Nuclear magnetic resonance (NMR) spectroscopy provides detailed information about the nature and concentration of many components in a chemical reaction because most molecules contain NMR-active nuclei. However, the application of NMR to in operando analysis under pressures greater than 1-2 atm has been limited by the difficulties of handling high pressures and achieving good gas-liquid mass transport in the NMR instrument.

The problem of handling high pressures in standard NMR instruments was largely solved by the development of sapphire NMR tubes that retained the general dimensions of conventional glass NMR tubes but withstand much higher pressures. The Landis group has combined sapphire tubes with an innovative method for performing gas-liquid transport and mixing in building the Wisconsin High-Pressure NMR Reactor (WiHP-NMRR) for the study of new catalytic reactions in conditions up to 1000 PSI.[1] The reactor has proven effective for NMR monitoring of fast gas-fed reactions, utilizing multiple nuclei, over time scales ranging from a few hours to several days.




[1] N. J. Beach, S. M. M. Knapp and C. R. Landis. “A reactor for high-throughput high-pressure nuclear magnetic resonance spectroscopy.” Review of Scientific Instruments 86(10) (2015) 104101.
[2] A. C. Brezny and C. R. Landis. “Recent Developments in the Scope, Practicality, and Mechanistic Understanding of Enantioselective Hydroformylation.” Acc Chem Res 51 (2018) 2344-2354.