- One-pot direct conversion of levulinic acid into high-yield valeric acid over a highly stable bimetallic Nb-Cu/Zr-doped porous silica catalyst
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The direct conversion of levulinic acid (LA) to valeric biofuel is highly promising for the development of biorefineries. Herein, LA is converted into valeric acid (VA) via one-pot direct cascade conversion over non-noble metal-based Nb-doped Cu on Zr-doped porous silica (Nb-Cu/ZPS). Under mild reaction conditions (150 °C and 3.0 MPa H2 for 4 h), LA was completely converted into VA in high yield (99.8%) in aqueous medium with a high turnover frequency of 0.038 h-1. The Lewis acid sites of ZPS enhanced the adsorption of LA on the catalyst surface, and both the Lewis and Br?nsted acidity associated with Nb2O5 and the metallic Cu0 sites promoted catalysis of the cascade hydrogenation, ring cyclization, ring-opening, and hydrogenation reactions to produce VA from LA. The bimetallic Nb-Cu/ZPS catalyst was also effective for the conversion of VA into various valeric esters in C1-C5 alcohol media. The presence of Nb2O5 effectively suppressed metal leaching and coke formation, which are serious issues in the liquid-phase conversion of highly acidic LA during the reaction. The catalyst could be used for up to five consecutive cycles with marginal loss of activity, even without catalyst re-activation.
- Karanwal, Neha,Verma, Deepak,Butolia, Paresh,Kim, Seung Min,Kim, Jaehoon
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supporting information
p. 766 - 787
(2020/02/25)
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- Isomerisation of ω-hydroxyalkenes under hydroxycarbonylation conditions in palladium catalysed aqueous phase systems
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The ω-hydroxyolefins 3-buten-1-ol, 3-buten-1-methyl-1-ol and 4-penten-1-ol were subjected to hydroxycarbonylation conditions in water in the presence of PdCl2(PhCN)2 and 4-8 equiv. of water soluble tris(3-sodiumsulfonatophenyl)phosphine (TPPTS), or N-bis(N′,N′-diethyl-2-aminoethyl)-4-aminomethylphenyl-diphenylphosphine (N3P). Under conditions of high conversion, the olefins primarily undergo isomerisation through a chain walking mechanism with selectivities for aldehyde ranging from 65% to 98%, with the lower values for longer chain alcohols. The lactones formed as the minor product are almost exclusively branched, indicating that in the first step 2,1-insertion is strongly favoured over 1,2-insertion. In the N3P system also linear lactone is produced at lower conversion. Running the reaction in D2O produces multiple deuterium incorporation in all positions of the carbon chain. A mechanism is discussed.
- Ionescu, Adriana,Ruppel, Markus,Wendt, Ola F.
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p. 3806 - 3815
(2007/10/03)
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- A VERSATILE SYNTHESIS OF 3-SUBSTITUTED 5-ALKYL BUTYROLACTONES VIA DYOTROPIC REARRANGEMENT
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Substituted acetic acid dianions are convertable to 3,5-disubstituted butyrolactones, employing a dyotropic rearrangement as the key step.
- Black, T. Howard,Fields, John D.
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p. 125 - 130
(2007/10/02)
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- Studies on New Synthetic Pathways to Δα,β-Butenolides from α-Methylbutanolides. II. Electrolytic Oxidation of Simple α-Carboxy-α-methylbutanolides
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A new approach to the synthesis of Δα,β-butenolides from γ-butanolides by means of the electrolytic oxidation of α-carboxy-α,γ-dimethyl-γ-butyrolactone (3b) and its α-carboxy-α-methyl analog (3d) resulted in predominant formation of the endocyc
- Kawamata, Takeshi,Inayama, Seiichi,Sata, Kazuko
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p. 277 - 281
(2007/10/02)
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