1、BRITISH STANDARD BS506-2: 1984 Incorporating Amendment No.1 Methanol for industrial use Part 2: Methods of test UDC 661.721:543.062BS506-2:1984 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Board of BSI an
2、d comes into effect on 30 March1984 BSI10-1999 The following BSI references relate to the work on this standard: Committee referenceCIC/4 Draft for comment81/50139DC ISBN 0 580 13781 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Chem
3、icals Standards Committee (CIC/-) to Technical CommitteeCIC/4 upon which the following bodies were represented: Chemical Industries Association Ministry of Defence Oil and Colour Chemists Association Royal Society of Chemistry Society of Chemical Industry The following bodies were also represented i
4、n the drafting of the standard, through subcommittees and panels: British Pharmacopoeia Commission British Society of Perfumers Cosmetic, Toiletry and Perfumers Association Limited Department of Industry (Laboratory of the Government Chemist) Amendments issued since publication Amd. No. Date of issu
5、e Comments 5450 January1987 Indicated by a sideline in the marginBS506-2:1984 BSI 10-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope and field of application 1 2 References 1 3 Sampling 1 4 Test report 1 5 Determination of density at20 C 1 6 Determination of residu
6、e on evaporation on a water bath 1 7 Measurement of colour 1 8 Determination of the distillation range 1 9 Determination of water content 1 10 Detection of alkalinity or determination of acidity to phenolphthalein 2 11 Estimation of content of carbonyl compounds present in small amounts Spectrometri
7、c method 2 12 Estimation of content of carbonyl compounds present in moderate amounts Titrimetric method 4 13 Test for miscibility with water 5 14 Determination of permanganate time 6 15 Determination of sulphur compounds 7 Figure 1 Reduction apparatus for the determination of sulphur compounds 9 Pu
8、blications referred to Inside back coverBS506-2:1984 ii BSI 10-1999 Foreword This Part of this British Standard has been prepared under the direction of the Chemicals Standards Committee and provides a comprehensive series of test methods for methanol for industrial use. Although applicable to the m
9、aterial in general, it includes all the test methods required to assess compliance with BS506-1. This Part of this standard is based on ISO1387:1982 “Methanol for industrial use Methods of test”. ISO1387, which constitutes the revision of ISO RecommendationR1387, has been prepared with the active pa
10、rticipation of the UK by Technical Committee47, Chemistry, of the International Organization for Standardization (ISO). With the following exceptions the technical content of this Part of this standard agrees with ISO1387. a) The method for the determination of methyl ketones has been omitted as a c
11、onsequence of its disapproval by the UK on technical grounds. b) References in the text to International Standards have been replaced by references to the corresponding British Standards. c) Hazard warnings have been included in respect of methanol and2,4-dinitrophenylhydrazine. d) To conform with U
12、K practice, additional ways have been given in11.6 and12.6 for expressing the carbonyl compounds content as a percentage by mass of acetone. e) A method for determination of sulphur compounds is included in this Part of this standard but not in ISO1387. ISO1387 records UK disapproval of the method f
13、or determination of permanganate time. It is, however, now acceptable to the UK as a consequence of alterations made to the published text and has therefore been included in this Part of this standard. For ease of production, it has been found convenient to reproduce the text of ISO1387, which has b
14、een amended to incorporate the differences outlined above. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use
15、a full point on the baseline as the decimal marker. In British Standards it is current practice to use the symbol “L” for litre (and in its submultiples), rather than “l”. NOTE 1It is not permissible to use duty-free ethanol, received under the provisions of The Alcoholic Liquors Duties Act1979, Sec
16、tion10, for purposes for which industrial methylated spirits is an acceptable alternative to ethanol. In such circumstances the ethanol used as a reagent in a determination may be replaced for this purpose by industrial methylated spirits,95% (V/V), complying with BS3591. It should be noted that the
17、 use of industrial methylated spirits is governed by The Methylated Spirits Regulations1983 (S.I.1983, No.252). NOTE 2Unless otherwise stated, water complying with the requirements of these determinations is specified in BS3978 “Water for laboratory use”. This Part of this standard specifies methods
18、 of test only and should not be used as a specification defining limits of purity. Reference to this Part of this standard should indicate that the methods of test used are in accordance with the appropriate clause(s) of BS506-2.BS506-2:1984 BSI 10-1999 iii A British Standard does not purport to inc
19、lude all 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, page
20、si toiv, pages1to10, 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.iv blankBS506-2:1984 BSI 10-1999 1 WARNING. Methanol is toxic and can have
21、 poisonous effects if drunk, inhaled or absorbed through the skin. Strict precautions should always be observed and, in particular, any pipettes used should be of the safety bulb type. 1 Scope and field of application This British Standard gives general instructions and describes methods of test for
22、 the analysis of methanol for industrial use. The methods of test relating to methanol for industrial use are the following: Determination of density at20 C Determination of residue on evaporation on a water bath Measurement of colour Determination of distillation range Determination of water conten
23、t Detection of the alkalinity or determination of the acidity to phenolphthalein Estimation of content of carbonyl compounds present in small amounts Spectrometric method Estimation of content of carbonyl compounds present in moderate amounts Titrimetric method Test for miscibility with water Determ
24、ination of permanganate time Determination of sulphur compounds 2 References The titles of the publications referred to in this standard are listed on the inside back cover. General instructions 3 Sampling 1) Place the laboratory sample in the dark, in a clean, dry and airtight, ground glass stopper
25、ed bottle or a screw-capped bottle fitted with a polyethylene cone insert of such capacity that it is almost filled by the sample. If it is necessary to seal the bottle, care shall be taken to avoid contaminating the contents in any way. NOTE 1Sufficient ullage should be left in the bottle to avoid
26、excessive pressure changes that could arise from temperature variations during storage and handling. About10% ullage is recommended. NOTE 2A sample of not less than1000ml is necessary for performing all the tests described in this standard. 4 Test report The test report, for each determination, shal
27、l contain the following particulars: a) an identification of the sample; b) the reference of the method used; c) the results and the method of expression used; d) any unusual features noted during the determination; e) any operation not included in this BritishStandard or in the British Standards to
28、 which reference is made, or regarded as optional. Methods of test 5 Determination of density at20 C Use the method specified in BS4522. 6 Determination of residue on evaporation on a water bath Use the method specified in BS4524. 7 Measurement of colour Use the method specified in BS5339. 8 Determi
29、nation of the distillation range Use the method specified in BS4591:1971 with the following modifications appropriate to methanol. 8.1 Thermometer (see BS4591, clause3.2) Use a thermometer complying with the requirements of BS4591 suitable for measuring temperatures in the range24to78 C. 8.2 Correct
30、ions to be applied to temperatures If the corrected barometric pressure deviates from1013mbar 2) , apply a correction to the observed temperature by subtracting0,025 C for every millibar above, or adding0,025 C for every millibar below,1013mbar. 9 Determination of water content Use one of the method
31、s specified in BS2511. 1) Additional guidance on sampling is given in BS5309-1 and BS5309-3. 2) 1bar=10 5 PaBS506-2:1984 2 BSI 10-1999 10 Detection of alkalinity or determination of acidity to phenolphthalein 10.1 Applicability The method is applicable to products having acidities, expressed as form
32、ic acid (HCOOH), greater than or equal to0,0008%(m/m). 10.2 Principle Dilution of a test portion with carbon dioxide-free water. Checking whether the test solution is alkaline or acid to phenolphthalein, and, if appropriate, determination of the acidity by titration with standard volumetric sodium h
33、ydroxide solution. 10.3 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity, carbon dioxide-free, recently prepared. 10.3.1 Water, carbon dioxide-free. Boil distilled water and allow it to cool in a flask fitted with a
34、 stopper carrying a soda-lime guard-tube. 10.3.2 Sodium hydroxide, standard volumetric solution, c(NaOH)=0,1mol/l. 10.3.3 Phenolphthalein,5g/l ethanolic solution. Dissolve0,5g of phenolphthalein in100ml of95% (V/V) ethanol and add the sodium hydroxide solution(10.3.2) until a pale pink coloration is
35、 obtained. 10.4 Apparatus Ordinary laboratory apparatus, and 10.4.1 Conical flask, of borosilicate glass, of capacity500ml, fitted with a ground glass stopper carrying a soda-lime guard-tube. 10.4.2 Burette, of capacity10ml, graduated in0,02ml. 10.5 Procedure 10.5.1 Test portion Take100 0,1ml of the
36、 laboratory sample (seeclause3). 10.5.2 Determination Place100ml of the water(10.3.1) in the conical flask(10.4.1), add0,5ml of the phenolphthalein solution(10.3.3) and restore the pale pink coloration by the addition of1or2drops of the sodium hydroxide solution(10.3.2). Add the test portion(10.5.1)
37、 and a further0,5ml of the phenolphthalein solution(10.3.3) and note whether the solution is alkaline; if acid, titrate the test solution with the sodium hydroxide solution(10.3.2), stoppering the flask and swirling its contents after each addition, until a pink coloration, persisting for about15s,
38、isobtained. Shake the contents of the flask, with the stopper in position, after each addition of sodium hydroxide solution. 10.6 Expression of results 10.6.1 Alkaline products Indicate whether the product is alkaline to phenolphthalein. 10.6.2 Acidic products The acidity, expressed as a percentage
39、by mass of formic acid (HCOOH), is given by the formula where V is the volume, in millilitres, of the sodium hydroxide solution(10.3.2) used for the determination; is the density, in grams per millilitre, of the sample at20 C (see clause5); 0,0046is the mass, in grams, of formic acid corresponding t
40、o1,00ml of sodium hydroxide solution, c(NaOH)=0,100mol/l. NOTEIf the concentration of the standard volumetric solution used is not exactly as specified in the list of reagents, an appropriate correction should be made. 11 Estimation of content of carbonyl compounds present in small amounts Spectrome
41、tric method 11.1 Applicability The method is applicable to products having carbonyl compounds contents, expressed as formaldehyde, between0,0002 and0,01% (m/m). NOTEThis method, which is used commercially, allows determination of only those carbonyl compounds which react under the specified conditio
42、ns.BS506-2:1984 BSI 10-1999 3 11.2 Principle Reaction in acid medium of the carbonyl compounds in a test portion with2,4-dinitrophenylhydrazine. Formation of the corresponding2,4-dinitrophenylhydrazones, which, after making the solution alkaline, take on a yellowish-red coloration. Spectrometric mea
43、surement of this red coloration at a wavelength of about445nm. 11.3 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 11.3.1 Methanol, free from carbonyl compounds, purified as follows. Boil under reflux1000ml of me
44、thanol with10g of2,4-dinitrophenylhydrazine and10drops of the hydrochloric acid solution(11.3.3), for2 to3h. Distil the methanol slowly using a Widmer distillation column, about300mm long and about25mm in diameter, or any other suitable column. Reject the first75ml of distillate and collect the next
45、850ml, rejecting the remainder. If the distillate is coloured, redistil it. 11.3.2 2,4-Dinitrophenylhydrazine, saturated solution in the methanol(11.3.1) at ambient temperature about0,06% (m/m) solution. WARNING.2,4-dinitrophenylhydrazine specified in11.3.1 and11.3.2 is harmful if inhaled, if in con
46、tact with skin or eyes, or if swallowed and carries the risk of explosion by shock, friction, heat or by other sources of ignition, particularly when dry. Inhalation of dust and contact with skin and eyes should be avoided. Particular care should be taken when using the dry material. 11.3.3 Hydrochl
47、oric acid, approximately1,19g/ml, about38% (m/m) solution. 11.3.4 Potassium hydroxide,100g/l solution in a70% (V/V) solution of the methanol(11.3.1). 11.3.5 Carbonyl compounds, standard solution corresponding to0,030g of carbonyl compounds, expressed as formaldehyde, per litre. Weigh, to the nearest
48、0,0001g,1,200g of acetophenone, and dissolve it in a little of the methanol(11.3.1). Transfer quantitatively to a100ml one-mark volumetric flask, dilute to the mark with the methanol and mix. Take5,0ml of this solution, transfer it to a500ml one-mark volumetric flask, dilute to the mark with the met
49、hanol(11.3.1) and mix. 1ml of this standard solution contains304g of carbonyl compounds, expressed as formaldehyde. 11.4 Apparatus Ordinary laboratory apparatus, and 11.4.1 Water bath, capable of being controlled at50 2 C. 11.4.2 Test tubes, fitted with ground glass stoppers. 11.4.3 Spectrometer with a radiation selector for continuous variation, fitted with cells of optical path length1cm, or 11.4.4 Spectrometer with a radiation selector for discontinuous variation, fitted with filters providing maximum transmission at a wave
