This invention has applications in the direct conversion of carbon dioxide from waste streams into cyclic carbonates compounds -- economically important compounds used as polar aprotic solvents, battery electrolytes, as well as feedstock for the production of polycarbonates.
The reaction between carbon dioxide and epoxides has been proposed as an environmentally friendly alternative to the conventional manufacturing process of cyclic carbonates, which uses crude oil as a feedstock. Specifically, the direct conversion of carbon dioxide from waste streams into cyclic carbonates using a continuous process could mitigate the polluting effect of facilities like coal power plants while generating an additional revenue stream for operators. However, continuous processing of carbon dioxide to produce cyclic carbonates has been an elusive goal due to the high temperatures, high pressures, and long reaction times associated with conventional reaction schemes. This invention provides a novel organocatalytic method to produce cyclic carbonates from carbon dioxide that overcomes these limitations.
This reaction scheme proposed in this invention is a dual catalyst system utilizing N-bromosuccinimide (NBS) and benzoyl peroxide simultaneously. The combined action of these catalytic compounds allow carbon dioxide to be reacted with terminal epoxides to produce cyclic carbonates with 82% yield within 20 minutes at 120 ℃ and 100 psi. In comparison, the same reactions catalyzed by previously known compounds, such as 4-(dimethylamino)pyridine (DMAP) or 2-bromoquinoline, require reaction time upwards of 6 hours to achieve comparable yields. This dramatic reduction in reaction time makes continuous in-situ processing of carbon dioxide from waste streams such as flue gas a viable proposition.
Shorter reaction times compatible with continuous processing and direct conversion of waste streams
- Lower temperature and pressure improves safety profile