Beneficial Micro Reactor Properties for Ugi Reactions

Concerning the information given above, the defined setting of residence times is an aspect making the use of micro reactors attractive [16]. This refers in particular to the individual residence times between the multiple injections. This allows an individual development of the single reactions one after the other. 

Micro reactors allow the sequential injection of the reaction partners, rather than introducing them in one step. By this means, the course of the reaction, in particular concerning the dynamic evolution of the concentration of reactants, may be changed. It is hoped that this may impact on selectivity. 

Apart from such process optimization issues, it may be desired to conduct combinatorial screening in micro channels. Here, specific micro-channel geometries for both liquid serial [110] and parallel [23] screening in organic chemistry have already been described. 

The possibility of isothermal processing in micro reactors may allow exothermic Ugi reactions to be conducted at room temperature rather than needing cooling much below ambient [25]. 

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