Oxo-vanadium Schiff base was covalently immobilized onto chemically functionalized graphene oxide (GO) using 3-aminopropyltriethoxysilane as a coupler. The loading of vanadyl Schiff base onto GO nanosheets was confirmed by FTIR, XRD, TGA, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The synthesized heterogeneous catalyst was found to be efficient and selective for the epoxidation of fatty acids and esters using t-butyl hydroperoxide (TBHP) as an oxidant. Interestingly, the immobilized catalyst showed a higher catalytic efficiency than the homogeneous vanadyl acetylacetonate. The recycling experiment results indicated that the catalyst was highly stable and maintained very high activity, and selectivity even after being used for six cycles.
以 3-aminopropyltriethoxysilane 为耦合剂,将
氧化钒席夫碱共价固定在
化学功能化的
氧化
石墨烯(GO)上。傅立叶变换红外光谱(FTIR)、X射线衍射(XRD)、热重分析(TGA)和电感耦合等离子体原子发射光谱(I
CP-
AES)证实了
钒席夫碱在 GO 纳米片上的负载。研究发现,合成的异相
催化剂在以
叔丁基过氧化氢(
TBHP)为
氧化剂进行
脂肪酸和
酯的环
氧化反应时具有高效性和选择性。有趣的是,与均相
乙酰丙酮酸香草
酯相比,固定化
催化剂显示出更高的催化效率。循环实验结果表明,该
催化剂具有很高的稳定性,即使在使用六个循环后仍能保持很高的活性和选择性。