Superbase/cellulose: an environmentally benign catalyst for chemical fixation of carbon dioxide into cyclic carbonates†
An environmentally benign catalytic system consisting of 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) and cellulose was developed for CO2 chemical fixation with epoxides under metal-free and halide-free conditions. Due to the dual roles played by DBU and cellulose on the activations of CO2 and epoxide, the reaction could be performed with high activity and selectivity. A possible catalytic cycle for the hydrogen bond assisted ring-opening of epoxide and the activation of CO2 induced by DBU was proposed. The process herein represents a simple, ecologically safe and efficient route for CO2 chemical fixation into high value chemicals.