ASTM_E_1899_-_08.pdf

Designation:E189908Standard Test Method forHydroxyl Groups Using Reaction with p-ToluenesulfonylIsocyanate(TSI)and Potentiometric Titration withTetrabutylammonium Hydroxide1This standard is issued under the fixed designation E1899;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.Scope*1.1 This test method covers the determination of hydroxylgroups attached to primary and secondary carbon atoms inaliphatic and cyclic compounds and phenols.It is not suitablefor determination of hydroxyl groups attached to tertiarycarbon atoms.This test method is applicable to polyacetals,temperature sensitive materials,high solids polymer polyols,and rigid polyols.Other available test methods listed in Note 1are not suitable for many of the sample types listed above.1.1.1 This test method is currently recommended for neutralrefined products.Successful application has been made,however,to some in-process samples that contain an excess ofacidic species.Proper validation must be performed,of course,to show that the acidic species either does not interfere,or thatthe acidic species interference has been obviated.NOTE1Other methods for determination of hydroxyl groups are givenin Test Methods D817,D871,D1957,D2195,D4252,D4273,D4274,E222,E326,and E335.1.2 Review the current appropriate Material Safety DataSheets(MSDS)for detailed information concerning toxicity,first aid procedures,and safety precautions.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 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.For specific hazards see Section 9.2.Referenced Documents2.1 ASTM Standards:2D817 Test Methods of Testing Cellulose Acetate Propionateand Cellulose Acetate ButyrateD871 Test Methods of Testing Cellulose AcetateD1193 Specification for Reagent WaterD1957 Test Method for Hydroxyl Value of Fatty Oils andAcids(Withdrawn 2007)3D2195 Test Methods for Pentaerythritol(Withdrawn 2011)3D4252 Test Methods for Chemical Analysis of AlcoholEthoxylates and Alkylphenol EthoxylatesD4273 Test Method for Polyurethane Raw Materials:Deter-mination of Primary Hydroxyl Content of Polyether Poly-olsD4274 Test Methods for Testing Polyurethane Raw Materi-als:Determination of Hydroxyl Numbers of PolyolsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)3E222 Test Methods for Hydroxyl Groups Using AceticAnhydride AcetylationE300 Practice for Sampling Industrial ChemicalsE326 Test Method for Hydroxyl Groups by Phthalic Anhy-dride Esterification(Discontinued 2001)(Withdrawn2001)3E335 Test Method for Hydroxyl Groups by PyromelliticDianhydride Esterification(Withdrawn 2002)33.Terminology3.1 Definitions:3.1.1 hydroxyl number(OH#)the milligrams of potassiumhydroxide equivalent to the hydroxyl content of 1 g of sample.1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and is the direct responsibility of SubcommitteeE15.01 on General Standards.Current edition approved April 1,2008.Published May 2008.Originallyapproved in 1997.Last previous edition approved in 2002 as E1899 02.DOI:10.1520/E1899-08.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.1.1 DiscussionIn the case of a pure compound,thehydroxyl number is inversely proportional to the hydroxylequivalent weight and the molecular weight:equivalent weightg/equivalent!556100OH#(1)and:molecular weightg/mol!5561003number of OH groups per moleculeOH#4.Summary of Test Method4.1 According to a reaction given in Manser et al.4(see Fig.1)the hydroxyl group is reacted with excess p-toluenesulfonylisocyanate(TSI),to form an acidic carbamate.Water is addedto convert unreacted isocyanate to sulfonamide,followed bydirect potentiometric titration of the acidic carbamate withtetrabutylammonium hydroxide(Bu4NOH)in nonaqueous me-dium.5.Significance and Use5.1 Hydroxyl is an important functional group and knowl-edge of its content is required in many intermediate and enduse applications.This test method is for the deter