Recent Applications of Propylene Carbonate as a Solvent in Sustainable Organic Synthesis.

Solvents are essential components for organic synthesis and are widely used across various industries. However, conventional solvents are frequently toxic volatile organic compounds (VOCs) that contribute significantly to waste generation and environmental pollution. This has driven the need to develop sustainable alternatives that maintain efficacy without the associated hazardous properties. Propylene carbonate (PC) has emerged as a promising green alternative for sustainable organic synthesis. As a polar aprotic solvent with similar physicochemical properties to acetonitrile and acetone, PC has been shown to afford high yields and selectivities comparable to those of traditional solvents in a wide range of synthetic transformations. It possesses favourable characteristics, such as low toxicity, high dielectric constant and solvation capacity, biodegradability and low vapour pressure. High thermal stability provides significant capacity for reusability across multiple reaction cycles with minimal loss of efficiency, a crucial feature for reaction scale-up. Moreover, PC can be readily prepared from propylene oxide and carbon dioxide, an abundant waste greenhouse gas, in a 100% atom-economical process. With an increasing number of reports on the topic, this paper presents an updated review of both the preparation and applications of PC, addressing methodological advances and new transformations.