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154:, then the sublimed material can be collected from the cooled surface once heating ceases and the vacuum is released. Although this may be quite convenient for small quantities, adapting sublimation processes to large volume is generally not practical with the apparatus becoming extremely large and generally needing to be disassembled to recover products and remove residue.
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Among the advantages of applying the principle to certain materials are the comparatively low working temperatures, reduced exposure to gases such as oxygen that might harm certain products, and the ease with which it can be performed on extremely small quantities. The same apparatus may also be used
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for conventional distillation of extremely small quantities due to the very small volume and surface area between evaporating and condensing regions, although this is generally only useful if the cold finger can be cold enough to solidify the condensate.
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A typical sublimation apparatus separates a mix of appropriate solid materials in a vessel in which it applies heat under a controllable atmosphere (air,
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being purified on a sublimation apparatus. Note the white purified camphor on the cold finger, and the dark-brown crude product.
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Simple sublimation apparatus. Water usually cold, is circulated in cold finger to allow the desired compound to be deposited.
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which for very low-temperature sublimation may actually be cryogenically cooled. If the operation is a
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or inert gas). If the material is not at first solid, then it may freeze under reduced
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More sophisticated variants of sublimation apparatus include those that apply a
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The form of the cooled surface often is a so-called
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