Fundamental Organic Chemistry
Fundamental Organic Chemistry
Fundamental Organic Chemistry
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apparatus, remove the cold finger or test tube carefully, and scrape the sublimed<br />
crystals into a tared container or onto a watch glass. Determine the melting point<br />
of the sample with a sealed capillary fig. (3).<br />
Fig.(3): atmospheric sublimation<br />
Vacuum Sublimation:<br />
For a vacuum sublimation, choose a side-arm test tube to hold the sample,<br />
and then insert a smaller test tube fitted into a neoprene adapter or large-holed<br />
stopper. Place ice in the inner tube, connect the side arm with heavy-walled<br />
rubber tubing to a trap (preferably chilled in an ice bath) and then to the aspirator.<br />
For an illustration of the trap and a discussion of using the aspirator.<br />
Turn on the aspirator and press the test tubes together to obtain a seal.<br />
Then, warm or heat the outer test tube. When the sublimation is complete, allow<br />
the apparatus to cool before breaking the vacuum. Take care in breaking the<br />
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