John Morris

The CatCart® system was designed to make the use of pyrophoric catalysts safer, easier to handle, and reusable with different substrates. The CatCart® is an integral, exchangeable part of the H-Cube® system and was created to make the process of hydrogenation easier and more efficient.

The CatCart® system is made up of a stainless steel tube packed with heterogeneous catalyst of a specific particle size range. A filter system at either end of the tube allows liquid to pass through the column, but prevents catalyst from leaking out.

ThalesNano has a wide range of different catalysts to suit most types of hydrogenations. These range from the more common types, such as palladium on carbon and Raney Ni, to catalysts used for more chemoselective hydrogenations, such as rhenium catalysts.

Insertion and exchange of CatCarts® is a very simple process. The user needs only unscrew the cartridge from the heater system, remove the CatCart®, and replace with another cartridge. The whole process takes only a few seconds.

During a reaction, a mixture of hydrogen and dissolved substrate enters the CatCart® and adsorbs onto the catalyst bed. The reaction takes place on the catalyst while the substrate/hydrogen mixture passes through the cartridge. The product then flows out of the CatCart® and into a collectionvial. All the catalyst remains in the cartridge, so the user need only evaporate the solvent to yield the product. After thorough washing with solvent, the CatCart® may be used again with another different substrate. This process can be repeated until the catalyst deactivates.

The process of flowing a hydrogen/substrate mixture through a catalyst bed vastly increases the interaction between the three phases (solid catalyst, liquid substrate, hydrogen gas). This interaction is important due to the limited solubility of hydrogen in solvent. The higher the mixing efficiency, the higher the mass transfer onto the catalyst, and therefore, the higher the reaction rates.

Another major advantage of the CatCart® system, is that the handling of highly pyrophoric catalysts, such as the Raney type catalysts, is much easier and safer. Catalyst fires most commonly occur upon addition of the catalyst to the reaction mixture and removal of the catalyst from the reaction mixture via filtration. With the CatCart® system, the filtration step is not necessary and containment of the catalyst in a cartridge for fast addition and removal of catalyst makes the process far safer and less hazardous than conventional methods.

Summary of the advantages

• Safer handling-no contact between user and catalyst
• Exchange of catalyst is quick and safe with no mess
• No catalyst filtration necessary
• Ability to reuse catalyst with different substrates
• More efficient mixing of the three phases leading to higher reaction rates