(CN) - Recent findings suggest a path toward cleaner emissions and greater independence from foreign oil could be on the horizon, as researchers have developed reactions that selectively produce butanol, a renewable energy source.
The researchers developed a process of reactions that enables the conversion of ethanol to butanol more efficiently.
"What we've been able to do is demonstrate that in a laboratory we can take ethanol and combine it to make butanol," Dr. William Jones, a professor at the University of Rochester and study co-author, said. "It's a step toward a more valuable fuel."
Jones and Dr. R. Tom Baker, a professor from the University of Ottawa, pursued a more efficient process after recognizing existing limitations within the Guerbet reaction, a common method for converting ethanol to butanol.
"We saw that the best selectivity was 80 percent. We thought that we could do better than that with a more selective catalyst," Jones said in a phone interview.
The Guerbet reaction involves removing hydrogen atoms temporarily, before adding them back to the final product. This reaction creates acetaldehyde, a chemical compound that can inadvertently react with ethanol and butanol, resulting in undesired molecules.
To avoid these limitations, the research team used iridium for the initial catalyst, followed by either copper hydroxide or nickel.
"We were able to find a catalyst that gave us 99 percent selectivity," Jones said. "But it's only been demonstrated on a lab scale, it's not ready for a production scale."
The duration of the reactions that the research team observed were fairly short, and would need to be extended.
"We need longer lift catalysts, and catalysts that will give more turnovers," Jones said. "After one day it stops working, and we need to find out why."
Iridium costs roughly the price of gold, so using it on a production scale would not make sense financially.
The search for a cheaper alternative is one of the next steps for Jones' team, who are searching for catalysts that meet their criteria.
"We need it to be water-tolerant, because water is produced in the process," Jones explained. "The obvious choice would be a first row metal - iron, cobalt, etc."
Moving away from ethanol alone represents an accomplishment that would align with national efforts to curb harmful emissions. And as an oxygenated fuel, ethanol on its own results in lower energy output and can be damaging to engines through corrosion.
"The efficiency is very good. This is a step in the right direction. It's a renewable source, and we can grow the crops and the biomaterial that we need to produce ethanol," Jones said.
Researchers will need additional funding in order to continue their work, which was funded initially by the National Science Foundation's support of the Center for Enabling New Technologies through Catalysis.
If they are able to get additional money, their processes could be licensed or incorporated into new production mechanisms by energy companies.
"The industry has shown interest. BP, DuPont and a couple others are trying to successfully produce a plant that will make butanol from ethanol," Jones said. "They haven't succeeded so far, but they're working on it."
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