(ISo International Standard 6839 INTERNATIONALORGANIZATION FOR STANDARDIZATION+MEXKAYHAPOAHAAOPrAHM3AUMANO CTAHAAPTW3AUMW+ORGANISATION INTERNATIONALEDE NORMALISATION Anionic surface active agents - Determination of solubility in water Agentsdesurfaceanioniques-DéterminationdelasolubilitedansI'eau First edition-1982-12-01 8102 ()7R61-6080NSI UDC661.185:620.1:541.8 Ref.No.ISO6839-1982(E) Descriptors : surfactants, anionic surfactants, tests, determination, solubility. Price based on 3 pages Copvriaht International Oranization for Standardization Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards institutes (iso member bodies). The work of developing Inter- national Standards is carried out through Iso technical committees. Every member body interested in a subject for which a technical committee has been set 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 Standardsadoptedbythetechnical committeesarecirculatedto the member bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 6839 was developed by Technical Committee ISo/TC 91, Surface active agents, and was circulated to the member bodies in February 1982. It has been approved by the member bodies of the following countries: Australia Germany, F.R. Poland Austria Hungary Romania Belgium Ireland South Africa, Rep. of China Italy Spain Czechoslovakia Japan Switzerland Egypt, Arab Rep. of Mexico USSR France Netherlands No member body expressed disapproval of the document. International Organization for Standardization,1982 Printed in Switzerland Covriaht Internatinal Oranization for Standardization ISO6839-1982(E) INTERNATIONALSTANDARD Anionic surface active agents s - Determination of solubility in water 0 Introduction Repetition of the test, varying the temperature of the bath within the range established by the preliminary determination, The method described in this International Standard is one of until theclearsolutionremains clearandthecloudysolutionre- the simplest of the methods which can be used for this pur- mains cloudy, or the solutions change very slowly from being pose; it is sufficiently accurate and is suitable for a number of cloudy to clear or vice versa. practical uses. From the surface active agent concentrations and the limiting temperatures of solubility, plotting the solubility curve. Scopeand field ofapplication 4 Reagent This International Standard specifies a method of establishing the curve representing the solubility of an anionic surface active During the determination, use only distilled water or water of agent in water as a function of temperature, and, conse- equivalent purity. quently, of allowing evaluation of its solubility at a given temperature 5 Apparatus The method is applicable both to pure surface active agents and to technical products or formulations of liquid anionic sur- Usual laboratory equipment, and face active agents,provided that the solutions of these prod- Test tubes, made of borosilicate glass, of diameter 20 mm and length 200 mm. NOTE E-The determination of solubility may be carried out without restriction in the temperature range from 0 to 90 C; at temperatures 5.2 Precision thermometers, complying with the re- lower than O oC,the determination is possibleprovided that the solu- quirements of ISo 653. tion does not freeze. The solubility curve obtained in the case of pure products may 5.3 Thermostatically controlled water bath, capable of possibly allow the Krafft temperature to be determined. being controlled at -5 °C to + 90 °C, to within ± 0,1 °C, with a transparent cell. 2 Reference 6 Sampling ISo607,Surfaceactiveagentsanddetergents-Methodsof The laboratory sample of anionic surface active agent shall be sampledivision. prepared and stored in accordance with the