1、Designation:D116621Standard Test Method forMethoxyl Groups in Wood and Related Materials1This standard is issued under the fixed designation D1166;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in
2、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 covers the determination of methoxylgroups in wood and related materials(1-7).2The test method isapplicable to milled wood or sawdus
3、t,or by suitable adjust-ment in size of the test specimen,to fractions isolated fromwood and lignin.1.2 This standard does not purport 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
4、environmental practices and deter-mine the applicability of regulatory limitations prior to use.Specific precautionary statements are given in Section 6.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Deci
5、sion on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Principle of Method2.1 The principle of the test method is the same as that in theoriginal method of Zeisel(1),except that th
6、e methyl iodide iscollected in an acetic acid solution of potassium acetatecontaining bromine.The following reactions then occur:CH3I1Br2CH3Br1IBr(1)IBr12Br213H2OHIO315HBrThe iodic acid is determined by titration of iodine liberatedby the reaction:HIO315HI3I213H2O(2)From the above equations,it follo
7、ws that one methoxylgroup(CH3O)liberates six atoms of iodine.3.Significance and Use3.1 Most of the methoxyl in wood is attributable to thelignin.This test method is used extensively in the study oflignin.4.Apparatus4.1 The apparatus shall be similar to that illustrated in Fig.1 and shall consist of
8、the following:4.1.1 Reaction Flask,4.1.2 Heat SourceA temperature controlled heatingmantle,4.1.3 Vertical Air-Cooled Condenser,4.1.4 Scrubber,and4.1.5 Two Absorption Vessels.5.Purity of Reagents and Water5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicat
9、ed,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 ofsufficiently high purity to permit
10、its use without lessening theaccuracy of the determination.5.2 WaterUnless otherwise indicated,references to watershall be understood to mean distilled water.6.Reagents6.1 Hydroiodic Acid(HI)(57%in water sp gr 1.70)Thisbest reagent grade HI,should be stored in the absence of lightand at a low temper
11、ature to keep its purity.6.2 Phenol.6.3 Cadmium Sulfate Solution(50 g CdSO4/L)Dissolve67.2 g of CdSO44H2O in water and dilute to 1 L.NOTE1A water suspension of red phosphorus is equally satisfactoryin the scrubber.1This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the di
12、rect responsibility of Subcommittee D07.01 on Fundamental TestMethods and Properties.Current edition approved April 1,2021.Published April 2021.Originallyapproved in 1956.Last previous edition approved in 2013 as D1166 84(2013).DOI:10.1520/D1166-21.2The boldface numbers in parentheses refer to the r
13、eferences listed at the end ofthis test method.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,BDH Ltd.,Poole,Dorset,U
14、.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmaceutical 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 in accordance with internationally
15、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.16.4 Sodium Thiosulfate Solution(50 g Na2S2O3/L)Dissolve 78.5 g
16、 of Na2S2O35H2O in water and dilute to 1 L(Note 1).6.5 Carbon Dioxide GasThe CO2may be drawn from acylinder of the compressed gas.It may be obtained also by theuse of a Kipp generator and washed,before introduction intothe apparatus,through two wash bottles,the first containingsaturated NaHCO3solution and the second containing H2SO4(sp gr 1.84).Solid CO2,or“dry ice,”is a convenient source(5)and the gas requires no purification.6.6 Potassium Acetate Solution in Acetic AcidDissolve100 g of anhydro