1、Designation: D 3125 06Standard Test Method forMonomethyl Ether of Hydroquinone in Colorless MonomericAcrylate Esters and Acrylic Acid1This standard is issued under the fixed designation D 3125; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of monom-ethyl ether of hydroquinone2(MEHQ) in colo
3、rless monomericacrylate esters and acrylic acid. The test method is applicableto the determination of MEHQ in the concentration range from0 to 1200 parts per million.1.2 For purposes of determining conformance of an ob-served or a calculated value using this test method to relevantspecifications, te
4、st result(s) shall be rounded off “to the nearestunit” in the last right-hand digit used in expressing thespecification limit, in accordance with the rounding-off methodof Practice E 29.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thi
5、sstandard.1.4 For hazard information and guidance, see the suppliersMaterial Safety Data Sheet.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of whoever uses this standard to consult andestablish appropriate safety an
6、d health practices and deter-mine the applicability of regulatory limitations prior to use.Specific precautionary statements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:3D 1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conf
7、ormance with SpecificationsE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals3. Summary of Test Method3.1 As shown in the equation, MEHQ reacts with nitrousacid (sodium nitrite in acidic media) to form the nitrosoderivative whi
8、ch equilibrates between two structures.3.2 The yellow color of the nitroso compound is measuredspectrophotometrically at a wavelength of 420 nm.4. Significance and Use4.1 Acrylic acid and its esters are normally inhibited withMEHQ only. This procedure presents a rapid and accuratemethod of determini
9、ng the MEHQ content of fresh acrylic acidand acrylate esters in the absence of other inhibitors.4.2 MEHQ effectiveness may decline with age and thisdecline in effectiveness may not be indicated by this testmethod.5. Interferences5.1 Hydroquinone (HQ), thiodiphenylamine, diphenylphe-nylene-diamine an
10、d p-hydroxydiphenylamine interfere ifpresent.6. Apparatus6.1 Spectrophotometer, with borosilicate-glass cells for de-termining absorbance at 420 nm.6.2 Volumetric Flasks, 50 and 100-mL capacity.6.3 Measuring Pipets, 5 and 10-mL capacity.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall
11、beused. Unless otherwise indicated, it is intended that all reagentsshall conform to the specifications of the Committee on1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.3
12、5 on Solvents, Plasticizers, and Chemical Intermediates.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1972. Last previous edition approved in 2001 as D 3125 97 (2001).2IUPAC-approved name is 4-methoxyphenol.3For referenced ASTM standards, visit the ASTM website, w
13、ww.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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive
14、, PO Box C700, West Conshohocken, PA 19428-2959, United States.Analytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the
15、 accuracy ofthe determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent grade waterconforming to Type IV of Specification D 1193.7.3 Acetic Acid, glacial.7.4 Monomethyl Ether of Hydroquinone (MEHQ) (4-methoxyphenol).7.5 Sodium Nitrite Solut
16、ion (2 %)Dissolve2gofsodiumnitrite (NaNO2) in water and dilute to 100 mL.8. Hazards8.1 Store samples of acrylic monomers in amber bottles orprotect from light by other means to aid in preventingpolymerization. Keep samples away from heat sources andchemicals that can cause free radical polymerizatio
17、n. Acrylicmonomers can polymerize violently, evolving considerableheat. Keep sample container size to a minimum. The inhibitor,monomethyl/ester of hydroquinone, requires oxygen to remainactive.9. Calibration9.1 Weigh 0.10 g of MEHQ to the nearest 0.1 mg into a100-mL volumetric flask containing appro
18、ximately 50 mL ofglacial acetic acid. Mix well until solution is complete thendilute to the mark with glacial acetic acid. Prepare a series ofstandards by pipetting 1, 2, 4, 6, and 10-mL portions of theMEHQ solution into respective 50-mL volumetric flasks.Dilute each flask to the mark with glacial a
19、cetic acid and mixwell. A10-mL aliquot of each of these standards containsapproximately 200, 400, 800, 1200, and 2000 g of MEHQ,respectively.9.2 Determine the absorbance of each of these standards bypipetting 10-mL aliquots into 50-mL volumetric flasks contain-ing 20-mLof glacial acetic acid. To eac
20、h flask add 1-mLof 2 %NaNO2solution and dilute to the mark with glacial acetic acid.Mix well and allow to stand for 10 min. With cells appropriateto the instrument, determine the absorbance at 420 nm usingacetic acid as the blank.9.3 Construct a calibration curve on rectangular coordinategraph paper
21、 by plotting the absorbances of the standards at 420nm against the micrograms of MEHQ.10. Procedure10.1 Perform analyses in duplicate and carry a blankthrough the analysis using 49 mL of glacial acetic acid in placeof the specimen solution.10.2 Weigh the appropriate amount of specimen (Table 1)into
22、a 50-mL volumetric flask containing 20-mL of glacialacetic acid.10.3 Add 1 mL of 2 % NaNO2solution to the specimen anddilute to the mark with glacial acetic acid. Mix well and allowto stand for 10 min.10.4 Using the procedure followed for the calibration,determine the absorbance of the solution at 4
23、20 nm with theblank solution in the reference position. From the calibrationcurve, determine the micrograms of MEHQ corresponding tothe absorbance obtained.11. Calculation11.1 Calculate the concentration of MEHQ in ppm asfollows:MEHQ, ppm 5 M/S (1)where:M = micrograms of MEHQ from calibration curve
24、andS = grams of specimen used in the test.12. Report12.1 Report the concentration of MEHQ as indicated inTable 2.13. Precision513.1 The precision statements are based upon an interlabo-ratory study in which one operator in each of twelve labora-tories analyzed in duplicate on two different days each
25、 of thefollowing samples:Acrylic MonomerMean MEHQConcentration, ppmEthyl acrylate 16.9Ethyl acrylate 48.22-Ethylhexyl acrylate 14.72-Ethylhexyl acrylate 47.3Acrylic acid 212Acrylic acid 4994Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For sug
26、gestions 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 Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5Supporting data have been f
27、iled at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D01-1016.TABLE 1 Amount of SpecimenExpected MEHQ Content, ppm Amount of Specimen, g0to25 25A25 to 100 10A100 to 250 5B250 to 550 2B550 to 1000 1BAWeigh to the nearest 10 mg.BWeigh to the nearest 1 mg.TABLE 2
28、 Reporting and Averaging of Duplicate RunsMEHQConcentration,ppmReport ppmDuplicate Runs That Agree Withinthe Following Amounts AreSuitable for Averaging (95 %Confidence Level)ppm15 0.1 0.5450 0.5 1.8200 1 5.5500 1 9.9D3125062The results were analyzed statistically in accordance withPractice E 180 an
29、d the within-laboratories coefficient of varia-tion was found to be 1.4 % relative with 61 degrees of freedomand the between-laboratories coefficient of variation was foundto be 4.6 % relative with 9 degrees of freedom. Based on thesecoefficients of variation, the following criteria should be usedfo
30、r judging the acceptability of results at the 95 % confidencelevel:13.1.1 RepeatabilityTwo results, each the mean of dupli-cates, obtained by the same operator on different days shouldbe considered suspect if they differ by more than 4.0 %relative.13.1.2 ReproducibilityTwo results, each the mean of
31、du-plicates, obtained by operators in different laboratories shouldbe considered suspect if they differ by more than 15 % relative.13.2 BiasBias cannot be determined for this test methodbecause there is no available material having an acceptedreference value.14. Keywords14.1 acrylate esters; acrylic
32、 acid; monomeric ester ofhydroquinoneSUMMARY OF CHANGESCommittee D01.35 has identified the location of selected changes to this standard since the last issue(D 3125 - 97 (2001) that may impact the use of this standard. (Approved June 1, 2006.)(1) Added reference to Practice E29in the Scope section.
33、(2) Added Practice E29to list of Referenced Documents.ASTM 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 r
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35、or revision of this standard or for additional 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 heari
36、ng you shouldmake your views known 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).D3125063
