1、Designation: D4794 94 (Reapproved 2017)Standard Test Method forDetermination of Ethoxyl or Hydroxyethoxyl Substitution inCellulose Ether Products by Gas Chromatography1This standard is issued under the fixed designation D4794; the number immediately following the designation indicates the year ofori
2、ginal 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 is applicable to the determination ofethoxyl
3、or hydroxyethoxyl substitution in cellulose ether prod-ucts by a Zeisel gas chromatographic technique.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, i
4、f any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For specific hazard statements, see Section 5 and Note 3.1.4 This interna
5、tional 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 World Trade Organization TechnicalBarriers to Trade (TBT) Com
6、mittee.2. Summary of Test Method2.1 When a cellulose ether containing ethyl or hydroxyethylsubstitutes is allowed to react with hydriodic acid, one mole ofiodoethane is liberated for each mole of ethoxyl or hydroxy-ethoxyl ether substituted on the cellulose chain. The iodoeth-ane is extracted in sit
7、u with o-xylene and quantitated by gaschromatography using an internal standard technique. It isrecommended to run duplicate samples.3. Apparatus3.1 Gas Chromatograph with thermal conductivity detectorand heated injection port.3.2 Electronic Integrator.3.3 Columnstainless steel, 1829 mm in length, 3
8、.2 mm inoutside diameter, packed with the reagent in 4.6, coiled to fitthe chromatograph used; or equivalent column and packing asappropriate.3.4 Syringe, 10 L.3.5 Reaction Vials, Caps, and Heating Block.23.6 Syringe, 100L.3.7 Cover, stainless steel, fabricated to cover the heatingblock.4. Reagents
9、and Materials4.1 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-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Oth
10、er grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.4.2 Iodoethane, 99 % minimum.4.3 O-xylene.4.4 Toluene.4.5 Hydriodic Acid, 57 % (sp gr 1.69 to 1.70).4.6 Column Packing, 10 % meth
11、yl silicone stationary phaseUSP code G1 coated on inert diatomite solid support USPcode S1A, 100/120 mesh.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.36 on Cellulose an
12、d Cellulose Derivatives.Current edition approved Dec. 1, 2017. Published December 2017. Originallyapproved in 1988. Last previous edition approved in 2009 as D4794 94 (2009).DOI: 10.1520/D4794-94R17.2The sole source of supply of a heating block, Silli-Therm Heating Module,Reacti-Block 21, Reacti-Via
13、ls, and Minnert valve tops, known to the committee atthis time is the Pierce Chemical Company P.O. Box 117, Rockford, IL 611059976.If you are aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameetin
14、g of the responsible technical committee,1which you may attend.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 LaboratoryChemicals,
15、BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed
16、 in accordance with internationally 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.15. Hazards5.1 Safety pr
17、ecautions must be taken for handling of hydri-odic acid.5.2 During the reaction, the glass vials are under pressure.Exercise precaution in handling the hot vials.6. Apparatus Preparation and Conditioning6.1 Column (Note 1)Columns are packed with reagentunder vacuum and mechanical vibration using sil
18、anized glasswool to contain the packing. Install each in the gas chromato-graph to facilitate on column injection. Condition the columnat 200C for 12 h, then allow it to come to equilibrium underthe conditions described in the following table:Oven temperature, C 130 isothermalInjection port temperat
19、ure, C 200Detector temperature, C 250Detector current, ma 175 maAttenuation 1Polarity ACarrier gas heliumColumn A, mL/min 30Column B, mL/min 30NOTE 1The conditions used here were determined to be optimum forthe column. Optimum conditions should be determined for each columnon an individual basis.6.2
20、 Integrator:6.2.1 Settings (Note 2):Attenuation 3Chart speed 1.0Peak width 0.04Threshold 4NOTE 2These settings were used with a Hewlett-Packard 3390AIntegrator. Other units may require different settings.6.2.2 Approximate Component Retention Times:Relative Retention Time Component0.38 iodoethane0.59
21、 toluene (internal standard)1.00 o-xylene7. Preparation of Standard Solutions7.1 Internal Standard Solution (25 mg toluene/mLo-xylene):7.1.1 Weigh 25.00 6 0.01 g of toluene into a 1000-mLvolumetric flask.7.1.2 Dilute with o-xylene to 1000 mL.7.2 Calibration Standard Solution:7.2.1 Pipet 2.0 mL of 57
22、 % hydriodic acid into a 5-mL vial.7.2.2 Pipet 2.0 mL of the internal standard solution (pre-pared in 7.1) into the vial and seal with the mininert valve.7.2.3 Weigh the vial and contents to the nearest 0.1 mg.7.2.4 Add 50 L of iodoethane to the vial with a syringe.7.2.5 Weigh and record the amount
23、of iodoethane added.7.2.6 Shake for 30 s and allow to stand for 20 minutes.8. Calibration of Electronic Integrator8.1 Inject 1.0 L of the upper solvent layer of the standardsolution prepared in 7.2 into the gas chromatograph and recordthe chromatogram.8.1.1 Calibrate the integrator according to the
24、manufactur-ers instructions.8.2 If an integrator is not available peak areas and responsefactors can be determined manually as follows:RF 5A 3 w 3 P13 F0.05 3 B 3 P2(1)where:RF = response factor,A = peak height of internal standard (toluene),w = weight of iodoethane, g,P1= purity of iodoethane,F =fa
25、ctor of 0.289 for ethoxylS45156D, 0.391 forhydroxyethoxyl,0.05 = weight of toluene, g,B = peak height of iodoethane, andP2= purity of toluene.9. Procedure9.1 Specimen Preparation:9.1.1 Dry the specimen at 105C for 1 h and store in adessicator until cool.9.1.2 Weigh 60 to 80 mg of the specimen prepar
26、ed in dry9.1.1 into a clean, tared 5-mL reaction vial (see 3.5).9.1.3 For a cellulose ether that is not soluble in o-xylene,add 2.0 mL of the internal standard solution prepared in 7.1 tothe vial.9.1.4 Add 2.0 mL of hydriodic acid to the vial.9.1.5 For a cellulose ether that is soluble in o-xylene,r
27、everse the order of addition of 9.1.3 and 9.1.4.9.1.6 Cap tightly and weigh the vial.9.1.7 Shake the specimen for 30 s.9.1.8 Place the vial in a heated block at 180 6 5C for 2 h.NOTE 3Warning: Vials contain a hot corrosive acid under pressure.9.1.9 Remove the vial and cool in the hood to roomtempera
28、ture. The specimen will separate into two layers.9.1.10 Reweigh to determine any loss due to leakage.Discard any specimen with loss greater than 25 mg.9.1.11 Shake the sample vigorously and allow to stand for20 minutes.9.2 Analysis:9.2.1 Enter the weight of the toluene (internal standard) andthe wei
29、ght of the specimen into the integrator if an integratoris being used.9.2.2 Inject 1.0 L of the upper layer of the specimen intothe gas chromatograph.10. Calculation10.1 If an integrator is not available, calculate the peak areasand concentrations using the following equation:ethoxyl, % or hydroxyet
30、hoxyl, % 5B 30.05 3 P23 RFA 3sample weight g!(2)D4794 94 (2017)2where:B = peak height of iodoethane,0.05 = weight of toluene, g,P2= purity of toluene,RF = response factor determined for calibration standardsolution, andA = peak height of toluene.11. Precision and Bias411.1 PrecisionThe relative prec
31、ision was found to be0.64 % at the 95 % confidence level.11.2 BiasNo justifiable statement can be made on the biasof the procedure in this test method because no suitablereference material for determining the bias exists.12. Keywords12.1 cellulose ether; ethoxyl or hydroxyethoxyl substitu-tion; gas
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33、ch 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 addi
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35、e 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
36、 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:/ data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report: RR:D01-1058. Contact ASTM Cus-tomer Service at serviceastm.org.D4794 94 (2017)3
