Page 234 - Demo

Apparatus and Supplies
Tubes, Melting Point, Thiele
The Thiele-Dennis tube is a modified Thiele tube which improves and increases the rate of circulation. Tube diameter is 25 mm. Economy choice melting point tube is also available. Tube diameter is 23 mm.
Tubes, Test
Test Tubes with Rims
Borosilicate glass tubes have fire-polished rims and optimal wall thick- ness for maximum heat and chemical resistance.
1-800-452-1261
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Thiele-Dennis Melting Point Tube GP6090
232
Catalog No.
Description
Price/Each
GP6090
Thiele-Dennis Melting Point Tube
$65.95
AP6991
Melting Point Tube, Thiele, Economy Choice
14.20
S0451
Silicone Oil, 250 mL
19.25
Catalog No.
o.d. x Length (mm)
Capacity (mL)
Price/Each
Price/Pkg.
Price/Case
GP6005
12 x 75
5
$ .51
$24.00/50
$ 90.00/200
GP6010
13 x 100
9
.54
26.00/50
100.00/200
GP6015
15 x 125
14
.72
34.00/50
128.00/200
GP6020
16 x 150
20
.88
41.50/50
156.00/200
GP6025
18 x 150
27
1.00
47.00/50
176.00/200
GP6030
20 x 150
34
.96
46.50/50
180.00/200
GP6035
25 x 150
55
1.65
79.50/50
306.00/200
GP6040
25 x 200
70
1.95
94.50/50
366.00/200
Test Tubes without Rims
Rimless, borosilicate glass tubes for convenience in plugging and rack storage. Ends are fire polished. Commonly referred to as culture tubes.
1Known as Kahn Tube 2Known as Wasserman Tube
Test Tubes without Rims GP6060, etc.
TUBES, TEST continued on next page.
Test Tubes with Rims GP6005, etc.
Melting Point Tube, Thiele AP6991
Catalog No.
o.d. x Length (mm)
Capacity (mL)
Price/Each
Price/Pkg.
Price/Case
GP6060
6 x 50
0.5
$ .46
$31.68/ 72
$302.40/ 720
GP6061
10 x 75
3.0
.48
33.12/ 72
316.80/ 720
GP6062
12 x 751
5.0
.48
33.12/ 72
316.80/ 720
GP6063
13 x 1002
9.0
.51
35.28/ 72
338.40/ 720
GP6064
16 x 100
11.0
.59
40.32/ 72
305.28/576
GP6065
16 x 125
15.0
.64
43.92/ 72
334.08/576
GP6066
16 x 150
20.0
.75
51.84/ 72
397.44/576
GP6067
18 x 150
27.0
.81
54.00/ 72
397.44/576
GP6068
20 x 150
34.0
.92
61.92/ 72
460.80/576
GP6069
25 x 150
55.0
1.60
111.60/ 72
432.00/ 288
Make Melting Point Determinations Using
a Thiele-Dennis Tube
A small quantity of the substance in question is placed into a small capillary tube. The capillary tube (with the unknown inside) is then attached to a thermometer. A rubber band will do it.
Fill the Thiele-Dennis tube (or an Erlenmeyer flask) with water if the melting point of the solid is less than 100 °C or oil if the melting point is greater than 100 °C (silicon oil is best but corn oil will do). Remember that heated oils may both expand and also smoke slightly at elevated temperatures. The rubber band may come loose if subjected to hot oil. Immerse the thermometer (with the capillary tube attached) so that the rubber band is kept out of the oil.
Heat the Thiele-Dennis tube (see drawing) at about 10 °C per minute temperature rise to get a rough melting point. Then repeat the procedure heating the tube at a much slower rate (about 1 °C per minute) to get an accurate melting point. A pure substance will begin to melt abruptly, and the melting will be complete within a 1–2 °C temperature range. The unique configuration of the Thiele-Dennis tube is designed to create continuous oil flow when heated so no stirring or shaking is required. Convection currents created by the heat do the stirring for you.
Cork or stopper notched to permit escape of air
Level of heating fluid at 200°
Level of heating fluid at room temperature
Capillary tube containing solid
Thiele-Dennis Tube or Erlenmeyer Flask
Thermometer
Rubber band or segment of rubber tubing
Heating fluid
Laboratory Burner