Optimal Addition Profiles to Control Reactivity and Selectivity of Catalytic Reactions

The final outcome of a chemical reaction depends on several parameters such as the temperature, the solvent and the concentration of reactants and catalyst. These parameters are routinely screened by modifying the initial reaction conditions to obtain the best outcome of the reaction. However, some of these parameters, for example the concentration of reactants and active catalyst, change during the course of the reaction. Thus, the optimal values for these concentrations also change during the course of the reaction. We can correct the concentration of reactants and catalysts by adding them continuously during the reaction. Unfortunately, finding the optimal rate of addition for each time of the reaction is much more complicated than finding the optimal concentration at the beginning of the reaction.

This project will elucidate the best rate of addition of reagents for three different kinds of crucially important catalytic reactions. We plan to do this by applying different strategies, which then may be ultimately applied to other reactions. Some of these strategies will use the knowledge derived from mechanistic studies to identify the concentrations that most affect the final result of the reaction and their optimal values. When possible, we will use the information of modern in situ reaction monitoring tools to instantaneously modulate the rate of addition, which will allow us to find the best rate of addition very quickly. For more challenging reactions, we have proposed a more conservative approach that analyses the behaviour of the reaction by sections. This approximation is more laborious and requires a larger number of experiments, but it can be generally applied to any reaction regardless of its intrinsic complications.

The final stage of study for each reaction aims to analyse the possibility of using the best addition profiles on large scale reactions. To do this, we will test how robust are the optimal addition profiles to the variation of different parameters such as the accuracy in the rate of the addition, the scale of the reaction or the stirring rate.

Ultimately, this project will convert cutting-edge catalytic processes developed in academia, which are unfit for industrial purposes, to useful processes for the manufacture of products such as pharmaceuticals and advanced materials.

The proposed project aims to improve the efficiency of catalytic reactions with a simple solution, the variable addition of some of the reaction components. This possibility is usually overlooked in the catalysis field and by exploiting it we will improve the outcome of the overall processes without having to change the quantity or the chemical nature of the reactants or catalysts. Therefore, this project should enhance the impact of catalytic reactions developed in academia and facilitate their translation into industrial processes. Also, it will make more competitive some of the expensive catalytic processes currently run industrially.

The potential improvement includes more selective processes and higher turnover numbers and turnover frequencies. This will lead to more environmentally sustainable reactions because it will reduce waste and potentially even reduce the amount of catalyst required to complete a reaction. Also, the reduction of expensive catalysts and/or potentially reaction times will increase the economic benefits of catalytic reactions and therefore contribute to more competitive chemical processes.

The project involves the implementation of an engineering solution using the basic chemical knowledge derived from detailed mechanistic studies. Therefore, the postdoctoral researcher will complement their training in synthetic chemistry with skills in reaction monitoring, mechanistic understanding and engineering design of reactions. Those skills are much appreciated in industrial process chemistry groups because they fill the current gap between pure synthetics chemists and engineers.