684 (ISO NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKAYHAPOIHA OPTAHW3ALIM HO CTAHIAPTW3AIIИW.ORGANISATION INTERNATIONALE DE NORMALISATION Analysis of soaps -- Determination of total free alkali Analyse des savons -- Détermination de la teneur en alcali libre total First edition -- 1974-11-01 00T 1 71974 ANST Itex Dot S. ISO 684-1974 (E) UDC 661.185.1 : 543.241.2 Ref. No. 1SO 684-1974 (E) Descriptors : surfactants, soaps, chemical analysis, determination of content, alkalis, volumetric analysis Price based on 2 pages Copyright International 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 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 Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the Iso Council. International Standard ISO 684 was drawn up by Technical Committee ISO/TC 91, Surface active agents. It was submitted directly to the Iso Council, in accordance with clause 6.12.1 of the Directives for the technical work of ISO This International Standard cancelsand replaces ISO Recommendation countries : Germany Argentina Romania Hungary Australia South Africa, Rep. of Austria Ireland Spain Belgium Israel Switzerland Brazil Japan Turkey Canada Netherlands United Kingdom Chile New Zealand Yugoslavia Egypt, Arab Rep. of Poland France Portugai No Member Body expressed disapproval of the document. @ International Organization for Standardization, 1974 Printed in Switzerland Copyright International Organization for Standardization Ise from IHS Not for Resale ISO 684-1974(E) INTERNATIONAL STANDARD Analysis of soaps -- Determination of total free alkali 1 SCOPE AND FIELD OF APPLICATION 5 REAGENTS This International Standard specifies a method for the During the analysis, use only reagents of recognized determination of the total free alkali content of commercial analytical reagent grade and only distilled water or water of soaps, excluding compounded products.1) equivalent purity. The method is not applicable if the soap contains additives 5.1 Ethanol, 95 % (V/V) solution, free from carbon (alkali silicates, etc.) which can be decomposed by sulphuric acid by the procedure specified. The method is dioxide. also not applicable to coloured soaps if the colour interferes Reflux this solution for 5 min, cool to ambient temperature with the phenolphthalein end point. and neutralize with the ethanolic potassium hydroxide solution (5.3) in the presence of 4 drops of the phenolphthalein solution (5.4) per 200 ml of ethanol. 2 REFERENCES 5.2 Sulphuric acid, approximately N standard volumetric ISO 685, Analysis of soaps -- Determination of total solution. alkali.2) IsO . . . , Soaps -- Sampling.3) 5.3 Potassium hydroxide, approximately 0,1 N ethanolic standard volumetric solution. 5.4 Phenolphthalein, solution of 1 g per 100 ml in 95 % 3 DEFINITION (V/V) ethanol. For the purpose of this International Standard, the following definition applies : 6 APPARATUS total free alkali : The sum of the free caustic alkali and the free carbonate alkali contents. Ordinary laboratory apparatus and The results are generally expressed as a percentage by mass as either sodium hydroxide (NaOH) for sodium soaps or 6.1 Conical flask, capacity 250 ml, with a conical ground potassium hydroxide (KOH) for potassium soaps. glass joint. They may also be expressed in milliequivalents per gram. 6.2 Reflux condenser, water-cooled, with a conical ground glass joint at the bottom. 4 PRINCIPLE