617-35-6Relevant articles and documents
Ruthenium-catalyzed glycine-selective oxidative backbone modification of peptides
Murahashi, Shun-Ichi,Mitani, Akira,Kitao, Kyuuhei
, p. 10245 - 10249 (2000)
The reaction of N,C-protected peptides containing glycine residues with peracetic acid in the presence of a ruthenium catalyst gives α-ketoamides derived from the oxidation at the C(α) position of the glycine residues selectively. (C) 2000 Elsevier Science Ltd.
Oxidative dehydrogenation of ethyl lactate over nanocarbon catalysts: Effect of oxygen functionalities and defects
Wang, Dan,Liu, Wei,Xie, Zailai,Tian, Siyuan,Su, Dangsheng,Qi, Wei
, p. 96 - 101 (2020)
Pyruvic acid and pyruvate derivatives are important chemical intermediates which are normally produced using metal-based catalytic materials that could cause serious environmental problems. In the present work, renewable nanocarbon catalysts are applied in this system, and a solvent free and highly selective oxidative dehydrogenation of ethyl lactate (EL) process is achieved to produce ethyl pyruvate (EP) under mild reaction conditions. Chemical titration results provide direct evidence that ketonic carbonyl groups on nanocarbon are active sites for this reaction. Raman, XPS and model catalyst experimental results have shown that there is a dynamic transformation between defects and oxygen functionalities during the catalytic reactions. The reaction pathway is revealed via kinetic analysis, which may shed light on the rational design of carbon catalysts and their potential catalytic applications in the field of fine chemical productions.
Highly Selective Oxidation of Ethyl Lactate to Ethyl Pyruvate Catalyzed by Mesoporous Vanadia-Titania
Zhang, Wei,Innocenti, Giada,Oulego, Paula,Gitis, Vitaly,Wu, Haihong,Ensing, Bernd,Cavani, Fabrizio,Rothenberg, Gadi,Shiju, N. Raveendran
, p. 2365 - 2374 (2018)
The direct oxidative dehydrogenation of lactates with molecular oxygen is a "greener" alternative for producing pyruvates. Here we report a one-pot synthesis of mesoporous vanadia-titania (VTN), acting as highly efficient and recyclable catalysts for the conversion of ethyl lactate to ethyl pyruvate. These VTN materials feature high surface areas, large pore volumes, and high densities of isolated vanadium species, which can expose the active sites and facilitate the mass transport. In comparison to homogeneous vanadium complexes and VOx/TiO2 prepared by impregnation, the meso-VTN catalysts showed superior activity, selectivity, and stability in the aerobic oxidation of ethyl lactate to ethyl pyruvate. We also studied the effect of various vanadium precursors, which revealed that the vanadium-induced phase transition of meso-VTN from anatase to rutile depends strongly on the vanadium precursor. NH4VO3 was found to be the optimal vanadium precursor, forming more monomeric vanadium species. V4+ as the major valence state was incorporated into the lattice of the NH4VO3-derived VTN material, yielding more V4+-O-Ti bonds in the anatase-dominant structure. In situ DRIFT spectroscopy and density functional theory calculations show that V4+-O-Ti bonds are responsible for the dissociation of ethyl lactate over VTN catalysts and for further activation of the deprotonation of β-hydrogen. Molecular oxygen can replenish the surface oxygen to regenerate the V4+-O-Ti bonds.
Vanadium-based highly active and selective catalysts for oxidative dehydrogenation of ethyl lactate to ethyl pyruvate
Doke, Dhananjay S.,Khomane, Sonali B.,Pandhare, Swati L.,Dongare, Mohan K.,Dumeignil, Franck,Umbarkar, Shubhangi B.
, (2019)
Pyruvates are important intermediates for various bioactive and pharmaceutical molecules. Synthesis of pyruvates is challenging due to low selectivity, as the pyruvates are prone to polymerisation. In the present work, oxidative dehydrogenation of ethyl lactate to ethyl pyruvate was carried out under very mild conditions using vanadium-based homogeneous and heterogeneous catalysts in the presence of aqueous t-butyl hydroperoxide as an oxidant. Homogenous vanadium-based catalyst, VO(acac)2 in acetonitrile solvent, gave excellent conversion (upto 83%) with 100% selectivity to ethyl pyruvate at room temperature. However, the heterogeneous catalyst, V2O5 exhibited very high activity for oxidative dehydrogenation of ethyl lactate only at higher temperature (80 °C). At higher temperature, significant TBHP decomposition was observed if all TBHP was added in one lot. In case of ethyl lactate dehydrogenation using V2O5 catalyst at 80 °C with two equivalents TBHP, 60% ethyl lactate conversion with 100% TBHP conversions were observed after 5 h when all TBHP was added initially in the reaction mixture. However, the ethyl lactate conversion at 80 °C, after 5 h increased to 72% when the same amount of TBHP was added batch wise over a period of 4 h, indicating improved conversion of TBHP to ethyl pyruvate. The heterogeneous catalyst, V2O5 exhibited up to 98% conversion with 100% ethyl pyruvate selectivity at 80 °C after 10 h with 3 equivalent TBHP added batch wise. The homogeneous catalyst could not be reused while V2O5 could be successfully recycled five times without catalytic performances loss. Oxidation proceeds by radical mechanism, as proved by experiment with radical scavenger.
Selective Aerobic Oxidation of Lactate to Pyruvate Catalyzed by Vanadium-Nitrogen-Doped Carbon Nanosheets
Zhang, Wei,Oulego, Paula,Slot, Thierry K.,Rothenberg, Gadi,Shiju, N. Raveendran
, p. 3381 - 3387 (2019)
The catalytic oxidative dehydrogenation of lactates with molecular oxygen is a promising yet challenging route for producing high-value pyruvates from biomass. Here we report a simple synthetic strategy for preparing nitrogen-doped carbon nanosheets (NCNs) starting from two abundant precursors, cheap melamine and glucose, and using a simple thermal-annealing process. The resulting NCNs feature numerous edges and holes for anchoring vanadium oxides (V-NCNs). This creates cooperative catalytic sites that boost the catalytic oxidation of ethyl lactate to ethyl pyruvate. Additionally, we systematically studied the surface nitrogen species of NCNs by varying the pyrolysis temperature, and found that the active pyridinic N-oxide species formed in a high thermal-annealing treatment, acting synergistically with vanadium active sites in converting ethyl lactate with oxygen into ethyl pyruvate under mild conditions.
Vapor-Phase Oxidation of Ethyl Lactate to Pyruvate over Various Oxide Catalysts
Sugiyama, Shigeru,Shigemoto, Naoya,Masaoka, Naoki,Suetoh, Souichi,Kawami, Hideaki,et al.
, p. 1542 - 1547 (1993)
Oxidation of ethyl lactate to pyruvate was carried out in vapor-phase over various oxides.MoO3 showed a higher selectivity than that of the other single oxide examined.Bindary oxides containing molybdenum such as Fe2O3-MoO3 and TeO2-MoO3 showed high selectivities to pyruvate over 90percent at 300 deg C with high lactate conversion over 75percent.The maximum activity on SnO2-MoO3 was observed at a low temperature of 250 deg C.
Titania-catalysed oxidative dehydrogenation of ethyl lactate: Effective yet selective free-radical oxidation
Ramos-Fernandez, Enrique V.,Geels, Norbert J.,Shiju, N. Raveendran,Rothenberg, Gadi
, p. 3358 - 3363 (2014)
We research here the catalytic oxidative dehydrogenation of ethyl lactate, as an alternative route to ethyl pyruvate. Testing various solid catalysts (Fe2O3, TiO2, V2O 5/MgO-Al2O3, ZrO2, CeO2 and ZnO), we find that simple and inexpensive TiO2 efficiently catalyses this reaction under mild conditions. Furthermore, molecular oxygen was used as the terminal oxidant. Importantly, this reaction runs well also using inexpensive commercial solvent mixtures. Both the desired reaction and the by-products formation follow a free-radical mechanism. Remarkably, adding activated carbon, a solid radical scavenger, hardly affects the catalytic activity, but enhances the product selectivity. This is because this solid radical scavenger hampers the formation of undesired products in solution, without suppressing the oxidation at the catalyst surface. This journal is the Partner Organisations 2014.
Redox-Active Zeolitic Transition Metal Oxides Based on ?μ -Keggin Units for Selective Oxidation
Zhang, Zhenxin,Ishikawa, Satoshi,Zhu, Qianqian,Murayama, Toru,Sadakane, Masahiro,Hara, Michikazu,Ueda, Wataru
, p. 6283 - 6293 (2019)
The design and development of zeolitic transition metal oxides for selective oxidation are interesting due to the combination of the redox properties and microporosities. Redox-active zeolitic transition metal oxides based on ?μ -Keggin iron molybdates were synthesized. O2 can be activated by the materials via an electron-transfer-based process, and the materials can be oxidized even at room temperature. The materials are oxidized and reduced reversibly while the crystal structures are maintained. V is uniformly incorporated in the materials without changing the basic structures, and the redox properties of the materials are tuned by V. The materials are used as robust catalysts for ethyl lactate oxidation to form ethyl pyruvate using O2 as an oxidant.
Designing effective solid catalysts for biomass conversion: Aerobic oxidation of ethyl lactate to ethyl pyruvate
Zhang, Wei,Ensing, Bernd,Rothenberg, Gadi,Raveendran Shiju
, p. 1866 - 1873 (2018)
The direct oxidative dehydrogenation of lactates with molecular oxygen is a promising route for producing bio-based pyruvates. But practical implementation of this route means high yields and mild conditions, which in turn require expensive noble-metal ca
Design of a folded, conformationally stable oxaloacetate decarboxylase
Taylor, Susan E.,Rutherford, Trevor J.,Allemann, Rudolf K.
, p. 751 - 755 (2002)
Oxaldie-4, a 31-residue polypeptide designed to catalyse the decarboxylation of oxaloacetate, has been synthesised and its structural and catalytic properties characterised. The solution structure of Oxaldie-4 was studied by CD and NMR spectroscopy. Oxaldie-4, the design of which was based on bovine pancreatic polypeptide, adopted a stably folded structure in solution, which was characterised by the tight packing of a poly-proline-like helix and an α-helix as shown by a large number of inter-helix NOEs. The structure of Oxaldie-4 was in sharp contrast to the molten globule-like structure formed by Oxaldie-3, which was based on avian pancreatic polypeptide. The stability of Oxaldie-4 with respect to thermal and urea denaturation was significantly improved when compared to Oxaldie-3. Oxaldie-4 catalysed the decarboxylation of oxaloacetate with Michaelis-Menten saturation kinetics. The kinetic parameters, which were independent of the concentration of the catalyst over the whole range studied, were determined in a spectrophotometric assay at pH 7 and 298 K to be 0.229 s-1, 64.8 mM, and 2.9 M-1 s-1 for kcat, KM, and kcat/KM, respectively. This catalytic efficiency corresponds to a rate increase of almost four orders of magnitude when compared to simple amines such as butylamine. However, despite the stable three-dimensional structure, the catalytic efficiency of Oxaldie-4 was only slightly improved relative to Oxaldie-3, most likely the consequence of the high flexibility of the lysine side chains, which make up the active site of Oxaldie-4.
