Catalysts - substances that speed up the rates of chemical reactions without themselves being chemically changed - are used to initiate virtually every manufacturing process that involves chemistry. There are two basic modes of catalytic reactors batch, in which a final chemical product is produced over a series of separate stages; and flow, in which chemical reactions run in a continuously flowing stream to yield a final product. With the implementation of microreactors, the pharmaceutical industry aims to make the switch from batch mode to flow mode, as flow reactors provide a highly recyclable, scalable and efficient setup that enhances the sustainability and performance of catalysts. However, the synthesis of pharmaceutical drugs is a multiphase, complex process that needs to be carefully monitored. Until now, there has been no capability to follow the multistep production process of pharmaceutical drugs in flow reactors without perturbing the flow reaction.
"Our method allows us to watch an entire catalytic movie, from reactants into products formation, instead of only snapshots of the catalytic process," says Gross. "In most cases before, chemists had to extrapolate information on the reaction process based on analysis of the final product. With our technique, we don't have to guess what happened in the first scene based on what we saw in the final scene, since now we're able to directly watch a high-resolution movie of the entire process."
For this study, Gross and his colleagues used a heterogeneous catalyst of gold nanoclusters loaded onto a silica support to produce dihydropyran, an organic compound whose formation involves multiple reactant steps. Each of these reactants shows a distinguishable infrared signature, allowing their evolution into the final product to be precisely monitored with an infrared beam. The infrared microspectroscopy was performed
|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory