Abstract

An efficient epoxidation catalyst was prepared through the immobilization of Venturello anion, {PO₄[W(O)(O₂)₂]₄}³⁻, onto aminopropyl-modified porous activated carbon (AC). First, the aminopropyl groups were anchored on the surface of AC by silylation with 3-aminopropyltriethoxysilane. Afterwards, electrostatic interaction between Venturello anions and ammonium groups located on the surface of AC produced the final catalyst. FT–IR spectroscopy, CHN elemental analysis, inductively coupled plasma optical emission spectroscopy, energy dispersive X-ray spectroscopy, and nitrogen adsorption–desorption analysis followed with BJH and BET calculations were used to characterize the prepared catalyst. Catalytic activity of the prepared catalyst was explored in epoxidation of different cyclic and terminal olefins with 30% H₂O₂ as green oxidant. The highest conversions were achieved for cyclooctene and cyclohexene due to the localization of higher electron density on their double bonds. The results revealed proper performance of the catalyst in epoxidation reaction with catalyst reusability for at least four times with no decrease in its activity.

中文翻译：

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固定在多孔活性炭表面上的Venturello阴离子作为烯烃环氧化的非均相催化剂

摘要

一种有效的环氧化催化剂是通过Venturello阴离子的固定化制备，{PO ₄ [W（O）（O ₂）₂ ] ₄ } ^3-在氨基丙基改性的多孔活性炭（AC）上。首先，通过用3-氨基丙基三乙氧基硅烷进行甲硅烷基化将氨基丙基固定在AC表面。之后，Ventrollo阴离子与位于AC表面的铵基之间的静电相互作用产生了最终的催化剂。FT-IR光谱，CHN元素分析，电感耦合等离子体发射光谱，能量色散X射线光谱，氮吸附-解吸分析以及BJH和BET计算被用来表征所制备的催化剂。在不同的环状和末端烯烃与30％H ₂ O _2的环氧化中，探讨了制备的催化剂的催化活性。作为绿色氧化剂。环辛烯和环己烯的转化率最高，这是因为较高的电子密度位于其双键上。结果表明，该催化剂在环氧化反应中具有适当的性能，并且催化剂可重复使用至少四次，而其活性没有降低。