Supported ionic liquids for effective ruthenium olefin metathesis

Supported olefin metathesis catalysts have attracted considerable interest for over two decades, regarding their facile separation, reusability and decreased product contamination. In this study two strategies toward synthesis of heterogeneous ruthenium-catalyst were explored using supported ionic liquid phase (SILP) and supported ionic liquid-like phase (SILLP) with multi-walled carbon nanotubes (MWCNTs) as a support. The structure of ionic liquids used for the construction of catalysts was varied regarding length of alkyl chain and anion in terms of providing influence on catalytic activity and stability as well as reaction product contamination. The activity of prepared catalysts was tested in ring-closing metathesis (RCM). The Ru-based SILLP catalyst demonstrated high performance (conversions >90 % in five reaction cycles), compared to SILP and Ru@MWCNTs catalyst synthesized using unmodified MWCNTs, additionally decreasing the product contamination with Ru (14 ppm).

Automated summary

This study explored two methods for synthesizing heterogeneous ruthenium catalysts using supported ionic liquid phase (SILP) and supported ionic liquid-like phase (SILLP) with multi-walled carbon nanotubes (MWCNTs) as a support. The structure of the ionic liquids used for the catalysts varied in terms of alkyl chain length and anion type, which affected the catalytic activity, stability, and product contamination. The SILLP catalyst based on Ru showed high performance in ring-closing metathesis, with conversions exceeding 90% in five reaction cycles, and decreased product contamination with Ru (14 ppm).