Triethanolamine/KI: A Multifunctional Catalyst for CO₂ Activation and Conversion with Epoxides into Cyclic Carbonates

Abstract

A catalytic system of triethanolamine/potassium iodide (KI) was proved to be efficient for the chemical fixation of CO₂ with epoxide. It was found that triethanolamine with dual function could activate both CO₂ and epoxides. Effects of parameters such as catalyst molar ratio and amount, reaction time, pressure, and temperature were studied systematically. As a result, 99% propylene oxide conversion as well as 99% propylene carbonate selectivity could be obtained under the optimal reaction condition. Furthermore, the catalyst was found to be applicable to a variety of terminal epoxides, providing the corresponding cyclic carbonates in good yields and selectivity. Moreover, the catalyst could be reused five times without loss of activity. This work presents an example of a cheap and efficient catalyst for the chemical fixation of CO₂ to high-value chemicals, which could help to improve the catalytic efficiency and decrease cost of products for larger applications.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]

GRAPHICAL ABSTRACT

Keywords:

• Carbon dioxide
• chemical fixation
• cyclic carbonates
• KI
• triethanolamine

ACKNOWLEDGMENTS

The authors acknowledge Suojiang Zhang for his contributions to this work. The authors are grateful for the financial support provided by National Basic Research Program of China (973 Program, 2009CB219901) and National Natural Science Foundation of China (21006117 and 20936005).

Notes

^a Reaction condition: PO (14.3 mmol), amine (1 mol%), metal halide (1 mol%), 110 °C, 2 MPa, 1 h.

^b Determined by GC/GC-MS.

^c Catalyst amount (8 wt%).

Note. Reaction condition: substrate (14.3 mmol), TEA (0.142 mmol), KI (0.145 mmol), 120 °C, 2 MPa.