High-throughput experimentation as a tool in catalyst design for the reductive amination of benzaldehyde

摘要

A combinatorial library of 24 carbon-supported noble metal catalysts is screened for reductive amination of benzaldehyde in the presence of ammonia.Gas chromatography is used to rapidly quantify the product yields and selectives obtained with the different candidates.The results show that the catalytic activity is strongly influenced by,both,the nature of the support and the nature of the metal.The activity is higher when the parent support,SX1G,has been treated by oxidawtion and subsequent sodium-exchange.With regard to the metal,the activity decreases in the order of Ru,Pd,Pt.Surprisingly,Ru-based catalysts,which do not rank among the mot commonly used for reductive amination processes,show the highest activity.The selectivity to a particular amine is controlled essentially by the nature of hte metal.Benzylamine is the major product obtained over Ru-based catalysts,while dibenzylamine is formed preferntially over Pd-based catalysts.Conventional methods are icomplete agreement with th trends observed by high-throughpout techniuqes.Consequently,high-throughput experimentation allows the discovery of new catalysts for a given reaction by-shortenng considerably the catalyst optimisation time.