Comparative Study of Batch and Continuous Flow Reactors in Selective Hydrogenation of Functional Groups in Organic Compounds: What Is More Effective?

Many research papers describe selective hydrogenation of functional groups, such as nitro groups, carbonyl groups, or unsaturated carbon bonds to obtain fine chemicals or precursors of pharmaceuticals. Quite often, the catalyst performance is investigated in batch or continuous flow reactors without finding advantages and disadvantages of this or that regime. At the same time, the transition from batch processes to continuous flow occurs on the industrial scale. However, the batch process can be preferable for some reactions, in spite of its drawbacks. This review article aims to identify all publications that consider selective hydrogenation of functional groups in organic compounds, both in batch and continuous flow reactors, at the same reaction conditions that allow making conclusions about the benefits of one of the regimes in a particular case.