Team discovers new catalytic process to upgrade hydrocarbon by-products of sulfur-free diesel production from natural gas and biomass
Researchers at the Cardiff Catalysis Institute (Cardiff University, UK) have found a potential catalytic route for upgrading by-products resulting from the production of sulfur-free diesel from natural gas and biomass. These byproducts, hydrocarbons such as decane and other low-value alkanes, currently have little practical use.
In the past, they note in a paper in Nature Chemistry, synthetic reactions starting from alkanes like decane have been fraught with difficulty. They tend either to over-dehydrogenate or to combust, depending on whether oxygen is present in the reaction. The Cardiff Catalysis Institute team reported the use of a mixed-metal catalyst to convert decane to a range of oxygenated aromatics.
The breakthrough came when the team fed a gas mixture of decane and air through an iron molybdate catalyst. At higher temperatures, the reaction formed water and decene, which is used in the production of detergents. At lower temperatures, however, the reaction took a different route to create oxygenated aromatic molecules. These included phthalic anhydride, used in the dyeing industry, and coumarin which helps in the production of anti-coagulant drugs.
This discovery breaks new ground as it implies the involvement of oxygen that has not yet made the full transition from its molecular form to its ionic form. This overturns a widely-held view that this type of oxygen was too reactive to form anything other than carbon monoxide and carbon dioxide in reactions with hydrocarbons.
While the increased production of sulfur-free diesel has been a positive move, the glut of low value by-products will become a problem. We hope our new process will lead to less waste and the creation of more useful chemicals for a range of industries.—Professor Stan Golunski, a member of the Institute team
Sivaram Pradhan, Jonathan K. Bartley, Donald Bethell, Albert F. Carley, Marco Conte, Stan Golunski, Matthew P. House, Robert L. Jenkins, Rhys Lloyd & Graham J. Hutchings (2012) Non-lattice surface oxygen species implicated in the catalytic partial oxidation of decane to oxygenated aromatics. Nature Chemistry 4, 134-139 doi: 10.1038/nchem.1245