1388/4 International Standard (ISO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAA OPTAHW3ALMA HO CTAHAAPTMUWW+ORGANISATION INTERNATIONALE DE NORMALISATION Ethanol for industrial use - Methods of test Part 4 : Estimation of content of carbonyl compounds present in moderate amounts - Titrimetric method Ethanol a usage industriel -- Methodes d'essai -- Partie 4 : Evaluation de la teneur en composés carbonyles presents en quantite modérée-Méthodetitrimétrique First edition - 1981-12-01 ISO 1388/4-1981 (E) UDC 661.722:543.854.6 Ref. No. ISO 1388/4-1981 (E) Descriptors:industrialproducts,ethanols,tests,determination,carbonylcompounds,titration Pricebased on3pages Standardizatior No reproduction or networking permitted without license from IHS 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 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 Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IsoCouncil. International Standard ISO 1388/4 was developed by Technical Committee ISO/TC 47, Chemistry, and was circulated to the member bodies in February 1980. It has been approved by the member bodies of the following countries : Australia Germany, F.R. Romania Austria Hungary South Africa, Rep. of Belgium India Switzerland Brazil Italy Thailand Bulgaria Korea, Rep.of United Kingdom China Netherlands USSR Czechoslovakia Philippines France Poland No member body expressed disapproval of the document. This International Standard has also been approved by the International Union of Pure and Applied Chemistry (IUPAC). International Standards ISO 1388/1 to ISO 1388/12 cancel and repiace ISO Recom- mendation R 1388-1970, of which they constitute a technical revision. Internationai Organization for Standardization, 1981 Printed inSwitzerland Copyright International Organization for Standardization No reproduction or networking permited without license from IHS Not for Resale ISO1388/4-1981 (E) INTERNATIONAL STANDARD Ethanol for industrial use - Methods of test - Part 4 : Estimation of content of carbonyl compounds present in moderate amounts -- Titrimetric method Scope and field of application 3.3 Hydrochloric acid, standard volumetric solution, c(HCI) = 0,1 mol/l. This part of IS0 1388 specifies a titrimetric method for estima- tion of the content of carbonyl compounds present in moderate 3.4 Bromophenol blue, 2 g/l ethanolic solution. amounts in ethanol forindustrial use. Dissolve 0,2 g of bromophenol blue in 1,5 ml of the sodium The method is applicable to products having carbonyl com- hydroxide solution (3.2) and dilute to 100 ml with 95 % (V/ V) poundscontents,expressedas acetaldehyde,equalto or greater than 0,01 % (m/ m). ethanol. NOTE -This method, which is used commercially, allows determina tion of only those carbonyl compounds which react under the specified 4. Apparatus conditions. Ordinary laboratory apparatus, and This document should be read in conjunction with ISo 1388/1 (see the annex). 4.1 Conical flasks, of capacity 150 ml, fitted with ground glass stoppers. 2 Principle Reaction of hydroxylammonium chloride with the carbonyl 5 Procedure compounds in a test portion and titration of the hydrochloric acid formed with standard volumetric sodium hydroxide solu- 5.1 Test portion tion, in the presence of bromophenol blue as indicator. Take 50 ± 0,1 ml of the laboratory sample and place it in one of the conical flasks (4.1). 3 Reagents During the analysis, use only reagents of recognized analytical