Microreaction Technology for Synthetic Chemistry

Synthesis of cyclic carbonates from CO2 cycloaddition to bio-based epoxides and glycerol: an overview of recent development

Anthropogenic carbon dioxide (CO₂) emissions contribute significantly to global warming and deplete fossil carbon resources, prompting a shift to bio-based raw materials. The two main technologies for reducing CO₂ emissions are capturing and either storing or utilizing it. However, while capture and storage have high reduction potential, they lack economic feasibility. Conversely, by utilizing the CO₂ captured from streams and air to produce valuable products, it can become an asset and curb greenhouse gas effects. CO₂ is a challenging C1-building block due to its high kinetic inertness and thermodynamic stability, requiring high temperature and pressure conditions and a reactive catalytic system. Nonetheless, cyclic carbonate production by reacting epoxides and CO₂ is a promising green and sustainable chemistry reaction, with enormous potential applications as an electrolyte in lithium-ion batteries, a green solvent, and a monomer in polycarbonate production. This review focuses on the most recent developments in the synthesis of cyclic carbonates from glycerol and bio-based epoxides, as well as efficient methods for chemically transforming CO₂ using flow chemistry and novel reactor designs.

Towards Heterogeneous Catalysis: A Review on Recent Advances of Depositing Nanocatalysts in Continuous-Flow Microreactors

As a promising technology, microreactors have been regarded as a potential candidate for heterogeneous catalytic reactions as they inherently allow the superior advantages of precise flow control, efficient reactant transfer, flexible operation, etc. However, the wide market penetration of microreactors is still facing severe challenges. One of the most important reasons is the preparation of a high-performance catalytic layer in the microreactor because it can directly influence the catalytic activity and stability the reactor and thus the deployment the microreactor technology. Hence, significant progress in depositing nanocatalysts in microreactors has been made in the past decades. Herein, the methods, principles, recent advances, and challenges in the preparation of the catalyst layer in microreactors were presented. A general description of the physicochemical processes of heterogeneous catalytic reactions in microreactors were first introduced. Then, recent advances in catalyst layer preparation in microreactors were systematically summarized. Particular attention was focused on the most common sol-gel method and its latest developments. Some new strategies proposed recently, including bio-inspired electroless deposition and layer-by-layer self-assembly, were also comprehensively discussed. The remaining challenges and future directions of preparing the catalytic layer in microreactors with high performance and low cost were highlighted.

A novel observation platform for determining the micro-dispersion performance in practical reaction systems

A novel observation platform by placing the downstream observation window vertically has been constructed, and the actual micro-dispersion state can be exactly reflected in the observation window.

An intensified chlorination process of 4-nitroaniline in a liquid–liquid microflow system

A strategy of dissolving chlorine gas in 1,2-dichloroethane for a liquid–liquid two-phase chlorination reaction was proposed to resolve the problems of low efficiency, strong corrosivity, and poor controllability of gas–liquid chlorination.