A new chemical catalyst developed at the University of Michigan is making it possible to produce more raw materials for the world’s second most common plastic.
The new catalyst can produce propylene from natural gas at least 10 times more efficiently than current commercial catalysts. It is made of platinum and tin nanoparticles with a silica skeleton.
Propylene has traditionally been produced in refineries in bulk steam cracking, which breaks down petroleum feedstocks into lighter hydrocarbon molecules. But cracking shale gas to produce propylene has proven ineffective.
The new catalyst efficiently produces propylene, a molecule with three carbon atoms and six hydrogens: it requires propane to produce it, which contains two additional hydrogens. It uses a process called non-oxidative dehydrogenation.
The key innovation of the new catalyst is that it uses silica as a support structure for platinum and tin nanoparticles, rather than the alumina used in modern catalysts. Alumina reacts with tin, causing it to separate from the platinum and destroy the catalyst. Since the new catalyst delays this reaction, the resulting feedstock has a longer life.