TS-1 industrial catalyst activity relies on titanium / Invention pair important for catalyst development.
‘Titanium silicalite-1’ (TS-1) is not a new catalyst: It has been almost 40 years since its development and discovery of its ability to convert propylene into propyl oxide, a key chemical in the chemical industry. Now, by combining a variety of methods, a team of scientists from ETH Zurich, the University of Cologne, the Fritz Haber Institute and BASF have uncovered a surprising mechanism of action of this catalyst. From Cologne, the group employed Professor Dr. Albrecht Berkessel in the Department of Chemistry involved. These findings will help catalyst research take important steps.
Propylene oxide is used in industry to make products such as polyurethane, antifungal additives and hydraulic fluids. More than 11 million metric tons of propyl oxide are produced annually in the world’s chemical industry, of which 1 million metric tons is produced by the oxidation of propylene and hydrogen peroxide. This chemical reaction is catalyzed by TS-1, a microporous, crystalline substance composed of silicon and oxygen and containing a small amount of titanium. Catalysts have been in use for 40 years and experts believe that the active centers in TS-1 contain individual titanium atoms, isolated which ensure the specific reactivity of the catalyst.
A team of researchers from ETH Zurich, the University of Cologne, the Fritz Haber Institute and BASF questioned this assumption. “In recent years, doubts have arisen as to whether assumptions about the mechanism of action are correct, as they rely primarily on the same analogy and catalyst and less on experimental evidence. in the wrong direction. So it is important to examine this assumption more closely, “explained BASF scientist Dr. Henrique Teles, one of the authors of the scientific publication, was the starting point for that collaboration.
In the present study published in nature, the team is able, using solid-state NMR studies and computer models, to show that two neighboring titanium atoms need to explain certain catalytic activities. This in turn led the research team to conclude that titanium atoms are not isolated but are more catalytically active centers made up of titanium pairs. “Not one of the methods we use in the study is basically new, but there is not a single research group involved in the study that can conduct the investigation alone,” stressed Prof. Christophe Copéret of ETH Zurich, author of this publication. , “Just combine some areas of awareness with some of the latter techniques to further examine the active center of the catalyst.”
“We have worked for many years to explain the mechanism of reaction of homogeneous titanium catalysts and to find that – contrary to the assumption in the literature – hydrogen peroxide is activated by titanium pairs. That is a special moment when we see in our current study applied to heterogeneous catalysis, “said another author Prof Albrecht Berkessel from the University of Cologne. And Dr. Thomas Lunkenbein, co-author of the Fritz Haber Institute in Berlin, adds: “We are very pleased we have been able to contribute to this study. With our analytics, we can prove a conclusion. Knowledge of active diatomical centers is crucial and opens up new possibilities in catalyst research . “
The team believes that the findings of this study will not only help to improve existing catalysts, but also to develop new homogeneous and heterogeneous catalysts.
References: “Efficient oxidation of nuclear sites in titanium silicalite-1” by Christopher P. Gordon, Hauke Engler, Amadeus Samuel Tragl, Milivoj Plodinec, Thomas Lunkenbein, Albrecht Berkessel, Joaquim Henrique Teles, Andrei-Nicolae Parvulescu and Christophe Copéret, October 28, 2020, nature,
DOI: 10.1038 / s41586-020-2826-3