243Processes for Production of Chemicals from Carbohydrates
So far, very little is disclosed in literature about the actual process of iso-butanol
toward para-xylene. Clearly, the chemistry is based on the fermentation technol-
ogy to iso-butanol developed by Gevo Inc.
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The theoretical stoichiometric route for
obtaining iso-butanol via the fermentation pathway developed by GEVO is
1 glucose → 1 iBuOH + 2 CO
2
+ H
2
O
Two moles of CO
2
are lost in this pathway, and even with a 100% theoretical
molar yield of the reaction above, only a 41% theoretical weight yield of isobutanol
per weight of glucose can be obtained. A practical isobutanol yield of approximately
82%–90% of theoretical was reported in the examples using corn starch as the start-