ASTM_D_2080_-_92_1998.pdf

Designation:D 2080 92(Reapproved 1998)Standard Test Method forAverage Molecular Weight of Fatty Quaternary AmmoniumChlorides1This standard is issued under the fixed designation D 2080;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(e)indicates an editorial change since the last revision or reapproval.This method was prepared jointly by the American Society for Testing and Materials and the American Oil Chemists Society.1.Scope1.1 This test method covers the determination of the averagemolecular weight of a fatty quaternary ammonium chloride byconverting to the acetate,titrating potentiometrically,andcorrecting for the nonquaternary components.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.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 2076 Test Methods for Acid Value and Amine Value ofFatty Quaternary Ammonium Chlorides3D 2077 Test Method for Ash in Fatty Quaternary Ammo-nium Chlorides3D 2079 Test Method for Nonvolatile Matter(Solids)inFatty Quaternary Ammonium Chlorides3E 70 Test Method for pH of Aqueous Solutions With theGlass Electrod43.Apparatus3.1 Buret,having a capacity of 25 mL.3.2 Glass Electrode pH Meter,conforming to the require-ments of Test Method E 704or similar potentiometric titrator,and carefully standardized in accordance with the manufactur-ers instructions.3.3 Magnetic Stirrer,with inert plastic-coated stirring bar.4.Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,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.5Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.4.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Specification D 1193,Type II.4.3 Acetic Acid(Glacial)(CH3COOH).4.4 Acetic Anhydride(CH3CO)2O.4.5 Chloroform(CHCl3).4.6 Mercuric Acetate SolutionDissolve 6 g of mercuricacetate Hg(C2H3O2)2 in 100 mL of glacial acetic acid.Prepare fresh for each determination.CautionMercury compounds are harmful and accumulatein the aquatic environment.Mixtures containing mercurycompounds should not be flushed down a drain but disposed ofas a hazardous waste.4.7 Perchloric Acid,Standard Solution(0.1 N):4.7.1 Add 28.4 g of 70 to 72%perchloric acid(HClO4)to1000 mL of glacial acetic acid in a 2-L beaker while stirring.Carefully add 46.6 g of acetic anhydride while stirring.Carefully pour the solution through a glass funnel into a 2-Lvolumetric flask and dilute to mark with glacial acetic acid.Mix the solution and allow to stand for 24 h before standard-izing.1This test method is under the jurisdiction of ASTM Committee D-1 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.32 on Drying Oils.Current edition approved March 15,1992.Published May 1992.Originallypublished as D 208062 T.Last previous edition D 2080 64(1987).2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 06.03.4Annual Book of ASTM Standards,Vol 15.05.5Reagent 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.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.4.7.2 Standardizeagainstacidpotassiumphthalate(HKC8H4O4).6Weigh 0.31 to 0.39 g to the nearest 0.1 mg offinely ground and dried HKC8H4O4into a 200-mL beaker.Add50 mL of glacial acetic acid and warm gently to dissolve.Cooland add an additional 50 mLof glacial acetic acid so as to washdown the sides of the beaker.Insert the stirring bar into thebeaker and adjust the beaker so that the lower half of eachelectrode of the pH meter is immersed in the solution.Start thestirrer and adjust the speed so that there is vigorous stirringwithout spattering.Titrate with the HClO4solution using themillivolt scale.Record the millivolt readings every millilitre,but in the vicinity of the end point,record the millivolt readingsevery 0.1 mL.Plot a graph showing the millivolts against themillilitres required for titration.Calculate the normality of the