1、Designation:D479494(Reapproved 2009)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 oforigina
2、l 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 or hydroxye
3、thoxyl 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,if any,associa
4、ted 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.For specific hazardstatements,see Section 5 and Note 3.2.Summary of Test Method2.1 When a cellulose ethe
5、r 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 situ with o-xylene and quantitated by gaschromatography using
6、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,3.2 mm inoutside diameter,packed with the reagent in 4.6,coiled
7、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 heatingblock.4.Reagents and Materials4.1 Purity of ReagentsReagent grade chemicals shall beused
8、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.3Other grades may beused,provided it is first ascertained that the reagent is
9、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%methyl silicone stationary phaseUSP code G1 coated on inert diatomite solid support USPc
10、ode S1A,100/120 mesh.5.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.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,M
11、aterials,and Applications and is the direct responsibility ofSubcommittee D01.36 on Cellulose and Cellulose Derivatives.Current edition approved Feb.1,2009.Published February 2009.Originallyapproved in 1988.Last previous edition approved in 2003 as D4794 94(2003).DOI:10.1520/D4794-94R09.2The sole so
12、urce of supply of a heating block,Silli-Therm Heating Module,Reacti-Block 21,Reacti-Vials,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 ASTMIntern
13、ational Headquarters.Your comments will receive careful consideration at ameeting 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 th
14、e 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-
15、2959.United States1 6.Apparatus Preparation and Conditioning6.1 Column(Note 1)Columns are packed with reagentunder vacuum and mechanical vibration using silanized glasswool to contain the packing.Install each in the gas chromato-graph to facilitate on column injection.Condition the columnat 200C for
16、 12 h,then allow it to come to equilibrium underthe conditions described below:Oven temperature,C130 isothermalInjection port temperature,C200Detector temperature,C250Detector current,ma175 maAttenuation1PolarityACarrier gasheliumColumn A,mL/min30Column B,mL/min30NOTE1The conditions used here were determined to be optimum forthe column.Optimum conditions should be determined for each columnon an individual basis.6.2 Integrator:6.2.1 Settings(Note 2):Attenuation3Chart speed1.0Peak width0.04Thresh