1、BRITISH STANDARD BS 1941:1993 Specification for 4-methylpentan-2-one (isobutyl methyl ketone) for industrial use UDC 547.284.6211BS1941:1993 This British Standard, havingbeen prepared under thedirection of the Chemicals Standards Policy Committee, waspublished under the authorityof the Standards Boa
2、rdand comes into effect on 15 February 1993 BSI 10-1999 First published February 1953 Second edition February 1968 Third edition February 1993 The following BSI references relate to the work on this standard: Committee reference CIC/51 Draft for comment 92/54151 DC ISBN 0 580 21596 2 Committees resp
3、onsible for this British Standard The preparation of this British Standard was entrusted by the Chemicals Standards Policy Committee (CIC/-) to Technical Committee CIC/51, upon which the following bodies were represented: British Pharmacopoeia Commission British Society of Perfumers Chemical Industr
4、ies Association Oil and Colour Chemists Association Royal Society of Chemistry Solvents Industry Association Ltd. Amendments issued since publication Amd. No. Date CommentsBS1941:1993 BSI 10-1999 i Content Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Descript
5、ion 1 4 Sampling and size of sample 1 5 Colour 1 6 Density 1 7 Distillation range 1 8 Residue on evaporation 1 9 Water content 1 10 Acidity 1 11 Alcoholic impurities 1 Annex A (normative) Determination of distillation range 2 Annex B (normative) Determination of acidity 2 Annex C (normative) Determi
6、nation of alcoholic impurities 3 List of references Inside back coverBS1941:1993 ii BSI 10-1999 Foreword This British Standard, which has been prepared under the direction of the Chemicals Standards Policy Committee, comprises a specification for 4-methylpentan-2-one to meet the requirements of a wi
7、de range of industrial users. This British Standard supersedes BS 1941:1968 which is withdrawn. In this revision of BS 1941 the requirements for water content and alcoholic impurities have been made more stringent and the requirement for relative density has been replaced by one for density at 20 C.
8、 This British Standard is related to ISO 2499:1974 but is not equivalent in technical content. ISO 2499 is published by the International Organization for Standardization (ISO) and lists various general test methods and test methods specifically for 4-methylpentan-2-one. Several of the methods liste
9、d in ISO 2499 correspond to those which are referred to in this British Standard. ISO 2499 however does not specify limits for any of the properties of 4-methylpentan-2-one. Annex B of this British Standard is related to ISO 2887:1973, published by ISO, but is not equivalent in technical content. Th
10、e main differences are that in the method described in ISO 2887 the test portion is diluted with either ethanol or propan-2-ol and carbon dioxide is removed by passing a stream of nitrogen through the solution. Annex C of this British Standard is related to ISO 2501:1974, published by ISO, but is no
11、t equivalent in technical content. The main differences are that in the method described in ISO 2501 phenolphthalein is used as the indicator and the calculation of results includes a correction for the acidity of the sample. A British Standard does not purport to include all the necessary provision
12、s 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. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an insi
13、de 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.BS1941:1993 BSI 10-1999 1 1 Scope This British Standard specifies requirements for 4-methylpentan-2-on
14、e (isobutyl methyl ketone) suitable for industrial purposes. 2 References 2.1 Normative references This British Standard incorporates, by reference, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publication
15、s are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this British Standard only when incorporated in it by updating or revision. 2.2 Informative references This British Standard refers to other publications that provide information or g
16、uidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Description The material shall be clear and free from matter in suspension, as assessed by visual inspection, and shall co
17、nsist essentially of 4-methylpentan-2-one, CH 3 COCH 2 CH(CH 3 ) 2 . 4 Sampling and size of sample 1) A representative sample of the material measuring not less than 1 l shall be taken from the bulk for the purpose of examination in accordance with this standard. The sample shall be placed in a clea
18、n, dry and airtight, ground glass-stoppered bottle, or screw-capped bottle fitted with a polyethylene cone insert, of such capacity that it is almost filled by the sample. NOTE 1When it is necessary to seal the container, care should be taken to avoid the risk of contaminating the contents in any wa
19、y. NOTE 2Sufficient ullage should be left in the bottle to avoid excessive pressure changes that could arise from temperature variations during storage and handling. About 10 % ullage is recommended. 5 Colour The colour of the material shall not exceed 10 Hazen units when measured by the method desc
20、ribed in BS5339:1976. 6 Density The density of the material at 20 C, determined by the method described in BS 4522:1988, shall be not lower than 0.799 g/ml and not higher than 0.802 g/ml. 7 Distillation range When the material is distilled by the method described in BS 4591:1990, modified as describ
21、ed in Annex A of this standard, the initial boiling point at101.3 kPa 2)pressure shall be not lower than114.0 C and the dry point at 101.3 kPa pressure shall be not higher than 117.0 C. 8 Residue on evaporation The residue on evaporation of the material shall not exceed 0.002 % (m/m) when determined
22、 by the method described in BS 4524:1983. 9 Water content The material shall contain not more than 0.10 % (m/m) of water when determined by one of the methods described in clause 5 of BS 2511:1970 using20 ml of the material. 10 Acidity The acidity of the material, calculated as acetic acid (CH 3 COO
23、H), shall not exceed 0.0020 % (m/m) when determined by the method described in Annex B. 11 Alcoholic impurities The material shall contain not more than 0.30 % (m/m) of alcoholic impurities, calculated as hexanol (C 6 H 13 OH), when determined by the method described in Annex C. 1) Detailed informat
24、ion on the sampling of liquid chemical products is given in BS 5309-1:1976 and BS 5309-3:1976. 2) 1 kPa = 10 mbar.BS1941:1993 2 BSI 10-1999 Annex A (normative) Determination of distillation range Determine the distillation range, in terms of the initial boiling point and the dry point, by the method
25、 described in BS 4591:1990, using the following thermometer, distillation conditions and temperature corrections. a) Thermometer (see 5.1.2 of BS 4591:1990). Use a thermometer designated F150C/100 conforming to BS 593:1989. b) Distillation (see 7.2 of BS 4591:1990). Regulate the rate of heating so t
26、hat the first drop of distillate falls from the end of the condenser after10 min to 15 min. c) Corrections to be applied to observed temperatures (see 9.1.2 of BS 4591:1990). If the corrected barometric pressure deviates from1013mbar apply corrections to the observed temperatures by subtracting 0.03
27、4 C for every millibar above 1013 mbar, or adding0.034 C for every millibar below1013mbar. NOTEThese corrections are valid only for pressures above933 mbar. Annex B (normative) Determination of acidity B.1 Principle A test portion is diluted with carbon dioxide-free water and titrated with standard
28、volumetric sodium hydroxide solution, using phenolphthalein as indicator. B.2 Reagents B.2.1 General During the analysis, use only reagents of recognized analytical grade, only methylated spirits conforming to BS 3591:1985, and only water conforming to grade 3 of BS 3978:1987. B.2.2 Sodium hydroxide
29、, standard volumetric solution, c(NaOH) = 0.100 mol/l. B.2.3 Phenolphthalein, 5 g/l ethanolic solution. Dissolve 0.5 g of phenolphthalein in 100 ml of95%(V/V) ethanol, or 95 % (V/V) industrial methylated spirits, and add the sodium hydroxide solution (B.2.2) until a pale pink coloration is obtained.
30、 NOTEThe use of industrial methylated spirits is governed by The Methylated Spirits Regulations, 1983 (S.I. 1983 No. 252) 1. It is not permissible to use duty-free ethanol, received under the provisions of The Alcoholic Liquor Duties Act 1979, Section102, for purposes for which industrial methylated
31、 spirits is an acceptable alternative to ethanol. B.3 Apparatus B.3.1 Ordinary laboratory apparatus B.3.2 Conical flask, of 500 ml capacity, of borosilicate glass, fitted with a ground glass stopper carrying a guard tube containing sodium hydroxide on an inert support (soda lime). B.3.3 Burette, of
32、10 ml capacity, graduated in0.02ml divisions, conforming to class A of BS846:1985. B.4 Procedure B.4.1 Test portion Take 100 ml 1 ml of the sample, measured at20 C. B.4.2 Determination Place 100 ml of water and a few clean anti-bumping granules in the conical flask (B.3.2) and boil gently for 5 min
33、to remove any carbon dioxide. Cool slightly and then add the test portion (B.4.1). Boil the mixture gently for a further 5 min. At the end of this period, insert the stopper and allow to cool to ambient temperature. Remove the stopper, add0.5ml of the phenolphthalein solution (B.2.3) and titrate wit
34、h the sodium hydroxide solution(B.2.2), using the burette (B.3.3), until a pink coloration, persisting for about 15 s, is obtained. Stopper the flask and swirl its contents after each addition of sodium hydroxide solution. B.5 Expression of results The acidity A, expressed as a percentage by mass of
35、 acetic acid (CH 3 COOH), is given by the equation: Report the value of A in % (m/m) to two significant figures. where V 1 is the volume of the sodium hydroxide solution used for the determination (inml); is the density of the sample at 20 C (determined by the method described in BS 4522:1988) (in g
36、/ml); 0.006 is the mass of acetic acid corresponding to1.00 ml of sodium hydroxide solution, c(NaOH) = 0.100 mol/l (in g). A 0.006 V 1 - =BS1941:1993 BSI 10-1999 3 Annex C (normative) Determination of alcoholic impurities C.1 Principle Any alcoholic impurities are acetylated by reaction with acetyl
37、chloride. The amount of acetyl chloride that has reacted is determined by titration with standard volumetric sodium hydroxide solution, using 3,3-bis(4-hydroxy-1-naphthyl)phthalide (1-naphtholphthalein) as indicator, and the alcohol equivalent is calculated. C.2 Reagents C.2.1 General During the ana
38、lysis, use only reagents of recognized analytical grade, only methylated spirits conforming to BS 3591:1985, and only water conforming to grade 3 of BS 3978:1987. C.2.2 Pyridine, dry. C.2.3 Acetylating reagent To 118 ml of acetyl chloride, add sufficient dry toluene to give a total volume of 1000 ml
39、. C.2.4 Sodium hydroxide, standard volumetric solution, c(NaOH) = 1.00 mol/l. C.2.5 3,3-bis(4-hydroxy-1-naphthyl)phthalide indicator solution, 5 g/l ethanolic solution. Dissolve 0.5 g of 3,3-bis(4-hydroxy-1-naphthyl)phthalide in 100 ml of 95 % (V/V) ethanol or 95 % (V/V) industrial methylated spirit
40、s. NOTEThe use of industrial methylated spirits is governed by The Methylated Spirits Regulations, 1983 (S.I. 1983 No. 252) 1. It is not permissible to use duty-free ethanol, received under the provisions of The Alcoholic Liquor Duties Act 1979, Section102, for purposes for which industrial methylat
41、ed spirits is an acceptable alternative to ethanol. C.3 Apparatus C.3.1 Ordinary laboratory apparatus C.3.2 Two conical flasks, of 250 ml capacity, fitted with ground glass stoppers. C.3.3 Pipette, of 10 ml capacity, conforming to classB of BS 1583:1986, fitted with an automatic suction device. C.3.
42、4 Water bath, capable of being maintained at60 C 1 C. C.4 Procedure C.4.1 Test portion Take 25 ml 0.1 ml of the sample, measured at20 C. C.4.2 Determination Dry the two conical flasks (C.3.2) and place 10.0 ml of the acetylating reagent (C.2.3) into each flask using the pipette (C.3.3). Add 2 ml of
43、the pyridine(C.2.2) to each flask, immediately insert the stoppers tightly and mix the contents thoroughly without wetting the stoppers. To one flask add the test portion (C.4.1), ensuring that all of it comes into contact with the acetylating reagent. Replace the stopper and mix the contents thorou
44、ghly without wetting the stopper. Place both flasks in the water bath (C.3.4), maintained at 60 C 1 C, loosening the stoppers momentarily to release any pressure and then replacing them tightly. Keep the flasks in the water bath for 20 min, shaking them occasionally, then remove the flasks and cool
45、them to ambient temperature. Add 25 ml of water and 0.5 ml of the indicator solution (C.2.5) to each flask and then titrate the contents of each flask in turn with the sodium hydroxide solution (C.2.4) until the appearance of a faint blue colour. C.5 Expression of results The alcohol content B, expr
46、essed as a percentage by mass of hexanol (C 6 H 13 OH), is given by the equation: Report the value of B in % (m/m) to two significant figures. where V 1 is the volume of the sodium hydroxide solution used for the titration of the blank (in ml); V 2 is the volume of the sodium hydroxide solution used
47、 for the titration of the test solution (in ml); is the density of the sample at 20 C (determined by the method described in BS4522:1988) (in g/ml). B 0.408 V 1 V 2 () - =4 blankBS1941:1993 BSI 10-1999 List of references (see clause 2) Normative references BSI standards publications BRITISH STANDARD
48、S INSTITUTION, London BS 593:1989, Specification for laboratory thermometers. BS 846:1985, Specification for burettes. BS 1583:1986, Specification for one-mark pipettes. BS 2511:1970, Methods for the determination of water (Karl Fischer method). BS 3591:1985, Specification for industrial methylated
49、spirits. BS 3978:1987, Specification for water for laboratory use. BS 4522:1988, Method for determination of absolute density at 20 C of liquid chemical products for industrial use. BS 4524:1983, Method for determination of residue on evaporation on a water bath. BS 4591:1990, Method for determination of distillation characteristics of organic liquids (other than petroleum products). BS 5339:1976, Method of measurement of colour in Hazen units (platinum-cob
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