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1、International Standard INTERNATIONAL ORGANIZATION FOR STANDhDIZATION.MEYHAPOHAR OPrAHHJAlJMR fl0 CTAHAPTH3Al.r, f$,;(yJ-j 3 :;J ; $1 i,j ,j . Gi UDC 661.722 : 643.241 !g Ref. No. IS0 1386/2-1981 (E) 2 Descriptors : industrial products, ethanols, tests, determination, alkalinity, acidity, phenolphtha
2、lein. B s Price based on 2 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 20:32:32 MDTNo reproduction or networking permitted without license from IHS -,-,- Foreword IS0 (
3、the International Organization for Standardization) is a worldwide federation of 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 commit
4、tee 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 b
5、efore their acceptance as International Standards by the IS0 Council. International Standard IS0 1388/2was 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
6、 Germany, F.R. Austria Hungary Belgium India Brazil Italy Bulgaria Korea, Rep. of China Netherlands Czechoslovakia Philippines France Poland Romania South Africa, Rep. of Switzerland Thailand United Kingdom USSR No member body expressed disapproval of the document. This International Standard has al
7、so been approved by the International Union of Pure and Applied Chemistry (IUPAC). International Standards IS0 1388/l to IS0 X388/12 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
8、 Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 20:32:32 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD 1388/2-1981
9、 (E) Ethanol for industrial use - Methods of test - Part 2 : Detection of alkalinity or determination of acidity to phenolphthalein 1 Scope and field of application This part of IS0 1388 specifies a method for the detection of alkalinity and, if appropriate, the subsequent determination of acidity o
10、f ethanol for industrial use. The method is applicable to products having acidities, ex- pressed as acetic acid (CHaCOOH), greater than or equal to 0,000 8 % (ml/n). This document should be read in conjunction with IS0 138811 (see the annex). 2 Principle Dilution of a test portion with carbon dioxid
11、e-free water. Checking whether the test solution is alkaline or acid to phenolphthalein, and, if appropriate, determination of the acidity by titration with standard volumetric sodium hydroxide solution. 3 Reagents During the analysis, use only reagents of recognized analytical grade and distilled w
12、ater or water of equivalent purity, carbon dioxide-free, recently prepared. 3.1 Water, carbon dioxide-free. Boil distilled water and allow it to cool in a flask fitted with a stopper carrying a soda-lime guard-tube. 3.2 Sodium hydroxide, standard volumetric solution, c(NaOH) = 0,l mol/l. 3.3 Phenolp
13、hthalein, 5 g/l ethanolic solution. Dissolve 0,5 g of phenolphthalein in 100 ml of 95 % (V/I/) ethanol and add the sodium hydroxide solution (3.2) until a pale pink coloration is obtained. 4 Apparatus Ordinary laboratory apparatus, and 4.1 Conical flask, of borosilicate glass, of capacity 500 ml, fi
14、tted with a ground glass stopper carrying a soda-lime guard- tube. 4.2 Burette, of capacity 10 ml, graduated in 0,02 ml. 5 Procedure 5.1 Test portion Take 100 k 0,l ml of the laboratory sample. 5.2 Determination Place 100 ml of the water (3.1) in the conical flask (4.11, add 0,5 ml of the phenolphth
15、alein solution (3.3) and, if necessary, restore the pale pink coloration by the addition of a few drops of the sodium hydroxide solution (3.2). Add the test portion (5.1) and a further 0,5 ml of the phenolphthalein solution (3.3) and note whether the solution is alkaline; if acid, titrate the test s
16、olution with the sodium hydroxide solution (3.21, stoppering the flask and swirling its contents after each addition, until a pink coloration, persisting for about 15 s, is obtained. Shake the contents of the flask, with the stopper in position, after each addition of sodium hydroxide solution. 6 Ex
17、pression of results 6.1 Alkaline products Indicate whether the product is alkaline to phenolphthalein. 6.2 Acidic products The acidity, expressed as a percentage by mass of acetic acid (CHsCOOH) , is given by the formula 0,006 x V .-I_ e where V is the volume, in millilitres, of the sodium hydroxide
18、 solution (3.2) used for the determination; Q is the density, in grams per millilitre, of the sample at 20 OC (see IS0 1388/l, clause 4); 0,006 is the mass, in grams, of acetic acid corresponding to 1 ml of sodium hydroxide solution, c(NaOH) = 0,100 mol/l. NOTE - If the standard volumetric solution
19、used is not of the exact concentration specified in the list of reagents, an appropriate correc- tion should be applied. 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 20:32:3
20、2 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 X388/2-1981 (E) Annex IS0 Publications relating to ethanol for industrial use IS0 1388/l - General. IS0 1388/2 - Detection of alkalinity or determination of acidity to phenolphthalein. IS0 1388/3 - Estimation of content
21、of carbonyl compounds present in small amounts - Photometric method. IS0 1388/4 - Estimation of content of carbonyl compounds present in moderate amounts - Titrimetric method. IS0 1388/5 - Determination of aldehydes content - Visual calorimetric method. IS0 1388/6 - Test for miscibility with water.
22、IS0 1388/7 - Determination of methanol content methanol contents between 0,Ol and 0.20 % (V/v)1 - Photometric method. IS0 1388/8 - Determination of methanol content methanol contents between 0,lO and I,50 % f V/ v)l - Visual calorimetric method. IS0 1388/g - Determination of esters content - Titrime
23、tric method after saponification. IS0 1388/10 - Estimation of hydrocarbons content - Distillation method. IS0 1388/11 - Test for detection of furfural. IS0 1388/12 - Determination of permanganate time. 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 20:32:32 MDTNo reproduction or networking permitted without license from IHS -,-,-
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