Direct synthesis of cyclic carbonates from olefins and CO2: Single- or multi-component catalytic systems via epoxide or halohydrin intermediate

Ionic Liquids in Metal, Photo-, Electro-, and (Bio) Catalysis

Ionic liquids (ILs) have unique physicochemical properties that make them advantageous for catalysis, such as low vapor pressure, non-flammability, high thermal and chemical stabilities, and the ability to enhance the activity and stability of (bio)catalysts. ILs can improve the efficiency, selectivity, and sustainability of bio(transformations) by acting as activators of enzymes, selectively dissolving substrates and products, and reducing toxicity. They can also be recycled and reused multiple times without losing their effectiveness. ILs based on imidazolium cation are preferred for structural organization aspects, with a semiorganized layer surrounding the catalyst. ILs act as a container, providing a confined space that allows modulation of electronic and geometric effects, miscibility of reactants and products, and residence time of species. ILs can stabilize ionic and radical species and control the catalytic activity of dynamic processes. Supported IL phase (SILP) derivatives and polymeric ILs (PILs) are good options for molecular engineering of greener catalytic processes. The major factors governing metal, photo-, electro-, and biocatalysts in ILs are discussed in detail based on the vast literature available over the past two and a half decades. Catalytic reactions, ranging from hydrogenation and cross-coupling to oxidations, promoted by homogeneous and heterogeneous catalysts in both single and multiphase conditions, are extensively reviewed and discussed considering the knowledge accumulated until now.

Fe(III)-Anchored Porphyrin-Based Nanoporous Covalent Organic Frameworks for Green Synthesis of Cyclic Carbonates from Olefins and CO2 under Atmospheric Pressure Conditions

The utilization of carbon dioxide (CO2) as a C1 source coupled with olefins, readily accessible feedstocks, offers dual advantages of mitigating atmospheric carbon dioxide and green synthesis of valuable chemicals. In this regard, herein we demonstrate the application of Fe(III)-anchored porphyrin-based covalent organic framework (P-COF) as a promising recyclable catalyst for one-step generation of cyclic carbonates (CCs), value-added commodity chemicals from olefins and CO2, under mild atmospheric pressure conditions. Moreover, this one-pot synthesis was applied to transform various olefins (aliphatic and aromatic) into the corresponding CCs in good yield and selectivity. In addition, the Fe(III)@P-COF showed good recyclability and durability for multiple reuse cycles without losing its catalytic activity. Notably, this one-step synthesis strategy presents an eco-friendly, atom-economic alternative to the conventional two-step process requiring epoxides. This work represents a rare demonstration of porphyrin COF-catalyzed one-pot CC synthesis by utilizing readily available olefins at atmospheric pressure of carbon dioxide.

Recent Achievements in the Synthesis of Cyclic Carbonates from Olefins and CO2: The Rational Design of the Homogeneous and Heterogeneous Catalytic System

With the consumption of fossil fuels, the level of CO2 in the atmosphere is growing rapidly, which leads to global warming. Hence, the chemical conversion of CO2 into high value-added products is one of the most important approaches to reducing CO2 emissions. Due to being simple, inexpensive and environmentally friendly, the direct synthesis of cyclic carbonates from olefins and CO2 is a promising project for industrial application. In this review, we discuss the design of the homogeneous and heterogeneous catalytic system for the synthesis of cyclic carbonates from the reaction of olefins and CO2. Usually, the catalyst contains the epoxidation active site and the cycloaddition active site, which could achieve the oxidation of oleifins and the CO2-insert, respectively. This review will provide a comprehensive overview of the direct synthesis of cyclic carbonates from olefins and CO2 catalyzed by homogeneous and heterogeneous catalysts. The focus mainly lies on the rational fabrication of multifunctional catalysts, and provides a new perspective for the design of catalysts.