Sunday, July 12, 2009

Chemicals from the Farm


Despite the low oil prices, work continues on converting waste biomass and cheap cellulosic sources like Switchgrass into fuel sources, so called bio-oil. It is fairly easy to turn waste biomass into gas by baking at 1000C. This product called synthesis gas is rich in hydrogen. It takes work to turn this back into a liquid fuel, which might be more convenient.

By baking at 500C, a liquid results, but the conversion is less than complete, and that is a waste of resources and energy.

The problem is that the cellulose is mixed with lignin, and the lignin is hard to degrade. Plus the combined ligno-cellulose is not very soluble.

Conrad Zhang of PNNL (Pacific Northwest National Labs and KiOR) says that lignocellulose dissolves in an imidazolium ionic liquid, and that once soluble it decomposes at 100C using copper chloride and chromium chloride as catalysts. This is a big break through if the other materials can be recycled. KiOR is working the Brasilian company Petrobras to develop the technology.


Of great interest in the chemical industry is the creation of feedstocks pure enough to use for producing chemicals. It appears that 5-hydroxymethyl furfural maybe one such chemical. C&E News reports that Hanson of the Technical University of Denmarkk can make 5-hydroxymethyl furfural from fructose by treatment with simply microwaves.

Of course the production of furfural from biomass is not new. Quaker Oats was making furfural from oat hulls EIGHTY-SEVEN years ago!!

As readers of my other blog know, furfural is found in the extract from oak barrels like those used for wine and for whiskey. Furfuryl is supposed to have a burnt taste, and 5-hydroxymethyl furfuryl is carmel tasting.

The oxidation of 5-hydroxymethyl furfural yields furan dicarboxylic acid, which could be used to make polyesters or nylon/polyamides. This could be interesting, and one could run reactions on the double bonds too.

In summary, there are not any new plants running new processes to make bio-oil, but ionic liquids show promise. Happily research in bio-fuels and bio-chemicals have survived the onset of the recession, and perhaps because of stimulus funding they will continue for a few years. It is just a matter of time until the world moves toward sustainable feedstocks for fuel and for chemicals.