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Name: Delilah S.
Status: educator
Age: 50s
Location: N/A
Country: N/A
Date: 8/6/2004


Question:
What happens when you heat wood in a vacuum? No fire is produced due to lack of oxygen in the atmosphere. Thank you.


Replies:
The wood being predominantly cellulose has the generic chemical formula: --[CH2O]--. It is a carbohydrate. Upon heating it would decompose into elemental carbon, CO, CO2, H2O and a complicated tarry residue.

Vince Calder


Delilah,

Heating the wood in a vacuum would not be all that easy because in the vacuum the only method of heat transfer would be that of radiation from the heat source and conduction through the wood itself. Wood isn't a very good conductor of heat. In the absence of some kind of atmosphere (an inert, oxygen-free gas, perhaps) there would be to convective pathway to transfer the heat to the wood.

Nevertheless, assuming what you propose could be easily accomplished, the wood would gradually degrade and liberate a host of complex volatile (and combustible in air) compounds which would be immediately drawn off toward the vacuum source. These come from the cellulosic and lignin parts of the wood. When they were (mostly) all gone, what's left would be a very high-grade and active form of charcoal.

Regards,
ProfHoff 903



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