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1、BRITISH STANDARD CONFIRMED AUGUST 1994 BS 5711-21: 1979 Methods of Sampling and test for glycerol Part 21: Determination of saponification equivalent NOTEIt is recommended that this Part of BS 5711 be read in conjunction with the general information given in BS 5711-0 “General introduction”, issued
2、separately. UDC 661.188.1:547.426.1:543.851.5 Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:13:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5711-21:1979 This British Standard, having been prepared under the direction of the Chemicals Standards Committee, was published under the autho
3、rity of the Executive Board and comes into effect on 30 November 1979 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference CIC/6 Draft for comment 75/53579 DC ISBN 0 580 11003 6 A British Standard does not purport to include all the necessary provisions o
4、f 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 cover, an inside front cover, pages i and ii, pages 1 and 2, an insid
5、e 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. Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffield
6、un, na, Mon Dec 04 15:13:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5711-21:1979 BSI 12-1999i Contents Page 1Scope and field of application1 2References1 3Principle1 4Reagents1 5Apparatus1 6Sampling1 7Procedure1 8Calculation1 9Test report1 Publications referred toInside back cover Licensed Cop
7、y: sheffieldun sheffieldun, na, Mon Dec 04 15:13:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:13:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5711-21:1979 BSI 12-19991 1 Scope and field of application This British Standard descr
8、ibes a titrimetric method for the determination of the saponification equivalent of dynamite grade and of chemically pure glycerol. 2 References The titles of the publications referred to in this standard are listed on the inside back cover. 3 Principle Neutralization of acids, saponification of the
9、 esters present and titration of the excess alkali with standard volumetric acid solution. 4 Reagents The reagents used shall be of a recognized analytical grade. Distilled water complying with the requirements of BS 3978 or water of at least equal purity and free from carbon dioxide shall be used.
10、(See Part 1 of this British Standard.) 4.1 Sodium hydroxide, 0.2N standard volumetric solution. 4.2 Sulphuric acid, 0.2N standard volumetric solution. 4.3 Phenolphthalein indicator solution, prepared as described in BS 4123. 5 Apparatus 5.1 Flask, 500 ml, round bottom, with a ground glass socket com
11、plying with the requirements of BS 572. 5.2 Condenser, water cooled, complying with the requirements of BS 3787, with ground glass cone to fit the flask (5.1). 5.3 Burette, 50 ml, complying with the requirements of BS 846. Two burettes are required. 6 Sampling Prepare the laboratory sample as descri
12、bed in Part 2 of this British Standard. 7 Procedure Weigh, to the nearest 0.1 g, about 100 g of the well mixed sample into the flask (5.1). Add 100 ml of hot, carbon dioxide-free water and 1 ml of the phenolphthalein indicator solution (4.3). If the solution is alkaline, adjust to neutrality with th
13、e sulphuric acid solution (4.2). Add from the burette (5.3) 20.0 ml of the sodium hydroxide solution (4.1). Connect the flask to the reflux condenser (5.2) and heat to boiling. Boil for 5 min, allow to cool somewhat and wash down the condenser with a little water. Disconnect the flask, close it with
14、 a stopper carrying a soda-lime tube and cool. Titrate with the sulphuric acid solution (4.2) from the burette (5.3). Carry out a blank test at the same time, but using 140 ml of the water instead of the test portion. NOTEIt is recommended that all tests should be carried out in duplicate. 8 Calcula
15、tion Calculate the saponification equivalent in milliequivalents per 100 g from the formula where 9 Test report The test report shall include the following particulars: a) a reference to this British Standard; b) the test result and the method of expression used; c) any unusual feature noticed durin
16、g the determination; d) any operation not included in this British Standard or regarded as optional. V0is the volume of the sulphuric acid used for the titration of the blank solution (ml) V1is the volume of the sulphuric acid used for the titration of the test solution (ml) mis the mass of the test
17、 portion (g). 20 V0V1() m - - Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:13:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 blank Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:13:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5711-21:1979 BSI 12-1999 Publications referre
18、d to BS 572, Interchangeable conical ground glass joints. BS 846, Burettes and bulb burettes. BS 3787, Glass condensers with standard joints. BS 3978, Water for laboratory use. BS 4123, Schedule of preferred chemical indicators. BS 5711, Methods of sampling and test for glycerol. BS 5711-1, Sampling
19、 and test methods: general. BS 5711-2, Methods of sampling. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:13:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5711-21: 1979 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body resp
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