1、BRITISH STANDARD BS 6829-1.6: 1991 ISO 6839:1982 Analysis of surface active agents (rawmaterials) Part1: General methods Section1.6 Method for determination ofsolubility in waterBS 6829-1.6:1991 This British Standard, having been prepared under the directionof the Chemicals Standards Policy Committe
2、e, waspublished under the authorityof the Standards Board and comes into effect on 31October1991 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference CIC/34 Draft for comment91/52314 DC ISBN 0 580 20105 8 Committees responsible for this British Standard T
3、he preparation of this British Standard was entrusted by the Chemicals Standards Policy Committee (CIC/-) to Technical Committee CIC/34, upon which the following bodies were represented: British Association for Chemical Specialities Chemical Industries Association Chemical Industries Association (GO
4、SIP) Department of Trade and Industry (Laboratory of the Government Chemist) Ministry of Defence Royal Society of Chemistry Soap and Detergent Industry Association Amendments issued since publication Amd. No. Date CommentsBS6829-1.6:1991 BSI 12-1999 i Contents Page Committees responsible Inside fron
5、t cover National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 Reference 1 3 Principle 1 4 Reagent 1 5 Apparatus 1 6 Sampling 1 7 Procedure 1 8 Expression of results 2 9 Test report 2 Table 3 Publication(s) referred to Inside back coverBS 6829-1.6:1991 ii BSI 12-1999 National for
6、eword This Section ofBS6829 has been prepared under the direction of the Chemicals Standards Policy Committee. It is identical withISO6839:1982 “Anionic surface active agents Determination of solubility in water”, published by the International Organization for Standardization (ISO). With reference
7、to5.2, precision thermometers complying withBS5074:1974 “Specification for short and long solid-stem thermometers for precision use” aretechnically equivalent to, and may be used in place of, those complying withISO653:1980. Additional information. With reference toclause1, it should be noted that,
8、despite the applicability of the method as stated, in the UK it is considered that the use of the method should be restricted to surface active agent raw materials and not applied to technical products or formulations. With reference toclause4, water complying with grade3 ofBS3978:1987 “Specificatio
9、n for water for laboratory use” is suitable. With reference to theTable, the name recommended in the UK for “sodium lauryl sulfate” is “sodium dodecyl sulfate” (seeBS2474:1983 “Recommendations for names for chemicals used in industry”). A British Standard does not purport to include all the necessar
10、y 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. Cross-references International Standard Corresponding British Standard ISO 607:1980 BS 3762 Analysis of
11、formulated detergents Part1:1983 Methods of sample division (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments inco
12、rporated. This will be indicated in the amendment table on the inside front cover.BS6829-1.6:1991 BSI 12-1999 1 0 Introduction The method described in this International Standard is one of the simplest of the methods which can be used for this purpose; it is sufficiently accurate and is suitable for
13、 a number of practical uses. 1 Scope and field of application This International Standard specifies a method of establishing the curve representing the solubility of an anionic surface active agent in water as a function of temperature, and, consequently, of allowing evaluation of its solubility at
14、a given temperature. The method is applicable both to pure surface active agents and to technical products or formulations of liquid anionic surface active agents, provided that the solutions of these products are optically clear and are not very strongly coloured. NOTEThe determination of solubilit
15、y may be carried out without restriction in the temperature range from0 to90 C; at temperatures lower than0 C, the determination is possible provided that the solution does not freeze. The solubility curve obtained in the case of pure products may possibly allow the Krafft temperature to be determin
16、ed. 2 Reference ISO 607, Surface active agents and detergents Methods of sample division. 3 Principle Preliminary determination on an aqueous solution of known anionic surface active agent concentration of the temperatures at which the solution changes, on heating, from being cloudy to clear and, on
17、 cooling, from being clear to cloudy. Placing in a bath, controlled at a temperature within the range established in the preliminary determination, of two solutions of the same concentration, one being colder and cloudy and the other being warmer and clear, and noting the appearance of the two solut
18、ions at temperature equilibrium. Repetition of the test, varying the temperature of the bath within the range established by the preliminary determination, until the clear solution remains clear and the cloudy solution remains cloudy, or the solutions change very slowly from being cloudy to clear or
19、 vice versa. From the surface active agent concentrations and the limiting temperatures of solubility, plotting the solubility curve. 4 Reagent During the determination, use only distilled water or water of equivalent purity. 5 Apparatus Usual laboratory equipment, and 5.1 Test tubes, made of borosi
20、licate glass, of diameter20mm and length200mm. 5.2 Precision thermometers, complying with the requirements ofISO653. 5.3 Thermostatically controlled water bath, capable of being controlled at5 C to+90 C, to within 0,1 C, with a transparent cell. 6 Sampling The laboratory sample of anionic surface ac
21、tive agent shall be prepared and stored in accordance with the instructions given inISO607. 7 Procedure 7.1 Test portion Weigh, to the nearest0,01g, the quantity of laboratory sample corresponding to one of the surface active agent concentrations to be studied concentrations usually between1 and50%
22、(m/m) then prepare approximately100ml of solution. If the solution contains dispersed impurities, it is advisable to filter it after heating to a temperature higher than that at which it is cloudy. This procedure shall not involve any alteration of the surface active agent concentration. 7.2 Prelimi
23、nary determination Transfer approximately10ml of the test solution(7.1) to a test tube(5.1) and heat it directly over a flame until the solution becomes clear. Allow to cool slowly in the ambient environment until it becomes cloudy, then slowly raise the temperature again, stirring the solution with
24、 a thermometer(5.2), and, as soon as the solution becomes clear, note the temperature (t 1 ). Allow to cool slowly, stirring the solution with the thermometer, and, as soon as the solution becomes cloudy, note the temperature (t 2 ). The temperature range thus determined is generally of the order of
25、10 C. 7.3 Determination of the limiting temperature of solubility Set the thermostatically controlled bath(5.3) at a temperature within the range defined by the preliminary determination(7.2) and keep it constant to within0,1 C.BS 6829-1.6:1991 2 BSI 12-1999 Fill two test tubes(5.1) with the solutio
26、n(7.1), stopper them, adjust their temperatures so that the solution in one becomes clear and the solution in the other becomes cloudy, and then place them in the thermostatically controlled bath. When the temperatures of the two solutions are equal to that of the water bath, note whether the two so
27、lutions are clear or cloudy. If both solutions are clear, lower the temperature ofthe water bath by a few degrees Celsius if both solutions are cloudy, raise it to a slightly higher temperature and repeat the above test. Carry out a third test, or more if necessary, controlling the bath at a tempera
28、ture deduced from the previous tests, until the change in appearance ofthe solutions (cloudy to clear or clear to cloudy) occurs very slowly or the clear solution remains clear and the cloudy solution remains cloudy. A maximum observation period of2 to3h may be adopted. Note the temperature at which
29、 this occurs to thenearest0,1 C, as the limiting temperature ofsolubility. If the appearance of the solutions remains unchanged, take the temperature immediately below that at which the two solutionsremained cloudy. NOTEThe speed with which the limpidity and cloudiness are reversed is a function of
30、the temperaturest 1and t 2determined in7.2 in relation to that of the bath. 7.4 Plotting the solubility curve Repeat the above procedures(7.1, 7.2 and7.3), using different quantities of test portion so as to cover the range of concentrations to be studied. Plotthe solubility curve as a function of t
31、he concentrations and corresponding limiting temperatures of solubility. This curve makes it possible to deduce the solubility of the surface active agent at a given temperature; determine, if required, the Krafft temperature. 8 Expression of results 8.1 Method of calculation Express the solubility
32、of the anionic surface active agent in water, for a given temperature, as a percentage by mass. 8.2 Precision Comparative analyses on samples of three differentsurface active agents, carried out in eight laboratories, have provided the information given intheTable. 9 Test report The test report shal
33、l include the following information: a) all the information necessary for the complete identification of the sample and details of the treatment of the test portion (and, if required, the temperature to which the solution was heated before filtration); b) the reference of the method used (reference
34、to this International Standard); c) the results obtained and the method of expression used: temperature (t 1 ) at which the solution becomes cloudy for the concentration being studied; temperature (t 2 ) at which the solution becomes clear for the concentration being studied; limiting temperature of
35、 solubility for the concentration being studied; d) if necessary, the solubility curve (and the Krafft temperature, if required); e) details of any operations not specified in this International Standard or regarded as optional, together with details of any incidents likely to have affected the resu
36、lts.BS6829-1.6:1991 BSI 12-1999 3 Table Surface active agent Concentration Mean observed limiting temperature of solubility Standard deviation ofreproducibility % (m/m) C C Sodium laurate, purity96,4% 2,5 5 10 20 30 24 27,7 31,7 38,6 42,7 2 1,7 2 1,6 1,6 Sodium lauryl sulphate, purity99% 2,5 5 10 20
37、 30 14 15,3 17 19,8 22,1 1,2 1,6 1,2 1,3 1,4 Sodium alkane sulphonate, purity98% 40 41 42 43 45 13,5 17,7 23 34,7 57,5 1,5 1 2,5 3 3,54 blankBS6829-1.6:1991 BSI 12-1999 Publication(s) referred to Seenational foreword.BS 6829-1.6: 1991 ISO 6839:1982 BSI 389 Chiswick High Road London W4 4AL BSIBritish
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