BS 6392-3-1983 Testing of ethanol for industrial use - Method for determination of carbonyl compounds content present in moderate amounts (titrimetric method)《工业用乙醇试验 第3部分 中等量的羰基化合.pdf

1、BRITISH STANDARD BS 6392-3: 1983 Ethanol for industrial use Part 3: Method for determination of carbonyl compounds content present in moderate amounts (titrimetric method) NOTEIt is recommended that this Part be read in conjunction with the information given in the “General introduction” published s

2、eparately as BS6392-0. UDC 661.722:543.24.062:543.854.6BS6392-3:1983 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect on 31 August1983 BSI 01-2000 The Committees responsible

3、for this British Standard are shown inPart 0. The following BSI references relate to the work on this standard: Committee reference CIC/4 Draft for comment 80/51209 DC ISBN 0580 13369 9 Foreword This Part of BS6392 is technically equivalent to ISO1388 “Ethanol for industrial useMethods of test” Part

4、 4 “Estimation of content of carbonyl compounds present in moderate amountsTitrimetric method”, published in1981 by the International Organization for Standardization (ISO). For ease of production, the text of ISO1388-4:1981, with the omission of the Annex, has been used for this British Standard. S

5、ome terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. This sta

6、ndard describes a method only and should not be used as a specification defining limits of purity. Reference to the standard should indicate that the method of test used is in accordance with BS6392-3. A British Standard does not purport to include all the necessary provisions of a contract. Users o

7、f British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2, an inside back cover and a ba

8、ck cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue CommentsBS6392-3:1983 BSI 01-2000 i Contents Page Foreword Insid

9、e front cover 1 Scope and field of application 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Procedure 1 6 Expression of results 1 Publication referred to Inside back coverii blankBS6392-3:1983 BSI 01-2000 1 1 Scope and field of application This Part of BS6392 describes a titrimetric method for estim

10、ation of the content of carbonyl compounds present in moderate amounts in ethanol for industrial use. The method is applicable to products having carbonyl compounds contents, expressed asacetaldehyde, equal to or greater than0,01% (m/m). NOTE 1This method, which is used commercially, allows determin

11、ation of only those carbonyl compounds which react under the specified conditions. NOTE 2The title of the publication referred to in this standard is given on the inside back cover. 2 Principle Reaction of hydroxylammonium chloride with the carbonyl compounds in a test portion and titration of the h

12、ydrochloric acid formed with standard volumetric sodium hydroxide solution, in the presence of bromophenol blue as indicator. 3 Reagents During the analysis, use only reagents of recognized analytical grade, and distilled water or water of equivalent purity. 3.1 Hydroxylammonium chloride reagent WAR

13、NING Corrosive and irritating. Avoid contact with eyes and skin. Dissolve4g of hydroxylammonium chloride in20ml of water and dilute to200ml with95% (V/V) ethanol. Heat under reflux for30min on a boiling water bath, cool to ambient temperature, add5ml of the bromophenol blue solution (3.4) and just s

14、ufficient of the sodium hydroxide solution (3.2) to produce a dichroic green coloration. NOTEIndustrial methylated spirits95% (V/V) is not suitable for use in place of the ethanol95% (V/V) used in the preparation of this reagent. 3.2 Sodium hydroxide, standard volumetric solution, c(NaOH)=0,1mol/l.

15、3.3 Hydrochloric acid, standard volumetric solution, c(HCl)=0,1mol/l. 3.4 Bromophenol blue,2g/l ethanolic solution. Dissolve0,2g of bromophenol blue in1,5ml of the sodium hydroxide solution (3.2) and dilute to100ml with95% (V/V) ethanol. NOTEIndustrial methylated spirits95% (V/V) is not suitable for

16、 use in place of the ethanol95% (V/V) used in the preparation of this reagent. 4 Apparatus Ordinary laboratory apparatus, and 4.1 Conical flasks, of capacity150ml, fitted with ground glass stoppers. 5 Procedure 5.1 Test portion Take50 0,1ml of the laboratory sample and place it in one of the conical

17、 flasks (4.1). 5.2 Determination Place50ml of the hydroxylammonium chloride reagent (3.1) in a second conical flask (4.1), to be used as the colour standard. Add1,25ml of the bromophenol blue solution (3.4) to the flask containing the test portion (5.1) and add, drop by drop, either the sodium hydro

18、xide solution(3.2) or the hydrochloric acid solution (3.3) until the colour matches that of the colour standard. Then add, to each of the flasks,25ml of the hydroxylammonium chloride reagent (3.1) and stopper the flask containing the colour standard. Loosely stopper the flask containing the test sol

19、ution and heat it for10min on a boiling water bath. Remove the flask from the water bath, cool to ambient temperature and titrate the solution with the sodium hydroxide solution (3.2) until the colour matches as closely as possible that of the colour standard. 6 Expression of results The carbonyl co

20、mpounds content, expressed as acetaldehyde (CH 3 CHO) as a percentage by mass, is given by the formula where V is the volume, in millilitres, of the sodium hydroxide solution (3.2) used for the determination; is the density, in grams per millilitre, of the sample at20 C (see BS4522); 0,004405is the

21、mass, in grams, of carbonyl compounds, expressed as acetaldehyde, corresponding to1ml of sodium hydroxide solution, c(NaOH) = 0,100mol/l; 50is the volume, in millilitres, of the test portion (5.1). NOTEIf the concentrations of the standard volumetric solutions used are not exactly as specified in th

22、e list of reagents, an appropriate correction should be made.2 blankBS6392-3:1983 BSI 01-2000 Publication referred to BS 4522, Method for the determination of density of liquids at20 C. BS 6392-3: 1983 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent nat

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