Cellulosic Cr(salen) complex as an efficient and recyclable catalyst for copolymerization of SO2 with epoxide.

The search for green catalytic processes for the synthesis of useful polymers and incorporating the waste SO2 in highly-selective pathways become extremely important in the coming years. Herein, cellulose was modified by ethylenediamine, and then synthesized Schiff base with 3,5-di-tert-butyl-2-hydroxybenzaldehyde to immobilize chromium chloride and formed a novel heterogeneous cellulosic Cr(salen)-type catalyst for the first time. The cellulosic Cr(salen)-type catalyst shows high efficiency and recyclability in copolymerization of cyclohexene oxide with SO2. The influence factors such as the molar ratio of the catalyst and cyclohexene oxide, reaction temperature, and reaction time were researched in detail to study the optimal conditions. The copolymer product was characterized by FTIR and 1H NMR for confirming the structure. The possible copolymer mechanism is given, and we believed that the novel cellulosic Cr(salen)-type complex will be used as an efficient catalyst in other chemical reactions.