1、Designation: D4711 89 (Reapproved 2009)Standard Test Method forSulfonic and Sulfuric Acids in Alkylbenzene Sulfonic Acids1This standard is issued under the fixed designation D4711; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 is applicable to the determination ofsulfonic and sulfuric acids in branched and linear alk
3、ylbenzenesulfonic acids used as intermediates in synthetic detergents.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
4、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. Material SafetyData Sheets are available for reagents and materials. Reviewthem for hazards prior to usage.2. Referenced
5、 Documents2.1 ASTM Standards:2D459 Terminology Relating to Soaps and Other DetergentsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals33. Summary of Test Method3.1 A methanolic solution of the sample is titrated withcyclohexyla
6、mine in methanol to yield a potentiometric curve.(See Fig. 1.) The first inflection represents the neutralization ofstrong acids, such as sulfonics and alkylsulfurics, and the firsthydrogen of sulfuric acid. The second inflection represents theneutralization of the second hydrogen of sulfuric acid.
7、Theamount of sulfonic acid is calculated based on the titrantvolume of the first inflection minus that between the twoinflections. The amount of sulfuric acid meanwhile is calcu-lated from the titrant volume between the two inflections,which is equivalent to the amount of base required forneutraliza
8、tion of the bisulfate anion.4. Significance and Use4.1 Alkylbenzene sulfonic acids are important intermediatesin the synthetic detergent industry and are defined under “alkylbenzene sulfonate” in Terminology D459. This test method issuitable for the rapid monitoring of the sulfonic and sulfuric1This
9、 test method is under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergents and is the direct responsibility of Subcommittee D12.12 onAnalysis and Specifications of Soaps, Synthetics, Detergents and their Components.Current edition approved Oct. 1, 2009. Published March 2010. Originall
10、yapproved in 1987. Last previous edition approved in 2003 as D4711-89(2003). DOI:10.1520/D4711-89R09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards D
11、ocument Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.Solvent. Methanol A. Differentiating titration curveTitrant. 0.1 N Cyclohexylamine B. First derivative curve of the curve AFIG. 1 Titration of a detergent intermedia
12、te containing alkylsulfonic acid and sulfuric acids.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.acid levels, both of which have a vital bearing on final productperformance and appearance.5. Interferences5.1 Strong acids, like nit
13、ric and hydrochloric, interfere, asdo weak acids, such as carboxylic acids. Small amounts ofwater originally present in the sample do not interfere in thedetermination. However, if as much as 5 % of water is presentin the total solution (solvent plus sample), the end pointbecomes less sharp.6. Appar
14、atus6.1 Potentiometric Titrator,4and combination calomel ref-erence electrode.6.2 Buret Assembly, having a 20 mL buret.46.3 Beaker, 180 mL tall form.6.4 Volumetric Flask, Class A, 500 mL.6.5 Magnetic Stirrer, and stirring bar.7. Reagents and Materials7.1 Methanol, anhydrous,7.2 Cyclohexylamine (0.10
15、 N)Dissolve 10 g of reagentcyclohexylamine in 1000 mL of anhydrous methanol. Stan-dardize against sulfamic acid as described in Section 8.7.3 Sulfamic Acid, acidimetric standard.58. Standardization of 0.10 N Cyclohexylamine8.1 All standardizations should be run in triplicate. Thismeans separate weig
16、hings for solution preparations in 8.2.8.2 Using an analytical balance, accurately weigh 0.10 to0.12 g of sulfamic acid to the nearest 0.1 mg into a 180 mL tallform beaker. Dissolve in 100 mL of anhydrous methanol. Mixwell.8.3 Titrate with 0.10N cyclohexylamine using the combina-tion electrode on th
17、e automatic titrator until the completedevelopment of a single break. Record the mL at the inflectionpoint.8.4 Calculate the normality of the cyclohexylamine solutionas follows:Normality of Cyclohexylamine 5 G!1000!/M!97.09! (1)where:G = grams of sulfamic acid, andM = mL of cyclohexylamine to inflec
18、tion point.9. Procedure9.1 Using an analytical balance, accurately weigh 1.2 to 1.5meq to the nearest 0.1 mg of sample directly into a 180 mL tallform beaker. Sample size may be calculated from the follow-ing:Grams sample 5 1.35 meq/meq/g acidity expected (2)NOTE 1Most detergent range alkylbenzene s
19、ulfonic acids have a totalacidity of about 3.35 meq/g meaning that the sample weight should beabout 0.35 to 0.45 g. This yields a total titer of about 12 to 15 mL of 0.10N cyclohexylamine and a difference of about 0.45 to 0.68 mL between thetwo breaks for a sample containing about 1.25 % sulfuric ac
20、id.9.2 Add a magnetic stirring bar, 100 mL of anhydrousmethanol, and stir with a magnetic stirrer until dissolved.9.3 Titrate potentiometrically on the automatic titrator usingthe combination electrode until a curve yielding two breaks isobtained. (See Fig. 1.)9.4 Record the volume of titrant to the
21、 first break as V1, andthat to the second break V2.10. Calculation10.1 Calculate the weight percent sulfuric acid (H2SO4) andweight percent sulfonic acid (RSO3H) as follows:% H2SO45 V22 V1!N!98.08!100!/W!1000! (3)%RSO3H 5 2V12 V2!N!MW!100!/W!1000! (4)where:V1,V2= millilitres of titrant at the first
22、and the second endpoints respectively.N = normality of titrant,W = sample weight, g, andMW = average equivalent weight of sulfonic acid.11. Precision and Bias6,711.1 Repeatability (Single Analyst)The standard deviationof results (each the average of duplicates) obtained by the sameanalyst on differe
23、nt days, has been estimated to be 0.03 %absolute at 14 degrees of freedom. Two such averages shouldbe considered suspect (95 % confidence level) if they differ bymore than 0.08 % absolute.11.2 Reproducibility (Multilaboratory)The standard de-viation of results (each the average of duplicates) obtain
24、ed byanalysts in different laboratories, has been estimated to be0.05 % absolute at 13 degrees of freedom. Two such averagesshould be considered suspect (95 % confidence level) if theydiffer by more than 0.16 % absolute.11.3 Checking Limits for DuplicatesReport the activecontent of the sample to the
25、 nearest 0.01 %. Duplicate runs thatagree within 0.1 % are acceptable for averaging (95 % confi-dence level).SULFONIC ACID PERCENT11.4 Repeatability (Single Analyst)The standard deviationof results (each the average of duplicates) obtained by the sameanalyst on different days, has been estimated to
26、be 0.16 %absolute at 14 degrees of freedom. Two such averages shouldbe considered suspect (95 % confidence level) if they differ bymore than 0.48 % absolute.11.5 Reproducibility (Multilaboratory)The standard de-viation of results (each the average of duplicates) obtained byanalysts in different labo
27、ratories, has been estimated to be0.36 % absolute at 13 degrees of freedom. Two such averages4Metrohm A436, or its equivalent, has been found suitable for this purpose.Available from Brinkman Instruments.5J. T. Baker No. 4898, or its equivalent, has been found suitable for this purpose.Available fro
28、m Sargent-Welch Scientific Co., 7300 Linder Ave., PO Box 1026,Skokie, IL 60077.6Supporting Data on file at ASTM Headquarters. Request RR:D12-1009.7Practice E180 was used to determine precision and bias.D4711 89 (2009)2should be considered suspect (95 % confidence level) if theydiffer by more than 1.
29、1 % absolute.11.6 Checking Limits for DuplicatesReport the activecontent of the sample to the nearest 0.01 %. Duplicate runs thatagree within 0.45 % are acceptable for averaging (95 % con-fidence level).11.7 BiasSince there is no accepted reference materialsuitable for determining the bias for the p
30、rocedure in this testmethod, no statement on bias is being made.NOTE 2The precision data were derived from results of cooperativetests by sixteen laboratories on a linear alkylbenzene sulfonic acid havingan average equivalent weight of 318.12. Keywords12.1 alkylbenzene sulfonic acid; sulfonic acid;
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34、own 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 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 ASTM website (www.astm.org/COPYRIGHT/).D4711 89 (2009)3
