ASTM_D_1106_-_96_2013.pdf

Designation:D110696(Reapproved 2013)Technical Association of Pulp and Paper IndustryStandard Method T 222-om-83Standard Test Method forAcid-Insoluble Lignin in Wood1This standard is issued under the fixed designation D1106;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method2covers the determination of theacid-insoluble lignin content of wood.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 and health practices and determine the applica-bility of regulatory limitations prior to use.Specific precau-tionary statements are given in 6.1.2.Referenced Documents2.1 ASTM Standards:3D1107 Test Method for Ethanol-Toluene Solubility of Wood3.Principle of Method3.1 When wood is treated with strong acids the carbohy-drates are hydrolyzed,leaving an insoluble residue which isdetermined as lignin.Since some of the wood extractives(oils,resins,fats,waxes,tannins,gums,and starch)would remaininsoluble with the lignin,these are first removed by propersolvents.The 72%sulfuric acid method for lignin contains twoand sometimes three preliminary extractive treatments,namely:(1)with alcohol,to remove the catechol tannins;(2)with alcohol-benzene solution,to remove the resins,oils,fatsand waxes;and(3)with hot water,to remove the remainingwater-soluble materials.3.2 The alcohol extraction is necessary in analysis of woodshigh in tannin;that is,oak,chestnut,redwood,etc.It has notbeen shown necessary in the more common pulpwoods,suchas the various species of spruce,pine,fir,hemlock,poplar,birch,beech,and maple.It is recommended that for thesewoods the alcohol extraction be omitted unless it is desirablefor a special purpose.In analysis of woods not listed,thedesirability of the alcohol extraction depends upon the purposeof the analysis and the report should state whether or notalcohol extraction was used.4.Significance and Use4.1 Wood contains approximately 20 to 30%lignin.Re-moval of the lignin is the primary objective of pulping andbleaching procedures.Determination of the lignin contentprovides information for the evaluation and application ofthese processes.5.Apparatus5.1 Extraction ApparatusA compact form of Soxhlet ex-traction apparatus,with ground-glass joints,is preferable.Theapparatus shall consist of the following items:5.1.1 Soxhlet Extraction Flask,having a capacity of 250mL.5.1.2 Soxhlet Extraction Tube,45 to 50 mm in insidediameter,having a capacity to the top of the siphon ofapproximately 100 mL and a siphon tube approximately 55mm in height.Extraction tubes of these dimensions siphonmore rapidly than extractors with higher siphon tubes.5.1.3 Condenser,of the Hopkins inner-cooled type.5.1.4 Extraction Crucibles,of Alundum or fritted glass andof medium or fine porosity.5.2 Filtering CruciblesAlundum,porous porcelain,orfritted-glass crucibles(all of fine porosity),or Gooch crucibleswith a glass-fiber mat,are recommended for filtering theseparated lignin.Glass crucibles cannot be used if the lignin isto be ashed.6.Reagents6.1 Ethylene-Toluene SolutionMix 1.0 L absolute ethanoland 427 mL toluene.(WarningAvoid inhalation of vaporsand contact with skin.)1This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.01 on Fundamental TestMethods and Properties.Current edition approved Aug.1,2013.Published September 2013.Originallyapproved in 1950.Last previous edition approved in 2007 as D1106 96(2007).DOI:10.1520/D1106-96R13.2For further information on this test method the following references may beconsulted:Bray,M.W.,“Methods Used at the Forest Products Laboratory for the ChemicalAnalysis of Pulps and Pulpwoods,”Paper Trade Journal,Vol 87,No.25,December20,1928,p.29.Ritter,G.J.,Seborg,R.M.,Mitchell,R.L.,Industrial and EngineeringChemistry,Analytical Edition,Vol 4,1932,p.202.Ritter,G.J.,and Barbour,J.H.,Industrial and Engineering Chemistry,Analytical Edition,Vol 7,1935,p.238.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 Sulfuric Acid(72%)Carefully pour 665 mL ofH2SO4(sp gr 1.84)into about 300 mL of water,with vigorousstirring,and after cooling,dilute to 1 L.Standardize againststandard NaOH solution,using methyl orange indicator.Adjustthe H2SO4to a strength of 72 6 0.1%by addition of water orH2SO4(sp gr 1.84)as may be found necessary.If desired,thesolution may be standar