Environmental Engineering Reference
In-Depth Information
4.6 Bio-Derived v. Fossil-Derived: Changing
Downstream Chemistry
A switch from fossil-derived base chemicals to bio-derived platform molecules
will likely require changes to the types of reactions typically used for the
production of commodity chemicals (those produced on a large scale direct from
base chemicals). Fossil-derived base chemicals, with the exception of MeOH, are
totally devoid of heteroatoms and contain only carbon and hydrogen. The result of
this is that many of reactions used to produce commodity chemicals in the current
petrochemical industry require the introduction of heteroatoms, most often
oxygen. Platform chemicals, inherently high in oxygen content, will not typically
require the same initial oxidation steps to reach useful commodity chemicals, but
instead may need reduction and dehydrations to reduce or tailor functionality. An
example of this difference in steps can be seen for the theoretical production of
ethyl acrylate from biomass compared with the current fossil-based route
(Figure 4.11). The primary base chemicals for the fossil route are propylene (for
acrylic acid formation) and ethene (for ethanol formation); both steps of base to
commodity chemical require the introduction of oxygen, either from oxidation or
Biomass
O
O
3HP
O
HO
HO
OH
OH
HO
HO
OH
OH
OH
Lactic acid
Fumaric acid
Glycerol
O
O
Oxidation
Dehydration
OH
O
OH
Acrolein
Ethanol
Ethene
Acrylic acid
O
O
Ethyl acrylate
OH
Ethanol
O
Oxidation
OH
Propene
Acrylic acid
Ethene
Crude oil
Figure 4.11
Fossil-derived and bio-derived routes to ethyl acrylate.
