NMR of petrochemical-type chemical reactions

A simple technique is presented for NMR of chemically reacting systems at conditions of high temperature and pressure. The method can follow reactions that are typical of refinery operations - hydrogenation, transfer dehydrogenation, methanol synthesis, and isomerization. All of the reacting materials are flame-sealed into a glass capillary. Gaseous agents such as O₂ and CO are loaded into the capillary by condensation at liquid N₂ temperature. H₂ is provided by loading LiAlH₄. The capillary holds the high pressure, up to 7 MPa, so the NMR probe can be a simple design with hot air flowing over the sample tube, up to 350 °C. Example reaction results are presented, including hydrogenation of benzene, hydrogenation/dehydrogenation of cyclohexene to benzene and cyclohexane (a disproportionation), and synthesis of methane, methanol and dimethyl ether from CO and H₂. In this work we present a simple, inexpensive method with rapid temperature response for tracking chemical reactions in real-time at high temperature and high pressure.