Production of ultra-deep sulfur-free diesels using a sustainable catalytic system based on UiO-66(Zr)

Granadeiro, Carlos M.; Ribeiro, Susana; Karmaoui, Mohamed; Valença, Rita; Ribeiro, Jorge C.; Castro, Balt­azar de; Cunha-Silva, Luı́s; Balula, Salete S.

doi:10.1039/c5cc03958d

Cited by 115 publications

(73 citation statements)

References 43 publications

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“…Different UiO-66 catalysts were prepared with or without crystallization agent (HCl) and/or a modulator (trifluoroacetic acid) to alter purposely the final structural and chemical properties of the materials and the activity of this series of defective UiO-66 was studied in the oxidative desulfurization reaction. [37] Better desulfurization performance was observed in the oxidation of dibenzothiophene using hydrogen peroxide in acetonitrile for UiO-66 (nonmodulated procedure and without the use of HCl). In contrast, poor activity was observed for the more crystalline samples, namely, UiO-66 HCl and UiO-66 HCl,mod for the same reaction under identical conditions.…”

Section: Nodes As Redox Sitesmentioning

confidence: 99%

Engineering UiO‐66 Metal Organic Framework for Heterogeneous Catalysis

et al. 2019

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frameworks (MOFs) are currently attracting considerable attention as heterogeneous catalysts at moderate temperatures, mainly for liquid-phase reactions. Since structural stability is one of the major concerns for the use of MOFs in catalysis, particularly considering that frequently some of the reported MOF materials are very unstable, the interest in this area has been focused on those MOFs exhibiting the highest structural robustness, UiO-66 being among the most widely used. Two introductory sections deal with the synthesis, structure and main properties of UiO-66, including its remarkable thermal (up to 350°C) and chemical (aqueous solution in a wide pH range) stability. The main body of the review summarizes those examples of using UiO-66 in catalysis grouped according to the nature of the active sites, starting with the use of UiO-66 as Lewis acids. In this section, emphasis has been made in the recent strategies to create structural defects in a controlled way that generate Lewis acidity. Other sections cover examples illustrating substituted terephthalate as active sites and the evidence that there is a synergy between acid and basic sites in close proximity that make some of these UiO-66 with substituents at the linker to act as dual acid-base catalysts. Other sections are focused on the use of UiO-66 as hosts of metal nanoparticles, metal oxides and other host, remarking the influence that the nature of UiO-66 and the possible presence of substituents in the framework play on the activity of the incorporated guest. The last section summarizes the current state of the art in the use of UiO-66 in catalysis and provides our views on future developments regarding the application of UiO-66 in industrial processes.

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Section: Nodes As Redox Sitesmentioning

confidence: 99%

Engineering UiO‐66 Metal Organic Framework for Heterogeneous Catalysis

et al. 2019

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“…It is known that approximately 54 %o fD BT can be extracted by acetonitrile in the studied reaction system. [32,36] If UiO-66-H was used as catalyst, only 58.6 %D BT can be removed. Interestingly, Ti-UiO-66-He xhibited much higherO DS activity than UiO-66-H.…”

Section: Catalytic Activitymentioning

confidence: 99%

Enhancement of Oxidative Desulfurization Performance over UiO‐66(Zr) by Titanium Ion Exchange

et al. 2017

ChemPhysChem

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Oxidative desulfurization is considered to be one of the most promising methods for producing ultra-low-sulfur fuels because it can effectively remove refractory sulfur-containing aromatic compounds under mild conditions. In this work, the oxidative desulfurization performance over UiO-66(Zr) is greatly enhanced by Ti ion exchange. This strategy is not only efficient for UiO-66(Zr) with crystal defects but also for UiO-66(Zr) with high crystallinity. In particular, the performance of UiO-66(Zr) with high crystallinity in the oxidative desulfurization of dibenzothiophene can be improved more than 11-fold, which can be mainly attributed to the introduction of active Ti sites.

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“…[21] Thereaction is known to be catalyzed by ar ange of Ti-containing materials including hierarchical titanium silicates and MIL-125, but also by other MOFs such as the vanadium-based MIL-47 and the zirconium-based UiO-66. [22][23][24] Reaction was performed with 15 mol %c atalyst and 2.5 equiv. tert-butylhydroperoxide (TBHP) as oxidant in toluene at 60 8 8C.…”

Section: Angewandte Chemiementioning

confidence: 99%

A Titanium(IV)‐Based Metal–Organic Framework Featuring Defect‐Rich Ti‐O Sheets as an Oxidative Desulfurization Catalyst

et al. 2019

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While titanium-based metal-organic frameworks (MOFs) have been widely studied for their (photo)catalytic potential, only af ew Ti IV MOFs have been reported owing to the high reactivity of the employed titanium precursors.T he synthesis of COK-47 is now presented, the first Ti carboxylate MOF based on sheets of Ti IV O 6 octahedra, whichc an be synthesized with ar ange of different linkers.C OK-47 can be synthesized as an inherently defective nanoparticulate material, rendering it ah ighly efficient catalyst for the oxidation of thiophenes.I ts structure was determined by continuous rotation electron diffraction and studied in depth by X-rayt otal scattering, EXAFS,a nd solid-state NMR. Furthermore,i ts photoactivity was investigated by electron paramagnetic resonance and demonstrated by catalytic photodegradation of rhodamine 6G.Metal-organic frameworks (MOFs) are crystalline coordination polymers constructed through the directional bonding of metal ions and polydentate organic linkers,o ften forming porous networks.O ver the last decade,M OFs have increas-ingly been investigated because of their highly tunable porosity and large density of accessible metal sites,m aking them suitable for catalytic applications,g as separation, and storage. [1][2][3][4] However,d eveloping chemically and thermally robust materials remains challenging.This has fueled interest in using oxophilic Group 4e lements such as Zr IV and Ti IV , which tend to form stable structures based on their strong metal-carboxylate bonds.Inthis context, numerous Zr MOFs have been reported, [5] but only 15 Ti IV MOFs have been described to date,ofwhich 5inthe past year, even though Ti precursors are cheap,n on-toxic,a nd Ti MOFs tend to show good redox activity and photoactivity. [6][7][8] Them uch higher tendency of Ti IV to form ill-defined oxyhydroxides lies at the basis of this discrepancyand makes the synthesis of Ti MOFs extremely challenging. [9,10] Themajority of the Ti MOFs reported to date contain Ti À Oclusters as secondary building unit (SBU), but very recently afew chain-based Ti MOFs were reported:DGIST-1, Ti-TBP, and MIL-177-HT. [7,11,12] Thed imensionality of the SBU greatly influences MOF properties,a swas exemplified by photoconductivity measurements on the chain-based MIL-177-HT and its cluster-based counterpart, MIL-177-LT. The latter showed negligible conductivity whereas MIL-177-HT features similar conductivity as nano-sized TiO 2 ,w hich demonstrates the benefit of increasing the SBU dimensionality to achieve bulk oxide properties.Herein, we report an ew,p hotoactive,T i IV 4,4'-biphenyldicarboxylate (bpdc 2À )M OF,t ermed COK-47, featuring ac omplex layer of TiO 6 octahedra as 2D SBU.I nterestingly, acareful choice of synthetic conditions allows for control over particle morphology and defect content, making COK-47 S (S = small particle) ah ighly active catalyst, for example towards the oxidation of dibenzothiophene.S everal isoreticular analogues with for instance terephthalate or 2,2'-bipyridine-5,5'-dicarboxylate linkers we...

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Production of ultra-deep sulfur-free diesels using a sustainable catalytic system based on UiO-66(Zr)

Abstract: The porous metal-organic framework UiO-66(Zr) obtained via non modulated synthesis, has revealed to be a notable heterogeneous catalyst, enabling extremely fast and very efficient desulfurization of a multicomponent model diesel and also a real diesel fuel.

Cited by 115 publications

References 43 publications

Engineering UiO‐66 Metal Organic Framework for Heterogeneous Catalysis

Engineering UiO‐66 Metal Organic Framework for Heterogeneous Catalysis

Enhancement of Oxidative Desulfurization Performance over UiO‐66(Zr) by Titanium Ion Exchange

A Titanium(IV)‐Based Metal–Organic Framework Featuring Defect‐Rich Ti‐O Sheets as an Oxidative Desulfurization Catalyst

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