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1、BRITISH STANDARD BS EN 15168:2006 Surface active agents Determination of hydroxyl value p-Toluensulfonyl isocyanate (TSI) method and potentiometric titration with tetrabutylammonium hydroxide The European Standard EN 15168:2006 has the status of a British Standard ICS 71.100.40 ? Licensed Copy: Lond
2、on South Bank University, London South Bank University, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS EN 15168:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 December 2006 BSI 2006 ISBN 0 580 49887 5 National fore
3、word This British Standard was published by BSI. It is the UK implementation of EN 15168:2006. The UK participation in its preparation was entrusted to Technical Committee CII/34, Methods of test for surface active agents. A list of organizations represented on CII/34 can be obtained on request to i
4、ts secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licens
5、ed Copy: London South Bank University, London South Bank University, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 15168 November 2006 ICS 71.100.40 English Version Surface active agents - Determination of hydroxyl value - p- Tolu
6、ensulfonyl isocyanate (TSI) method and potentiometric titration with tetrabutylammonium hydroxide Agents de surface - Dtermination de lindice dhydroxyle - Mthode la p-tolunesulfonylisocyanate (TSI) et titrage potentiomtrique avec lhydroxyde de ttrabutylammonium Grenzflchenaktive Stoffe - Bestimmung
7、der Hydroxylzahl - p-Toluolsulfonylisocyanat-(TSI-) Verfahren und potentiometrische Titration mit Tetrabutylammoniumhydroxid This European Standard was approved by CEN on 6 October 2006. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for givi
8、ng 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 Standard exists in three official versi
9、ons (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 standards bodies of Austria, Belgium, C
10、yprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION
11、 COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2006 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15168:2006: E Licensed Copy: London South Bank University, Lo
12、ndon South Bank University, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 15168:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references4 3 Terms and definitions .4 4 Principle4 5 Reagents.5 6 Apparatus .5 7 Sampling.6 8 Procedure .6 9 Calculation and expression of res
13、ults.8 10 Precision.8 11 Test report8 Annex A (informative) Interferences9 Annex B (informative) Titration apparatus settings.10 Annex C (informative) Example for a typical potentiometric titration curve.11 Annex D (informative) Statistical and other data derived from the results of inter-laboratory
14、 tests .12 Bibliography13 Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 15168:2006 (E) 3 Foreword This document (EN 15168:2006) has been prepared by Technical Committee CEN/TC 276 “Surface active agents”,
15、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 May 2007, and conflicting national standards shall be withdrawn at the latest by May 2007. According to t
16、he CEN/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, Luxem
17、bourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 15168:2006 (E) 4 1 Scope This
18、European Standard specifies a method for the determination of hydroxyl value of aliphatic and cyclic hydroxyl compounds with hydroxyl groups attached to primary and secondary carbon atoms. This European Standard is applicable to polyacetals, temperature sensitive materials, high solids polymer polyo
19、ls and rigid polyols and phenols. This European Standard is not suitable for determination of hydroxyl groups attached to tertiary carbon atoms. NOTE This method is currently recommended for neutral refined products. However for products that contain an excess of acidic species a validation should b
20、e carried out to show that the acidic species either does not interfere or that the acidic species interference has been obviated. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. F
21、or undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696:1987) ISO 607, Surface active agents and detergents Methods of sample division 3 Terms and definitions Fo
22、r the purposes of this document, the following term and definition applies. 3.1 hydroxyl value, OHV number of milligrams of potassium hydroxide corresponding to the hydroxyl groups in 1 g of material 4 Principle A known mass of test sample is reacted with an excess of p-toluenesulfonyl isocyanate to
23、 form an acidic carbamate. Water is added to convert un-reacted isocyanate to sulfonamide followed by direct potentiometric titration of the acidic carbamate with tetra-n-butyl ammonium hydroxide in non-aqueous medium. The reactions occurring are as follows: a) formation of acidic carbamate; CH3 SO2
24、-NCO + R-OH CH3 SO2-NHCOOR b) hydrolysis of the excess of isocyanate; CH3 SO2-NCO + H2O CH3 SO2 NH2 + CO2 Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 15168:2006 (E) 5 c) titration of the acidic carbamate
25、 formed. CH3 SO2-NH COOR + OH- CH3 SO2-N- - COOR + H2O 5 Reagents During the analysis, unless otherwise specified, use only reagents of recognized analytical grade that have been checked in advance as to not interfere with the analytical results. WARNING Acetonitrile, p-toluenesulfonyl isocyanate an
26、d tetrabutylammonium hydroxide being hazardous chemicals: conduct all the operations under a well-ventilated fume hood. 5.1 Water complying with grade 3 as defined in EN ISO 3696. 5.2 Acetonitrile, with water content 0,01 % (m/m) (CAS number : 75-05-8). 5.3 Toluene, minimum purity 99 % (m/m) (CAS nu
27、mber : 108-88-3). 5.4 Tetrahydrofurane (THF), minimum purity 99 % (m/m) (CAS number : 109-99-9). 5.5 p-Toluenesulfonyl isocyanate (TSI), minimum purity 96 % (m/m) (CAS number : 4083-64-1). Maintain a nitrogen pad above this reagent after opening the flask. 5.6 p-Toluenesulfonyl isocyanate (TSI) reag
28、ent solution. Pipette 20 ml of TSI (5.5) into a dry 500 ml volumetric flask half filled with acetonitrile. Make up to the mark with acetonitrile and mix well. This reagent shall be prepared fresh monthly. 5.7 Potassium hydrogen phthalate, primary standard minimum purity 99 %(m/m) dried 2 h at 120 C
29、(CAS number : 877-24-7). 5.8 Tetra-n-butyl ammonium hydroxide standard volumetric solution, c(CH3 (CH2) 3 4NOH) = 0,1 mol/l (CAS number : 2052-49-5). in 2-propanol/methanol. 5.9 Electrolyte: 0,4 mol/l tetraethyl ammonium bromide solution (CAS number : 71-91-0) in ethylene glycol (CAS number:107-21-1
30、). 5.10 Electrolyte: saturated LiCl solution (CAS number : 7447-41-8) in ethanol (CAS number : 64-17-5). 6 Apparatus Normal laboratory apparatus, and the following. 6.1 Automatic potentiometer, with drift-controlled data acquisition and dynamic titrimetric dosing equipped with an automatic burette a
31、ssembly and a magnetic stirrer. 6.2 Electrodes: There are two options for the electrodes definition. 6.2.1 Two electrodes system 6.2.1.1 Glass pH electrode. 6.2.1.2 Ag/AgCl double-junction ground joint diaphragm reference electrode, inner and outer chambers filled with 0,4 mol/l solution of tetraeth
32、yl ammonium bromide in ethylene glycol (5.9). or Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 15168:2006 (E) 6 6.2.2 One electrode system Combined glass pH electrode for titrations in non aqueous media (e
33、.g. Solvotrode1), filled with 0,4 mol/l solution of tetraethyl ammonium bromide in ethylene glycol (5.9). NOTE For electrode maintenance it is recommended to follow the manufacturer instructions. A saturated lithium chloride solution in ethanol (5.10) can also be used as electrolyte to fill the elec
34、trodes. 7 Sampling The sample shall be taken and stored in accordance with ISO 607. Samples that are solids at room temperature shall be heated prior to weighing to obtain a clear liquid, at the lowest possible temperature (50 C to 70 C) to avoid any undesirable changes in the sample. If higher temp
35、eratures are required to melt the sample, for example 110 C, then the sample shall be removed from the oven as soon as a clear liquid is obtained. After heating, invert the sample container about twenty times to ensure complete homogenisation. Samples that are liquid at room temperature only require
36、 inversion mixing. 8 Procedure 8.1 Standardization of tetra-n-butyl ammonium hydroxide standard volumetric solution Weigh about 0,18 g of dried potassium hydrogen phthalate (5.7) (m0) to the nearest 0,1 mg into a 100 ml beaker, dissolve it in about 60 ml of freshly boiled water and stir several minu
37、tes to ensure complete dissolution. Carry out a potentiometric titration directly with the tetra-n-butyl ammonium hydroxide standard volumetric solution (5.8). Record the volume V of the tetra-n-butyl ammonium hydroxide standard volumetric solution (5.8) at the inflection point of the titration curv
38、e. Carry out three to five standardization titrations to obtain a reliable mean value for the 0,1 mol/l tetra-n-butyl ammonium hydroxide concentration (5.8). Calculate the concentration, c, of the tetra-n-butyl ammonium hydroxide standard volumetric solution (5.8), expressed in moles per litre, usin
39、g the Equation (1): VM m c = 1000 0 (1) where m0 is the mass of potassium hydrogen phthalate (5.7), in grams; V is the volume, in millilitres, of the tetra-n-butyl ammonium hydroxide standard volumetric solution (5.8) consumed to the inflection point. The results shall be given to four decimal place
40、s. 1) Solvotrode is the trade name of a product supplied by Metrohm Ltd. (CH-9101 Herisau, Switzerland). This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN. Equivalent products may be used if they can be shown to lead to the
41、 same results. Licensed Copy: London South Bank University, London South Bank University, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 15168:2006 (E) 7 8.2 Test portion Calculate the optimum sample to be weighed, m, expressed in grams, by the Equation (2): ()E 40 OHV m = (2) whe
42、re (OHV)E is the expected hydroxyl value, in milligrams KOH per sample gram. For expected hydroxyl values 2, weigh about 15 g to 20 g of sample as maximum. 8.3 Determination Weigh the calculated mass of the test portion, m, to the nearest 0,1 mg into a clean and dry 100 ml beaker. With a measuring c
43、ylinder, add 10 ml of acetonitrile (5.2). Add a magnetic stirring bar and stir slowly on a magnetic stirrer until the test portion is dissolved (30 s are usually sufficient). NOTE 1 Although acetonitrile has been found to dissolve a wide range of product types and should be used where possible, tetr
44、ahydrofuran or pentene stabilized chloroform may be used as solvent for products that may be insoluble in acetonitrile (5.2). Alternatively, 3 ml of toluene (5.3) may be used to dissolve a product, followed immediately by addition of 7 ml of acetonitrile (5.2). Superior potentiometric titration curv
45、es are obtained in acetonitrile media. Pipet (10 0,1) ml of TSI reagent (5.6) into the test solution, cover the beaker with a watch glass and stir slowly on the magnetic stirrer for 5 min. Add 0,5 ml of water to destroy excess of TSI reagent (5.6) and stir for 1 min at slow speed. Add about 60 ml of
46、 THF (5.4) and start the titration with 0,1 mol/l tetra-n-butyl ammonium hydroxide standard volumetric (5.8) solution using the electrodes defined in 6.2. NOTE 2 A set of titration parameters is given in Annex B for advice. After titration rinse the electrode(s) to remove residual organic material a
47、nd next rinse with water and immerse the electrode bulb in water to maintain good hydration of electrode between titrations. A typical potentiometric titration curve will have two or three inflections as those in Figure C.1. Record the volume (V1) at the first potentiometric end point and the volume
48、 (V2) at the second potentiometric end point. Although pH values will not enter into the calculations, record the “apparent“ pH values at each of the potentiometric inflection points. Perform the test solution analysis in duplicate. Licensed Copy: London South Bank University, London South Bank Univ
49、ersity, Thu Mar 01 08:55:48 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 15168:2006 (E) 8 9 Calculation and expression of results The experimental hydroxyl value, OHV, in milligrams of KOH per gram of the test portion, is calculated by the Equation (3): () m , cVVOHV 1156 12 = (3) where V2 is the volume of the tetra-n-butyl ammonium hydroxide standard volumetric solution (5.8) corresponding to the second equivalence point, in millilitres; V1 is the volume of the tetr