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1、EthylhydroxyethylcellulosePreparedatthe49thJECFA(1997)supersedingspecificationspreparedatthe29thJECFA(1985),publishedinFNP34(1986)SYNONYMINSNo.467DEFINITIONEthylHydroxyethylCelluloseiscelluloseinwhichbothethylandhydroxyethylgroupsareattachedtotheanhydroglucoseunitsbyetherlinkages.Ethy
2、lhydroxyethylcelluloseispreparedfromcellulosebytreatmentwithalkali,ethyleneoxideandethylchloride.Thearticleofcommercemaybespecifiedfurtherbytheviscosityofitsaqueoussolutions.ChemicalnamesEthylhydroxyethylcellulose,2-hydroxyethyletherofethylcelluloseC.A.S.number9004-58-4Chemicalformula
3、[C6H7O2(OH)x(OC2H5)y[O(CH2CH2O)mH]z]nwherenisthedegreeofpolymerisationx+y+z=3y=0.7-1.5(degreeofethylsubstitution,DS)m+z=0.5-2.5(molarhydroxyethylsubstitution,MS)StructuralformulaPossiblestructuralformulaforarepeatingunitofanethylhydroxyethylcellulosewithaDS=1.0andaMS=1.0FormulaweightU
4、nsubstitutedstructuralunit:162.14StructuralunitwithDS=MS=1.0:234StructuralunitwithDS=1.0;MS=2.0:278StructuralunitwithDS=1.5;MS=0.5:226Macromolecules:fromabout40,000(nabout175)uptoabout350,000(nabout1,300)AssayNotlessthan7%andnotmorethan19%ofethoxylgroups(-OC2H5),andnotlessthan10%andno
5、tmorethan38%ofoxyethylenegroups(-OCH2CH2-),onthedriedandsalt-freebasis.DESCRIPTIONHygroscopicwhiteorslightlyyellowishorgreyish,odourlessgranulesorfinepowder.FUNCTIONALEmulsifier,stabilizer,thickenerUSESCHARACTERISTICSIDENTIFICATIONSolubilitySwellinginwater,producingacleartoopalescent,
6、viscous,colloidalsolution;insolubleinboilingwaterandethanol.FoamformationVigorouslyshakea0.1%solutionofthesample.Alayeroffoamappears.Thistestpermitsthedistinctionofcelluloseethersfromsodiumcarboxymethylcellulose,alginates,andnaturalgums.PrecipitateformationTo5mlofan0.5%solutionofthesa
7、mpleadd5mlofa5%solutionofcoppersulfateorofaluminiumsulfate.Noprecipitateappears.Thistestpermitsthedistinctionofcelluloseethersfromsodiumcarboxymethylcellulose,gelatine,carobbeangumandtragacanth.PrecipitateformationbywarmingA1%watersolutionofasampleisslowlyheatedfromroomtemperature,whi
8、lesti
