BUTANOL PRODUCT
Figure 1. New catalysts provide high selectivity in converting ethanol to n-butanol. Source: University of Bristol.
"Butanol is much better. It contains about 30% more energy per gallon than ethanol, is easier to handle, and more of it can be blended into each gallon of gasoline. In fact, you could fuel a car on pure butanol and it would run absolutely fine," notes Duncan Wass, a professor of catalysis at the university's dept. of chemistry and a member of the research team.
"These new catalysts are much better than any previously in existence," he says. "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."
The ruthenium-based catalysts boast unparalleled and extremely high selectivity for making n-butanol — over 94% — at more than 20% conversion.
Key challenges remaining to be addressed are catalyst robustness and process scale-up, notes Wass.
"We are working on new catalysts as well as optimization and a more-detailed understanding of our current system… The more-scientific study should take 12–18 months. Optimization in terms of scale-up to a commercial-scale trial will take a lot longer — my experience is at least five years even if everything works well."
Scale-up studies will investigate issues such as how many cycles the catalyst can withstand as well as its susceptibility to poisoning.
"In a continuous process, there is no reason why [yield] shouldn't approach 100%. In a batch process, there is always the compromise between conversion and selectivity," says Wass.
BP, London, provided funding for the research and continues to collaborate on the development.
