A High Mobility Reactor Unit for R&D Continuous Flow Transfer Hydrogenations

A suitcase sized mobile reactor unit (MRU) weighing in at less than 10 kg was designed for laboratory scale transfer hydrogenations in continuous flow. Simple cyclohexene and a cosolvent in combination with a palladium-on-charcoal packed bed reactor provided a setup with isolation of nearly all products without the need for further purification. Several functional groups including olefins, triple bonds, nitro-groups, carbonyls, and so forth were effectively reduced with retention times as low as 2 min. Additionally, standard protection groups such as Cbz, benzyl, and allyl ether or esters were removed in high yields. To prove the flexibility of the setup an example of the Mizoroki–Heck reaction was also performed on the MRU. Finally, two scale-up transfer hydrogenation experiments were performed affording isolation of the desired target compounds in 0.5 and 0.8 mol scales with less than 4 h of continuous operation on the MRU.