1、BRITISH STANDARD CONFIRMED MARCH 1990 BS 662-3:1979 Carbon disulphide for industrial use Part 3: Additional methods of test UDC 661.22:546.265.14:543.06BS662-3:1979 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authorityo
2、fthe Executive Boardon 31January1979 BSI 12-1999 First published 1936 First revision March1950 Second revision January1979 The following BSI references relate to the work on this standard: Committee reference CIC/4 Draft for comment 77/52746 DC ISBN 0 580 10667 5 Cooperating organizations The Chemic
3、als Standards Committee, under whose direction this BritishStandard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Fatty Acid Distillers British Tar Industry Association Chemical Industries Association*
4、Chemical Society, Analytical Division Department of Health and Social Security Department of Industry, Laboratory of the Government Chemist Fertiliser Manufacturers Association Ltd. Hydrocarbon Solvents Association Institution of Gas Engineers Ministry of Agriculture Fisheries and Food Ministry of D
5、efence National Sulphuric Acid Association Paintmakers Association of Great Britain Ltd. Royal Institute of Public Health and Hygiene Soap and Detergent Industry Association Standardization of Tar Products Tests Committee The organizations marked with an asterisk in the above list, together with the
6、 following, were directly represented on the committee entrusted with the preparation of this British Standard: British Man-made Fibres Federation British Plastics Federation Oil and Colour Chemists Association Pharmaceutical Society of Great Britain Royal Institute of Chemistry Individual Company A
7、mendments issued since publication Amd. No. Date of issue CommentsBS662-3:1979 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Determination of hydrogen sulphide and sulphur dioxide 1 4 Determination of thiophene, benzene and hydrocarbo
8、ns 1 5 Determination of mercaptans (thiols) 2 Table 1 Wavenumbers for the determination of thiophene, benzene and hydrocarbons 2 Publications referred to Inside back coverBS662-3:1979 ii BSI 12-1999 Foreword This British Standard has been prepared under the direction of the Chemicals Standards Commi
9、ttee to provide a specification and methods of test for carbon disulphide for industrial use. The first edition of this standard was issued in1936. A revision, published in1950, was amended in1954 to include the determination of sulphur dioxide, and was confirmed in1960. The present edition extends
10、the scope of the specification and incorporates ISO3144. This standard is presented in three Parts: Part 1: Specification; Part 2: Sampling and methods of test; Part 3: Additional methods of test. Part2 is identical with ISO3144 “Carbon disulphide for industrial use Sampling and methods of test” and
11、 includes the following test methods: Determination of density Determination of distillation characteristics Determination of residue on evaporation Determination of inorganic sulphur content Determination of alkalinity or acidity Part3 specifies methods of test for thiophene, benzene, mercaptans (t
12、hiols) and hydrocarbons, which are not included in the ISO publication, and gives an alternative method for the determination of hydrogen sulphide and inorganic sulphur which avoids the use of the extremely deliquescent disodium sulphide nonahydrate. A British Standard does not purport to include al
13、l the necessary provisions 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, pagesi andi
14、i, pages1 to4, an inside 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.BS662-3:1979 BSI 12-1999 1 1 Scope This Part of BS662 specifies methods for the
15、determination of sulphur compounds, benzene and hydrocarbons in carbon disulphide for industrial use. WARNING NOTE. Carbon disulphide is highly volatile and gives off vapour at normal room temperature. It is harmful by inhalation of the vapour, by prolonged or repeated contact with the liquid or if
16、taken into the mouth. Further information is available in Technical Data note2 published by the Health and Safety Executive on an annual basis. Carbon disulphide is a highly flammable volatile liquid with a low flash point, a wide explosive range and an auto-ignition temperature lower than120 C. Con
17、tact with exposed steam lines or the surface of an ordinary electric light bulb can cause ignition. Because of its hazardous nature, carbon disulphide should always be handled in accordance with the suppliers safety recommendations. 2 References The titles of the publications referred to in this sta
18、ndard are listed on the inside back cover. 3 Determination of hydrogen sulphide and sulphur dioxide 3.1 Principle. Titration of an aliquot portion of the laboratory sample with a standard volumetric iodine solution to a permanent pink colouration. 3.2 Reagents. Use only reagents of a recognized anal
19、ytical quality and water complying with the requirements of BS3978. 3.2.1 Iodine. 0.01N standard volumetric solution. 3.3 Apparatus. In addition to ordinary laboratory apparatus the following is required. 3.3.1 Burette, complying with the requirements of class A of BS846, capable of being read to0.0
20、5ml. 3.4 Procedure. Place in a clean dry250ml glass stoppered flask a100ml aliquot portion of the test sample which has been previously filtered through a clean dry filter paper. Add from the burette (3.3.1) the standard volumetric iodine solution (3.2.1), in0.1ml portions. Stopper the flask and sha
21、ke it for15s after each addition. Continue the titration until there is a permanent pink coloration in the carbon disulphide. Record the volume of standard volumetric iodine solution required to give the permanent pink coloration. Repeat the procedure on a fresh aliquot portion. 3.5 Expression of re
22、sults. The hydrogen sulphide plus sulphur dioxide content, expressed as milligrams of hydrogen sulphide per kilogram, is given by the expression: where 3.6 Precision. The precision of the method, as obtained by statistical examination of interlaboratory test results is as follows. 3.6.1 Repeatabilit
23、y. The difference between two test results, obtained by the same operator, with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed0.05mg/kg only in one case in twenty. 3.6.2 Reproduc
24、ibility. No data are available for the reproducibility of the method. 3.7 Test report. The test report shall include: a) a reference to this British Standard; b) the results and method of expression used; c) any unusual features noted during the determination; d) any operation not included in this B
25、ritishStandard. 4 Determination of thiophene, benzene and hydrocarbons 4.1 Principle. Spectrophotometric measurement at the appropriate wavelength and determination of the concentration of the impurity from a calibration curve. 4.2 Reagents. Use only reagents of a recognized analytical quality and w
26、ater complying with the requirements of BS3978. 4.2.1 Carbon disulphide, spectrometric quality, free from thiophene, benzene and hydrocarbons. 4.2.2 Thiophene 4.2.3 Benzene 4.2.4 Hydrocarbon oil, boiling range160 C to250 C. 4.3 Apparatus. In addition to ordinary laboratory apparatus the following ar
27、e required. 4.3.1 Infra-red spectrophotometer V is the volume (in ml) of the standard volumetric iodine solution (3.2.1) required to give the permanent pink coloration; is the density (in g/ml) of the carbon disulphide 1.7 V -BS662-3:1979 2 BSI 12-1999 4.3.2 Sodium chloride cells, one matched pair,
28、path length1cm. 4.4 Procedure. Using the carbon disulphide (4.2.1) and the matched cells (4.3.2) set the spectrophotometer (4.3.1) to zero in accordance with the manufacturers instructions. Using the carbon disulphide (4.2.1), prepare three series of standard solutions of the thiophene (4.2.2), the
29、benzene (4.2.3) and the hydrocarbon oil (4.2.4) of the following concentrations: 10 20 30 40 50 60 70 80 90 100mg/kg Measure the absorbance of each series of solutions using the spectrophotometer (4.3.1) set at the appropriate wavenumber (wavelength) given inTable 1 and with carbon disulphide in the
30、 reference cell. Table 1 Wavenumbers for the determination of thiophene, benzene and hydrocarbons Plot calibration curves from each series of measurements. Charge one of the matched cells (4.3.2) with a filtered portion of the test sample and measure and record the absorbance at each of the wavenumb
31、ers (wavelengths) given inTable 1. 4.5 Expression of results. For each of the absorbance values obtained for the test sample as described, read off from the appropriate calibration curve the concentration, in mg/kg, of thiophene, benzene and hydrocarbons present in the test sample. 4.6 Precision. Th
32、e precision of the method as obtained by statistical examination of interlaboratory test results is as follows. 4.6.1 Repeatability. The difference between two test results, obtained by the same operator, with the same apparatus under constant operating conditions on identical test material, would i
33、n the long run, in the normal and correct operation of the test method, exceed the values given in one case in twenty. 4.6.2 Reproducibility. The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would
34、, in the long run, in the normal and correct operation of the test method, exceed the values given in one case in twenty. 4.7 Test report. The test report shall include: a) a reference to this British Standard; b) the results and method of expression used; c) any unusual features noted during the de
35、termination; d) any operation not included in this BritishStandard. 5 Determination of mercaptans (thiols) 5.1 Principle. Treatment with silver nitrate solution followed by titration of an aqueous extract with0.01N standard volumetric sodium hydroxide solution. 5.2 Reagents. Use only reagents of a r
36、ecognized analytical quality and water complying with the requirements of BS3978. 5.2.1 Silver nitrate, approximately10% (m/m) solution. 5.2.2 Sodium hydroxide, 0.01N standard volumetric solution. 5.2.3 Methyl red indicator solution, prepared in accordance with the requirements of BS4123. 5.2.4 Carb
37、on disulphide, free from mercaptans (thiols), prepared by shaking, in a separating funnel, with the silver nitrate solution (5.2.1) until no coloration is produced and then washing with distilled water. 5.3 Apparatus. Ordinary laboratory apparatus. 5.4 Procedure WARNING NOTE. During the procedure ve
38、nt the separating funnel frequently. Test for the presence of hydrogen sulphide and, if present, remove it by shaking the test portion with50ml of a5% solution of acidified cadmium chloride. Separate the carbon disulphide layer and wash with water until the washings are neutral. Solute Wavenumber (w
39、avelength) cm 1 4m Thiophene Benzene Hydrocarbons 125 180.8 293.3 (8.00) (5.53) (3.41) thiophene 10 mg/kg benzene 10 mg/kg hydrocarbons 10 mg/kg thiophene 20 mg/kg benzene 20 mg/kg hydrocarbons 20 mg/kgBS662-3:1979 BSI 12-1999 3 To a300ml aliquot portion of the test sample in a clean, dry500ml separ
40、ating funnel, add25ml of the silver nitrate solution (5.2.1) and50ml of water. Stopper and shake the funnel, allow the layers to separate, collect the carbon disulphide layer in a second separating funnel and wash with50ml of water. Combine the aqueous layers in a250ml conical flask. Add a few drops
41、 of the methyl red indicator solution (5.2.3) and titrate with the sodium hydroxide solution (5.2.2) to the green end point. Carry out a blank determination using the carbon disulphide free from mercaptans (5.2.4) in place of the test portion. 5.5 Expression of results. The mercaptan content, expres
42、sed in milligrams of mercaptan sulphur per kilogram, is given by the expression: 0.85 (V 1 V 2 ) where 5.6 Precision. No data are available for the precision of the method. 5.7 Test report. The test report shall include: a) a reference to this British Standard; b) the results and the method of expre
43、ssion used; c) any unusual features noted during the determination; d) any operation not included in this BritishStandard. V 1 is the volume (in ml) of the sodium hydroxide solution (5.2.2) required for the test portion; V 2 is the volume (in ml) of the sodium hydroxide solution (5.2.2) required for
44、 the blank.4 blankBS662-3:1979 BSI 12-1999 Publications referred to BS 846, Burettes and bulb burettes. BS 3978, Water for laboratory use. BS 4123, Schedule of preferred chemical indicators. BS 662-3:1979 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent
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