ASTM D1106-1996(2007) Standard Test Method for Acid-Insoluble Lignin in Wood《木材中酸不溶木素的标准试验方法》.pdf

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1、Designation: D 1106 96 (Reapproved 2007)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 D 1106; the number immediately following the designation indicates the year ofo

2、riginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method2covers the determination of theacid-insolu

3、ble 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 p

4、rior to use. Specific precau-tionary statements are given in 6.1.2. Referenced Documents2.1 ASTM Standards:3D 1107 Test Method for Ethanol-Toluene Solubility ofWood3. Principle of Method3.1 When wood is treated with strong acids the carbohy-drates are hydrolyzed, leaving an insoluble residue which i

5、sdetermined 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

6、,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, che

7、stnut, 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

8、 of woods not listed, thedesirabilty 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 pu

9、lping andbleaching procedures. Determination of the lignin contentprovides information for the evaluation and application ofthese processes.5. Apparatus5.1 Extraction ApparatusA compact form of Soxhletextraction apparatus, with ground-glass joints, is preferable.The apparatus shall consist of the fo

10、llowing 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 rap

11、idly 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 crucibles

12、with 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.)6.2 Sulfuric Acid (72 %

13、)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 or1This test method is under the ju

14、risdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.01 on Fundamental TestMethods and Properties.Current edition approved April 1, 2007. Published April 2007. Originallyapproved in 1950. Last previous edition approved in 2001 as D 1106 96 (2001).2For further

15、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., Industri

16、al 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.or

17、g. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.H2SO4(sp gr 1.84) as may be found necessary. If desired, thesolut

18、ion may be standardized by an accurate determination ofits specific gravity. For 72 % H2SO4the specific gravity at20/4C is 1.6338; for use of this specific gravity methodappropriate tables should be consulted.7. Test Specimen7.1 The test specimen shall consist of1gofwood that hasbeen ground to pass

19、a 425-m (40 mesh) sieve and thoroughlyair-dried.8. Procedure8.1 Weigh two 1-g test specimens in tared glass-stopperedweighing bottles. Dry in an oven for2hat100to105C,replace and stopper, and cool in a desiccator. Loosen thestopper to equalize the pressure and weigh. Continue thedrying for 1-h perio

20、ds until the weight is constant. Calculatethe percentage of moisture-free wood.8.2 Weigh in the extraction crucibles two additional 1-g testspecimens for the lignin determination in duplicate. Place theextraction crucible containing the specimen in a Soxhletextraction apparatus. Extract with 95 % al

21、cohol for 4 h, unlessthe wood is known not to contain catechol tannins, in whichcase this extraction with alcohol will not be required. Thenextract the test specimen with ethanol-toluene solution asdescribed in Test Method D 1107. Remove as much of thesolvent by suction as possible and wash by sucti

22、on with 50 mLof ethanol to remove the toluene. Remove the excess ethanol,transfer to a beaker, and digest with 400 mL of hot water in asteam or hot-water bath at approximately 100C for 3 h. Filter,wash with 100 mL of hot water, and finally with 50 mL ofethanol to facilitate the removal of the test s

23、pecimen from thecrucible. After these preliminary extractions, let the specimendry in the air.8.3 Transfer all of the air-dried test specimen to a glass-stoppered weighing bottle or a small beaker with a glass coverand add slowly, while stirring, 15 mL of cold (12 to 15C)H2SO4(72 %). Mix the specime

24、n well with the acid by stirringconstantly for at least 1 min. Allow to stand for 2 h, withfrequent stirring, at a temperature of 18 to 20C. A water bathmay be necessary to keep the temperature within these limits.Wash the material into a 1-L beaker or Erlenmeyer flask, diluteto a 3 % concentration

25、of H2SO4by adding 560 mL of distilledwater, and boil for 4 h, either under a reflux condenser or in thenearly constant volume condition maintained by the occasionaladdition of hot water to the flask.8.4 After allowing the insoluble material to settle, filter intoa filtering crucible that has been dr

26、ied at 100 to 105C andweighed in a glass-stoppered weighing bottle. Wash the residuefree of acid with 500 mL of hot water and dry the crucible andcontents in an oven for2hat100to105C. Place in theweighing bottle, cool in a desiccator, loosen the stopper of thebottle, and weigh the contents of the cr

27、ucible as lignin. Repeatthe drying and weighing until the weight is constant.8.5 If a correction for ash is desired, transfer the lignin to atared platinum crucible and determine the ash by igniting at900C. If the lignin cannot be quantitatively transferred, it maybe ashed in the filtering crucible,

28、 provided the latter has beenignited to constant weight before filtration of the lignin residue.Ignition cannot be performed in fritted-glass crucibles.9. Report9.1 Report the results as percentage by weight of lignin inmoisture-free unextracted wood. If the wood was extractedwith alcohol, or if the

29、 lignin was corrected for ash, state this inthe report.10. Precision and Bias410.1 An interlaboratory study conducted by nine laborato-ries on six woods indicates that the precision both within andbetween laboratories is approximately constant throughout therange of lignin content. A range of conten

30、t from 19 to 30 %gave a repeatability of 0.34 and a reproducibility of 0.79.11. Keywords11.1 acid-insoluble lignin; woodASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are express

31、ly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,

32、either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may att

33、end. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States.

34、Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4Data in this section obtained form the Technical Association of the Pulp andPaper Industry, P.O. Box 105113, Atlanta, GA 30348.D 1106 96 (2007)2