Multi-objective Bayesian optimisation using q-Noisy Expected Hypervolume Improvement (qNEHVI) for Schotten-Baumann reaction

Amide bond formation is one of the most prevalent reactions in pharmaceutical industry, among which the Schotten-Baumann reaction has attracted attention as a potential green amide formation approach. However, the use of water in the reaction system often causes undesired hydrolysis and can generate a multiphase system. This makes the reaction space complex and challenging to find the optimal conditions. In this study, a Schotten-Baumann reaction was studied in continuous flow and was optimised with two objectives using a Bayesian optimisation algorithm based on the q-Noisy Expected Hypervolume Improvement (qNEHVI) acquisition function. The algorithm guided the experiment design over a range of electrophiles, equivalents, solvents and flow rates, and was able to identify the Pareto front of optimal solutions efficiently. Based on the optimisation results, reaction under flow and batch conditions were compared; undesired hydrolysis was suppressed successfully using the flow conditions. Finally, the relationship between solvent and flow rate was discussed to gain more insights into this reaction

Mass Transfer and Droplet Behaviors in Liquid-Liquid Extraction Process Based on Multi-Scale Perspective: A Review

Liquid-liquid extraction is an important separation technology in the chemical industry, and its separation efficiency depends on thermodynamics (two-phase equilibrium), hydrodynamics (two-phase mixing and contact), and mass transfer (molecular diffusion). For hydrodynamics, the dispersion size of droplets reflects the mixing of two phases and determines the mass transfer contact area of the two phases. Therefore, a deep understanding of the droplet dispersion mechanism can help guide process intensification. The mass transfer and droplet behaviors in the liquid-liquid extraction process are reviewed based on three scales: equipment, droplets, and the interface between two liquids. Studies on the interaction between mass transfer and other performance parameters in extraction equipment as well as liquid-liquid two-phase flow models are reviewed at the equipment scale. The behaviors of droplet breakage and coalescence and the kernel function of the population balance equation are reviewed at the droplet scale. Studies on dynamic interfacial tension and interaction between interfaces are reviewed at the interface scale. Finally, the connection among each scale is summarized, the existing problems are analyzed, and some future research directions are proposed in the last section

Multi-objective Bayesian optimisation using <i>q</i>-noisy expected hypervolume improvement (<i>q</i>NEHVI) for the Schotten–Baumann reaction

Multi-objective Bayesian optimisation allows for finding trade-off solutions of the Schotten–Baumann reaction in a continuous flow. The effect of mixing efficiency on the fast reaction results in the complexity of the reaction space.</jats:p