Chapter 6

Sublimation

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Sublimation

Sublimation is the process whereby a solid evaporates from a warm surface and condenses on a cold surface as a solid.

Sublimation is preferred over crystallization for < 100mg purification as there is little loss of material.

Use apparatus shown in Figure 6.21, p. 130. You are to use vacuum sublimation for high mp substances (>80 o C). Vacuum line is attached to the side arm of the filter flask.

Sublime two known and one unknown substance.

Determine mass, % yield, and mp for unknown characterization (Table 6.3, p. 132).

NOTE: Do NOT get water in the apparatus

Postlab Questions

(also stated in the lab handout)

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What is sublimation?

the preparative benefit of Cite some example of substances that sublime. According to your experience, how can one improve the sublimation process?