1、BRITISH STANDARD BS 5962:1980 Specifications for Naphthalene (including test methods) UDC 661.715.7:547.652.1BS5962:1980 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authorityofthe Executive Boardand comes into effect on
2、 30September1980 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference CIC/45 Draft for comment 76/54257 DC ISBN 0 580 11564 X Cooperating organizations The Chemicals Standards Committee, under whose direction this BritishStandard was prepared, consists of
3、 representatives from the following: Association of Fatty Acid Distillers British Tar Industry Association* Chemical Industries Association* Chemical Society, Analytical Division Consumer Standards Advisory Committee of BSI Department of Health and Social Security Department of Industry (Laboratory
4、of the Government Chemist) Fertiliser Manufacturers Association Ltd. Hydrocarbon Solvents Association Ministry of Agriculture, Fisheries and Food Ministry of Defence National Sulphuric Acid Association Paintmakers Association of Great Britain Ltd. Royal Institute of Public Health and Hygiene Soap an
5、d Detergent Industry Association Standardization of Tar Products Tests Committee* The organizations marked with an asterisk in the above list were directly represented on the Technical Committee entrusted with the preparation of this British Standard. Amendments issued since publication Amd. No. Dat
6、e of issue CommentsBS5962:1980 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Requirements 1 4 Sampling 1 Appendix A Determination of non-volatile matter 3 Appendix B Determination of crystallizing point 3 Appendix C Determination of a
7、sh 4 Appendix D Sulphuric acid test 5 Appendix E Determination of total sulphur content 5 Figure 1 Heating block for non-volatile matter determination 9 Figure 2 Crystallizing-point apparatus 10 Figure 3 Reduction apparatus 11 Table 1 Naphthalene, grade 1 1 Table 2 Naphthalene, grade 2 1 Table 3 Nap
8、hthalene, grade 3 2 Table 4 Test portion required for determination sulphur content 7 Publications referred to Inside back coverBS5962:1980 ii BSI 12-1999 Foreword This British Standard was prepared under the direction of the Chemicals Standards Committee in order to provide specifications and metho
9、ds of test for naphthalene for industrial purposes. In the drafting of this standard, account has been taken of specifications used by the Ministry of Defence. By agreement with the Standardization of Tar Products Tests Committee (STPTC), some of the methods of testing and descriptions of apparatus
10、contained in the appendices have been reproduced with editorial modifications from the publication “Standard methods of testing tar and its products” (6thedition1967) 1) . NOTEThe following definitions have been approved by the STPTC and have been adopted for the purposes of this British Standard: a
11、ccuracy, for statistical purposes, is the closeness of the test results to the true value. Variations due to sampling errors are included and these are often responsible for most of the difference between the test result and the true value. No estimates of the accuracy of the test methods are given.
12、 precision is the closeness of agreement among test results obtained under any definite test conditions. Thus, a method may be precise without being accurate. Repeatability and reproducibility are aspects of precision under two such defined sets of conditions. (SeealsoBS4306.) repeatability is a mea
13、sure of the precision of test results obtained by one operator using one set of apparatus. Repeatability (r) is defined as the difference between duplicate results on the same sample that would be equalled or exceeded, in the long run, in only one case in twenty. reproducibility is a measure of the
14、precision of test results obtained by different operators using different sets of the same apparatus. Reproducibility (R) is defined as the difference between a single result by one operator at one laboratory and a single result by another operator at another laboratory that would be equalled or exc
15、eeded, in the long run, in only one case in twenty. A number of industries, e.g.the petroleum industry, use methods of test that are also applicable to naphthalene and, wherever appropriate, these methods have been adopted. For routine purposes, methods of test alternative to those given in this Bri
16、tish Standard may be used provided that they give results of sufficient accuracy. However, in the event of doubt or dispute, only the specified methods of test should be used. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are re
17、sponsible 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 12, an inside back cover and a back cover. This standard has
18、 been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) These methods are intended to be carried out in accordance with the general principles and apparatus requirements laid down in the STPTC publicatio
19、n mentioned.BS5962:1980 BSI 12-1999 1 1 Scope This British Standard specifies requirements and methods of test for three grades of naphthalene for industrial purposes. It is applicable to materials that consist essentially of naphthalene, C 10 H 8 . NOTEFor the purposes of this British Standard, the
20、 word “essentially” is understood to mean “at least94.6%”. See the footnotes toTable 1, Table 2 andTable 3, which give the percentages by mass of naphthalene corresponding to the specified corrected wet crystallizing points. 2 References The titles of the publications referred to in this standard ar
21、e listed on the inside back cover. 3 Requirements The material shall comply with the requirements specified inTable 1, Table 2 orTable 3, as appropriate. NOTESolid naphthalene is available in a variety of physical forms such as flake, balls, eggs, etc. Users of this standard are advised to specify t
22、he form in which the material is to be supplied. 4 Sampling A representative sample of not less than1000g shall be taken from the bulk of the material to provide three separate laboratory samples. Recommended methods of sampling are given in Parts1, 3 and4 of BS5309. Table 1 Naphthalene, grade 1 (de
23、signated BS5962-1) Table 2 Naphthalene, grade 2 (designated BS5962-2) Characteristic Requirement Test method Appearance (colour) White or faintly yellow and free from foreign matter or visible impurities Visual inspection Physical state Solid or liquid Visual inspection Matter non-volatile at250 C N
24、ot greater than0.1% by mass Appendix A Water content Not greater than0.2% by mass BS4385 Corrected wet crystallizing point Not lower than79.6 C a Appendix B Total sulphur content Not greater than0.3% by mass Appendix E Ash (residue after ignition) Not greater than0.1% by mass Appendix C Sulphuric ac
25、id test (acid wash test) Not deeper than the standard colour solution Appendix D a Corresponding to98.75% (m/m) of naphthalene. Characteristic Requirement Test method Physical state Solid or liquid Visual inspection Matter non-volatile at250 C Not greater than0.3% by mass Appendix A Water content No
26、t greater than1% by mass BS4385 Corrected wet crystallizing point Not lower than78.5 C aand not higher than79.6 C Appendix B Total sulphur content Not greater than1% by mass Appendix E Ash (residue after ignition) Not greater than0.1% by mass Appendix C a Corresponding to96.65% (m/m) of naphthalene.
27、BS5962:1980 2 BSI 12-1999 Table 3 Naphthalene, grade3 (designated BS5962-3) Characteristic Requirement Test method Physical state Solid or liquid Visual inspection Matter non-volatile at250 C Not greater than0.3% by mass Appendix A Water content Not greater than1% by mass BS4385 Corrected wet crysta
28、llizing point Not lower than77.5 C aand not higher than78.5 C Appendix B Total sulphur content Not greater than1% by mass Appendix E Ash (residue after ignition) Not greater than0.1% by mass Appendix C a Corresponding to94.64% (m/m) of naphthalene.BS5962:1980 BSI 12-1999 3 Appendix A Determination o
29、f non-volatile matter A.1 Principle Melting and heating a test portion on a heating block for a specified time; cooling and weighing to determine the loss of mass. A.2 Apparatus Ordinary laboratory apparatus is required, together with the following. A.2.1 Electrically heated metal block 2) , capable
30、 of being maintained at250 5 C for1h and conforming to the dimensions given inFigure 1. A.2.2 Petri dish, complying with the requirements of BS611, of heat-resisting glass and of the following dimensions: Height161mm, diameter631mm. A.2.3 Thermometer, complying with the requirements of type GP360C-1
31、00 of BS1704. A.3 Procedure A.3.1 Test sample. Melt the laboratory sample by immersing the laboratory sample container in a hot water bath. Stir thoroughly. Pour a little more than5g of the laboratory sample into a porcelain dish and reseal the laboratory sample container. Allow the test sample in t
32、he dish to cool in a dry atmosphere and then crush the solidified material. A.3.2 Method. Weigh, to the nearest0.01g, approximately5g of the well-mixed test sample into the Petri dish (A.2.2), preconditioned at100 C to130 C for1h, allowed to cool in a desiccator and weighed to the nearest0.1mg, and
33、place the Petri dish in the well of the heating block (A.2.1), maintained at250 5 C. Maintain the block and test portion at this temperature for not less than30min and not more than35min, remove, cool the dish and contents in a desiccator and then weigh to the nearest0.1mg. A.4 Expression of results
34、 The matter non-volatile at250 C, expressed as a percentage by mass, is given by the expression: where m 0is the mass of the Petri dish (A.2.2) (ing) m 1is the mass of the Petri dish and test portion (ing) m 2is the mass of the Petri dish and residue (ing) A.5 Precision (see foreword) Appendix B Det
35、ermination of crystallizing point B.0 Introduction The difference between the crystallizing points of dry naphthalene and of naphthalene containing a small quantity of water is appreciable. The depression of crystallizing point reaches a maximum and remains constant at0.85 C when at least2% by mass
36、of water is present. The depression of the crystallizing point is also affected by the presence of phenols. If more than1% of phenols is present, the figure of0.85 C is invalid. B.1 Definitions B.1.1 uncorrected wet crystallizing point. The crystallizing point when water has been added in excess of2
37、% by mass. B.1.2 corrected wet crystallizing point. The crystallizing point when the correction of0.85 C has been added to the uncorrected wet crystallizing point. This corresponds to the crystallizing point of the material on the dry basis. B.2 Principle Melting and cooling of a test portion and pl
38、otting of a cooling curve. 2) Information on supplies of suitable blocks may be obtained on application to the Secretary, Standardization of Tar Products Test Committee, British Carbonization Research Association, Wingerworth, Chesterfield, Derbyshire, S426JS. m 2 m 0 m 1 m 0 -100 % (m/m) Non-volati
39、le matter Repeatability, r Reproducibility, R 0.05 0.025 0.045 0.10 0.035 0.06 0.50 0.07 0.14 1.00 0.10 0.20 1.50 0.13 0.24 2.00 0.15 0.28 3.00 0.18 0.34BS5962:1980 4 BSI 12-1999 B.3 Apparatus B.3.1 Crystallizing point apparatus, as illustrated inFigure 2, comprising a glass test tube150mm 25mm nomi
40、nal size placed inside a200mm 38mm test tube which has been cut down to160mm 38mm. The latter tube is so flanged that it may be supported centrally by a metal cover plate in a1000ml tall-form beaker filled with water to within20mm of the top. The wider tube is weighted with lead shot or similar mate
41、rial and the inner tube is closed by means of a cork which carries a glass stirrer and the thermometer (B.3.2) through its centre. The stirrer has a loop of outside diameter18mm, to surround the thermometer. The thermometer is so fixed in the cork that the bottom of the bulb is about15mm from the bo
42、ttom of the inner tube. A thermometer for the water bath passes through a hole in the cover plate and is held by a rubber ring. B.3.2 Thermometer, complying with the requirements of type A100C/total of BS593. B.3.3 Pipette, 1ml graduated, complying with the requirements of class B of BS700. B.4 Proc
43、edure B.4.1 Place about40g of the laboratory sample in a conical flask, cork loosely and warm in a water bath until just molten. Warm the inner tube of the crystallizing point apparatus in the water bath, and pipette0.5ml of water into the tube. Thoroughly mix the contents of the flask and pour abou
44、t20g into the inner tube. Insert the cork carrying the thermometer and stirrer. If the test portion has begun to crystallize, heat it gently until it regains complete fluidity and then cool it rapidly to determine the approximate crystallizing point. Warm the tube in the water bath at about5 C above
45、 this point so that the crystals, except for a trace necessary for seeding, melt. Replace the tube in its jacket with the water in the beaker maintained at6 C to8 C below the expected crystallizing point. Stir the contents of the tube continuously and with sufficient vigour to ensure thorough mixtur
46、e of the sample and water. Record thermometer readings at30s intervals when the temperature has fallen to2 C above the expected crystallizing point. The uncorrected wet crystallizing point corresponds to the highest of the first five consecutive readings, corrected for thermometer error, during whic
47、h the temperature remains constant to within0.05 C. If supercooling occurs, as shown by a rise in temperature, observe the constant temperature after the rise. A temperature rise of1 C is the maximum allowable. If five consecutive readings within0.05 C are not obtained, record six readings commencin
48、g with the point at which the maximum temperature is first attained. Plot the complete cooling curve of temperature against time and draw a straight line to lie evenly between the first and second and between the fifth and sixth points mentioned above. Extend this line to meet the section of the coo
49、ling curve before the inflexion. Record the temperature reading, adjusted for thermometer error, corresponding to the point of intersection as the uncorrected wet crystallizing point, and then add0.85 C to the result to give the corrected wet crystallizing point. B.5 Precision (see foreword) The following values are applicable to results on “as received” samples and to uncorrected results on wet samples. Appendix C Determination of ash C.1 Principle Ignition of a test portion; weighing of the residu
