1、Designation:D556295(Reapproved 2011)Standard Test Method forDetermination of the Acidity as Free Fatty Acids/AcidNumber in the Presence of Ammonium or TriethanolamineSoaps1This standard is issued under the fixed designation D5562;the number immediately following the designation indicates the year of
2、original 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 covers determination of the acidity asfree fatty
3、acids in the presence of ammonium or trietha-nolamine soaps,or both,existing in a sample of sulfonated orsulfated oil,or both,by calculation from the total alkalinity andfree-and-alkali combined fatty acids.1.2 The values stated in SI units are to be regarded asstandard.1.3 This standard does not pu
4、rport 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.2.Referenced Documents2.1 ASTM Standards:2D5350
5、 Test Method for Determination of Organically Com-bined Sulfuric Anhydride by Titration,Test Method A3.Significance and Use3.1 This test method is intended for use in the determinationof the acid number of sulfonated and sulfated oils for thepurpose of quality assurance.4.Apparatus4.1 The apparatus
6、required consists of a glass flask providedwith a glass stopper and an air condenser.The connectionbetween the flask and the condenser shall be a ground joint.Perforated glass beads shall be used to prevent bumping.4.1.1 FlaskAn Erlenmeyer flask(Fig.1)made of a boro-silicate glass,having a capacity
7、of approximately 300 mL andprovided with a glass stopper.4.1.2 Condenser,consisting of a glass tube,915 mm(36 in.)in length and 8 mm(516in.)in outside diameter.The lower endof the tube shall be flared and ground to fit the mouth of theErlenmeyer flask.4.1.3 Glass BeadsPerforated glass beads,made of
8、chemi-cally resistant glass,approximately 4 mm(532in.)in diameter.Before using,the glass beads shall be boiled thoroughly inseveral portions of water or until the wash water reacts neutralto a methyl orange indicator.5.Reagents5.1 Ethyl Ether.5.2 Methyl Orange Indicator Solution(1 g/L)Dissolve 0.1g
9、of methyl orange in 100 mL of water.5.3 Sodium Chloride(NaCl),solid.5.4 SodiumHydroxide,StandardSolution(1N)Accurately prepare and standardize a 1 N sodium hydroxide(NaOH)solution.Express the strength or concentration of thesolution as mg of KOH per mL;1 mL of 1 N NaOH solutionis equivalent to 56.1
10、mg of KOH.5.5 Sodium Hydroxide,Standard Solution(0.5 N)Accurately prepare and standardize a 0.5 N NaOH solution.Express the strength of the solution as mg of KOH per mL;1mLof 0.5 N NaOH solution is equivalent to 28.05 mg of KOH.5.6 Sulfuric Acid,Standard(0.5 N)Accurately prepare andstandardize a 0.5
11、 N sulfuric acid(H2SO4)solution.Express thestrength of the solution as mg of KOH per mL;1 mL of 0.5 NH2SO4is equivalent to 28.05 mg of KOH.5.7 Sulfuric Acid(1+19)Carefully mix 1 volume ofconcentrated sulfuric acid(H2SO4,sp gr 1.84)into 19 volumesof water while stirring.6.Procedure6.1 The procedure c
12、onsists of two determinations:(1)totalalkalinity and(2)free-and-alkali-combined fatty acids.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.08 on Fats and Oils.This testmethod was developed in cooperation with the Ameri
13、can Leather Chemists Assn.(Method H 52-1956).Current edition approved Jan.1,2011.Published March 2011.Originallyapproved in 1994.Last previous edition approved in 2006 as D5562 95(2006).DOI:10.1520/D5562-95R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer
14、 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 6.1.1 Total AlkalinityDetermine the total alka
15、linity asdescribed in the determination of organically combined sulfu-ric anhydride(see Test Method D5350).6.1.2 Free and Alkali-Combined Fatty AcidsExtract thetotal sulfated and sulfonated fatty matter as described in thedetermination of total active ingredients(see Test MethodD5350),but omit the d
16、ehydration of the extract(see Note 1).Add exactly 0.5 mL of 0.5 N NaOH solution to the extract,evaporate the ether to a volume of approximately 25 mL,addapproximately 50 mL of neutral alcohol,and titrate the mixturewith 0.5 N NaOH solution to a phenolphthalein end point.NOTE1In the presence of acetates,wash the ether layer carefully withconcentrated NaCl solution until one or two drops of 0.5 N NaOH solutionadded to the final wash water are neutral to phenolphthalein indicator.7.Calculation7.1 C
