Abstract
The first plasma-assisted immobilization of an organocatalyst, namely a bifunctional phosphonium salt in an amorphous hydrogenated carbon coating, is reported. This method makes the requirement for prefunctionalized supports redundant. The immobilized catalyst was characterized by solid-state (13) C and (31) P NMR spectroscopy, SEM, and energy-dispersive X-ray spectroscopy. The immobilized catalyst (1 mol %) was employed in the synthesis of cyclic carbonates from epoxides and CO(2) . Notably, the efficiency of the plasma-treated catalyst on SiO(2) was higher than those of the SiO(2) support impregnated with the catalyst and even the homogeneous counterpart. After optimization of the reaction conditions, 13 terminal and four internal epoxides were converted with CO(2) to the respective cyclic carbonates in yields of up to 99 %. Furthermore, the possibility to recycle the immobilized catalyst was evaluated. Even though the catalyst could be reused, the yields gradually decreased from the third run. However, this is the first example of the recycling of a plasma-immobilized catalyst, which opens new possibilities in the recovery and reuse of catalysts.