If the conversion of carbohydrates to oxygen-containing chemicals has been largely investigated, the replacement of bulk aromatic petrochemical compounds has received so far relatively little attention and limited success. Fermentation of glucose to a number of aromatic structures has been described in the patent literature. However, these aromatic structures themselves were neither bulk products nor the desired end product of the fermentation process (adipic acid; Haveren et al., 2008).
Utilization of specific terpenes could offer potential for the production of aromatic compounds such as, for example, substituted phenols or terephthalic acid and fine and
|
|
|
5 BIOREFINERY TO REPLACE EXISTING FOSSIL BULK CHEMICALS
|
|
|
specialty chemicals to be applied in the chemical or pharmaceutical industry (Costantino et al., 2009). However, current production volumes of terpenes are rather in the range of hundreds of thousands of tons instead of the million tons needed to substitute a significant amount of aromatics production.
Thanks to its original structure, the most promising feedstock for production of aromatics from biomass is lignin. The ideal conversion pathway would include the possibility to efficiently and selectively depolymerize lignin and separate from the resulting mixture the components of interest (e. g., BTX). Prior to be able to isolate aromatics and phenols from lignin, major technological improvements are needed. Another long term possibility to synthesize aromatics from biomass is the Diels-Alder cyclo-addiction of butadiene over a catalyst. Clearly, this route relies on an economic production pathway to butadiene prior being industrially taken into consideration.
|
|
|
|
