1、BRITISH STANDARD BS1994:1993 Specification for Dichloromethane (methylene chloride)BS1994:1993 This British Standard, having been prepared under the directionof the Chemicals Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 15November1993 BSI
2、03-1999 First published July 1953 Second edition November 1993 The following BSI references relate to the work on this standard: Committee reference CIC/51 Draft for comment 93/503100 DC ISBN 0 580 22559 3 Committees responsible for this British Standard The preparation of this British Standard was
3、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 Industries Association Health and Safety Executive Imperial Chemical Industries Limite
4、d Institute of Refrigeration Oil and Colour Chemists Association Royal Society of Chemistry Solvents Industry Association Ltd. Amendments issued since publication Amd. No. Date CommentsBS1994:1993 BSI 03-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Reference
5、s 1 3 Description 1 4 Sampling and size of sample 1 5 Density 1 6 Distillation range 1 7 Residue on evaporation 1 8 Water content 1 9 Acidity 1 10 Free chlorine 1 Annex A (normative) Determination of distillation range 2 Annex B (normative) Determination of acidity 2 Annex C (normative) Detection of
6、 free chlorine 3 List of references Inside back coverBS1994:1993 ii BSI 03-1999 Foreword This British Standard, which has been prepared under the direction of the Chemicals Standards Policy Committee, comprises a specification for dichloromethane. BS 1994 was first published in1953 as one of a serie
7、s of standards for solvents and allied products. This new edition of BS1994 supersedes BS1994:1953, which is withdrawn. Although the technical content remains the same, changes have been made to use up-to-date terminology and SI units and to eliminate procedures which are considered potentially unsa
8、fe (e.g.of asbestos). This British Standard is related to ISO1869:1977 but is not equivalent in technical content. ISO1869 lists various test methods for dichloromethane. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are respons
9、ible 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, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been upd
10、ated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS1994:1993 BSI 03-1999 1 1 Scope This British Standard specifies requirements for dichloromethane suitable for industrial purposes. 2 References 2.1 Normative r
11、eferences This 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 publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these pu
12、blications apply to this standard only when incorporated in it by updating or revision. 2.2 Informative references This standard refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside ba
13、ck cover, but reference should be made to the latest editions. 3 Description The material shall be clear, colourless and free from matter in suspension and shall consist essentially of dichloromethane, CH 2 Cl 2 . 4 Sampling and size of sample A representative sample of the material measuring not le
14、ss than1l shall be taken from the bulk for the purpose of examination in accordance with this standard. The sample shall be placed in a clean, dry and air-tight ground glass-stoppered bottle of dark amber glass of such capacity that it is nearly filled by the sample. The sample shall be kept in the
15、dark. NOTE 1Detailed information on the sampling of liquid chemical products is given in BS5309-1:1976 and BS5309-3:1976. NOTE 2When it is necessary to seal the container, care should be taken to avoid the risk of contaminating the contents in any way. NOTE 3Sufficient ullage should be left in the b
16、ottle to avoid excessive pressure changes that could arise from temperature variations during storage and handling. About10% ullage is recommended. 5 Density The density of the material at20 C, when determined by the method described in BS4522:1988, shall be not lower than1.321g/ml and not higher th
17、an1.331g/ml. 6 Distillation range When the material is distilled by the method described in BS4591:1990, modified as described in Annex A of this standard, at101.3kPa pressure it shall yield not less than95% by volume between39.0 C and40.5 C. 7 Residue on evaporation The residue on evaporation of th
18、e material shall not exceed0.01%(m/m) when determined by the method described in BS4524:1983. 8 Water content The material shall contain not more than0.05%(m/m) of water when determined by one of the methods described in clause5 of BS2511:1970 using20g of the material. 9 Acidity The acidity of the m
19、aterial, calculated as hydrochloric acid, HCl, shall not exceed0.001%(m/m) when determined by the method described in Annex B. 10 Free chlorine The material shall not show any free chlorine when determined by the method described in Annex C.BS1994:1993 2 BSI 03-1999 Annex A (normative) Determination
20、 of distillation range Determine the distillation range, as percentage yield by volume between39.0 C and40.5 C, in accordance with BS4591:1990 with the following modifications. a) Thermometer (see 5.1.2 of BS4591:1990). Use a thermometer designated F150C/100 conforming to BS593:1989. b) Distillation
21、 (see 7.2 of BS4591:1990). Regulate the rate of heating so that the first drop of distillate falls from the end of the condenser after10min to15min. c) Corrections to be applied to observed temperatures (see 9.2.2 of BS4591:1990). If the corrected barometric pressure deviates from101.3kPa, correct t
22、he observed temperatures by subtracting0.038 C for every1.0kPa above101.3kPa, or adding0.038 C for every1.0kPa below101.3kPa. NOTEThese corrections are valid only for pressures above93.3kPa. Annex B (normative) Determination of acidity B.1 Principle A test portion is diluted with carbon dioxide free
23、 water and titrated with standard volumetric sodium hydroxide solution, using phenolphthalein indicator. B.2 Reagents B.2.1 General During the analysis use only reagents of recognized analytical grade, only water conforming to grade3 of BS3978:1987 and only methylated spirits conforming to BS3591:19
24、85. NOTEThe use of industrial methylated spirits is governed by the Methylated Spirits Regulations,1983 (S.I.1983 No2521). It is not permissible to use duty-free ethanol, received under the provisions of the Alcoholic Liquor Duties Act1979, Section102, for purposes for which industrial methylated sp
25、irits is an acceptable alternative to ethanol. B.2.2 Sodium hydroxide, standard volumetric solution, c(NaOH)=0.100mol/l. B.2.3 Phenolphthalein,5g/l ethanolic solution, prepared by dissolving0.5g of phenolphthalein in100ml of95% (V/V) ethanol or95% (V/V) industrial methylated spirits and adding the s
26、odium hydroxide solution(B.2.2) until a pale pink colour is obtained. B.3 Apparatus B.3.1 Ordinary laboratory apparatus. B.3.2 Conical flask, of500ml capacity, of borosilicate glass, fitted with a ground glass stopper carrying a guard tube containing sodium hydroxide on an inert support (soda lime).
27、 B.3.3 Burette, of10ml capacity, graduated in0.02ml divisions, conforming to class A of BS846:1985. B.4 Procedure B.4.1 Test portion Take100ml 1ml of the sample, measured at20 C. B.4.2 Determination Place100ml of water and a few clean anti-bumping granules in the conical flask(B.3.2) and boil gently
28、 for5min to remove any carbon dioxide and allow to cool. Add the test portion(B.4.1) and shake vigorously. Allow the layers to separate, add0.5ml of the phenolphthalein solution(B.2.3) and titrate with the sodium hydroxide solution(B.2.2), using the burette(B.3.3) until a pink colour, persisting for
29、 about15s, is obtained. B.5 Expression of results The acidity A, expressed as a percentage by mass of hydrochloric acid, is given by the equation: where Report the value of A as a percentage (m/m) to two significant figures. V 1 is the volume of sodium hydroxide solution used for the determination (
30、inml); is the density of the sample at20 C (determined by the method described in BS4522:1988) (in g/ml); 0.00365 is the mass of hydrochloric acid corresponding to1.00ml of sodium hydroxide solution, c(NaOH)=0.100mol/l (in g). A 0.00365V 1 - =BS1994:1993 BSI 03-1999 3 Annex C (normative) Detection o
31、f free chlorine C.1 Principle The presence of free chlorine is indicated by development of a pink colour with the addition of3,3-dimethylnaphthidine solution. C.2 Reagent C.2.1 3,39-Dimethylnaphthidine solution, 0.05g/l, prepared by dissolving0.01g of finely ground3,39-dimethylnaphthidine in5ml of g
32、lacial acetic acid in a200ml one-mark graduated flask and diluting rapidly with water conforming to grade3 of BS3978:1987. Store the solution in the dark. C.3 Procedure C.3.1 Test portion Take50ml 0.5ml of the sample. C.3.2 Detection Place the test portion(C.3.1) into a glass stoppered50ml measuring
33、 cylinder, add5ml of the3,39-dimethylnaphthidine solution(C.2.1), stopper and shake the cylinder for30s. Note whether a pink colour develops, indicating the presence of free chlorine.4 blankBS1994:1993 BSI 03-1999 List of references Normative references BSI Standards publications BRITISH STANDARDS I
34、NSTITUTION, London BS593:1989, Specification for laboratory thermometers. BS846:1985, Specification for burettes. BS2511:1970, Methods for the determination of water (Karl Fischer method). BS3591:1985, Specification for industrial methylated spirits. BS3978:1987, Specification for water for laborato
35、ry use. BS4522:1988, Method for the determination of absolute density at20 C of liquid chemical products for industrial use. BS4524:1983, Method for the determination of residue on evaporation on a water bath. BS4591:1990, Method for the determination of distillation characteristics of organic liqui
36、ds (other than petroleum products). Informative references BSI Standards publications BRITISH STANDARDS INSTITUTION, London BS5309, Methods for sampling chemical products. BS5309-1:1976, Introduction and general principles. BS5309-3:1976, Sampling of liquids. ISO publications INTERNATIONAL ORGANIZAT
37、ION FOR STANDARDIZATION (ISO), Geneva. (All publications are available from Customer Services, Publications, BSI.) ISO1869:1977, Methylene chloride for industrial use List of methods of test 1) . Other references 1 GREAT BRITAIN. The Methylated Spirits Regulations,1983 (S.I. No252). London:HMSO. 2 G
38、REAT BRITAIN. The Alcoholic Liquor Duties Act1979, Section10. London:HMSO. 1) Referred to in the foreword only.BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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