Over the past several years GSK has been developing the capability to perform continuous hydrogenations within trickle bed reactors. Motivation to develop this technology stems from the ability of trickle bed reactors to perform hydrogenations at high pressures (up to 100 bar within GSK), which is considerably greater than our current hydrogenation batch vessels (5 bar). This allows access to chemistry with improved quality and productivity, with the added benefit of enhanced process control, reduced reactor size, reduced vessel cleaning time, greener processes, and increased safety. To support this ambition a new generation of catalysts for pharmaceutical-scale continuous hydrogenations have been developed with traditional and nontraditional catalyst suppliers. Herein we discuss a procedure to characterize and assess the suitability of the new catalysts from a nontraditional supplier for use in laboratory and pilot plant scale reactors (reactor volume 0.1 to 0.5 L).

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Nine sponge nickel catalysts were assessed for the reduction of an aliphatic nitro group in a trickle bed reactor. Focused beam reflectance measurement (FBRM) was used to assess the mechanical strength and particle size distribution of the catalysts. The continuous reduction of (S)-7-methyl-7-(nitromethyl)-1,4-dioxaspiro[4.5]decane was investigated using a Raney nickel catalyst in a fixed bed reactor. The use of a Luna ODiSl temperature probe and an FLIR thermal imaging camera were investigated to monitor the catalyst performance while the process was run. A 1.12 kg sample of the aliphatic nitro compound was reduced to the corresponding amine using a single 20 mL reactor containing 43 g of 3111A Raney nickel over a period of 17 h.