4326 (ISO International Standard Non-ionic surface active agents - Polyethoxylated derivatives Determination of hydroxyl value - Acetic anhydride method Agents de surface non ioniques -- Dérivés polyéthoxyles -- Détermination de I'indice d'hydroxyle -- Méthode a I'anhydre acétique First edition -- 1980-03-01 Ref. No. ISO 4326-1980 (E) UDC 661.185.4 : 543.854 O 4326-1980 (E) Descriptors : surfactants, non-ionic surfactants, polyethoxyl compounds, chemical analysis, determination, hydroxyl value. Price based on 3 pages CopyrightInternational Organization for Standardization Not for Resale FOREWORD Iso (the International Organization for Standardization) is a worldwide federation of national standards institutes (IsO member bodies). The work of developing International Standards is carried out through ISO technical committees. Every up has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the technical committees are circulated the member bodies for approval before their acceptance as International to Standards by the ISO Council. InternationalStandardISO 4326 6was developed by Technical Committee ISO/TC91, Surface active agents, and was circulated to the member bodies in June 1976. It has been approved by the member bodies of the foliowing countries : Australia Ireland Romania Austria ueder South Africa, Rep. of Belgium Korea, Rep. of Switzeriand Brazil Mexico Turkey Chile Netherlands United Kingdom France New Zealand USA Germany, F.R. Philippines USSR India Poland The member body of the following country expressed disapproval of the document on technical grounds : Spain @ International Organization for Standardization,1980 Printed in Switzerland ed without license from IHS Not for Resale ISO 4326-1980 (E) INTERNATIONAL STANDARD Non-ionic surface active agents - Polyethoxylated Determination of hydroxyl value - Acetic derivatives - anhydride method 0 INTRODUCTION including some tertiary amines, interfere by reacting with the acetic acid produced. In these cases a correction may be made for the acidity or alkalinity (see ISO 4314). The classical method for the determination of the hydroxyl value described in this International Standard requires Epoxides are known to interfere, but the method can still because of the toxic effects of pyridine and acetic anhy- dride, that all handling and the titration be conducted be used if it is possible to eliminate them, by cold vacuum under a well ventilated fume hood. However, for infor- distillation, without affecting the hydroxyl value. By this mation, it is pointed out that annex C of ISO 4327 provides means, free ethylene oxide, which interferes at levels a procedure using a special apparatus which reduces the above 0,5 % (m/m), can be eliminated. danger due to pyridine and acetic anhydride. The presence of water in the sample is revealed by reaction with the acetic anhydride, but the method may nevertheless be used without risk if the precautions described in the 1 SCOPE procedure are followed. This International Standard specifies a method for the This method is not applicable to propoxylated products. determination of the hydroxyl value of polyethoxylated condensates by esterification of the hydroxyl groups with acetic anhydride. 3 REFERENCES IS0 607, Surface active agents and detergents - Methods of sample division. 2 FIELD OF APPLICATION ISO 2211, Liquid chemical products - Measurement of This method is applicable to the determination of the colour in Hazen units (platinum-cobalt scale). phatic and alicyclic compounds (in particular, of ethylene ISO 4314, Surface active agents -- Determination of free oxide adducts of primary fatty alcohols, of alkylphenols and of fatty acids) and can be used for the determination alkalinity or free acidity - Titrimetric method. of hydroxyl values from 10 to 1 000. ISO 4317, Surface active agents