1、International Standard INTFRNATIONAI “ROANIZATION FOR STANDARDIZATION*MEWiYHAPOIlHAR OPAHl43AUMR fl0 CTAHAPTH3AUllMORGANlSATlON INTERNATIONALE DE NORMALISATION Volatile organic liquids - Determination of boiling range of organic solvents used as raw materials Liquides organiques volatils - Dktermina
2、tion de lintervalle de distillation des solvants organiques utilisbs comme mat final boiling point : The maximum tem- Dimensions in millimetres perature noted (corrected, if required) during the final phase of a distillation carried out under standardized conditions. 4 PRINCIPLE Distillation of a 10
3、0 ml test portion under prescribed conditions which are equivalent to a simple batch distil- lation. Systematic observation of thermometer readings and volumes of condensate and calculation of the results from these data with correction to standard atmospheric pressure. 5 APPARATUS The apparatus, a
4、suitable form of which is shown in figures 1 to 4, shall comprise the following items : 5.1 Distillation flask, of heat-resistant glass, of capacity 200 ml, conforming to the dimensions shown in figure 1. NOTE - Superheating of liquid in a new flask may be prevented by depositing a small amount of c
5、arbon in the bottom of the flask. This may be accomplished by heating and decomposing a pinch of tartaric acid in the bottom of the flask. The flask is then prepared for use by washing with water, rinsing with acetone, and drying. An exception is made for diacetone alcohol : in order to avoid an err
6、atic value for the initial boiling point, the distillation flask should be clean and free of any residual carbon deposit. Reinforcing bead f$ ext. 73 + 1 FIGURE 1 - Distillation flask (5.1) 2 Copyright International Organization for Standardization Provided by IHS under license with ISONot for Resal
7、eNo reproduction or networking permitted without license from IHS-,-,-TABLE 1 - Solvent distillation thermometers Designation ) 38 C-75 39 c-75 40 c-75 41 C-62 42 C-62 102 C-65 103 C-65 104 c-75 105 C-65 106 C-75 107 c-75 Immersion, mm 100 100 100 100 100 100 100 100 100 100 100 Range, “C 24 to 78 4
8、8 to 102 72to 126 98 to 152 95 to 255 123 to 177 148 to 202 173 to 227 198 to 252 223 to 277 248 to 302 Graduation, “C 0.2 0.2 0.2 0.2 0,5 02 02 02 0.2 02 0.2 Longer lines at each, “C 1 1 1 1 1 1 1 1 1 1 1 Figured at each, “C 2 2 2 2 5 2 2 2 2 2 2 0.2 up to 0.4 up to Scale error not to exceed, “C 02
9、 0.2 0.2 0.2 0.5 150 “C 0,4 0.4 225 C 0.3 over 0,6 over 0.8 1.0 150C 225C Overall length, mm 395 f 5 395 t 5 395t 5 395 f 5 395 f 5 395 * 5 395k 5 395 f 5 395 f 5 395 f 5 395? 5 Stem diameter, mm 6,0 to 7.0 6.0 to 7.0 6,0 to 7,0 6.0 to 7.0 6,0 to 7.0 6,0 to 7,0 6.0 to 7.0 6,0 to 7,0 6.0 to 7,0 6.0 t
10、o 8,0 6,0 to 8,0 Bulb length, mm 15to20 15to20 15to20 15to20 15to20 15to20 15to20 15to20 15to20 15to20 15to20 Distance from bottom of bulb. mm - to 24C 48C 72C 98C 95C 123C 148 “C 173Oc 198 “C 223 “C 248 “C 125 to 145 125 to 145 125 to 145 125 to 145 125 to 145 125 to 145 125 to 145 125 to 145 125 t
11、o 145 125 to 145 125 to 145 - to 78C 102 Oc 126C 152C 255 “C 177 OC 202 “C 227 “C 252 C 277 “2 302 =C 335 to 360 335 to 360 335 to 360 335 to 360 335 to 360 335 to 360 335 to 360 335 to 360 335 to 360 335 to 360 335 to 360 Expansion chamber to allow 105 130 heating to, C 150 180 280 200 225 250 275
12、300 325 1) These designations correspond to those in ASTM El, Standard specification for ASTM thermometers. Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-!SO 4626-1980
13、(E) In each of the two narrower sides of the draught screen, there shall be two circular holes of diameter 25 mm, the centres of which are situated 215 mm below the top of the shield, as shown in figure 2. Whichever type of heater is employed, direct heat shall only be applied to the flask through t
14、he central hole in the ceramic board. In each of the four sides of the draught screen, there shall be three circular holes of diameter 12,5 mm, the centres of which are situated 25 mm above the base of the draught screen. These holes shall occupy the positions shown in figure 2. At the middle of eac
15、h of the wider sides, a vertical slot for the condenser tube, dimensioned approximately as shown in figure 2, shall be cut downwards from the top of the screen. A removable shutter of suitable dimensions shall be provided for closing whichever vertical slot is not in use. This arrangement enables th
16、e condenser (5.6) to be placed on either side of the draught screen. A shelf of ceramic material, of thickness 3 to 6 mm and possessing a centrally cut circular hole of diameter 75 to 100 mm, shall be supported horizontally in the screen and shall fit closely to the sides of the screen, to ensure th
17、at hot gases from the source of heat (5.5) do not come in contact with the sides or neck of the flask (5.1). The supports for this shelf may conveniently consist of triangular pieces of metal sheet firmly fixed to the screen at its four corners. A board as described in 5.4 shall rest on this shelf.
18、In one of the narrower sides of the screen, a door shall be provided having the approximate dimensions shown in figure 2 and overlapping the opening in the screen by approximately 5 mm all round. 5.3.2 For use with an electric heater When an electric heater is employed, the portion of the draught sc
19、reen above the shelf shall be as described in 5.3.1, but the lower portion (including the shelf) may be modified or omitted, provided that the change does not expose the distillation flask to draughts (see figure 3). Provision shall be made for adjustment of the shelf to facilitate fitting of the fl
20、ask. 5.4 Ceramic boards, of thickness 3 to 6 mm, with central holes of diameter 32 or 38 mm respectively and overall dimensions not less than 150 mm square. When a gas heater is employed, this board shall rest on the shelf described in 5.3.1. When an electric heater is employed, the same arrangement
21、 shall be adopted if the shelf is present; alternatively, the board may be placed directly on the heater or it may form the top of the heater. Provision shall be made for adjusting the height of the heater. 5.5 Source of heat, comprising either a gas burner so constructed that sufficient heat can be
22、 obtained to distill the product at the uniform rate specified in 8.3.1 (a sensitive regulating valve or governor are desirable adjuncts) or an electric heater capable of complying with the same requirements. (A heater of low heat retention, adjustable from 0 to 1 kW, has been found satisfactory.) S
23、ee also 9.6. 5.6 Condenser, of seamless brass tubing, of length 560 mm, outside diameter 14 mm and wall thickness 0,8 to 0,9 mm, surrounded by a metal cooling bath, preferably of copper or brass. The tube shall be set so that a length of approximately 390 mm is in contact with the cooling medium in
24、the cooling bath, with about 50 mm outside the cooling bath at the upper end, and about 115 mm outside at the lower end. The length of the tube projecting at the upper end shall be straight and set at an angle of 75 to the vertical. The section of the tube inside the cooling bath may be either strai
25、ght or bent in any suitable continuous smooth curve; the average gradient of this section shall be 0.26 mm per linear millimetre of the condenser tube (sine of angle of 15), and no part of it shall have a gradient less than 0,24 mm nor more than 0,28 mm per linear millimetre of the tube. The project
26、ing lower portion of the condenser tube shall be curved down- ward for a length of 76 mm and slightly backward so as to ensure contact with the wall of the receiver (5.7) at a point 25 to 32 mm below the top of the receiver when it is in a position to receive the distillate. The lower end of the con
27、denser tube shall be cut off at an acute angle so that the tip may be brought into contact with the wall of the receiver. The capacity of the cooling bath shall be not less than 5,5 litres of cooling medium. The arrangement of the tube in the cooling bath shall be such that its centre line is not le
28、ss than 32 mm below the plane of the top of the bath at its point of entrance, and not less than i9 mm above the floor of the bath at its exit. Clearances between the condenser tube and the walls of the bath shall be at least 13 mm, except for the section adjacent to the points of entrance and exit.
29、 The cooling bath may be provided with a tap at the bottom for drainage or inlet, and with an overflow tube near the top. The main dimensions of the tube and cooling bath are shown in figure 2. 4 Copyright International Organization for Standardization Provided by IHS under license with ISONot for R
30、esaleNo reproduction or networking permitted without license from IHS-,-,-200 c Windok I I n Water bath, capacity not e I N c7 r E 8 1 b iI7 IJls Ik , ; bottom . Condenser Condenser tube Shield FIGURE 3 - Distillation apparatus using electric heater 6 Copyright International Organization for Standar
31、dization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 4626-1980 (E) 5.7 Receiver, of capacity 100 ml, complying with the details shown in figure 4. None of the graduation lines shall be in error by more than 1 ml. The sh
32、ape of the base is optional but it shall be such that the receiver does not topple when placed empty on a surface inclined at an angle of 15 to the horizontal. 5.8 Barometer, accurate to the nearest 1 mbar, 0.1 kPa or 1 mmHg. Dimensions in millimetres / Fire-polished 0 3 J I 4- I 0 ti ml 0 Lx 3- 100
33、 P : Y 2 90 5 5 3 80 60 50 40 z 30 20 lis-l 10 FIGURE 4 - Distillation receiver 6 SAMPLING Representative samples, each having a volume of not less than 500 ml, should, wherever possible, be taken in triplicate from one or more original and previously unopened containers or from the bulk during pack
34、ing, as may be agreed between the interested parties, and shall be packaged in clean, dry, airtight containers of dark glass or metal. The containers shall be of such a size that they are nearly filled by the sample. Each sample container so filled shall be sealed with a material unaffected by the c
35、ontents and marked with the full details and date of sampling. Guidance on sampling is given in IS0 842. 7 ASSEMBLY AND PREPARATION OF APPARATUS 7.1 Assembly Assemble the apparatus as shown in figure 2 or figure 3, swabbing out the condenser with a piece of lint-free cloth attached to a wire cord or
36、 by any other suitable means, and paying attention to the following details. 7.1 .I Position and choice of thermometer Use the thermometer listed in the specification for the product under test, or that indicated in table 3. If no thermometer is specified, select one from table 1, with the smallest
37、graduations that will cover the entire boiling range of the product. Centre the thermometer into the neck of the flask through a tight-fitting silicone-rubber or cork stopper so that the upper end of the contraction chamber is level with the lower side of the vapour tube at its junction with the nec
38、k of the flask. NOTE - It is far more important that the greatest possible volume of mercury be immersed in the refluxing zone than that the immer- sion mark on the thermometer be placed at any specific point. 7.1.2 Support for flask If a draught screen with ceramic shelf is used, place the appropri
39、ate ceramic board (see 5.4 and 8.3) on top of the shelf so that the two holes are concentric. 7.1.3 Connection of flask to condenser Make a leak-proof connection of the flask (5.1) to the tube of the condenser (5.6) by means of a tight-fitting silicone- rubber or cork stopper through which the vapou
40、r tube of the flask passes. Connect the flask to the condenser so that the flask is in a vertical position; the end of the vapour tube shall extend at least 25 mm and not more than 50 mm beyond the cork into the condenser tube and shall be co-axial with it. Place the flask in such a position on the
41、board that the base completely closes the hole in the board. 7.2 Filling of cooling bath Fill the bath with water or with water and cracked ice in sufficient quantity to cover the condenser tube, SO as to ensure that the temperature of the bath at the start of and during distillation is as shown in
42、table 2. 7 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 4626-1980 (E) 7.3 Adjustment of temperature of sample Adjust the temperature of the sample to the appropria
43、te value shown in table 2, to prevent excessive evaporation of the product. TABLE 2 - Temperatures t initial boiling point OC Below 50 50 to 70 70 to 150 Above 150 Condenser “C oto 3 oto10 25 to 30 35 to 50 Sample “C oto 3 10 to 20 20 to 30 20 to 30 8 PROCEDURE 8.1 Test portion Using the graduated r
44、eceiver (5.7), measure 100 + 0,5 ml of the sample at the temperature to which it has been adjusted as specified in 7.3. Remove the flask (5.1) from the apparatus and transfer the test portion directly to the flask, allowing the receiver to drain for 15 to 20 s. Do not allow any of the test portion t
45、o enter the vapour tube. NOTE - For viscous liquids, a longer drainage period may be necessary to complete the transfer of the test portion to the flask, but the drainage time should not exceed 5 min. 8.2 Apparatus assembly Connect the flask to the condenser (5.6) and insert the thermometer (5.2) as
46、 described in 7.1.1 and position the flask as described in 7.1.3. Place the receiver (5.7), without drying, at the outlet of the condenser tube in such a position that the condenser tube extends into the receiver at least 25 mm but does not extend below the 100 ml mark. If the initial boiling point
47、of the sample is below 70 C, immerse the receiver in a transparent bath and maintain it at the temperature as specified for the sample in table 2 throughout the distillation. Place a flat cover on the top of the receiver to prevent entry of condensed moisture. 8.3 Operating conditions A certain amou
48、nt of judgment is necessary in choosing the best operating conditions to obtain acceptable accuracy and reproducibility for materials having different distil- lation temperatures. As a general guide it is recommended that : 8.3.1 For materials having an initial boiling point below 150 C, the followi
49、ng conditions shall be established : 8.3.1.1 F/ask support - Hole diameter, 32 mm. 8.3.1.2 Heating t-are - Time from application of heat to Read and record the barometric pressure to the nearest collection of first drop of distillate, 5 to 10 min, and time 1 mbar, 0,l kPa or 1 mmHg. 8 for rise of vapour column in neck of flask to side arm, 2,5 min to 3,5 min. 8.3.2 For materials having an initial boiling point above 150 C, the following conditions shall be esta
