1、Designation:D479494(Reapproved 2022)1Standard 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 oforigin
2、al 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.1NOTEEditorial update made to 1.3 and 9.1.8 in June 2022.1.Scope1.1 This test metho
3、d is applicable to the determination ofethoxyl 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 p
4、urport 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For specific hazard statements,s
5、ee Section 5 and 9.1.8.1.1.4 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 World Trade Organizat
6、ion TechnicalBarriers to Trade(TBT)Committee.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.
7、The iodoeth-ane is extracted in situ 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 Columnstai
8、nless steel,1829 mm in length,3.2 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,100 L.3.7 Cover,stainless steel,fabricated to cover the he
9、atingblock.4.Reagents 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 specification
10、s are available.3Other 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 Packi
11、ng,10%methyl 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 Cellu
12、lose and Cellulose Derivatives.Current edition approved June 1,2022.Published July 2022.Originally approvedin 1988.Last previous edition approved in 2017 as D4794 94(2017).DOI:10.1520/D4794-94R22E01.2The sole source of supply of a heating block,Silli-Therm Heating Module,Reacti-Block 21,Reacti-Vials
13、,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 ameeting of the
14、responsible technical committee,1which you may attend.3ACS Reagent Chemicals,Specifications and Procedures for Reagents andStandard-Grade Reference Materials,American Chemical Society,Washington,DC.For suggestions on the testing of reagents not listed by the American ChemicalSociety,see Analar Stand
15、ards for Laboratory Chemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeia and National Formulary,U.S.Pharma-copeial Convention,Inc.(USPC),Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international stan
16、dard was developed 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 precautions 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 a
