Sublimation microwave-assisted

This microwave-assisted reaction was carried out on a 3-g scale in a glass vessel placed in a bath of alumina/magnetite. The anthraquinone (m.p. 284°C) produced was collected as it sublimed from the reactor. Further, o-benzoylbenzoic acid was added and the reaction repeated. The main advantage of the microwave-assisted reaction lies in the recycling of the catalyst. The yield in the conventional heating process falls to 50% after four uses of catalyst, whereas in the microwave-assisted process the yield is still 84% after fifteen uses. 

Subsequent to freeze stabilization, wet books can be thawed and air dried with or without interleaving or they can be vacuum dried in heated chambers (5). The moisture in frozen books can be sublimed by freeze drying (10) or removed by a vacuum/thaw/outgassing process (8), with microwave energy (6, 14), with dielectric energy (6), or by solvent extraction with or without vacuum assistance (5). 

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