1、Designation: D5376 06 (Reapproved 2017)Standard Test Method forRubber Compounding MaterialsDetermination of the BasicNitrogen Content in Rubber Antioxidant: Polymerized TMQ1This standard is issued under the fixed designation D5376; the number immediately following the designation indicates the year
2、oforiginal adoption or, in the case of revision, 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 the nitro-ge
3、n content of polymerized 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ). It is based on a potentiometrictitration of an acetone solution of TMQ with perchloric acid inacetic acid.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1
4、.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. Specific precau
5、-tionary statements are given in Section 9.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the Wo
6、rld Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 l
7、ot samplea production sample representative of astandard production unit, normally referred to as “the sample.”4. Summary of Test Method4.1 A sample of 2,2,4-trimethyl-1,2-dihydroquinoline(TMQ) is dissolved in acetone and the nitrogen in TMQ isdetermined by a potentiometric titration with perchloric
8、 acid inacetic acid.5. Significance and Use5.1 This test method is designed to determine the nitrogencontent of oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline(TMQ) antioxidant. TMQ is used for heat protection ofvulcanized rubber.5.2 This test method is suitable for assessing productspecifications s
9、ince nitrogen content is related to productperformance, that is, antioxidant efficiency and heat protection.For comparison of product quality at different productionfacilities sufficient interlaboratory accuracy and precision arerequired.6. Interferences6.1 Based on past experience, one significant
10、source of errorin this test method is the titration end point assessment.Problems can be avoided by closely following the procedure.6.2 Theoretically, any material containing basic nitrogen,capable of forming HCl-salt, will be measured by this testmethod. Extensive high performance liquid chromatogr
11、aph(HPLC) analyses of the product indicates that the mostsignificant interfering impurities are products formed by sidereactions between aniline and acetone, such as those given inFig. 1.6.3 Other possible interfering impurities may include theanilino end groups attached to TMQ oligomers, such as th
12、osegiven in Fig. 2.7. Apparatus7.1 Standard Laboratory Glassware and Equipment.7.2 Potentiometer.7.3 Reference Electrode, platinum electrode in an electro-lytic glass cell with a frit of porosity 4, filled with a saturatedsolution of lithium perchlorate in acetic acid (see Fig. 3).7.4 Glass Electrod
13、e.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand Rubber-like Materials and is the direct responsibility of Subcommittee D11.11on Chemical Analysis.Current edition approved May 1, 2017. Published July 2017. Originally approvedin 1993. Last previous edition approved in
14、2012 as D5376 06 (2012). DOI:10.1520/D5376-06R17.2For 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 Document Summary page onthe ASTM website.Copyright AS
15、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Sta
16、ndards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.17.5 Weighing Pipet, 5cm3.7.6 Buret, 25 cm3, Class A, graduated in 0.1 cm3incre-ments.7.7 Buret, 50 cm3, Class A, graduated in 0.1 cm3incre-ments.7.8 Magnetic Stirrer.7.9 Erlenmeyer
17、Flask, 300 cm3narrow-neck.7.10 Measuring Cylinder, 50 cm3.7.11 Beaker, 150 cm3.7.12 Beaker, 400 cm3.7.13 Dropping Funnel, 50 cm3.7.14 Thermometer, range 20 to +60C.7.15 Pipet, 5cm3.7.16 Volumetric Flask, 2dm3.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless
18、otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity
19、to permit its use without lessening the accuracy ofthe determination.8.2 Acetic Acid, p.a.8.3 Acetic Anhydride, p.a.8.4 Acetone, p.a.8.5 Lithium Perchlorate, 3H2O p.a.8.6 Perchloric acid, p.a. approx. 70 %.8.7 Phenolphthalein, 1 % dissolved in ethanol.8.8 Potassium Hydrogen Phthalate, p.a.8.9 Sodium
20、 Hydroxide (1 N)Aqueous sodium hydroxide.9. Hazards9.1 Perchloric acid (70 to 72 %) is a strong oxidant. Caremust be exercised to keep it from contacting organic matter.Seventy to 72 % perchloric acid must be kept at or below roomtemperature. When hot and concentrated it is known to beexplosive.9.2
21、Acetic anhydride is a noxious chemical and corrosive tothe skin. Avoid breathing vapors and use gloves and goggles3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Soci
22、ety, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 1(a) 2,2-bis (4-amino-phenyl)-propaneFIG. 2 1(b) (Top)3(4-amino-phenyl)-terminated oligomeric 2,
23、2,4-trimethyl-1,2-dihydroquinoline;(Bottom)6-(4-amino-phenyl)-terminated oligomeric 2,2,4-trimethyl-1,2-dihydroquinolineFIG. 3 Titration VesselD5376 06 (2017)2for protection. Acetone is flammable and vapors form explo-sive mixtures. Consult appropriate texts for further informationon the use and dis
24、posal of these chemicals.10. Sampling10.1 To ensure sample homogeneity, grind a minimum of10 g of a “lot” sample with a mortar and pestle. Take test unit(0.4 g) from this composite.11. Reagent Preparation and Standardization11.1 As is the case with any titration method, it is extremelyimportant that
25、 the titrants are accurately standardized.11.2 Prepare the primary titrant (0.1 N perchloric acid) bydiluting 70 % perchloric acid with acetic acid, having firsteliminated the water content by reaction with acetic anhydride.11.2.1 The exact concentration of the approximately 70 %perchloric acid is d
26、etermined as follows: weigh about3goftheapproximately 70 % perchloric acid to the nearest 0.1 mg in aweighing pipet, dissolve in 50 cm3water and titrate with 1 NNaOH using phenolphthalein as indicator. Determine theconcentration of perchloric acid as follows:C15V 3N 3MW31001000(1)where:C1= % concent
27、ration of perchloric acid,V = volume of NaOH, cm3,N = normality of the NaOH solution,M = molecular mass of perchloric acid, 100.5, andW = sample mass of approximately 70 % perchloric acid, g.11.2.2 To prepare 2 dm3of 0.1 N perchloric acid solution inacetic acid, the mass (W1) of perchloric acid to b
28、e taken is:W152 310.05 3100C1(2)where:W1= mass of perchloric acid, g, andC1= % concentration of perchloric acid from 11.2.1.11.2.2.1 The amount of acetic anhydride (W2) required toeliminate the water content in W1g of perchloric acid iscalculated thus:W25100 2 C1! 310.05 32 3100 3MaC1318 3C2(3)where
29、:Ma = molecular mass of acetic anhydride = 102,C1= % concentration of perchloric acid, andC2= % concentration of acetic anhydride.11.2.3 Add 8.5 cm3of 70 to 72 % perchloric acid to 100 to200 cm3glacial acetic acid. Add 20 cm3of acetic anhydrideand allow the solution to stand for at least 0.5 h. Dilu
30、te to 1dm3with glacial acetic acid. To standardize, weigh to thenearest 0.1 mg, about 0.4 g of potassium hydrogen phthalate,dissolve completely in 50 cm3acetone and titrate potentio-metrically with perchloric acid.11.2.4 These solutions are stable over a long period of time.12. Procedure12.1 Assembl
31、e appropriate glassware from Section 7 ac-cording to Fig. 3 and place this assembly on the magneticstirrer.12.2 Prepare the specimen according to Section 10 andweigh 0.4 g to the nearest 0.1 mg into a 150-cm3beaker,dissolve with 50 cm3of acetone and titrate potentiometricallywith 0.1 N perchloric ac
32、id using a 25 cm3buret as illustrated inFig. 3.12.3 Determine the blank value of the solvent following thesame procedure.NOTE 1The water introduced with the perchloric acid is removed byadding a calculated amount of acetic anhydride to combine with the water.The acid-catalyzed reaction of acetic anh
33、ydride with water is fairly rapid.When titrating a primary or secondary amine that might react with aceticanhydride, it is important to avoid any excess acetic anhydride in thetitrant.13. Calculation13.1 Determine the percent total basic nitrogen content asfollows:% nitrogen 5V12 V0! 3N 31410003100S
34、(4)where:V1= volume of perchloric acid required for titration of thesample, cm3V0= volume of perchloric acid required for blank titration,cm3,N = normality of the perchloric acid solution, andS = specimen mass, g.14. Report14.1 Report the following information:14.1.1 Proper identification of the sam
35、ple, and14.1.2 Results obtained from the two individual determina-tions and their average as percent nitrogen to the nearest 0.1 %.15. Precision and Bias15.1 This precision and bias section has been prepared inaccordance with Practice D4483. Refer to Practice D4483 forterminology and other statistic
36、al calculation details.15.2 The precision results in this precision and bias sectiongive an estimate of the precision of this test method with thematerials used in the particular interlaboratory programs asdescribed in this section. The precision parameters should notbe used for acceptance or reject
37、ion testing of any group ofmaterials without documentation that they are applicable tothose particular materials and the specific testing protocols thatinclude this test method.15.3 A Type 1 (interlaboratory) precision was evaluated in1990. Both repeatability and reproducibility are short term. Aper
38、iod of a few days separates replicate test results.Atest resultis the mean value of two determinations, as specified by thistest method, of the assay results.D5376 06 (2017)315.4 Three sources of TMQ differing slightly in percentnitrogen were analyzed in six laboratories on two differentdays.15.5 Th
39、e results from one laboratory were eliminated fromthe analysis since they were substantially different in valuethan the other five taken as a whole.15.6 The results of the precision calculation for repeatabilityand reproducibility are given in Table 1.15.7 RepeatabilityThe repeatability, r, of this
40、test methodhas been established as the appropriate value in Table 1.Twosingle test results, obtained under normal test methodprocedures, that differ by more than the tabulated r (for anygiven level) must be considered as derived from different ornonidentical sample populations.15.8 ReproducibilityTh
41、e reproducibility, R, of this testmethod has been established as the appropriate value in Table1. Two single test results obtained in two different laboratories,under normal test method procedures, that differ by more thanthe tabulated R (for any given level) must be considered tohave come from diff
42、erent or nonidentical sample populations.15.9 Repeatability and reproducibility expressed as a per-cent of the mean level, (r) and (R), have equivalent applicationstatements as above for r and R. For the (r) and (R) statements,the difference in the two single test results is expressed as apercent of
43、 the arithmetic mean of the two test results.15.10 BiasIn test method terminology, bias is the differ-ence between an average test value and the reference (or true)test property value. Reference values have not been evaluatedfor this test method. Bias, therefore, cannot be determined.15.11 The full
44、details and test results of the interlaboratorytest program used for this precision section are complete and inthe process of being prepared in the proper format forsubmission as a research report to ASTM.16. Keywords16.1 2,2,4-trimethyl-1,2-dihydroquinoline; antioxidant; ni-trogen; TMQASTM Internat
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46、ir 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 standardsand should
47、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 Committee on Standar
48、ds, 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
49、-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:/ 1 Precision of Percent Nitrogen Analysis for TMQAMaterial AverageWithin Laboratories Between LaboratoriesSr r (r) SR R (R)No. 3 7.30 0.0187 0.052 0.71 0.112 0.314 4.30No. 1 7.41 0.0330 0.092 1.24 0.122 0.342 4.62No. 2 7.78 0.0195 0.055 0.71 0.101 0.284 3.65Pooled 7.50 0
