1、Designation: D2959 95 (Reapproved 2009)Standard Test Method forEthylene Oxide Content of Polyethoxylated NonionicSurfactants1This standard is issued under the fixed designation D2959; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 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 This test method covers the determination of ethyleneoxide in polyethoxylated nonionic surfactants. It ca
3、n also beused for compounds containing propylene oxide or any com-pounds (glycols and glycol and polyglycol ethers and esters)which form unstable 1,2-diiodides on reaction with hydriodicacid.NOTE 1Compounds in which the oxyalkylene group is connected to anitrogen cannot be entirely decomposed. This
4、can be used to determine thepercent of an ethoxylated surfactant in a mixture, if the ethylene oxidecontent of the ethoxylated surfactant is known.NOTE 2This method reports results as percent ethylene oxide. If thismethod is applied to unknown compounds or compositions, the analystshould be aware of
5、 the possible presence of material other than ethyleneoxide.NOTE 3For use on built syndet compositions the organic activeingredient must be isolated in accordance with Test Method D2358.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thi
6、sstandard.1.3 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. Mate
7、rial SafetyData Sheets are available for reagents and materials. Reviewthem for hazards prior to usage.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD2358 Test Method for Separation of Active Ingredientfrom Surfactant and Syndet Compositions3. Summary of Test Method
8、3.1 By cleaving nonionic surfactants containing polyethyl-ene oxide chains with hydriodic acid, the unstable 1,2-diiodoethane is formed. This vicinal diiodide decomposes toform ethylene and iodine.3.2 The percent ethylene oxide is determined by measuringthe amount of free iodine formed, since one mo
9、le of iodine isformed for each mole of ethylene oxide in the polyoxyalkylenechain. The free iodine is titrated with a standard sodiumthiosulfate solution.4. Apparatus (Fig. 1)4.1 Heat Sources, two. The source of heat should be anelectric heater provided with a sliding rheostat or other meansof heat
10、control.4.2 Flasks, two, 100-mL, round bottom. Each flask shouldbe equipped with a standard ground-glass joint to accommo-date a vertical condenser, and with a side arm through whichcarbon dioxide can be passed to blanket the reaction mixture.4.3 Condensers, two, with standard joints to fit the flas
11、ks.4.4 Gas Bubbler, filled with dibutyl phthalate.4.5 Buret, 50-mL, with 0.1-mL graduations.4.6 Pipet, 5-mL.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 Commi
12、t-tee on Analytical Reagents of the American Chemical Society,1This method is under the jurisdiction of ASTM Committee D12 on Soaps andOther Detergents and is the direct responsibility of Subcommittee D12.12 onAnalysis and Specifications of Soaps, Synthetics, Detergents and their Components.Current
13、edition approved Oct. 1, 2009. Published December 2009. Originallyapproved in 1971 as D2959 71 T. Last previous edition approved in 2003 asD2959 95(2003). DOI: 10.1520/D2959-95R09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org
14、. 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.where such specifications are available.3Other grades may beused,
15、provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type III reagent waterconforming to Sections 1, 2, and 3
16、of Specification D1193.5.3 Carbon Dioxide or Nitrogen, cylinder gas.5.4 Lubricant for ground-glass joints.5.5 Dibutyl Phthalate.5.6 Glass Beads.5.7 Hydriodic Acid (55 to 58 %) (suitable for methoxyldeterminations)The hydriodic acid (HI) should not containhypophosphorus acid (H3PO2) stabilizer. The f
17、ree iodine con-tent should be less than 10 mL of 0.1 N sodium thiosulfatesolution/5 mL of HI.5.8 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).5.9 Methanol.5.10 Potassium Dichromate (K2Cr2O7), primary standard.5.11 Potassium Iodide Solution (200 g/L)Dissolve 200 gof potassium i
18、odide (KI) in distilled water and dilute to 1000mL.5.12 Sodium Thiosulfate, Standard Solution (0.1 N)Dissolve 24.8 g of sodium thiosulfate (Na2S2O3) in water anddilute to 1000 mL. Standardize by accurately weighing 0.16 to0.22 g of finely ground and dried K2Cr2O7into a 500-mLiodine flask. Dissolve i
19、n 25 mL of water, add 5 mL of HCl and15 mL of KI solution and swirl to mix. Allow to stand for 5min, then add 100 mL of distilled water. Titrate with standardNa2S2O3solution, shaking continuously until the yellow colorhas almost disappeared. Add a small amount of Paragonindicator4or 1 to 2 mLof star
20、ch indicator solution and continuethe titration, adding the Na2S2O3solution slowly until the bluecolor has just disappeared. Calculate the normality of theNa2S2O3solution as follows:N 5 C/0.04904 3 D! (1)where:N = normality of the Na2S2O3solution,C = grams of K2Cr2O7used, andD = millilitres of Na2S2
21、O3solution required for titration ofthe solution.5.13 Starch Indicator SolutionMake a homogeneouspaste of 10 g of soluble starch in water. To this add with rapidstirring 1 L of boiling water and then cool. As a preservative,add 1.25 g of salicylic acid per litre. Store the indicator in arefrigerator
22、 at 4 to 10C. Prepare fresh indicator when thetitration end point from blue to colorless fails to be sharp.6. Procedure6.1 Assemble the apparatus as shown in Fig. 1. Lubricatethe ground-glass joints with a very thin film of lubricant. Thedual apparatus is designed to permit a sample and a blank to b
23、erun simultaneously; however, it should not be necessary tomake more than two blank determinations each day.6.2 Accurately weigh a sample of such size that 4 to 5 meqof iodine will be liberated (about 0.15 g of a nonionicsurfactant that contains 60 % ethylene oxide) into a 100-mLround bottom flask.
24、Pipet exactly 5.0 mL of HI into the flask,and add a glass bead. Connect the vertical condenser to theflask using a thin seal of lubricant at the outer edge. Prepare ablank by pipetting 5.0 mL of HI into a second flask containinga glass bead. Connect the condenser as described above, andallow water t
25、o circulate through the condensers.6.3 Attach the tubes from the carbon dioxide manifold to thesidearms on the flasks. Open the valve on the gas cylinder andadjust the flow to a rate of 1 to 5 bubbles per second throughthe bubbler, blanketing the solutions in the reaction flasks. Theflow of carbon d
26、ioxide should continue for 10 min before heatis applied to the reaction flasks. After 10 min turn on the heat,and reflux the contents gently for 90 min.6.4 After the 90-min boiling period, wash the walls of eachcondenser with 15 mL of 20 % KI solution to dissolve any freeiodine in the condensers. Wa
27、sh the condensers with two 10-mLportions of water and disconnect. Wash the tips of the con-densers with water, adding the washings to the flasks. Transferthe contents of the reaction flasks to Erlenmeyer flasks bywashing with water.NOTE 4Rinse any iodine that adheres to the condensers into the flask
28、s3Reagent 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 LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmaco
29、peiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.4The sole source of supply of the Paragon indicator for iodine titrations knownto the committee at this time is Eastern Chemical Corp., 34 Spring St., Newark, NJ07104 If you are aware of alternative suppliers, pleas
30、e provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.FIG. 1 ApparatusD2959 95 (2009)2with a small amount of methanol. On rare occasions some samples leavea tarry resid
31、ue as a button.Add methanol to dissolve the residue, and washinto the Erlenmeyer flask.6.5 Titrate with standard Na2S2O3solution, shaking con-tinuously until the yellow color has almost disappeared. Add asmall amount of Paragon indicator or 1 to 2 mL of starchindicator solution and continue the titr
32、ation, adding theNa2S2O3solution slowly until the blue color has just disap-peared.7. Calculation7.1 Calculate the ethylene oxide content as follows:Ethylene oxide, weight % 5 A 2 B! 3 N 3 2.203/W (2)where:A = millilitres of Na2S2O3solution required to titrate thesample,B = millilitres of Na2S2O3sol
33、ution required to titrate theblank,N = normality of Na2S2O3solution, andW = grams of sample.8. Precision and Bias8.1 The following criteria should be used for judging theacceptability of results (Note 5):8.1.1 Repeatability (Single Analyst)The standard devia-tion of results obtained by the same anal
34、yst was estimated to be0.47 % absolute at 9 df. Two such values should be consideredsuspect (95 % confidence level) if they differ by more than1.5 % absolute.8.1.2 Reproducibility (Multilaboratory)5The standard de-viation of results (each the average of duplicate determina-tions), obtained by analys
35、ts in different laboratories, has beenestimated to be 1.81 % absolute at 7 df. Two such valuesshould be considered suspect (95 % confidence level) if theydiffer by more than 6.0 % absolute.NOTE 5The precision estimates are based on an interlaboratory studyon Igepal CO 630 by nine laboratories. Howev
36、er, this procedure as writtencalls for the use of 100-mL reaction flasks (instead of 50-mL flasks whichwere used in the interlaboratory study). Data obtained by Continental OilCo. indicate an improvement in precision when the larger flask is used.9. Keywords9.1 ethylene oxide content; nonionic surfa
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38、s, 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 andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional s
39、tandardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM C
40、ommittee 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 abovead
41、dress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).5Data supporting the precision statements are on file at ASTM Headquarters.Request Research Report No. D12-1000.D2959 95 (2009)3
