Conversion of levulinic acid to γ-valerolactone over ultra-thin TiO<sub>2</sub> nanosheets decorated with ultrasmall Ru nanoparticle catalysts under mild conditions

Li, Shaopeng; Wang, Yanyan; Yang, Youdi; Chen, Bingfeng; Tai, Jing Lei; Liu, Huizhen; Han, Buxing

doi:10.1039/c8gc03529f

Cited by 58 publications

(32 citation statements)

References 35 publications

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“…Having these POMPs with hierarchical porosity and atomically dispersed active sites in hand, their activities function as single‐site catalysts were then investigated. As an important platform molecule in laboratory and industrial applications, γ‐valerolactone (GVL) has attracted considerable attention . Therefore, the hydrogenation of biomass levulinic acid (LA) to GVL was selected as the first model reaction.…”

Section: Fabrication Of Pomp‐nhc‐m By Direct Knitting With Different mentioning

confidence: 99%

“…It has to be pointed out, there are few reports on Pd‐catalyzed hydrogenation of LA to GVL under hydrogen atmosphere, and good result and enhanced catalytic activity could be achieved by POMP‐NHC‐Pd 2 even at 130 ppm catalyst loadings. Furthermore, other privileged and commercially available catalysts ( 10‐12 ) were also employed in this transformation, only trace to inferior yields were obtained under optimal reaction conditions (Figure a). Although our previously reported self‐supported catalyst 13 also gave a quantitative yield under the identical reaction conditions, a record turnover number (TON) of 1.01 × 10 6 could be achieved by further decreasing the catalyst loading of POMP‐NHC‐Ir 1d to 0.678 ppm (Figure b).…”

Section: Fabrication Of Pomp‐nhc‐m By Direct Knitting With Different mentioning

confidence: 99%

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Hierarchical Porous Organometallic Polymers Fabricated by Direct Knitting: Recyclable Single‐Site Catalysts with Enhanced Activity

et al. 2019

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supported catalysts by simply knitting rigid aromatic ligands via hypercross-linking (Friedel-Crafts reactions) has recently been proposed. [13] After further postmodification/activation, several MCPPs have been successfully developed. [14][15][16][17] However, with postmodification, avoiding the problems, like low density of catalytic sites due to incomplete modification and random/ nonselective metal anchoring, can be difficult. These issues may still lead to low catalytic activity and selectivity, especially in some challenging transformations. [18] In light of N-heterocyclic carbene-metal (NHC-M) complexes can act as robust and viable catalysts in a broad range of reactions, [19][20][21][22][23][24][25][26][27][28] various strategies have been developed for their immobilization. [29,30] Among them, selfsupporting strategy may represent one of the most practical and efficient approaches. [31][32][33][34] It has to be noted that NHC ligands still have to be carefully designed and modified before selfsupporting. Alternatively, the high catalytic activities and robustness of NHC-M complexes make them perfect candidates for direct knitting. To the best of our knowledge, there are only two reported examples on MCPPs in which the NHC ligands are firstly knitted and then coordinated to active metal ions (postmodification approach). [14,15] Direct knitting of NHC-M complexes to fabricate porous organometallic polymers (POMPs) that do not require postmodification/activation is still unknown.Herein, we have designed and prepared a series of unprecedented porous organometallic polymers POMPs-NHC-M 1-3 via direct knitting three types of bis-chelating NHC-M complexes (M = Ir, Pd, and Ru, Figure 1a). Using this facile strategy, which does not require postmodification/activation, 1) the metal active sites are atomically dispersed in the hierarchical porous matrix, and 2) the intrinsic well-defined bis-chelating mode and their molecular catalytic properties are maximally retained, which allows 3) the precise design and control of the immobilized catalysts at the molecular level. The advantages of direct knitting allow the resulting POMPs-NHC-M 1-3 to behave as recyclable solid single-site catalysts and exhibit extremely high catalytic activities in both hydrogenation and dehydrogenation reactions.In light of their robustness toward Friedel-Crafts reaction conditions, bis-chelating NHC-M (Ir, Pd and Ru) complexes 4, 5 and 6, derived from corresponding benzimidazolium salts, [24,25,27] were selected to fabricate POMPs via direct knitting with benzene ( Figure 1a). Concerning the plausible impact Porous organometallic polymers (POMPs) with hierarchical pore structures, high specific surface areas, and atomically dispersed metal (Ir, Pd, Ru) centers are successfully fabricated by a facile one-pot method through direct knitting of diverse N-heterocyclic carbene metal (NHC-M) complexes. These polymers can function as recyclable solid single-site catalysts and exhibit excellent catalytic activity and selectivity in both dehydrogenat...

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Section: Fabrication Of Pomp‐nhc‐m By Direct Knitting With Different mentioning

confidence: 99%

Section: Fabrication Of Pomp‐nhc‐m By Direct Knitting With Different mentioning

confidence: 99%

Hierarchical Porous Organometallic Polymers Fabricated by Direct Knitting: Recyclable Single‐Site Catalysts with Enhanced Activity

et al. 2019

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“…The effect of support should not be neglected. Li S. P. et al (2019) decorated Ru on the ultrathin anatase TiO 2 nanosheets with exposed (001) facets, which proved that the different electronic and surface properties of support can strongly affect the activity of the catalysts. Ru/TiO 2 -n, which contains most (001) planes, showed the highest activity because of the presence of more Ru (0) on the surface.…”

Section: Noble Metal Catalystsmentioning

confidence: 87%

Recent Advances in Aqueous-Phase Catalytic Conversions of Biomass Platform Chemicals Over Heterogeneous Catalysts

Zhang

Wang

et al. 2020

Front. Chem.

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A series of biomass-derived platform molecules, such as glucose, furans, levulinic acid, 5-hydroxymethylfurfural, and acetic acids, can be converted into a variety of value-added chemicals through catalytic transformations that include dehydration, hydrogenation, oxidation, isomerization, reforming, ketonization, and aldol condensation over heterogeneous catalysts. Aqueous-phase processing is an important issue and a great challenge for the heterogeneous catalytic conversion of biobased chemicals due to the high water content of the biomass and the formation of water during the transformation process. In this paper, heterogeneous catalysts that are applicable to the aqueous-phase conversion process of biomass platform chemicals, including noble metal catalysts, non-noble metal catalysts, bimetallic catalysts, metal oxides, and zeolite, are introduced, and a comprehensive evaluation of the catalyst performance, including the catalytic activity, stability, and regeneration performance of different kinds of heterogeneous catalysts, are made. Besides, we highlighted the effect of water on heterogeneous catalysts and the deactivation mechanism in the aqueous phase. Beyond this, several catalytic mechanisms of aqueous-phase conversion over heterogeneous catalysts are summarized in order to help understand the reaction process on the surface of catalysts in the aqueous phase, so as to design targeted catalysts. At last, a prospect of biobased chemicals and fuels is forecasted.

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“…Numerous devotion to improving stabilization of Ru NPs on catalyst supports have been implemented, resulting from the combination of Ru NPs and metal oxide catalyst supports, such as Al 2 O 3 , TiO 2 , ZrO 2 , and heteroatom-doped carbons. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] However, it is still advisable to investigate further the synergetic combination of Ru NPs and catalyst supports to escape from deactivation over subsequent cycles or in continuous flow production.…”

Section: Introductionmentioning

confidence: 99%

“…In heterogeneous‐catalyzed LA hydrogenation reactions, commercial Ru/C catalyst exhibited high catalytic efficiency and deactivated rapidly due to leaching and aggregation. Numerous devotion to improving stabilization of Ru NPs on catalyst supports have been implemented, resulting from the combination of Ru NPs and metal oxide catalyst supports, such as Al 2 O 3 , TiO 2 , ZrO 2 , and heteroatom‐doped carbons [27–43] . However, it is still advisable to investigate further the synergetic combination of Ru NPs and catalyst supports to escape from deactivation over subsequent cycles or in continuous flow production.…”

Section: Introductionmentioning

confidence: 99%

NNN Pincer‐functionalized Porous Organic Polymer Supported Ru(III) as a Heterogeneous Catalyst for Levulinic Acid Hydrogenation to γ‐Valerolactone

et al. 2020

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A novel porous organic polymer that incorporates NNN pincer type of ligand, i. e., 2,6‐Bis(pyrazol‐3‐yl)pyridine, (3‐bpp‐POP) is prepared via solvent‐knitting method. Through the characterizations, 3‐bpp‐POP is demonstrated to possess abundant porous structure, high surface area, and excellent thermal durability. A ruthenium molecular catalyst immobilized on the 3‐bpp‐POP support exhibits substantial catalytic performance for the hydrogenation of LA to GVL with an initial turnover frequency (TOF) of 1680 h−1 and a maximum turnover number (TON) of 14762 over 24 h for LA conversion with selectivities of 91.1 % for GVL and 8.9 % for HPA. The catalyst demonstrated excellent durability during successive recycles without leaching Ru3+, which ascribe to the strong binding of pincer ligand to metal centers.

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Conversion of levulinic acid to γ-valerolactone over ultra-thin TiO₂ nanosheets decorated with ultrasmall Ru nanoparticle catalysts under mild conditions

Abstract: Herein, we successfully loaded Ru nanoparticles onto TiO2 nanosheet catalyst, which could exhibit highly efficient catalytic activity during the conversion of levulinic acid to γ-valerolactone at mild condition.

Cited by 58 publications

References 35 publications

Hierarchical Porous Organometallic Polymers Fabricated by Direct Knitting: Recyclable Single‐Site Catalysts with Enhanced Activity

Hierarchical Porous Organometallic Polymers Fabricated by Direct Knitting: Recyclable Single‐Site Catalysts with Enhanced Activity

Recent Advances in Aqueous-Phase Catalytic Conversions of Biomass Platform Chemicals Over Heterogeneous Catalysts

NNN Pincer‐functionalized Porous Organic Polymer Supported Ru(III) as a Heterogeneous Catalyst for Levulinic Acid Hydrogenation to γ‐Valerolactone

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Conversion of levulinic acid to γ-valerolactone over ultra-thin TiO2 nanosheets decorated with ultrasmall Ru nanoparticle catalysts under mild conditions

Abstract: Herein, we successfully loaded Ru nanoparticles onto TiO2 nanosheet catalyst, which could exhibit highly efficient catalytic activity during the conversion of levulinic acid to γ-valerolactone at mild condition.

Cited by 58 publications

References 35 publications

Hierarchical Porous Organometallic Polymers Fabricated by Direct Knitting: Recyclable Single‐Site Catalysts with Enhanced Activity

Hierarchical Porous Organometallic Polymers Fabricated by Direct Knitting: Recyclable Single‐Site Catalysts with Enhanced Activity

Recent Advances in Aqueous-Phase Catalytic Conversions of Biomass Platform Chemicals Over Heterogeneous Catalysts

NNN Pincer‐functionalized Porous Organic Polymer Supported Ru(III) as a Heterogeneous Catalyst for Levulinic Acid Hydrogenation to γ‐Valerolactone

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Conversion of levulinic acid to γ-valerolactone over ultra-thin TiO₂ nanosheets decorated with ultrasmall Ru nanoparticle catalysts under mild conditions