1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 1791 : 1997 The Eur
2、opean Standard EN 1791 : 1997 has the status of a British Standard ICS 71.100.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Surface active agents Fatty alkyl dimethyl amine oxides Determination of the amine oxide contentBS EN 1791 : 1997 This British Standard, having been
3、 prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 July 1997 BSI 1997 The following BSI references relate to the work on this standard: Committee reference CII/34 Draft for comment 95/120
4、251 DC ISBN 0 580 27616 3 Amendments issued since publication Amd. No. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee CII/34, Methods of test for surface active agents, upon which the following bodies
5、were represented: British Association for Chemical Specialities Chemical Industries Association Chemical Industries Association (GOSIP) Laboratory of the Government Chemist Ministry of Defence (DRA) Soap and Detergent Industry AssociationBS EN 1791 : 1997 BSI 1997 i Contents Page Committees responsi
6、ble Inside front cover National foreword ii Foreword 2 Text of EN 1791 3ii BSI 1997 BS EN 1791 : 1997 National foreword This British Standard has been prepared by Technical Committee CII/34, and is the English language version of EN 1791 : 1997, Surface active agents Fatty alkyl dimethyl amine oxide
7、s Determinaiton of the amine oxide content, published by the European Committee for Standardization (CEN). Cross-references Publication referred to Corresponding British Standard ISO 607 : 1980 BS 3762 Analysis of formulated detergents Part 1 : 1983 Methods of sample division ISO 1042 : 1983 BS 1792
8、 : 1982 Specification for one-mark volumetric flasks 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, the EN title page, pages 2 to 6, an inside back cover and
9、a back cover.CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1997 Copyright reserved to CEN members Ref. No. EN 1791 : 1997 E EUROPEAN STANDARD EN 1791 NORME EUROPE ENNE EUROPA IS
10、CHE NORM February 1997 ICS 71.100.40 Descriptors: Surfactants, chemical analysis, determination of content, oxides, tertiary amines, titration, potentiometric methods English version Surface active agents Fatty alkyl dimethyl amine oxides Determination of the amine oxide content Agents de surface Ox
11、ydes dalkyldime thylamine grasses De termination de la teneur en oxyde damine Grenzfla chenaktive Stoffe Fettalkyldimethylaminoxide Bestimmung des Aminoxidgehalts This European Standard was approved by CEN on 1997-01-05. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
12、 stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Stand
13、ard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national stand
14、ards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 1791 : 1997 BSI 1997 Foreword This European Standard has been prepared by Technical Committee CEN/TC
15、 276, Surface active agents, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 1997, and conflicting national standards shall be withdrawn at the la
16、test by August 1997. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway
17、, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Annexes A and B are informative. Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Principle 3 4 Reagents 3 5 Apparatus 3 6 Sampling 3 7 Procedure 3 7.1 Titration of the sum : Amine oxide and tertiary amine 3 7.2 Polonovski r
18、eaction and titration of tertiary amine 4 8 Expression of results 4 8.1 Calculation 4 8.2 Precision 4 9 Test report 4 Annex A (informative) Instrument settings 4 Annex B (informative) 5Page 3 EN 1791 : 1997 BSI 1997 1 Scope This European Standard specifies a method for the determination of up to app
19、roximately 2 milli-equivalents of tertiary amine oxide. Components which lose their basicity in reaction with acetic anhydride by forming an amide (e.g. primary and secondary amines) interfere. If present, these primary and secondary amines should be determined by a different procedure e.g. reaction
20、 with carbon sulfide. The method is applicable to solids or to aqueous solutions of the active material. The molecular mass of the amine oxide shall be known if its content is expressed as a percentage of mass. 2 Normative references This European Standard incorporates by dated or undated reference,
21、 provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated i
22、n it by amendment or revision. For undated references the latest edition of the publication referred to applies. ISO 607 1980 Surface active agents and detergents Methods of sample division ISO 1042 1983 Laboratory glassware One-mark volumetric flasks 3 Principle This European Standard is based on t
23、he Polonovski reaction in which the fatty alkyldimethylamine oxide reacts with acetic anhydride to form a N,N-disubstituted acetamide and an aldehyde (see equation 1). Free tertiary amine, residual raw material of technical amine oxide, remains unreacted and after dissolution of the sample in mixtur
24、e of acetic acid and acetic anhydride 2:1 (as a volume fraction) is titrated with a perchloric acid solution (see equation 2). In this medium the acetamide is not titrated. In a second titration the sum of amine oxide and tertiary amine is determined by potentiometric titration in acetic acid medium
25、 with a perchloric acid solution (see equation 3). R2 N(CH 3 ) 2 0 + (CH 3 CO) 2 0R2 N(CH 3 )COCH 3 + HCHO + CH 3 COOH (1) R2 N(CH 3 ) 2 + HCIO 4 R2 NH(CH 3 ) CI0 (2) 2 + 4 2 R2 N(CH 3 ) 2 0+R2N(CH 3 ) 2 + 2HCI0 4 R N(CH 3 ) 2 0H + CIO + R2 NH(CH 3 ) CI0 (3) 4 2 2 + 4 2 The difference between these
26、two titrations (32 2) gives the amine oxide content. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Perchloric acid, standard volumetric solution of known titre, c = 0,1 mol/l in acetic acid. 4.2 Acetic aci
27、d, glacial (purity 99 % as a mass fraction (minimum), density 1,05 g/ml at 20 C). 4.3 Acetic anhydride, (purity 99 % as a mass fraction (minimum), density 1,08 g/ml at 20 C). 5 Apparatus Ordinary laboratory apparatus and the following : 5.1 Recording potentiometer, equipped with a 20 ml plunger bure
28、tte and stirrer. NOTE. An example of instrument settings is given in annex A. 5.2 Combined glass electrode. 5.3 Magnetic stirrer, with electrically heated hot plate, capable of maintaining a temperature of (100 5) C. 5.4 Beaker, 150 ml capacity. 5.5 Measuring cylinder, 100 ml capacity. 5.6 Conical f
29、lask, 100 ml capacity. 5.7 Reflux condenser. 5.8 Analytical balance. 6 Sampling The laboratory sample of the detergent shall be prepared and stored in accordance with instructions given in ISO 607. 7 Procedure 7.1 Titration of the sum : Amine oxide and tertiary amine Weigh (m 1 ), to the nearest 0,1
30、 mg, a portion of the laboratory sample containing approximately 1,5 milli-equivalent of amine oxide into a 150 ml beaker (see 5.4). Add 50 ml acetic acid (see 4.2) with a measuring cylinder (see 5.5) and dissolve the sample. Place the beaker on the potentiometer (see 5.1) and insert a stirring bar.
31、 Insert the combined glass electrode (see 5.2) and start stirring. Titrate with the perchloric acid standard volumetric solution (see 4.1) until slightly beyond the potential jump and record the volume of perchloric acid solution necessary to reach equivalent point (V 1 ) (see annex B).Page 4 EN 179
32、1 : 1997 BSI 1997 7.2 Polonovski reaction and titration of tertiary amine Weigh (m 2 ), approximately 5 g to the nearest 10 mg of the laboratory sample into a conical flask (see 5.6). Add 25 ml of acetic anhydride (see 4.3) with a measuring cylinder and dissolve the sample. Insert a stirring bar, pl
33、ace the flask on the hot plate (see 5.3) and connect the reflux condenser (see 5.7). Heat to the boiling point and maintain a moderate reflux for 10 min while stirring. Cool to room temperature and add 50 ml of acetic acid. Place the flask on the potentiometer (see 5.1). Insert the combined glass el
34、ectrode (see 5.2) and start stirring. Titrate with the perchloric acid standard volumetric solution (see 4.1) until slightly beyond the potential jump and record the volume of perchloric acid solution necessary to reach the equivalent point (V 2 ) (see annex B). 8 Expression of results 8.1 Calculati
35、on The amine oxide content (A) expressed as a percentage by mass is given by the following equation : A = 3 C3 % (4) 2 V 1 m 1 V 2 m 2 M3 100 1000 where: V 1 is the volume of the perchloric acid standard volumetric solution (see 4.1) necessary to reach the equivalence point in 7.1,i n millilitres; V
36、 2 is the volume of the perchloric acid standard volumetric solution necessary to reach the equivalence point in 7.2, in millilitres; m 1 is the mass of the laboratory sample, weighed in 7.1, in grams; m 2 is the mass of the laboratory sample, weighed in 7.2, in grams; C is the concentration of the
37、perchloric acid standard volumetric solution; M is the mean molecular mass of the amine oxide. Express the result to one decimal place. 8.2 Precision 8.2.1 Repeatability 0,8 % at a level of approximately 31 % tertiary amine oxide. In the normal and correct operation of the method, the difference bet
38、ween two individual results obtained within the shortest feasible time interval by the same operator using the same apparatus and identical test material will exceed the repeatability value on average not more than once in 20 cases. 8.2.2 Reproducibility 0,9 % at a level of approximately 31 % tertia
39、ry amine oxide. In the normal and correct operation of the method, individual results obtained by two different laboratories using identical test material will differ by more than reproducibility value on average not more than once in 20 cases. 9 Test report The test report shall include the followi
40、ng particulars: a) all information necessary for the complete identification of the sample; b) the method used (a reference to this European Standard); c) the results obtained and the way in which they have been expressed; d) details of any operations not specified in this European Standard or in th
41、e International Standards to which reference is made, and any operations regarded as optional, as well as any incidents likely to have affected the results. Annex A (informative) Instrument settings Data given are settings for the Metrohm Potentiograph type E 536 and are intended to act as guide onl
42、y : Stop % U off Autocontrol 10 Min/100 % vol 5 mV x 100 mV scale 500 Recording mV/pH mV/pH 100 % Temperature 25 C Scan speed 400 mm/100 % vol.Page 5 EN 1791 : 1997 BSI 1997 Figure B.1 Titration of the sum: Amine oxide and tertiary amine (see 7.1) Annex B (informative)Page 6 EN 1791 : 1997 BSI 1997
43、Figure B.2 Titration of tertiary amine after Polonovski reaction (see 7.2) BSI 1997 BS EN 1791 : 1997 List of references See national foreword.BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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