New catalysts convert ethanol to butanol with high selectivity; potential low-cost upgrade for ethanol plants
11 April 2013
Researchers at the University of Bristol (UK) have developed a new family of catalysts that enables the conversion of ethanol into n-butanol—a higher alcohol with better characteristics for transportation applications than ethanol—with selectivity of more than 95% at good conversion. The team presented a pair of papers on their work at the Spring meeting of the American Chemical Society this week in New Orleans.
While butanol has emerged as a potential sustainable liquid fuel replacement for gasoline, development of biosynthetic pathways for its synthesis are challenged by very low conversion and modest selectivity, they noted. Although catalytically upgrading the more readily available bioethanol to butanol is theoretically attractive, this has been hampered by modest selectivity in most cases.
The Bristol team developed homogeneous ruthenium diphosphine catalysts for the upgrade of ethanol to butanol. At the ACS meeting, they presented results from a preliminary mechanistic study into the new catalysts suggesting that high selectivity is achieved because the catalyst imparts control over acetaldehyde aldol condensation reactions, with evidence for an on-metal condensation step.
These new catalysts are much better than any previously in existence. There’s a long way to go before they are commercialized, but we are reporting a fundamental advance in that direction. Quite simply, they are the world’s best catalysts for making the gasoline of the future.
—Professor Duncan Wass
The new catalysts could reduce the costs of converting ethanol factories to production of butanol. Efforts already have begun to convert some ethanol factories in the Corn Belt to production of butanol, Wass explained, but converting those factories to ferment corn into butanol would require modifications estimated at $10 million-$15 million for a typical plant.
However, with the new catalysts, the ethanol produced in conventional facilities could simply be upgraded to butanol in an additional reaction step.
Wass’ team acknowledges funding from BP.
Resources
Duncan Wass, Rich Wingad, George Dowson, Jason Lee (2013) CATL 195 - Catalytic conversion of ethanol to an advanced biofuel: Unprecedented selectivity to n-butanol
Richard L Wingad, Duncan F Wass, George Dowson, Jason Lee (2013) CATL 197 - Catalytic conversion of ethanol to an advanced biofuel: Exploring ligand effects
butanol is expensive, this may be a low cost way to make it.
Posted by: Herm | 11 April 2013 at 10:05 AM
They can rethink the E15 idea and have E10 plus 5% butanol. We can synthesize ethanol from biomass, coal and/or natural gas. Now we can make butanol from ethanol and save the corn grain for food/feed.
Posted by: SJC | 11 April 2013 at 10:20 AM
I am not sure that doing ethanol 1st and then transforming it in butanol is the most efficient way to do butanol, it is interesting because you can retrofit existing ethanol plant. But I think there is more direct way to do butanol
Posted by: Treehugger | 11 April 2013 at 01:07 PM
"Since the 1950s, most butanol in the United States is produced commercially from fossil fuels. The most common process starts with propene (propylene), which is run through a hydroformylation reaction to form butyraldehyde, which is then reduced with hydrogen to 1-butanol and/or 2-butanol."
http://en.wikipedia.org/wiki/Butanol
I don't know the efficiency nor complexity of either process, my point is they can use butanol instead of E15.
Posted by: SJC | 11 April 2013 at 01:55 PM
This could be a really big deal. Butanol is a much better fuel than ethanol, but harder to produce.
if you can convert ethanol to butanol efficiently, you have an interesting proposition.
However, annual production of Ruthenium is 20 tonnes (wiki) !! so they may have to find a more readily available catalyst.
However, this points the way to efficient conversion of Ethanol to Butanol, and that has to be worth at least an OBE.
Posted by: mahonj | 11 April 2013 at 03:46 PM
Would it be possible to produce a higher energy density fuel + more efficient jet engines for commercial planes to increase range and effective payload?
Posted by: HarveyD | 11 April 2013 at 04:02 PM
It has already been done, Shell GTL jet fuel has a higher BTU per unit volume than refined jet fuel.
Posted by: SJC | 11 April 2013 at 04:24 PM
I want to clarify the previous statement.
"Concurrent to the PM reductions is an immediate reduction in CO2 emissions from F-T fuel. F-T fuels inherently reduce CO2 emissions because they have higher energy content per carbon content of the fuel, and the fuel is less dense than conventional jet fuel allowing aircraft to fly further on the same load of fuel."
http://en.wikipedia.org/wiki/Synthetic_fuel#Aviation_fuel
Rather is is not BTUs per gallon, but BTUs per pound.
Posted by: SJC | 11 April 2013 at 05:03 PM