Effective and reusable microcrystalline cellulosic Salen complexes for epoxidation of alpha-pinene

2,3-Epoxypinane, one of the alpha-pinene derivatives, has great economic value. Among the catalyst systems for the epoxidation of alpha-pinene, Salen transition metal complexes have shown exceptional catalytic activities, yet their reusability was a major problem. Herein, for the first time, we developed a heterogeneous microcrystalline cellulosic Salen complex using a facile method. Compared with some catalytic systems, the complex displayed superior catalytic activities in the epoxidation of alpha-pinene. Moreover, the key advantage is cellulose, the most abundant regenerable biopolymer in accordance with the requirements of green chemistry, which has been employed to synthesize a Salen complex. The reusability of the catalyst and different oxidant systems were also investigated in detail. The results demonstrated that the catalyst maintains excellent catalytic activity and selectivity after being used six times when using O-2 and the co-oxidant. These interesting results unveil the potential of the cellulosic Salen complex for heterogeneous catalytic reactions.