1、BRITISH STANDARDBS EN1890:2006Surface active agents Determination of cloud point of non-ionic surface active agents obtained by condensation of ethylene oxideThe European Standard EN 1890:2006 has the status of a British StandardICS 71.100.40g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g
2、54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 1890:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2006 BSI 2006ISBN 0 580 48935
3、 3National forewordThis British Standard is the official English language version of EN 1890:2006. It supersedes BS EN 1890:1999 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee CII/34, Methods of test for surface active agents, which has the responsib
4、ility to: A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “Internat
5、ional Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a Britis
6、h Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and Euro
7、pean developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendm
8、ents issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 1890June 2006ICS 71.100.40 Supersedes EN 1890:1999 English VersionSurface active agents - Determination of cloud point of non-ionicsurface active agents obtained by condensation of ethyleneoxideAgent
9、s de surface - Dtermination du point de trouble desagents de surface non ioniques obtenus par condensationdoxydes dthylneGrenzflchenaktive Stoffe - Bestimmung desTrbungspunktes nichtionischer, durch Anlagerung vonEthylenoxid hergestellter grenzflchenaktive StoffeThis European Standard was approved b
10、y CEN on 18 May 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards m
11、ay be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Cent
12、ral Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Polan
13、d, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any m
14、eans reservedworldwide for CEN national Members.Ref. No. EN 1890:2006: EEN 1890:2006 (E) 2 Contents Foreword3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and Definitions .5 4 Principle6 5 Reagents.6 6 Apparatus .6 7 Preparation and storage of samples7 8 Procedure .7 9 Expression of re
15、sults 9 10 Precision.9 11 Test report 9 Bibliography. 10 EN 1890:2006 (E) 3 Foreword This document (EN 1890:2006) has been prepared by Technical Committee CEN/TC 276 “Surface active agents”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national sta
16、ndard, either by publication of an identical text or by endorsement, at the latest by December 2006, and conflicting national standards shall be withdrawn at the latest by December 2006. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rig
17、hts. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 1890:1999. The main changes are: the purity of Butyldigycol was changed to correspond to commercially available products; the apparatus was simplified. According to the CE
18、N/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg
19、, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 1890:2006 (E) 4 Introduction Solutions of non-ionic surface active agents obtained by the reaction of ethylene oxide with a hydrophobic base molecule, in water or in mixture
20、s of water and organic solvents become turbid at a given temperature as the temperature increases and finally separate into two liquid phases. The process is reversible and the system becomes homogeneous again upon cooling. The temperature at which the solution becomes clear upon cooling is determin
21、ed as the “cloud point“. This temperature is characteristic for a particular surfactant. This temperature increases with the amount of ethylene oxide chemically combined in the surfactant molecule for a given composition of solvents. This phenomenon is not limited to ethoxylated surfactants and the
22、cloud point can be determined also for other non-ionic compounds. The knowledge of the cloud point of non-ionic surfactants obtained by the reaction of ethylene oxide with hydrophobic bases is important for their use. For a given base molecule, the cloud point is indeed a simple measure of the amoun
23、t of the combined ethylene oxide. Moreover, the cloud point suggests directly the temperature at which many functional surfactant properties change dramatically. The curve of cloud point versus degree of ethoxylation is asymptotic; therefore molecules containing high amounts of ethylene oxide show o
24、nly small differences in their cloud point. In these cases the cloud point loses its significance. EN 1890:2006 (E) 5 1 Scope This document specifies methods for the determination of the cloud point of solutions of non-ionic surface active agents obtained by the reaction of ethylene oxide with a hyd
25、rophobic base molecule. This document primarily applies to surfactants obtained by reaction of ethylene oxide with hydrophobic base molecules, such as fatty alcohols, fatty acids, long-chain alkylphenols, fatty amines, fatty acid esters of sugar derivatives among other ethoxylated non-ionic surfacta
26、nts, which are by far the most commonly used. NOTE Other non-ionic surfactants containing other structural units, such as propylene oxide-ethylene oxide block copolymers, have distinctive behaviours that make the determination of the cloud point more difficult. This leads sometimes to a continuous t
27、urbidity over a temperature range of several degrees or even to the occurrence of two cloud points at significantly different temperatures. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited a
28、pplies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 862:1995, Surface active agents - Vocabulary - Trilingual version (ISO 862:1984/Cor 1:1993). EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3
29、696:1987). ISO 607, Surface active agents and detergents Methods of sample division. 3 Terms and Definitions For the purposes of this document, the terms and definitions given in EN ISO 862:1995 and the following apply. 3.1 cloud temperature temperature above which aqueous solutions of certain non-i
30、onic surface active agents become heterogeneous by the separation into two liquid phases (coacervation) EN ISO 862:1995 NOTE 1 The value of the cloud temperature depends on the concentration of the solution. NOTE 2 The temperature at which the system becomes homogeneous upon cooling is called “tempe
31、rature of clarification”. The cloud temperature and the temperature of clarification do not need to coincide for reasons concerned with the measurement procedure. However, for practical reasons, the temperature of clarification is conventionally called the “cloud point”. 3.2 cloud point critical low
32、er phase-separation temperature (lower consolute temperature) above which the system is a cloudy solution and a further temperature rise results in two immiscible phases that are in equilibrium NOTE 1 The cloud point is measured as the temperature falls. NOTE 2 The cloud point depends on the number
33、of ethylene oxide units linked to the base molecule and on their statistical distribution. It is also very sensitive to the presence of electrolytes and other organic substances in the aqueous solution. Therefore it should operate under well established conditions. 3.3 temperature of clarification t
34、emperature at which the mixture of two liquid phases of aqueous solution of certain non-ionic surface active agents exhibiting a cloud temperature, becomes homogeneous on cooling EN ISO 862:1995 NOTE The temperature of clarification is often determined as “cloud point“. EN 1890:2006 (E) 6 4 Principl
35、e The surfactant solution is heated until it is completely cloudy. Then it is slowly cooled with constant stirring while measuring the temperature. The temperature at which the turbidity disappears and the solution becomes homogeneous is recorded as the cloud point. Depending on the nature of the su
36、rfactant and the purity of the materials the solution can become completely clear or slightly opalescent but in this case a definite change from the cloudy solution is observed. 5 Reagents During the test, unless otherwise stated, use only reagents of recognized analytical grade. 5.1 Water according
37、 to grade 3 in EN ISO 3696 or water of at least equivalent purity. 5.2 Diethylene glycol mono-n-butylether (special quality) C4H9-O-CH2-CH2-O-CH2-CH2-OH (also commercially known as butyldiglycol). 5.2.1 Specifications The butyldiglycol (BDG) shall have the following: minimum purity : 99 % (m/m) (GC)
38、; density at 20 C : (0,953 0,002) g/ml ; refractive index : nD20= (1,432 0,001); water content : 0,1 % (m/m). NOTE Impurities present in diethylene glycol mono-n-butylether and differences in concentration of its 25 % as mass fraction aqueous solution affect the cloud point to some extent. For arbit
39、ration purposes samples of diethylene glycol mono-n-butylether shall be exchanged between laboratories. 5.2.2 Butyldiglycol/water, solution at 25 % (m/m). Dissolve 250 g of butyldiglycol (5.2.1) with 750 g of water. 5.3 Sodium chloride aqueous solutions 5.3.1 50,00 g NaCl per litre solution in water
40、. 5.3.2 100,00 g NaCl per litre solution in water. 6 Apparatus Normal laboratory apparatus and the following: 6.1 Calibrated thermometer, graduated in 0,1 C, with a range appropriate to the temperature to be measured or a calibrated electronic measuring instrument with digital display. 6.2 Conical f
41、lask, capacity 250 ml, with glass or plastic stopper or other suitable vessel. 6.3 Test tube, capacity at least 30 ml, with a good temperature endurance. 6.4 Conventional heating appliance, for example Bunsen burner, hand-held hot air blower or thermostated oil bath. EN 1890:2006 (E) 7 7 Preparation
42、 and storage of samples Prepare and store the sample of the surface active agent in accordance with ISO 607. 8 Procedure 8.1 Selection of test method Five methods of cloud point determination are described; select from those given in 8.2 to 8.6, the most appropriate method for the particular surfact
43、ant under test, depending upon the temperature at which the solution of the test sample becomes turbid. NOTE The temperature at which the solution of a surfactant becomes turbid depends on the ethylene oxide content (see Figure 1). The choice between methods A, B, C, D and E is based on the sharpnes
44、s of the cloud point and the sensitivity of the method. It should be noted that the methods B and C and methods D and E will produce different cloud point results and so the method used should be fully noted when reporting any results. Key 1 Temperature A 1 g sample + 100 g of water (5.1) 2 Ethylene
45、 oxide content B 1 g sample + 100 g of 50g/l NaCl solution (5.3.1) C 1 g sample + 100 g of 100g/l NaCl solution (5.3.2) D 5 g sample + 45 g of 25 % (m/m) BDG solution (5.2.2) E 5 g sample + 25 g of 25 % (m/m) BDG solution (5.2.2) Figure 1 Cloud point behaviour of typical fatty alcohol ethoxylates us
46、ing different test methods EN 1890:2006 (E) 8 8.2 Method A : Water solution NOTE 1 Method A is used when an aqueous solution of 1 g of sample plus 100 g of water becomes turbid at a temperature between 10 C and 90 C. Weigh 1,0 g of the sample (see clause 7) to the nearest 0,01 g into the conical fla
47、sk (6.2), add 100 g of water, stopper the flask and stir until the sample has dissolved to form a clear solution. Pour about 15 ml to 25 ml of this solution into the test tube (6.3). Put the thermometer (6.1) into the tube and heat with a heating appliance (6.4) under slow stirring with the thermome
48、ter until it is completely opaque. NOTE 2 The opacity appears as bands, which thicken, and results in turbidity. The temperature of the solution should not exceed by more than 10 C the temperature at which the opacity appears. Allow to cool slowly in the air while stirring. Read the temperature at w
49、hich the opaque bands disappear. Repeat the determination, using a fresh solution, until at least two results differ from each other by not more than 0,5 C. NOTE 3 A fresh solution is used to avoid loss of water due to evaporation. 8.3 Method B : Salt solution of NaCl at 50 g/l NOTE Method B is used when an aqueous solution of 1 g of sample plus 100 g of water becomes turbid at a temperature above 90 C. Weigh 1,0 g of the sample (see clause 7) to the nearest 0,01 g into the conical flask (6.2), add 100 g of sodium chloride solutio
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