BS 1715-2 5-1989 Analysis of soaps - Quantitative test methods - Method for determination of unsaponifiable unsaponified and unsaponified saponifiable matter contents《肥皂分析 第2部分 定量试.pdf

1、BRITISH STANDARD BS 1715-2.5: 1989 ISO 1067:1974 Analysis of soaps Part 2: Quantitative test methods Section 2.5 Method for determination of unsaponifiable, unsaponified, and unsaponified saponifiable matter contents ISO title: Analysis of soapsDetermination of unsaponifiable, unsaponified and unsap

2、onified saponifiable matter UDC 661.18:543BS1715-2.5:1989 This British Standard, having been prepared under the directionof the Chemicals Standards Policy Committee, waspublished under the authorityof the Board of BSI andcomes into effect on 31July1989 BSI 09-1999 The following BSI references relate

3、 to the work on this standard: Committee reference CIC/34 Draft for comment 88/53277 DC ISBN 0 580 17319 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Chemicals Standards Policy Committee (CIC/-) to Technical Committee CIC/34, upon w

4、hich the following bodies were represented: Chemical Industries Association Consumer Policy Committee of BSI Department of the Environment Department of Trade and Industry (Laboratory of the Government Chemist) Ministry of Defence Royal Society of Chemistry Soap and Detergent Industry Association So

5、ciety of Dyers and Colourists Amendments issued since publication Amd. No. Date of issue CommentsBS1715-2.5:1989 BSI 09-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Field of application 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Sampling 1 7 Proce

6、dure 1 8 Expression of results 2 9 Test report 2 Publications referred to Inside back coverBS1715-2.5:1989 ii BSI 09-1999 National foreword This Section of BS1715 has been prepared under the direction of the Chemicals Standards Policy Committee. It is identical with ISO1067:1974 “Analysis of soapsDe

7、termination of unsaponifiable, unsaponified and unsaponified saponifiable matter” published by the International Organization for Standardization (ISO). This method supersedes the methods for determination of unsaponified neutral fat and unsaponifiable matter, given in BS1715:1963, which are deleted

8、 by amendment. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to

9、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. The symbol “l” has been used to denote litre (and in its submultiples). InBritishStandards it is current practice to use the symbol “L”.

10、Wherever the words “relative molar mass” appear, they should be read as “relative molecular mass”. Wherever the words “International Standard” appear, referring to this standard, they should be read as “Section of BS1715”. With reference to5.5, a British Standard related to ISO/R648 (now revised as

11、ISO648:1977) is BS1583:1986 “Specification for one-mark pipettes”. The International Standard for sampling of soaps (seeclause6) is not yet published. Relevant information is included in BS1715 “Analysis of soaps”, Part1:1989 “General introduction, sampling, and test for presence of synthetic anioni

12、c-active surface active agents”. Additional information. With reference to clause4, water complying with grade3 of BS3978 “Specification for water for laboratory use” is suitable, and the reagents used should be of a recognized analytical grade, unless otherwise specified. For the purposes of4.1, 4.

13、4, 4.5 and4.6, the ethanol may be replaced by industrial methylated spirits complying with BS3591 “Specification for industrial methylated spirits” of appropriate strength. It should be noted that the use of industrial methylated spirits is governed by the Methylated Spirits Regulations, 1983(SI1983

14、 No.252). It is not permissible to use duty-free ethanol, received under the provisions of the Alcoholic Liquors Duties Act1972, Section10, for purposes for which industrial methylated spirits is an acceptable alternative. With reference to4.4 and4.5, the potassium hydroxide standard volumetric solu

15、tions, expressed as amount-of-substance concentrations, are c(KOH)=0.1mol/L and c(KOH)=2mol/L respectively. This Section describes a method of test only, and should not be used or quoted as a specification defining limits of purity. Reference to this Section should indicate that the method of test u

16、sed is in accordance with BS1715-2.5. Cross reference International Standard Corresponding British Standard ISO 1773:1976 (replacing ISO/R1773) BS 2734:1984 Specification for boiling flasks (narrow-necked), conical, flat bottom and round bottom (Identical)BS1715-2.5:1989 BSI 09-1999 iii A British St

17、andard does not purport to include all the necessary provisions of a contract. Users of 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 cove

18、r, an inside front cover, pagesi to iv, pages1and2, an inside back cover and a back 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.iv blankBS1715-2.5:1989 BSI 09-1999 1 1 Sco

19、pe This International Standard specifies a method for the determination of the contents of unsaponifiable, unsaponified and unsaponified saponifiable matter in commercial soaps, excluding compound products. 2 Field of application This method is applicable to the determination of the contents of prod

20、ucts, other than free fatty acids, which are soluble in hexane or light petroleum (unsaponifiable+unsaponified matter), and which can be saponified (unsaponified saponifiable matter). The method is not applicable to soaps enriched with sterols or long chain alcohols, nor to soaps containing perfume.

21、 3 Principle Extraction of matter soluble in hexane, and titration of the free fatty acids removed, with potassium hydroxide solution. Saponification of products soluble in hexane neutralized in this way and extraction of the unsaponifiable matter by hexane. 4 Reagents The water used shall be distil

22、led water or water of equivalent purity. The reagents shall have the following characteristics: 4.1 Ethanol, free from carbon dioxide, neutralized hot with the ethanolic potassium hydroxide solution(4.4) using the phenolphthalein solution(4.6) as indicator. 4.2 Sodium hydrogen carbonate, 10g/l solut

23、ion. 4.3 n-Hexane, technical grade or, failing this, light petroleum distilling at between40 and60 C, having a bromine number less than1, and free from residue. 4.4 Potassium hydroxide, 0,1N standard volumetric solution in ethanol. 4.5 Potassium hydroxide, 2N standard volumetric solution in ethanol.

24、 4.6 Phenolphthalein, 10g/l solution in95% (V/V) ethanol. 5 Apparatus Ordinary laboratory apparatus and, in particular: 5.1 Beaker, 250ml. 5.2 Separating funnels, 50ml and 250ml. 5.3 Round-bottomed flasks, 100ml and 250ml, complying with ISO/R1773. 5.4 Microburette, 2ml. 5.5 Pipette, 10ml, complying

25、 with ISO/R648. 5.6 Oven, capable of being controlled at103 2 C. 6 Sampling The laboratory sample of soap shall be prepared and stored in accordance with the instructions given in ISO. . ., Soaps Sampling. 1) 7 Procedure 7.1 Test portion Weigh, to the nearest0,001g, about5g of the laboratory sample,

26、 the soap being finely grated, into the250ml beaker(5.1). 7.2 Determination Add50ml of the neutralized ethanol(4.1) and50ml of the sodium hydrogen carbonate solution(4.2) to the test portion(7.1). Dissolve the soap by heating to not above70 C. After the soap is completely dissolved, allow the soluti

27、on to cool. Transfer the solution quantitatively to the250ml separating funnel(5.2), rinsing the beaker several times with a mixture of equal volumes of the neutralized ethanol(4.1) and the sodium hydrogen carbonate solution(4.2), and extract three times, stirring carefully, each time with50ml of th

28、e hexane or the light petroleum(4.3). Combine the extracts, filter them if necessary, and wash them until neutral to phenolphthalein, using for each wash50ml of a mixture of equal volumes of the neutralized ethanol(4.1) and water. Normally three washings are sufficient. Transfer the solution quantit

29、atively to the250ml flask(5.3), previously dried in the oven(5.6) controlled at103 2 C, allowed to cool in a desiccator and weighed to the nearest0,2mg. Evaporate most of the solvent on a boiling water bath and remove the last traces with the aid of a gentle current of dry air directed into the flas

30、k while it is held obliquely, almost entirely immersed in the bath, and rotated. 1) In preparation.BS1715-2.5:1989 2 BSI 09-1999 Dry the flask and residue for5min in the oven(5.6) controlled at103 2 C, allow it to cool in a desiccator and weigh to the nearest0,2mg. Repeat the operations of drying, c

31、ooling and weighing until the difference between two successive weighings does not exceed2mg. Let this mass be m 1 . Dissolve the residue in a few millilitres of the neutralized ethanol(4.1). Using the microburette(5.4), titrate the free acidity with the potassium hydroxide solution(4.4), using the

32、phenolphthalein solution(4.6) as indicator, until the solution turns pink. Note the volumeV of this solution used for the titration. Add10,0ml of the potassium hydroxide solution(4.5), using the pipette(5.5). Bring the solution to boiling point and boil it under reflux for30min. Then add a volume of

33、 water equal to the volume of the solution and transfer the solution quantitatively to the50ml separating funnel(5.2), using a few millilitres of a mixture of equal volumes of the neutralized ethanol(4.1) and water to rinse the flask. Extract three times, each time with10ml of the hexane or the ligh

34、t petroleum(4.3). Combine the extracts and wash them until neutral to phenolphthalein, using for each wash10ml of a mixture of equal volumes of the neutralized ethanol(4.1) and water. Normally three washings are sufficient. Transfer the solution quantitatively into the100ml flask(5.3), previously dr

35、ied in the oven(5.6) controlled at103 2 C, allowed to cool in a desiccator and weighed to the nearest0,2mg. Evaporate most of the solvent on a boiling water bath and remove the last traces with the aid of a gentle current of dry air directed into the flask while it is held obliquely, almost entirely

36、 immersed in the bath, and rotated. Dry the flask and residue for5min in the oven(5.6) controlled at103 2 C, allow it to cool in a desiccator and weigh to the nearest0,2mg. Repeat the operations of drying, cooling and weighing until the difference between two successive weighings does not exceed2mg.

37、 Let this mass be m 2 . 8 Expression of results The percentage, by mass, of unsaponified matter+unsaponifiable matter in the soap is equal to The percentage, by mass, of unsaponifiable matter in the soap is equal to The percentage, by mass, of unsaponified saponifiable matter in the soap is equal to

38、 where m 0 is the mass, in grams, of the test portion; m 1 is the mass, in grams, of the first extract; m 2 is the mass, in grams, of the second extract; M is the mean relative molar mass of the fatty acids of the soap (see note); V is the volume, in millilitres, of the 0,1 N standard volumetric eth

39、anolic potassium hydroxide solution (4.4) used to determine the acidity of the first extract. NOTEThe mean relative molar mass M of the fatty acids of the soap can be determined by titration of the fatty acids isolated after the saponification of a sample of the original soap, the elimination of uns

40、aponifiable matter and the acidification of the soap solution. 9 Test report The test report shall indicate the method used and the results obtained. It shall also mention all test conditions and procedural details not specified in this International Standard, or which are optional, and any factors

41、which may have affected the results. The test report shall give all information necessary for the complete identification of the sample. m 1 VM 10 000 - 100 m 0 - m 2 100 m 0 - m 1 VM 10 000 -m 2 100 m 0 - BS1715-2.5:1989 BSI 09-1999 Publications referred to See national foreword.BS 1715-2.5: 1989 I

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