properpH ran
19、ge.6. Reagents6.1 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 Chemical Society,where such specifications are available.3Ot
20、her 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.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specifi
21、cation D 1193.6.3 Chloroform.6.4 Ethanol.6.5 Petroleum Ether, boiling range 30 to 50C.6.6 Phenolphthalein Indicator Solution (1 %)Dissolve 1g of phenolphthalein in 95 % ethanol and dilute to 100 mL.6.7 Sodium Hydroxide, Standard Solution (0.1 N)Preparea 0.1 N solution of sodium hydroxide (NaOH).6.8
22、Sodium Hydroxide, Standard Solution (1 N)Prepare a1 N solution of NaOH.6.9 Sodium Hydroxide, Standard Solution (50 %)Preparea 50 % solution of NaOH.6.10 Sodium Lauryl Sulfate, Standard Solution, (0.004 M).6.10.1 Weigh accurately between 1.14 and 1.16 g of sodiumlauryl sulfate and dissolve in 200 mL
23、of water.6.10.2 Transfer to a stoppered graduated 1-L flask and diluteto volume with water.6.10.3 Calculate the molarity of the solution as follows:Molarity 5 W23 P!/288.4 3 100! (1)where:W2= sodium lauryl sulfate, g, andP = purity of the sodium lauryl sulfate, %.6.11 Sodium Sulfate (Na2SO4), anhydr
24、ous.6.12 Sulfuric Acid, Standard (0.1 N)Prepare a 0.1 Nsolution of sulfuric acid (H2SO4).6.13 Sulfuric Acid, Standard (0.5 N)Prepare a 0.5 Nsolution of H2SO4.6.14 Sulfuric Acid, Standard (1 N)Prepare a 1 N solutionof H2SO4.7. Safety Precaution7.1 This test method includes the use of small amounts of
25、chloroform. Appropriate safety practices, such as those in-cluded in the Material Safety Data Sheets for chloroform,should be employed. Good ventilation is especially important.8. Primary Standard8.1 The primary standard used in this procedure is sodiumlauryl sulfate.4Three tests are made on this pr
26、imary standard asfollows:8.2 Purity:8.2.1 This test should be run in duplicate.8.2.2 Weigh, to the nearest 0.1 mg, 10 6 0.2 g of theprimary standard into a 250-mL round-bottom flask.8.2.3 Add exactly 25 mL of 0.5 N H2SO4. It is not necessaryto standardize this acid.8.2.4 Reflux under a water condens
27、er for 2 h. Heat moder-ately in the beginning until the solution clarifies and thefoaming ceases; then increase the heat input until a vigorousreflux is attained.8.2.5 Remove the heat source, cool the flask, and then washdown the condenser with approximately 30 mL of ethanolfollowed by 50 mL of wate
28、r. Add the washings to the reactionflask.8.2.6 Disconnect the condenser and wash the point and theneck with water. Add these washings to the reaction flask.8.2.7 Add a few drops of 1 % phenolphthalein indicatorsolution and titrate the H2SO4with standardized 1 N NaOHsolution.8.2.8 Determine a blank v
29、alue by titrating 25 mL of the 0.5N H2SO4with the standardized 1 N NaOH solution. Thisshould be done in duplicate and the average used.8.2.9 Calculate the percent purity of the primary standard asfollows:Purity, % 5 28.84 3 A 2 B! 3 N#/W (2)where:A = NaOH solution used in sample titration, mL,B = Na
30、OH solution used in blank titration, mL,N = normality of the NaOH solution, andW = primary standard used, g.8.2.10 For best precision and accuracy, temperature andburet corrections should be made when titrating the hydroly-sate of the sodium lauryl sulfate with 1 N NaOH solution.8.3 Alcohols:8.3.1 T
31、he primary standard, sodium lauryl sulfate, is sold ashaving not more than 1 weight % (Note 1) of a sum of decyland tetradecyl alcohol sulfates. The following test should berun in duplicate.NOTE 1The term “weight” is temporarily used in this standardbecause of established trade usage. The word is us
32、ed to mean both “force”and “mass,” and care must be taken to determine which is meant in eachcase (SI unit for force = newton and for mass = kilogram).3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents no
33、tlisted 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. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.4Manufactured by British Drug House, Ltd. as Product No. 30176. It
34、 is sold asbeing more than 99 % pure. It is available in the United States from Gallard-Schlesinger Chemical Manufacturing Corp., Carle Place, Long Island, NY 11514.D 3049 89 (2003)28.3.2 Mix approximately5gofsodium lauryl sulfate with25 mL of 1 N H2SO4in a 250-mL round-bottom flask.8.3.3 Reflux und
35、er a water condenser for at least 2 h. Heatmoderately at first until the solution clarifies and foamingceases.8.3.4 Cool the contents of the flask and transfer with waterto a separatory funnel.8.3.5 Extract this solution with 50 mL of petroleum ether(boiling range 30 to 50C).8.3.6 Extract four more
36、times with 25-mL portions ofpetroleum ether.8.3.7 Combine the petroleum ether fractions in a 250-mLbeaker.8.3.8 Allow the aqueous phase to settle out; then decant thepetroleum ether phase through anhydrous Na2SO4to removewater. Collect the effluent in another 250-mL beaker.8.3.9 Evaporate the petrol
37、eum ether on a steam bath.8.3.10 Determine the carbon number distribution of thealcohols present by gas liquid chromatography.58.4 Free Acid Or Alkali:8.4.1 This test, when run on a newly received lot of theprimary standard, gives an estimate of the acidity or alkalinityof the material. Subsequently
38、, it can be used as a check onhydrolysis of the sodium lauryl sulfate during storage.8.4.2 Weigh to two decimal places1gofthesodium laurylsulfate.8.4.3 Dissolve the sample in about 150 mL of ethanol thathas been neutralized to phenolphthalein.8.4.4 Add a few drops of phenolphthalein indicator soluti
39、onand titrate with either 0.1 N H2SO4or 0.1 N NaOH solution.8.4.5 Record the millilitres of reagent solution necessary toreturn the solution to neutrality as well as the normality of thetitrant.9. Preparation of the Mixed Indicator Solution9.1 Disulphine Blue6.9.2 Dimidium Bromide7.9.3 Mixed Indicat
40、or Stock SolutionWeigh 0.5 6 0.005 gof dimidium bromide into a 50 mL-beaker. Weigh 0.25 60.005 g of disulphine blue into a second 50-mL beaker. Add 25to 30 mL of 1+10 (v/v) hot ethanol-water solution to eachbeaker. Stir each until the dye is dissolved; then add bothsolutions to a 250-mL volumetric f
41、lask. Rinse each beaker withthe 1+10 ethanol-water solution and add the rinsings to thevolumetric flask. Dilute the stock solution to the mark withdeionized water. After 6 months, this solution should bediscarded.9.4 Acid Indicator SolutionAdd 200 mL of water and 20mL of the mixed indicator stock so
42、lution to a 500-mLvolumetric flask having a stopper. Add 20 mL of 2.5 M H2SO4.Mix well and dilute to the mark with water. Store in a darkplace.10. Preparation of 0.004 M Hyamine 1622 Solution810.1 Weigh between 1.75 and 1.85 g of Hyamine 1622 anddissolve in water. Transfer to a glass-stoppered 1-L v
43、olumetricflask. Add 0.4 mL of 50 % NaOH solution (to keep buret clean)and dilute to the mark with water.10.2 The molecular weight of Hyamine 1622, after removalof one molecule of water by drying, is 448 which correspondsto a weight of 1.792 g required for the preparation of 1 L of a0.004 M solution.
44、 If desired, to provide an approximate checkon the sodium lauryl sulfate standardization, the Hyamine 1622may be dried in an oven at 105C and the dried productaccurately weighed for the preparation of the 0.004 M solution.10.3 For the solution quantities larger than 1 L, multiply theamount of Hyamin
45、e and NaOH by the number of litres desired.11. Standardization of Hyamine 1622 Solution11.1 Pipet 20 mL of 0.004 N sodium lauryl sulfate solutioninto a stoppered 100-mL graduated mixing cylinder.11.2 Add 10 mL of water, 15 mL of chloroform, and 10 mLof acid indicator solution. Precaution, see 7.1.11
46、.3 Add slightly less than an equivalent amount of the0.004 M Hyamine 1622 solution (that is, about 20 mL); stopperand shake the vessel vigorously for 30 s. Then allow the vesselto stand until the emulsion breaks and two phases appear. Thelower layer initially will be colored pink. Continue the titra
47、tion,shaking vigorously after each addition of titrant for at least 15s. As the end point is approached, emulsions formed duringshaking tend to break easily. Continue the titration withdropwise addition of titrant and shaking between additions,until the end point is reached. Take the end point as th
48、e pointat which the pink color is completely discharged from thechloroform layer, which later is then a faint grayish blue. Withexcess Hyamine the chloroform layer is blue. Note the volumeof titrant added.11.4 Calculate the normality of the Hyamine solution asfollows:Normality 5 N 3 20!/V (3)where:N
49、 = normality of the sodium lauryl sulfate solution, andV = Hyamine solution, mL.12. General Procedure for Anionic-Active Material12.1 Weigh accurately a quantity of sample to containapproximately 4 meqs of anionic-active material.5A method similar to that of Link, Hickman, and Morrissette, Journal of theAmerican Oil Chemists Society, Vol 36, 1959, p. 20, is suggested.6This product is available as “Patent Blue VF Extra Concentrate” from GeneralAniline and Film Corp. It is also available as British Drug Houses“ Erioglaucine(Alphazuring 6 or Disulphine Blue V)” whic
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