Phosphotungstic acid encapsulated in the mesocages of amine-functionalized metal–organic frameworks for catalytic oxidative desulfurization

Abstract

Highly dispersed Keggin-type phosphotungstic acid (H₃PW₁₂O₄₀, PTA) encapsulated in the mesocages of amine-functionalized metal–organic frameworks MIL-101(Cr)-NH₂ has been prepared by an anion-exchange method. PTA anions (PW₁₂O₄₀³⁻) are stabilized in the mesocages via the electrostatic interaction with amino groups of the MIL-101(Cr)-NH₂. The obtained catalyst (denoted PTA@MIL-101(Cr)-NH₂) exhibits high catalytic activity in the extractive and catalytic oxidative desulfurization (ECODS) system under mild conditions. Moreover, it can be easily recovered and recycled several times without leaching and loss of activity.