1、Designation: D 2106 071Standard Test Methods forDetermination of Amine Acid Acceptance (Alkalinity) ofHalogenated Organic Solvents1This standard is issued under the fixed designation D 2106; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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.This standard has been approved for use by agencies of the Department of Defense.1NOTEAdded research report fo
3、otnote to Section 18 editorially in September 2008.1. Scope1.1 These test methods, where applicable, cover the deter-mination of the acid acceptance of halogenated organic sol-vents due to the presence therein of an organic amine titratableby standard acid. These test methods are suitable for sample
4、s of0.001 to 0.02 weight percent (10 200 ppm) alkalinity asNaOH. Two test methods are covered as follows:1.1.1 Test Method A pH Method, and1.1.2 Test Method B Indicator Method.1.1.3 Test Method CGC Method.1.2 This standard does not purport to address all of thesafety concerns, if any, associated wit
5、h 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.2. Referenced Documents2.1 ASTM Standards:2D 6806 Practice for Analysis of Halogenated Organic Sol-vents and T
6、heir Admixtures by Gas ChromatographyE70 Test Method for pH of Aqueous Solutions With theGlass ElectrodeE 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis3. Terminology3.1 Definition:3.1.1 amine acid acceptancethe degree to which an o
7、r-ganic amine present in the halogenated organic solvent iscapable of absorbing or neutralizing acid generated by thesolvent or introduced into it from an external source.4. Significance and Use4.1 This test method is useful for the determination of theamount of acid acceptance contributed by amines
8、 or bases ascompared to other acid-accepting compounds.5. Purity of Reagents5.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, it is intended that all reagents shallconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society,
9、where suchspecifications are available.3Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.5.2 Purity of Water Unless otherwise indicated, refer-ences to water shall be unders
10、tood to mean distilled water orwater of equal purity. Additional requirements are specified in8.1 and 12.1.TEST METHOD ApH METHOD6. Summary of Test Method6.1 The amine acid acceptance of the halogenated organicsolvent is determined, after extraction into a volume of waterpreadjusted to a pH of 3.9,
11、by titrating with standard acid to apH of 3.9. The extraction is performed either by stirring the1These test methods are under the jurisdiction of ASTM Committee D26 onHalogenated Organic Solvents and Fire Extinguishing Agents and are the directresponsibility of Subcommittee D26.04 on Test Methods.C
12、urrent edition approved Feb. 1, 2007. Published March 2007. Originallyapproved in 1962. Last previous edition approved in 2005 as D 2106 05.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volum
13、e information, refer to the standards Document Summary page onthe ASTM website.3Reagent 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 Labo
14、ratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.immiscible liquids mec
15、hanically or by shaking the immisciblelayers of liquids manually.7. Apparatus7.1 pH Meter, equipped with a pH indicating electrode andpH reference electrode or combination electrode.7.2 Stirrer, electric stirring bar, air-driven or magnetic.8. Reagents8.1 WaterAdjust the pH of 1 L (or any convenient
16、quantity) of water to 3.9. Boil 1 L of distilled water for 5 minin a borosilicate glass or stainless steel container, then coverand cool to room temperature. Titrate a 50-mL aliquot to a pHof 3.8 to 4.0 with 0.01 N hydrochloric acid (HCl) (or 0.01 NNaOH if the pH is below 3.8). From this titer, calc
17、ulate thevolume of 0.01 N HCl (or NaOH) required to adjust the pH ofthe remaining 950 mL of boiled distilled water to a pH of 3.8to 4.0. The calculation is as follows:950503 titer (1)Add the calculated amount of 0.01 N HCl (or NaOH)together with the titrated 50 mL aliquot of water to the 950 mLstock
18、 and mix thoroughly. Determine the pH of a secondaliquot. If further adjustment is necessary to obtain a pH of 3.8to 4.0, repeat the preceding procedure.8.2 Hydrochloric Acid, Standard (0.01 N)Dilute 1.8 mLof concentrated hydrochloric acid (HCl, sp gr 1.19) to 1 L withwater and standardize in accord
19、ance with Practice E 200,Sections 20 through 23. Certified reagent of 0.01 N HCl may bepurchased from supply houses.8.3 pH 4.0 Buffer Solution, available from most supplyhouses.8.4 pH 7.0 Buffer Solution, available from most supplyhouses.NOTE 1Hydrochloric acid of about 0.01 to about 0.02 N can be u
20、sed.It can be difficult to see the end point when using hydrochloric acid muchbelow about 0.01 N and concentrations much above 0.02 N increase thelikelihood of over-titrating the end point when titrating samples of lowalkalinity. For alkalinity below about 0.00075 % (75 ppm), 0.01 N HCl isappropriat
21、e. For alkalinity above about 75 ppm, 0.02 N HCl is appropriate.9. Procedure9.1 Calibrate the pH meter in accordance with Test MethodE70.9.1.1 Prepare a blank using 100 mL of water previouslyadjusted to pH 3.9, and subject it to the same type and degreeof agitation as the test samples. Titrate the b
22、lank to pH 3.9 andrecord the volume of titrant as B.9.2 Using Mechanical AgitationTransfer 50 mL of thehalogenated organic solvent to a 150-mL beaker and add 50mL of water previously adjusted to a pH of 3.9. Insert a stirrer,and stir as vigorously as possible for 10 s. Stop the stirrer andlift it ou
23、t of the beaker. Allow the liquids to separate. Insert thepH meter electrodes into the separated aqueous upper layer,avoiding contact of the electrodes with the solvent layer, andtitrate the water layer with 0.01 N HCl to a pH of 3.9. When theend point has been reached, remove the electrodes and rei
24、nsertthe stirrer. Stir vigorously for 10 s again. Remove the stirrer,insert the electrodes, and again titrate to a pH of 3.9. Repeat thesteps until additional stirring does not result in a change of pH(Note 2). Record the final titration and calculate the amine acidacceptance. When a magnetic stirri
25、ng bar is used, it is notnecessary to remove it between agitation periods.NOTE 2If the readings of the pH meter are erratic because theelectrodes have been wet with halogenated solvent, it may be treated byrinsing the electrode with acetone or alcohol, followed by thoroughrinsing with water and soak
26、ing in water for a short time.9.3 Using Hand AgitationIf no stirrer is available, theextraction and titration may be carried out as follows: Transfer50 mL of the halogenated organic solvent to a 250-mLglass-stoppered Erlenmeyer flask, add 50 mL of water pread-justed to a pH of 3.9, and stopper the f
27、lask. Shake vigorouslyfor 5 s. Pour the contents into a 150-mL beaker and allow theimmiscible liquids to separate into layers. Insert the pH meterelectrodes and titrate the water layer with 0.01 N HCl to a pHof 3.9. When the end point has been reached, remove theelectrodes, return the liquids to the
28、 flask, and extract again for5 s. Repeat the titration. Repeat the extraction and titration untilno change in pH results from additional shaking (Note 2).Record the final titration and calculate the amine acid accep-tance.10. Calculation10.1 Calculate the Amine Acid Acceptance (alkalinity) asNaOH, i
29、n weight percent as follows:Amine Acid Acceptance alkalinity!, as NaOH, Weight Percent 5$V2B/2! 3 NX0.040/W% 3 100 (2)or as parts per million as follows:Amine Acid Acceptance alkalinity!, as NaOH, ppm 5$V2B/2! 3 NX0.040/W% 3 1000000 (3)where:V = millilitres HCl required for titration of the sample,
30、mL,N = normality of the HCl,B = millilitres HCl required for titration of the blank, mL,andW = weight sample used (or volume in millilitres times itsspecific gravity), g.11. Precision and Bias11.1 The precision limits of this test have been determinedas 0.0005 % (equivalent NaOH, weight percent).TES
31、T METHOD BINDICATOR METHOD12. Summary of Test Method12.1 The amine acid acceptance of the halogenated organicsolvent is determined, after extraction into a volume of waterpreadjusted to the bromphenol blue end point yellow, bytitrating with standard acid to the bromphenol blue end point,blue to yell
32、ow.13. Reagents13.1 WaterAdd bromphenol blue indicator solution (1drop for each 10 mL of water) to 1 L (or any convenientvolume) of water and adjust to the bromphenol blue colorchange end point.D2106071213.2 Bromphenol Blue Indicator Solution (10 g/L)Dissolve1gofbromphenol blue in 100 mL of water.13
33、.3 Hydrochloric Acid, Standard (0.01 N)See 8.2.14. Procedure14.1 Prepare a blank using 100 mL of water previouslyadjusted to the color change point of the indicator being used,and subject it to the same type and degree of agitation as thetest samples. Titrate the blank to the color change point of t
34、heindicator and record the volume of titrant as B.14.2 Transfer 50 mL of the halogenated organic solvent to aclean 250-mL glass-stoppered Erlenmeyer flask, and add 50mL of water adjusted to the bromphenol blue end point (Note3). Stopper the flask and shake for 10 s. Allow the immiscibleliquids to se
35、parate, and titrate the aqueous upper layer with0.01 N HCl to the bromphenol blue end point. Stopper theflask, and again shake for 5 s. If the end point has changed,titrate to the bromphenol blue end point again. Repeat until nochange in indicator results when additional shaking is done.Record the t
36、itration and calculate the amine acid acceptance.NOTE 3Methyl orange indicator solution, modified methyl orangeindicator solution, or bromothymol blue indicator solution may besubstituted for bromphenol blue indicator solution where an operator hasdifficulty observing certain color changes.14.3 Mech
37、anical agitation may be used as described in 9.2.15. Calculation15.1 See Section 10.16. Precision and Bias416.1 Precision determinations were performed at concentra-tions of 0.0009, 0.0018, and 0.0194 weight percent as NaOH.16.2 The standard deviation of results (each the average of5 replicates) obt
38、ained by different analysts on different dayswithin the same laboratory has been estimated to be 0.0002weight percent absolute at 12 degrees of freedom. The 95 %limit for the difference between two such averages is 0.0005weight percent absolute.16.3 The standard deviation of results (each the averag
39、e of5 replicates) obtained by analysts in different laboratories hasbeen estimated to be 0.0003 weight percent absolute at 4degrees of freedom. The 95 % limit for the difference betweentwo such averages has been estimated to be 0.0008 weightpercent absolute.16.4 The bias of this test method was not
40、determined.TEST METHOD CGAS CHROMATOGRAPHYMETHOD17. Procedure17.1 Determine the weight ppm or weight percent of theamine or amines present using gas chromatography with a gaschromatographic method that is in compliance with PracticeD 6806.17.2 It will be necessary to calibrate the gas chromatographw
41、ith a known standard of the amine or amines present. Theknown standard should be of approximately the same concen-tration as the amine to be measured.17.3 If the amine is unknown it can be identified by GCmass spectroscopy.17.4 Calculate the Amine Acid Acceptance (alkalinity) bythe following formula
42、:Amine Acid Acceptance alkalinity!, as NaOH 540 3 ppmMWor40 3 wt %MW(4)where:40 = the molecular weight of NaOH,ppm = ppm of the amine as determined in 17.1,wt % = weight percent of the amine as determined in 17.1,andMW = the molecular weight of the amine.17.5 If more than one amine is present the am
43、ine acidacceptance (alkalinity) will be the sum of the acid acceptance(alkalinity) of the individual amines.18. Precision and Bias518.1 Precision and bias data was obtained with two differentamines, n-methyl morpholine at about 20 ppm as NaOH inperchloroethylene, and diisopropyl amine, at about 3 pp
44、m intrichloroethylene.18.2 There was no statistically significant difference be-tween alkalinity as determined between Methods B (titrationwith indicator) and Method C (determination of amine by GC).No bias is present.18.3 The reproducibility of the method was found to aver-age 2.1 % Relative Standa
45、rd Deviation at 3 and 20 ppm.18.4 Repeatability was calculated at 6.39 % RDS, that istwo determinations should differ less than 6.39 % RSD (1.3ppm at 20 ppm alkalinity).19. Keywords19.1 acid acceptance; alkalinity; amine acid acceptance;halogenated organic solvents4A Research Report is available fro
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