TS-1 CATALYST
Titanium silicalite-1 (TS-1) has been used for nearly 40 years for the catalytic conversion of propylene and hydrogen peroxide into propylene oxide (PO), but the mechanism for the conversion has not been well understood. Now, a team of researchers from BASF SE (Ludwigshafen, Germany; www.basf.com), ETH Zurich (Switzerland), the University of Cologne and the Fritz Haber Institute (Berlin, both Germany) have used a variety of tools to unveil this mechanism, which was reported last month in Nature.
TS-1 is a microporous, crystalline material made up of silicon and oxygen, with small amounts of titanium. Up to now, experts assumed that the active center in TS- 1 contains individual, isolated titanium atoms. Combining solid-state nuclear-magnetic resonance (NMR) studies with computer modeling, the team was able to show that two neighboring titanium atoms are required to explain the catalytic activity, rather than isolated Ti atoms.
The team believes the findings will not only help to improve existing catalysts, but also to develop new homogeneous and heterogeneous catalysts.