1、Designation: D2959 95 (Reapproved 2017)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 ofActive Ingredient fromSurfactant and Syndet Compositions3. Summary of Test Method3
8、.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 mol
9、e 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 c
10、ontrol.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 flask
11、s.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 Commit
12、-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 e
13、dition approved Jan. 1, 2017. Published February 2017. Originallyapproved in 1971 as D2959 71 T. Last previous edition approved in 2009 asD2959 95(2009). DOI: 10.1520/D2959-95R17.2For 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internat
15、ionally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1where such specifications are available.3Other grad
16、es 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 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type III reagent waterconforming to Sectio
17、ns 1, 2, and 3 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) st
18、abilizer. The free 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
19、gof potassium iodide (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 fl
20、ask. Dissolve in 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
21、 to 2 mLof starch 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 = milli
22、litres of Na2S2O3solution required for titration ofthe solution.5.13 Starch Indicator SolutionMake a homogeneous pasteof 10 g of soluble starch in water. To this add with rapid stirring1 L of boiling water and then cool. As a preservative, add 1.25g of salicylic acid per litre. Store the indicator i
23、n a refrigeratorat 4 to 10C. Prepare fresh indicator when the titration endpoint 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 a
24、nd a blank to berun 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
25、 bottom flask. 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, a
26、ndallow water to 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. Thef
27、low of carbon dioxide 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
28、 condensers. Wash the condensers with two 10-mL3Reagent 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,
29、 Dorset, U.K., and the United States Pharmacopeiaand 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
30、you are aware of alternative suppliers, please 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 (2017)2portions of water and disconnect. Was
31、h 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 flaskswith a small amount of methanol. On rare occasions some samples leav
32、ea tarry residue 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 con
33、tinue the titration, 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 32.203#/W (2)where:A = millilitres of Na2S2O3solution required to titrate thesample,B = millilitres
34、of Na2S2O3solution 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
35、the same analyst 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 duplicatedeterminations), obtaine
36、d by analysts in different laboratories,has been estimated to be 1.81 % absolute at 7 df. Two suchvalues should be considered suspect (95 % confidence level) ifthey differ by more than 6.0 % absolute.NOTE 5The precision estimates are based on an interlaboratory studyon Igepal CO 630 by nine laborato
37、ries. However, 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; non
38、ionic surfactantsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of
39、 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 andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for a
40、dditional standardsand 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
41、 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
42、the aboveaddress 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ supporting the precision statements are on file at ASTM Headquarters.Request Research Report No. RR:D12-1000.D2959 95 (2017)3
