Efficient Oxidative Desulfurization Processes Using Polyoxomolybdate Based Catalysts

Abstract

This work proposes an efficient desulfurization system to produce low sulfur diesel under sustainable and moderate experimental conditions. Treatment of a real diesel with a sulfur content of 2300 ppm led to 80% desulfurization after 2 h. The processes used conciliate liquid-liquid extraction and sulfur oxidative catalysis. The catalytic performance of the commercial Keggin-polyoxomolybdate H 3 [PMo 12 O 40 ] (PMo 12) was strategically increased by simple cation exchange, using a long carbon chain (ODAPMo 12 , ODA = CH 3 (CH 2) 17 (CH 3) 3 N), and by its incorporation into the Metal-Organic Framework (MOF) NH 2-MIL-101(Cr), forming a new active heterogeneous PMo 12 @MOF composite catalyst. Activity of both catalysts was similar; however, the solid catalyst could be easily recovered and reused, and its stability was confirmed after multiple continuous cycles.

Metal‐Organic Framework‐Based Catalysts for Oxidative Desulfurization

“…Amine‐functionalized MOFs have been used for the efficient immobilization of POMs through electrostatic interaction in order to overcome leaching issues. Some example include PTA@NH 2 ‐MIL‐101(Cr), PTA@NH 2 ‐MIL‐101(Al) and phosphomolybdic acid PMA@NH 2 ‐MIL‐101(Cr) . In particular, the PMA@NH 2 ‐MIL‐101(Cr) showed high efficiency in the desulfurization of multicomponent model and real diesel using H 2 O 2 as oxidant.…”

An Effective Hybrid Heterogeneous Catalyst to Desulfurize Diesel: Peroxotungstate@Metal–Organic Framework

“…In fact, various other polyoxometalates were previously incorporated into the porous MIL-101(Cr) structure, and these have been used as heterogeneous catalysts in ECODS systems. Most of these polyoxometalates are also derivated from the Keggin structure, like the Venturello PW 4 compound: trivacant-phosphotungstate (PW 9 @ MIL-101(Cr)) [ 39 ], europium-sandwich type (Eu(PW 9 ) 2 @MIL-101(Cr)) [ 18 ], terbium-sandwich type (Tb(PW 9 ) 2 @ MIL-101(Cr)) [ 40 ], Keggin-type phosphotungstate (PW 12 @ MIL-101(Cr)) [ 41 ], phosphomolybdate (PMo 12 @MIL-101(Cr)) [ 42 ] and zinc-substituted phosphotungstate (PW 11 Zn@MIL-101(Cr)) [ 43 ]. Using these catalysts, complete desulfurization was achieved under similar experimental conditions, for a reaction time higher than 2 h using model diesel with similar sulfur content or even with less sulfur components and a total sulfur concentration not higher than 2000 ppm.…”

Heterogenisation of polyoxometalates and other metal-based complexes in metal–organic frameworks: from synthesis to characterisation and applications in catalysis

“…The reactivity difference was again assigned to the difference in electron density on the sulfur atoms. More recently, Balula et al studied the PMo12@NH2-MIL-101(Cr) composite, 71 whereby experiments were conducted on a multi-component model oil containing BT, DBT, 4-MDBT and 4,6-DMDBT dissolved in n- Please do not adjust margins Please do not adjust margins octane (total sulfur concentration: 2000 ppm). After addition of H2O2, PMo12@NH2-MIL-101(Cr) exhibited a conversion yield of ca.…”

“…Lastly, the authors worked on real oil desulfurisation with a 2300 sulfur ppm in a 1:1 (v/v) mixture of MeCN:diesel at 50 °C, leading to a 69% conversion rate. 71 The immobilization of POMs in the iron-based MOF MIL-100(Fe) was also considered for similar catalytic purposes. Wang et al reported in 2017 the use of a PW12@MIL-100(Fe) composite for ODS.…”