ISO-1388-5-1981.pdf
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1、International Standard 138815 INTERNATIONAL ORGANIZATION FOR STANDARDlZATION*MEXQYHAPO,WlAR OPrAHM3AUblR fl0 CTAHAAPTH3AUHHORGANlSATlON INTERNATIONALE DE hORMALISATION i I , ! j, . * : : _ : j : n * 7. : , 8 ! Ethanol for industrial use - Methods of test - Part 5 : Determination of aldehydes content
2、 - Visual calorimetric method Ethanol B usage industriel - Mkthodes d essai - Partie 5 : Dosage des aldbhydes - M Descriptors : industrial products, ethanols, tests, determination of content, aldhehydes, calorimetric analysis. 8 2 Price based on 3 pages Copyright International Organization for Stand
3、ardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 07:35:09 MDTNo reproduction or networking permitted without license from IHS -,-,- Foreword IS0 (the International Organization for Standardization) is a worldwide federation o
4、f national standards institutes (IS0 member bodies). The work of developing Inter- national Standards is carried out through IS0 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. Internat
5、ional 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 IS0 Council. Internati
6、onal Standard IS0 1388/5was 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. Austria Hungary Belgium India Brazil Italy Bulgaria Korea, Rep.
7、of China Netherlands Czechoslovakia Philippines France Poland No member body expressed disapproval of the document. Romania South Africa, Rep. of Switzerland Thailand United Kingdom USSR This International Standard has also been approved by the International Union of Pure and Applied Chemistry (IUPA
8、C). International Standards IS0 1388/l to IS0 1388/12 cancel and replace IS0 Recom- mendation R 1388-1970, of which they constitute a technical revision. 0 International Organization for Standardization, 1981 0 Printed in Switzerland Copyright International Organization for Standardization Provided
9、by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 07:35:09 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD IS0 X388/5-1981 (E) Ethanol for industrial use - Methods of test - Part 5 : Determination
10、of aldehydes content - Visual calorimetric method 1 Scope and field of application This part of IS0 1388 specifies a visual calorimetric method for the determination of the aldehydes content of ethanol for industrial use. The method is applicable to products having aldehyde con- tents, expressed as
11、acetaldehyde, in the range 0,000 25 to 0,001 25 % (m/m). This document should be read in conjunction with IS0 1388/l (see the annex). 2 Principle Reaction of the aldehydes present in a test portion with Schiff reagent. Visual comparison of the colour obtained with the col- ours of standard calorimet
12、ric solutions containing known quan- tities of acetaldehyde. 3 Reagents During the analysis, use only reagents of recognized analytical grade, and distilled water or water of equivalent purity. 3.1 Ethanol, 95 % (V/v), aldehydes-free, purified as follows. Boil 1 500 ml of absolute ethanol, under ref
13、lux, for 2 h, with 15 g of m-phenylenediamine. Distil the mixture, rejecting the first and last 50 ml fractions of the distillate. Adjust the concen- tration to 95 % (V/v) by adding an appropriate volume of water and mix. Use the procedure specified in clause 5 to verify that the purified ethanol is
14、 free from aldehydes. 3.2 Schiff reagent. WARNING - Basic fuchsin is carcinogenic. Avoid skin contact with basic fuchsin and its solutions and inhala- tion of its dust. 3.2.1 Preparation Place 1 500 ml of water in a 3 000 ml conical flask, add 4,500 + 0,065 g of p-rosaniline hydrochloride (basic fuc
15、hsin), and swirl to dissolve. Add 9,60 + 0,05 g of &odium disulphite sodium metabisulphite (Na$O,)l, mix and allow to stand for 5 to 10 min. Add 40 ml of approximately 295 g/l sulphuric acid solution, mix thoroughly, stopper the flask and allow to stand for about 12 h. Decolorize the solution if nec
16、essary, by treat- ment with activated carbon. 3.2.2 Determination and adjustment of free sulphur dioxide content Transfer 10 ml of the colourless reagent (3.2.1) to a 250 ml con- ical flask. Add 20 ml of water and 5 ml of freshly prepared starch solution, and titrate the solution with standard volum
17、etric iodine solution, c(1/2 I,) = 0,l mol/l, until the characteristic dark blue colour is just obtained. NOTE - 1 ml of iodine solution, c(1/2 12) = 0.1 mol/l, corresponds to 0,003 2 g of so2. If the free sulphur dioxide content does not fall within the op- timum range (0,18 to 0,31 g per 100 ml of
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