- Selective production of dihydroxyacetone and glyceraldehyde by photo-assisted oxidation of glycerol
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Glycerol is a by-product during biodiesel production and represents a potential low-cost raw material for obtaining high-cost products like Dihydroxyacetone (DHA) and glyceraldehyde (GCD) amongst others. In this work, Fe-Pillared clay (Fe-PILC) was assessed as catalyst of the selective photo-oxidation of glycerol to obtain DHA and GCD at moderate conditions (298 K and atmospheric pressure). This was conducted in a 100 mL Pyrex glass batch reactor where a Pen-Ray lamp of mercury of 5.5 W UV light (UVP) was placed at the centre. The Fe-PILC was prepared by ion exchange. The pillaring was confirmed by XRD, and a 17% w/w of Fe was determined by Atomic Absorption Spectroscopy. The active phases were established by XPS and found to be FeO and Fe3O4. The specific surface area of the clay (bentonite), determined by N2 physisorption, increased from 34 m2/g to 227 m2/g and the pore volume increased from 0.058 cm3/g to 0.106 cm3/g. The studied variables were catalyst loading and glycerol initial concentration. An experiment with TiO2 Degussa P25 was also performed as reference. It was found that by adding Fe-PILC to the glycerol oxidation system, selectivity towards DHA or GCD can be tuned. A selectivity towards DHA was found to be 87% with 0.1 g/L of Fe-Pillared after 8 h reaction. The in situ production of H2O2 was observed and therefore concluded that the glycerol oxidation occurs via a fenton process, i.e. via free radicals.
- Mendoza, Arisbeht,Romero, Rubí,Gutiérrez-Cedillo, Galilea P.,López-Tellez, Gustavo,Lorenzo-González, Omar,Gómez-Espinosa, Rosa María,Natividad, Reyna
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- Photocatalytic production of dihydroxyacetone from glycerol on TiO2 in acetonitrile
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In this paper, photocatalytic production of dihydroxyacetone (DHA) from glycerol in acetonitrile on TiO2 was investigated. HPLC-MS analysis showed that glycerol was converted to DHA, glyceraldehyde (GAD), glyceric acid and several other chemicals. Using acetonitrile as the reaction medium instead of water not only provided a more selective process for production of DHA but also increased the glycerol conversion. After 300 min, with 1 g L-1 catalyst loading and 4 mM initial glycerol concentration, glycerol conversion and DHA selectivity were 96.8% and 17.8% in acetonitrile compared to 36.1% and 14.7% in water, respectively. The half-life of glycerol decreased by a factor of 6.2, from 467 min to 75 min, by changing the solvent from water to acetonitrile. Experiments using biodiesel-derived crude glycerol verified the effectiveness of the proposed process for the photocatalytic production of DHA from crude glycerol. A mechanism was proposed to explain the higher selectivity towards DHA over GAD in this process.
- Farnood, Ramin,Gong, Jianyu,Imbault, Alexander Luis
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- A practical synthesis of 2-butyl-4(5)-chloro-5(4)-hydroxymethyl-1H-imidazole
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A practical process for the synthesis of 2-butyl-4-hydroxymethyl imidazole (4) followed by chlorination to provide chloroimidazole 1 in an overall 71% yield has been developed.
- Shi,Frey,Tschaen,Verhoeven
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- Cu-Al composite oxides: A highly efficient support for the selective oxidation of glycerol to 1,3-dihydroxyacetone
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A series of Au catalysts supported on Cu-Al composite oxides were prepared and applied for the selective catalytic oxidation of glycerol to 1,3-dihydroxyacetone (DHA) in base-free conditions. The optimal Au/CuAlO-3 catalyst (the molar ratio of Cu/Al was 5:1) exhibited the best performance, and reached the glycerol conditions of 76.7% and DHA selectivity of 97.3% under the optimized reaction conditions. The high catalytic activity of the Au/CuAlO-3 catalyst correlated to the large concentration of surface-active oxygen species, the low reduction temperature of the support, the small size of Au nanoparticles (NPs) and the interactions between Au NPs and the support. This work demonstrates that Cu-Al composite oxides are promising supports for selective catalytic oxidation of glycerol to DHA, and may offer guidelines for designing efficient support for the selective conversion of glycerol to other high value-added products. This journal is
- Ke, Yi-Hu,Wang, Xue,Qin, Hong-Yu,Liu, Hai,Yuan, Hong,Liu, Chun-Ling,Dong, Wen-Sheng
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- Cooperative transformation of nitroarenes and biomass-based alcohols catalyzed by CuNiAlOx
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A simple CuNiAlOx catalyst was prepared for the cooperative transformation of nitrobenzene derivatives and biomass-based alcohols. Under the optimized reaction conditions, a range of nitrobenzene derivatives can be smoothly converted into the corresponding amines and glycerol was directly transformed into 1,3-dihydroxypropan-2-one.
- Dai, Xingchao,Cui, Xinjiang,Yuan, Hangkong,Deng, Youquan,Shi, Feng
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- One-Pot Homogeneous and Heterogeneous Oxidation of Glycerol to Ketomalonic Acid Mediated by TEMPO
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Glycerol, an increasingly abundant by-product of biodiesel production, is selectively converted to ketomalonic acid in one pot at pH 10 using NaOCl as regenerating oxidant in water at 2 °C in the presence of catalytic Br - along with the radical TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) . The reaction can also be conducted at completion over a sol-gel silica glass doped with the nitroxyl radical. Considering the stability and versatility of such doped glasses, these materials show real promise as reusable metal-free catalysts for the conversion of a readily available and renewable biofeedstock into a highly valued compound.
- Ciriminna, Rosaria,Pagliaro, Mario
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- Sol-gel entrapped visible light photocatalysts for selective conversions
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A general method to heterogenize, stabilize and significantly enhance the activity of selective visible light photocatalysts for aerobic oxidation of glycerol is devised. The new method makes use of the sol-gel encapsulation of photocatalytic species in silica-based matrices to afford leach-proof catalysts capable to afford valued products at low cost with little or no waste generation. In particular, the photocatalytic selective conversion of glycerol is performed in water solvent under ambient conditions with molecular oxygen as oxidant and visible light as the driving energy source, thereby meeting all requirements for a green chemical process. Entrapment of the semiconductor-based photocatalyst inside the transparent porous silica matrix enhances substrate adsorption, thus improving its local concentration and favoring reaction with the photogenerated active species.
- Zhang, Yanhui,Ciriminna, Rosaria,Palmisano, Giovanni,Xu, Yi-Jun,Pagliaro, Mario
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- A Prolific Catalyst for Selective Conversion of Neat Glycerol to Lactic Acid
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We report the synthesis and reactivity of a very robust iridium catalyst for glycerol to lactate conversion. The high reactivity and selectivity of this catalyst enable a sequence for the conversion of biodiesel waste stream to lactide monomers for the preparation of poly(lactic acid). Furthermore, experimental data collected with this system provide a general understanding of its reactive mechanism.
- Lu, Zhiyao,Demianets, Ivan,Hamze, Rasha,Terrile, Nicholas J.,Williams, Travis J.
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- Immobilizing Systems Biocatalysis for the Selective Oxidation of Glycerol Coupled to InSitu Cofactor Recycling and Hydrogen Peroxide Elimination
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The combination of three different enzymes immobilized rationally on the same heterofunctional carrier allowed the selective oxidation of glycerol to 1,3-dihydroxyacetone (DHA) coupled to insitu redox-cofactor recycling and H2O2 elimination. In this cascade, engineered glycerol dehydrogenase with reduced product inhibition oxidized glycerol selectively to DHA with the concomitant reduction of NAD+ to NADH. NADH oxidase regenerated the NAD+ pool by oxidizing NADH to NAD+ to form H2O2 as the byproduct. Finally, catalase eliminated H2O2 to yield water and O2 as innocuous products, which avoided the spontaneous DHA oxidation triggered by H2O2. The co-immobilization of the three enzymes on the same porous carrier allowed the insitu recycling and disproportionation of the redox cofactor and H2O2, respectively, to produce up to 9.5mM DHA, which is 18- and 6-fold higher than glycerol dehydrogenase itself and a soluble multienzyme system, respectively.
- Rocha-Martin, Javier,Acosta, Andreína,Guisan, Jose M.,L?pez-Gallego, Fernando
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- Post-synthetic preparation of Sn-, Ti- and Zr-beta: A facile route to water tolerant, highly active Lewis acidic zeolites
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A two-step procedure for the post-synthetic preparation of Lewis acidic Sn-, Zr- and Ti-zeolite β is reported. Dealumination of a commercially available Al-β zeolite leads to the formation of highly siliceous material containing silanol nests, which can be filled in a second step via the solid-state ion-exchange or impregnation of an appropriate metal precursor. Spectroscopic studies indicate that each metal is subsequently coordinated within the zeolite framework, and that little or no bulk oxides are formed-despite the high metal loadings. The synthesised catalysts demonstrate excellent activity for the isomerisation of glyceraldehyde to dihydroxyacetone, a key model reaction for the upgrading of bio-renewable feedstocks, and the epoxidation of bulky olefins.
- Wolf, Patrick,Hammond, Ceri,Conrad, Sabrina,Hermans, Ive
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- A novel glycerol valorization route: Chemoselective dehydrogenation catalyzed by iridium derivatives
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Organoiridium derivatives of the type Ir(diene)(N-N)X (diene = 1,5-hexadiene,1,5-cyclooctadiene; N-N = 2,2′-bipyridine, 1,10-phenanthroline and substituted derivatives; X = Cl, I) catalyze the hydrogen transfer reaction from glycerol to acetophenone, yielding dihydroxyacetone and phenylethanol. The catalytic reactions are performed at temperatures of 100 °C or higher, in the presence of a basic cocatalyst. The effect of experimental conditions on overall conversion and catalyst lifetime is discussed, as well as on the degradation of dihydroxyacetone, which can lead to an apparent decrease of selectivity of the catalytic reaction.
- Farnetti, Erica,Kaspar, Jan,Crotti, Corrado
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- NEW MECHANISTIC PROPOSAL FOR SOME HEPTAMOLYBDATE-ION-CATALYZED ISOMERIZATIONS
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Heptamolybdate-ion(HM)-catalyzed C(2) epimerization of D-glucose and racemization of D-glyceraldehyde proceed with comparable rates and activation parameters; HM catalyzes the isomerisation of glucal and galactal triacetates as well.For all of the above transformations, a common, new mechanism is proposed that invokes stabilization of 3-oxa-allylic cation species by the central Mo(VI) atom.
- Klaic, Branimir,Raza, Zlata,Sankovic, Mauricio,Sunjic, Vitomir
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- Bioactive MIL-88A Framework Hollow Spheres via Interfacial Reaction In-Droplet Microfluidics for Enzyme and Nanoparticle Encapsulation
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Functional bio-MOF hollow spheres with controlled size in the 35-2000 μm range were successfully synthesized by interfacial reaction using a continuous-flow droplet microfluidic system in a single step and one-flow strategy. The architecture of MIL-88A frameworks was extended from single-shell to double-shell hollow spheres. Moreover, various functional nanoparticles (silica, cobalt, and UiO-66(Zr) MOF) were directly encapsulated in the single-shell hollow spheres, while maintaining the functionality of the cargo. In particular, three kinds of enzymes (glycerol dehydrogenase, horseradish peroxidase, and acetylcholinesterase) were also encapsulated inside the single-shell hollow spheres under mild conditions. The catalytic activity and the superior recyclability of the encapsulated enzymes were demonstrated against free enzymes.
- Jeong, Guan-Young,Ricco, Raffaele,Liang, Kang,Ludwig, Johanna,Kim, Jin-Oh,Falcaro, Paolo,Kim, Dong-Pyo
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- Kinetics of glycerol biotransformation to dihydroxyacetone by immobilized Gluconobacter oxydans and effect of reaction conditions
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Biotransformation of glycerol to 1,3-dihydroxyacetone was carried out in an isothermal isochoric batch reactor with Gluconobacter oxydans immobilized in poly(vinyl alcohol) gel capsules. The reaction course was described with a three-step kinetic model. Two reaction schemes were proposed and compared with 8 kinetic experiments at 25°C. The experimental dependences of glycerol and dihydroxyacetone concentrations on reaction time were simulated very well by the autocatalytic model. The effects of reaction temperature and initial concentrations of yeast extract and glycerol were studied. Temperature 25-30°C, initial yeast extract concentration 2-4 g l-1 and initial glycerol concentration 20-50 g l-1 were found as optimal. The determined rate constants can be used to advantage for industrial production of dihydroxyacetone from glycerol.
- Raska, Jiri,Skopal, Frantisek,Komers, Karel,Machek, Jaroslav
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- FSAB: A new fructose-6-phosphate aldolase from Escherichia coli. Cloning, over-expression and comparative kinetic characterization with FSAA
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Fructose-6-phosphate aldolase B (FSAB) from Escherichia coli was successfully over-expressed as His-tagged recombinant protein. A decameric protein was observed as for FSAA. Unlike FSAA, FSAB is not thermally stable at temperatures higher than 60 °C. The 70% identity between the two aldolases has allowed the generation of a 3D structure which has shown a high similarity of the two active sites. Full kinetic studies towards several substrates have revealed that FSAB catalytic activity is very close to FSAA activity, corroborated by the similarity of their active sites. FSAB has been able to react with three known donors (dihydroxyacetone, hydroxyacetone and glycolaldehyde) but always slightly slower than FSAA.
- Sanchez-Moreno, Israel,Nauton, Lionel,Thery, Vincent,Pinet, Agnes,Petit, Jean-Louis,De Berardinis, Veronique,Samland, Anne K.,Guerard-Helaine, Christine,Lemaire, Marielle
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- One-pot biotransformation of glycerol into serinol catalysed by biocatalytic composites made of whole cells and immobilised enzymes
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Biocatalytic cascades afford the development of economically sustainable and green processes. Herein we examined the unprecedented coupling of co-immobilisedGluconobacter oxydansand an isolated transaminase to synthesise serinol from glycerol. Through this approach, we manufactured up to 36 mM serinol, the highest titer ever reported for a non-fermentative biosynthesis. More importantly, similar productivities are obtained starting from the industrial by-product crude glycerol, demonstrating the possibilities of this hybrid heterogenenous biocatalyst for valorising bio-based raw materials.
- Ripoll, Magdalena,Velasco-Lozano, Susana,Jackson, Erienne,Diamanti, Eleftheria,Betancor, Lorena,López-Gallego, Fernando
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- Selective oxidation of glycerol to formic acid catalyzed by iron salts
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Glycerol is oxidized by hydrogen peroxide to formic acid with excellent selectivity in the presence of iron salts. The oxidation takes place at room temperature in water; at the end of the reaction the catalytic system is still active and available to restart the oxidation.
- Farnetti,Crotti
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- Nano-structured Pd-Sn catalysts for alcohol electro-oxidation in alkaline medium
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Abstract Active self-supported Pd1Snx catalysts are synthesized by the sacrificial support method. Their catalytic activities towards C1 to C3 alcohol oxidation are determined in alkaline medium. The comparison of the activities allows discarding a first base-catalyzed deprotonation reaction of alcohol as oxidation rate-determining step, speaking up for mechanisms involving a C-adsorption of carbon bearing an alcohol function. It is also shown that desorption of dihydroxyacetone is the glycerol oxidation-limiting step at low potentials.
- Zalineeva, Anna,Serov, Alexey,Padilla, Monica,Martinez, Ulises,Artyushkova, Kateryna,Baranton, Stève,Coutanceau, Christophe,Atanassov, Plamen
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- Semicrystalline dihydroxyacetone copolymers derived from glycerol
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The ring-opening polymerization of glycerol-derived six-membered cyclic dimethylacetal dihydroxyacetone carbonate (MeO2DHAC) have been studied both in solution and bulk conditions with organic catalysts. The guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was the most active catalyst in solution, whereas the thiourea/sparteine catalytic system displayed the most predictable kinetics. Ring-opening polymerization of MeO2DHAC or copolymerization with ε-caprolactone (CL) in the melt occurred readily with TBD as catalyst to afford random copolymers. Acetal deprotection afforded the polycarbonate poly(dihydroxyactone carbonate) (p(DHAC)) or poly(carbonate ester) copolymers p(DHAC-r-CL). The polycarbonate p(DHAC) is a high-melting thermoplastic with a melting point of 246 °C. The p(DHAC-r-CL) copolymers all displayed semicrystalline behavior as evidenced by DSC and WAXS analysis with Tg and Tm changing as a function of comonomer composition. These new materials could have potential use in biomedical applications or as biomass-derived thermoplastics.
- Simon, Jeff,Olsson, Johan V.,Kim, Hyunuk,Tenney, Ian F.,Waymouth, Robert M.
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- Selective Formation of Triose from Formaldehyde Catalyzed by Thiazolium Salt
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In the self-condensation of formaldehyde catalyzed by thiazolium salts, dihydroxyacetone (triose), but not glycolaldehyde, was formed selectively and in high yield.This is of much interest as a facile and novel synthesis of triose from this C1 compound.A mechanism which can account for the selective formation of dihydroxyacetone is described.
- Matsumoto, Toshihiko,Yamamoto, Hiroki,Inoue, Shohei
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- Deactivation and regeneration of: In situ formed bismuth-promoted platinum catalyst for the selective oxidation of glycerol to dihydroxyacetone
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Glycerol oxidation over a Pt catalyst can be effectively enhanced by a Bi additive in terms of activity and 1,3-dihydroxyacetone (DHA) selectivity. However, this catalyst system can suffer from serious deactivation. Here, a Bi-promoted Pt catalyst was developed to selectively produce DHA by maintaining the glycerol solution with Bi(NO3)3·5H2O to meet the continuous operation of practical applications. The catalyst deactivation mechanism was investigated in terms of leaching, over-oxidation, agglomeration and poisoning. It was ascertained that the catalyst deactivation was due to the adsorption of chelating intermediates on the catalyst surfaces. A regeneration method by post-heat-treatment at 200-300 °C could remove the intermediates and regenerate the catalyst, allowing recycling for at least 5 runs without clear catalyst deactivation.
- Ning, Xiaomei,Zhan, Liang,Wang, Hongjuan,Yu, Hao,Peng, Feng
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- Catalytic conversion of fructose to 1,3-dihydroxyacetone under mild conditions
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A novel zwitterionic catalyst containing imidazole, carboxyl and amino functional groups was synthesized to catalyze the retro-aldol condensation of fructose. The catalyst displayed efficiently catalytic activity for the conversion of fructose to 1,3-dihydroxyacetone (DHA). The yield of DHA and selectivity of DHA achieved 27.9percent and 46.5percent after reaction 2 h, respectively, at pH 9.5, 85 °C. A possible catalytic mechanism was suggested. The charged functional groups on the catalyst exhibited synergistic effect and played role in electron induction and proton transfer, which leaded to a good selectivity of DHA in the conversion of fructose under mild conditions.
- Huang, Hong,Lv, Jing,Meng, Xiang-Guang,Wang, Fei,Wu, Yan-Yan,Yu, Wen-Wang
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- Photocatalytic properties of sodium decatungstate supported on sol-gel silica in the oxidation of glycerol
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Photoexcitation of Na4W10O32 dissolved in water produces a powerful oxidizing reagent that is able to form hydroxyl radicals from water. OH radicals formation has been demonstrated by EPR spin-trapping technique using DMPO as spin trap. The photooxidation of glycerol occurs through its reaction with OH radicals and is characterized by low selectivity and partial degradation of the substrate to CO2. Entrapment of Na4W10O32 inside a silica matrix by a sol-gel procedure gives a new heterogeneous photocatalyst characterized by the presence of micropores (7 and 13 ) and mesopores (30 ). Interaction between polyoxoanion and protonated silanol groups are strong and prevent any kind of leaching. The solid support affects the selectivity of the O2- assisted photooxidation process of glycerol. In particular, silica surface enhances alcohol adsorption improving its local concentration, so favouring its reaction with photogenerated OH radicals that leads to glyceraldehyde and dihydroxyacetone. At the same time, carbon dioxide is not formed, thus indicating that it is possible to control the high oxidizing power of sodium decatungstate through its heterogenization on a suitable support.
- Molinari, Alessandra,Maldotti, Andrea,Bratovcic, Amra,Magnacca, Giuliana
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- One-pot electrocatalytic oxidation of glycerol to DHA
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One-pot, waste-free oxidation of glycerol to 1,3-dihydroxyacetone (DHA) was achieved by simply applying a small electric potential (1.1 V vs Ag/AgCl) to a glycerol solution in water buffered at pH 9.1 in the presence of 15 mol % TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl). Prolonging the reaction time affords comparable amounts of hydroxypyruvic acid.
- Ciriminna, Rosaria,Palmisano, Giovanni,Pina, Cristina Della,Rossi, Michele,Pagliaro, Mario
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- Formose Reactions. XXI. A Selective Formation of Dihydroxyacetone in the Formose Reaction in N,N-Dimethylformamide
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Dihydroxyacetone (DHA) was obtained in good yield from the selective formose reaction which was conducted with 2-(dimethylamino)ethanol and vitamin B1 in N,N-dimethylformamide (DMF).The major products were isolated from the formose and identified as dihydroxyacetone and 2-(1,2-dihydroxyethyl)-5-(2-hydroxyethyl)-4-methylthiazole by spectral data.Vitamin B1 suppressed the vaporization of formaldehyde from the reaction solution.Irrespective of the 2-(dimethylamino)ethanol concentration (above 0.1 M (1M=1 mol dm-3)), the maximum yield of DHA was 80-90 glcpercent at 1.0 M formaldehyde concentration, when the formaldehyde consumption was above 90percent.Above 3.0 M formaldehyde concentration, selective formation of DHA (above 80 glcpercent) was obtained at he early stage of the reaction.The scheme for the formation of DHA in the formose reaction in the presence of vitamin B1 was also proposed.
- Shigemasa, Yoshihiro,Sasaki, Yoshihiro,Ueda, Nasuo,Nakashima, Ruka
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- Selective catalytic oxidation of diglycerol
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The selective oxidation of α,α-diglycerol was studied using oxygen as a clean oxidant in the presence of a palladium/neocuproine complex. After optimization of the reaction parameters, the mono-oxidation product was obtained with 93% NMR yield (up to 76% isolated yield). The product was named “diglycerose” considering that it mainly exists as a cyclic hemi-ketal form.
- Wang, Huan,Vu, Nam Duc,Chen, Guo-Rong,Métay, Estelle,Duguet, Nicolas,Lemaire, Marc
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p. 1154 - 1159
(2021/02/26)
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- Assembly of platinum nanoparticles and single-atom bismuth for selective oxidation of glycerol
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Selective oxidation of the secondary hydroxyl group of glycerol to dihydroxyacetone (DHA) is an extremely challenging yet important reaction. The main difficulty is that the three hydroxyl groups in glycerol are prone to randomly oxidize, resulting in an unsatisfactory DHA selectivity. We show here that an assembly of platinum nanoparticles (NPs, ～2 nm) and N-stabilized single-atom bismuth (Bi), namely Pt/Bi@NC, shows a record-high DHA selectivity of ～95.0% towards glycerol oxidation under optimized reaction conditions. Characterization and theoretical calculations confirm that single-atom Bi in the vicinity of Pt NPs provides a preferred site to chelate with the primary -OH of glycerol, and its secondary -OH is prone to bind to a surface Pt atom of a Pt NP with a shorter Pt-H bond length. This as-formed unique adsorption configuration of glycerol on the Pt-Bi dual site significantly facilitates the oxidation of the secondary -OH of glycerol, thus contributing to a record-high selectivity to DHA. This journal is
- Huang, Ning,Jiang, Dong,Jiang, Pingping,Leng, Yan,Lu, Yubing,Tian, Jinshu,Yue, Chenguang,Zhang, Pingbo,Zhang, Zihao
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supporting information
p. 25576 - 25584
(2021/12/07)
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- Design of a synthetic enzyme cascade for the: In vitro fixation of a C1carbon source to a functional C4sugar
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Realizing a sustainable future requires intensifying the waste stream conversion, such as converting the greenhouse gas carbon dioxide into value-added products. In this paper, we focus on utilizing formaldehyde as a C1 carbon source for enzymatic C-C bond formation. Formaldehyde can be sustainably derived from other C1 feedstocks, and in this work, we designed a synthetic enzyme cascade for producing the functional C4 sugar erythrulose. This involved tailoring the enzyme formolase, which was optimized for fusing formaldehyde, from a three-carbon producer (dihydroxyacetone) to sets of variants with enhanced two-carbon (glycolaldehyde) or four-carbon (erythrulose) activity. To achieve this, a high-throughput combinatorial screening was developed, and every single variant was evaluated in terms of glycolaldehyde, dihydroxyacetone and erythrulose activity. By applying the two most promising variants in an enzyme cascade, we were able to show for the first time production of ERY starting from a C1 carbon source. In addition, we demonstrated that one of our tailored formolase variants was able to convert 25.0 g L-1 glycolaldehyde to 24.6 g L-1 erythrulose (98% theoretical yield) in a fully atom-economic biocatalytic process. This represents the highest achieved in vitro concentration of erythrulose to date.
- Güner, Samed,Pick, André,Sieber, Volker,Wegat, Vanessa
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supporting information
p. 6583 - 6590
(2021/09/10)
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- Enantioselective Reductive Oligomerization of Carbon Dioxide into l-Erythrulose via a Chemoenzymatic Catalysis
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A cell-free enantioselective transformation of the carbon atom of CO2has never been reported. In the urgent context of transforming CO2into products of high value, the enantiocontrolled synthesis of chiral compounds from CO2would be highly desirable. Using an original hybrid chemoenzymatic catalytic process, we report herein the reductive oligomerization of CO2into C3(dihydroxyacetone, DHA) and C4(l-erythrulose) carbohydrates, with perfect enantioselectivity of the latter chiral product. This was achieved with the key intermediacy of formaldehyde. CO2is first reduced selectively by 4e-by an iron-catalyzed hydroboration reaction, leading to the isolation and complete characterization of a new bis(boryl)acetal compound derived from dimesitylborane. In an aqueous buffer solution at 30 °C, this compound readily releases formaldehyde, which is then involved in selective enzymatic transformations, giving rise either (i) to DHA using a formolase (FLS) catalysis or (ii) to l-erythrulose with a cascade reaction combining FLS and d-fructose-6-phosphate aldolase (FSA) A129S variant. Finally, the nature of the synthesized products is noteworthy, since carbohydrates are of high interest for the chemical and pharmaceutical industries. The present results prove that the cell-freede novosynthesis of carbohydrates from CO2as a sustainable carbon source is a possible alternative pathway in addition to the intensely studied biomass extraction andde novosyntheses from fossil resources.
- Bontemps, Sébastien,Clapés, Pere,Desmons, Sarah,Dumon, Claire,Fauré, Régis,Grayson-Steel, Katie,Hurtado, John,Nu?ez-Dallos, Nelson,Vendier, Laure
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supporting information
p. 16274 - 16283
(2021/10/12)
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- Earth-abundant manganese oxide nanoneedle as highly efficient electrocatalyst for selective glycerol electro-oxidation to dihydroxyacetone
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In this study, earth-abundant manganese oxide (MnO2) was used as a catalyst for the electrocatalytic glycerol oxidation with a satisfactory yield and high selectivity under mild pH media; that is, the high current density of 6.0 mA cm?2 and selectivity of ca. 46% for dihydroxyacetone (DHA). MnO2 also exhibited reasonable durability without considerable changes for 3 h. More importantly, by combination of operando Raman and electrochemical studies, a tentative reaction pathway was also proposed. It is found that high selectivity of formic acid at low potential was due to predominant coverage of α-MnO2 on catalyst surface. Meanwhile, at high applied potential, partial transformation of α-MnO2 to δ-MnO2 causes decreasing C-C bond cleavage, leading to high DHA selectivity. The results of this work not only demonstrate that MnO2 holds promise as an efficient electrocatalyst for selectively producing DHA but also provides realistic details on electrochemically generated species under working condition.
- Chiang, Chia-Ying,Tran, Giang-Son,Vo, Truong-Giang
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p. 139 - 148
(2021/10/07)
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- Efficiently selective oxidation of glycerol by BiQDs/BiOBr-Ov: promotion of molecular oxygen activation by Bi quantum dots and oxygen vacancies
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Selective oxidation of biomass resource glycerol to produce high value-added formic acid, dihydroxyacetone and other fine chemicals is in line with the current development concept of green and sustainable chemistry. A Bi quantum dot and oxygen vacancy modified BiOBr photocatalyst was applied to the selective aerobic oxidation of glycerol. A series of characterization results showed that the introduction of Bi quantum dots and oxygen vacancies can promote the effective transfer of photo-generated electrons and the adsorption of molecular oxygen on the catalyst surface to promote the activation of molecular oxygen, thereby significantly improving the photocatalytic efficiency of BiOBr. BiQDs/BiOBr-Ovcan efficiently catalyze the oxidation of glycerol to yield FA and DHA (FA selectivity 46.2%, DHA selectivity 26.9% at 98.4% glycerol conversion) under mild conditions, which is around 2.9 times that of normal BiOBr. In addition, the relevant reaction mechanism and path were systematically studied: two reaction paths to yield FA and DHA independently were found, where photo-generated holes and superoxide radicals played important roles. This work provided an efficient catalyst modification scheme by promoting the activation of molecular oxygen to improve the photocatalytic oxidation efficiency of biomass resources.
- Dong, Yuming,Fan, Mingming,Haryono, Agus,Jiang, Pingping,Leng, Yan,Li, Chenhao,Yue, Chengguang,Zhang, Pingbo
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p. 12938 - 12944
(2021/08/03)
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- The selective oxidation of glycerol over metal-free photocatalysts: insights into the solvent effect on catalytic efficiency and product distribution
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Selective oxidation of glycerol to high value-added derivatives is a promising biomass conversion pathway, but the related reaction mechanism, in particular the solvent effect, is rarely studied. In this work, O-doped g-C3N4was used as a metal-free catalyst to catalyze the selective oxidation of glycerol in different solvents. It was found that solvents can affect both catalytic efficiency and product distribution. A series of controlled experiments and theoretical calculation were applied to attest that the difference in interaction between glycerol and catalysts in different solvents is the main factor: competitive adsorption and hydrogen bond network from water inhibit the adsorption and activation of glycerol on the catalyst surface and reduce the conversion efficiency, while in acetonitrile, the stronger adsorption makes the oxidation reaction continue to yield esters. Two reaction routes in different solvents over O-doped g-C3N4are proposed for the first time, which is helpful for people to better understand the related reaction mechanism.
- Fan, Mingming,Haryonob, Agus,Jiang, Pingping,Leng, Yan,Yue, Chengguang,Zhang, Pingbo
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p. 3385 - 3392
(2021/06/06)
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- Selective oxidation of glycerol over different shaped WO3 supported Pt NPs
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In this work, different shaped WO3 (rod-like, lamellar and cuboid) supported Pt catalysts were prepared in a facile routine and tested in the selective oxidation of glycerol in base-free aqueous solution. Characterizations indicated that rod-like WO3 supported Pt catalyst (Pt/R-WO3) possesses higher surface area because of the formation of vertical pore channels and highly exposed plane (100), the deposited Pt atoms combined strongly with the terminal [sbnd]W[dbnd]O in rod-like WO3. These properties promoted the adsorption, storage and surface diffusion of oxygen over Pt/R-WO3 which exhibited the excellent activity for the selective oxidation of glycerol. And the higher amount of acid sites on the surface of Pt/R-WO3 enhanced the selectivity of glyceric acid. The calculated turnover frequency of each Pt atom in Pt/R-WO3 reached 946 h–1 at 60 °C.
- Yang, Lihua,Jiang, Yuanyuan,Zhu, Zihui,Hou, Zhaoyin
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- Photocatalytic Conversion of Xylose to Xylitol over Copper Doped Zinc Oxide Catalyst
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Abstract: In the present investigation, photocatalytic conversion of xylose by Copper (Cu) doped Zinc oxide (ZnO) was investigated under Ultraviolet Light emitting diode (UVA-LED) illumination. Photocatalysts were synthesized successfully by chemical prec
- Rohini,Hebbar, H. Umesh
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p. 2583 - 2594
(2021/02/05)
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- A proof of concept for cooperation from the quinone groups adjacent to N sites during the metal-free oxidation of glycerol by nitrogen-rich graphene oxide
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Glycerol is a key by-product in biodiesel production and can be utilized in the synthesis of value-added chemicals. The low cost and fairly abundant availability of glycerol can be advantageous in producing a variety of pharmaceuticals and cosmetic products. Among the various catalytic transformations, selective oxidation is a promising pathway for the valorization of glycerol. In this present report, we deliver a first proof of concept for the involvement of quinone groups adjacent to N sites on the GO surface, for the selective oxidation of glycerol to dihydroxyacetone (DHA). Graphene oxide is covalently functionalized with 2,4-dihydroxypyridine (DHP), which resembles the identified active sites in the carbon clusters. As anticipated, the DHP-functionalized graphene oxide catalyst (DHP@GO) improved the conversion of glycerol to DHA, the main product, along with minor amounts of glyceric acid (GA) and fumaric acid (FA).
- Barlocco, Ilaria,Dogra, Ashima,Gupta, Neeraj,Sharma, Vinit,Villa, Alberto
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supporting information
p. 19651 - 19654
(2021/11/12)
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- Mesoporous CuO-CeO2 Application of composite oxide supported Au catalyst in catalytic oxidation of glycerol
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The invention discloses a mesoporous CuO - CeO. 2 The composite oxide supported Au catalyst uses glycerol aqueous solution and mesoporous, in the application 100-1000, of catalytic oxidation of glycerol in a molar ratio of glycerol to gold CuO - CeO. 2 The complex oxide supported Au catalyst was added to the autoclave, and oxygen, was introduced into the autoclave at a temperature of 60-100 °C, for 0.1-1.5MPa hours 2-10 to give, dihydroxyacetone 1,3 - in which CuO - CeO mesopores, were obtained. 2 The supported amount of gold in the composite oxide supported Au catalyst is 1%-5%. experiment results showing, mesopores CuO - CeO. 2 The composite oxide supported Au catalyst is used for catalytic oxidation of glycerol, glycerol conversion rate and 1,3 -dihydroxyacetone selectivity, with wide application prospect.
- -
-
Paragraph 0008; 0011-0024
(2020/03/17)
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- Totally atom-economical synthesis of lactic acid from formaldehyde: combined bio-carboligation and chemo-rearrangement without the isolation of intermediates
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Non-fermentative chemoenzymatic transformations have attracted great interest from both academia and industry. Here, we report a green chemoenzymatic cascade reaction that converts the C1 compound formaldehyde into lactic acid using a newly identified formolase variant and NaOH as catalysts with 100% atom economy and 82.9% overall yield under near-ambient conditions. The engineered formolase variant in this study exhibits a 19-fold substantially improved activity and improved formaldehyde resistance (up to 500 mM) and alters the main product from two-carbon glycolaldehyde (GA) to three-carbon dihydroxyacetone (DHA). The crystal structures of the parent formolase and identified variants were resolved to elucidate the molecular reason for the obtained improvement. Molecular dynamics simulation and molecular mechanics/generalized born surface area (MM/GBSA) analysis suggested that the identified amino acid substitutions allow more stable TPP-GA complexes in the active center of the dimeric formolase which is beneficial for the subsequent DHA generation. This journal is
- Jiang, Huifeng,Li, Jinlong,Li, Tianzhen,Lin, Jianping,Liu, Haifeng,Liu, Pi,Liu, Weidong,Ma, Yanhe,Tan, Zijian,Tang, Zijing,Wei, Hongli,Zheng, Yingying,Zhu, Leilei
-
supporting information
p. 6809 - 6814
(2020/11/10)
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- Preparation of AuPd/ZnO-CuO for the directional oxidation of glycerol to DHA
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Selective activation of the C-O bond of glycerol is a considerable challenge in current academic research. Herein, we fabricate an efficient AuPd/ZnO-CuO catalystviaa simple precipitation method and use it in the selective oxidation of glycerol (GLY) to produce dihydroxyacetone (DHA). Under base-free conditions, the AuPd/ZnO-CuO catalyst exhibits preferable catalytic performance compared with AuPd/ZnO and AuPd/CuO. The turnover frequency (TOF) of AuPd/ZnO-CuO reaches 687.1 h?1, which is 25 times that of AuPd/CuO and 6 times that of AuPd/ZnO. The AuPd/ZnO-CuO catalyst also shows good selectivity toward DHA and the highest DHA yield of 65.3%, which is at the top level among the reported results. Through STEM-EDS, XRD and Raman analyses, we find that ZnO-CuO is a composite oxide and that Zn and Cu elements in the ZnO-CuO support are uniformly distributed. Furthermore, HRTEM, EPR, and XPS results show that AuPd/ZnO-CuO has smaller AuPd alloy nanoparticles (NPs) but a higher concentration of surface defect sites compared with AuPd/ZnO and AuPd/CuO. Together with the catalytic performance and feasible mechanism, we consider that the enhanced performance of the AuPd/ZnO-CuO catalyst could be mainly ascribed to the rich surface defect sites, which facilitate the adsorption and activation of the secondary hydroxyl groups of glycerol.
- Zhao, Gengqiang,Wu, Guandong,Liu, Yanan,He, Yufei,Feng, Junting,Li, Dianqing
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p. 6223 - 6234
(2020/10/14)
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- Expeditious Syntheses to Pharmochemicals 1,3-Dihydroxyacetone, 1,3-Dichloro-, 1,3-Dibromo- And 1,3-Diiodoacetone from Glycerol 1,3-Dichlorohydrin Using Homogenous and Heterogenous Medium
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New efficient and reproductive routes to production of 1,3-dihydroxyacetone (1), 1,3-dichloroacetone (6), 1,3-dibromoacetone (7) and 1,3-diiodoacetone (8) from glycerol 1,3-dichlorohydrin (3) were developed. The synthesis of 1 was processed in three steps from glycerol 2 (1,3-selective chlorination of 2 to 3, oxidation of 3 to 6 and subsequent di-hydroxylation) in 51% overall yield. On the other hand, 7 and 8 were produced from 3, via a trans-bromination and trans-iodination, respectively, followed by oxidation and hydroxylation steps, in 38-52% overall yield. It was used homogeneous media with different reagents (HCl/AcOH, pyridinium chlorochromate (PCC), PCC-HIO4) and heterogeneous media with reagents supported on polymer resins such as Amberlyst A26-HCrO4– form, PV-PCC (polyvinyl-pyridinium chlorochromate) and Amberlyst A26-OH– form or reagents supported on alumina such as KI/Al2O3, KBr/Al2O3, in solvent free conditions.
- Pereira, Vera Lúcia P.,da Silva, Fernanda Priscila N. R.,da Silva, Sara R. B.,dos Santos, Priscila F.
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p. 1725 - 1731
(2020/10/09)
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- Bi-Functional Magnesium Silicate Catalyzed Glucose and Furfural Transformations to Renewable Chemicals
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Bio-refinery is attracting significant interest to produce a wide range of renewable chemicals and fuels from biomass that are alternative to fossil fuel derived petrochemicals. Similar to petrochemical industries, bio-refinery also depends on solid zeolite catalysts. Acid-base catalysis plays pivotal role in producing a wide range of chemicals from biomass. Herein, the Mg framework substituted MTW zeolite is synthesized and explored in the valorisation of glucose and furfural. Bi-functional (acidic and basic) characteristics are confirmed using pyridine adsorbed FT?IR analysis and NH3 and CO2 temperature-programmed desorption techniques. Textural properties and morphological information are retrieved from N2-sorption, X-ray photoelectron spectroscopy, and electron microscopy. The activity of the catalyst is demonstrated in the selective isomerisation of glucose to fructose in ethanol. Glucose is converted to methyl lactate in high yield using the same catalyst. Further, the bi-functional activity of this catalyst is demonstrated in the production of fuel precursor by the reaction of furfural and isopropanol. Mg?MTW zeolite exhibits excellent activity in the production of all these chemicals and fuel derivative. The catalyst exhibits no significant loss in the activity even after five recycles. One simple catalyst affording three renewable synthetic intermediates from glucose and furfural will attract significant attention to catalysis researchers and industrialists.
- Kumar, Abhinav,Srivastava, Rajendra
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p. 4807 - 4816
(2020/08/24)
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- Tuning product selectivity in the catalytic oxidation of glycerol by employing metal-ZSM-11 materials
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Copper and chromium supported on ZSM-11 (MEL-type structure) microporous zeolites were investigated as catalysts for glycerol oxidation towards dihydroxyacetone and lactic acid. ZSM-11 was synthesized by hydrothermal crystallization. Subsequently, alkaline treatment of desilication was carried out in order to generate zeolites with micro-mesoporosity. Ion exchange with ammonium chloride was performed to recover acidic sites and then, Cr(iii) and Cu(ii) species were incorporated onto these materials. Finally, thermal treatment at 500 °C was carried out. These materials were characterized by different techniques and then evaluated in the glycerol oxidation reaction by employing H2O2 as an oxidizing agent. The maximum conversion of glycerol (～70%) was reached over the Cr-ZSM-11 catalyst with a selectivity of ～28% towards dihydroxyacetone. Meanwhile, Cu-ZSM-11 offered 50% glycerol conversion with a selectivity of 68% towards lactic acid. In both the cases, the optimal reaction conditions were studied to maximize the selectivity towards the products mentioned above.
- Diguilio, Eliana,Galarza, Emilce D.,Domine, Marcelo E.,Pierella, Liliana B.,Renzini, María S.
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supporting information
p. 4363 - 4375
(2020/03/26)
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- Plasmonic Oxidation of Glycerol Using Au/TiO2 Catalysts Prepared by Sol-Immobilisation
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Abstract: Au nanoparticles supported on P25 TiO2 (Au/TiO2) were prepared by a facile sol-immobilisation method and investigated for the surface plasmon-assisted glycerol oxidation under base-free conditions. The Au/TiO2 samples were characterized by UV–vis spectroscopy and transmission electron microscopy. Catalysts were prepared using polyvinyl alcohol as stabiliser as well as in the absence of polymer stabiliser. Both the conversion and the reaction selectivity are affected by the plasmon-assisted oxidation and there is an interplay between the presence of the stabiliser and the Au nanoparticle size. Graphic Abstract: [Figure not available: see fulltext.].
- Abis, Laura,Dimitratos, Nikolaos,Sankar, Meenakshisundaram,Freakley, Simon J.,Hutchings, Graham J.
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- Selective oxidation of glycerol with oxygen in base-free solution over N-doped-carbon-supported Sb?PtSb2 hybrid
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Selective oxidation of glycerol with molecular oxygen in base-free aqueous solutions has become a hot topic, as the rapidly increasing production of biodiesel is creating a surplus of glycerol. In this work, an N-doped-carbon-supported core-shell structured Sb?PtSb2 hybrid catalyst was prepared via a facile synthesis route, in which a mixture of glucose, melamine, and SbCl3 (Sb-NC) was pyrolyzed, then impregnated with Pt by immersion in an aqueous solution of H2PtCl6, and further treated in hydrogen flow. Characterization of the catalyst products indicated that introducing SbCl3 can increase the surface area of the binary glucose + melamine pyrolyzed support (NC), and Sb?PtSb2 hybrids could be formed on the surface of an Sb-NC support during hydrogen treatment at 700 °C. It was found that the Sb?PtSb2/NC catalyst was more active for the selective oxidation of glycerol in a base-free aqueous solution than Sb-free NC-supported Pt (Pt/NC). Further characterization also indicated that the promising performance of Sb?PtSb2/NC might be attributed to its enhanced oxygen activation.
- Yang, Lihua,He, Tianqu,Lai, Chujun,Chen, Ping,Hou, Zhaoyin
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p. 494 - 502
(2019/12/26)
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- Aerobic oxidation of glycerol catalyzed by M salts of PMo12O403-(M = K+, Zn2+, Cu2+, Al3+, Cr3+, Fe3+)
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Glycerol is a co-product in the manufacture of biodiesel from vegetable oil and animal fat. A significant increase in biodiesel production results in adramatic overproduction of glycerol. The oxidation of glycerol to lactic acid (LA)by O2 is considered to be a promising technology to increase the value of glycerol. Studies on the fundamental reaction mechanism vary for different catalytic systems. In this work we have chosen Keggin polyoxometalates (POMs)as an exemplary family of water-soluble hydrolytically and oxidatively-stable, fully-inorganic complexes with transition-metal and non-transition-metal counter-cations (M in the formula, MPMo12O40, where M = H+, K+, Zn2+, Cu2+, Al3+, Cr3+, Fe3+ in appropriate number to counterbalance the 3- charge of PMo12O403?). Reactions involving hydrogen peroxide, an intermediate during glycerol oxidation, produce free radicals. A kinetic analysis reveals that the radical chain length under typical conditions is about 20–30. After minimal optimization, the yield of LA was 88% at glycerol conversion > 97% (1.0 M aqueous solution of glycerol, 4.0 mM of the Al salt of PMo12O403?, henceforth “AlPMo”, 10 bar O2 at 60 °C, reaction time 6.0 h).
- Tao, Meilin,Li, Yiming,Geletii, Yurii V.,Hill, Craig L.,Wang, Xiaohong
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- Method for synthesizing 1,3-dihydroxyacetone through indirect oxidation of glycerol
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The invention relates to a method for synthesizing 1,3-dihydroxyacetone through indirect oxidation of glycerol, the method comprises the following steps: carrying out an acetalation reaction, to be more specific, an organic solvent is used as a water-carrying agent, glycerol and benzaldehyde are subjected to acetalation reaction under the action of a solid acid catalyst to obtain 2-phenyl-5-hydroxy-1,3-dioxane (HPD); oxidizing reaction, to be more specific, in an organic solvent, the 2-phenyl-5-hydroxy-1,3-dioxane (HPD) is oxidized into 2-phenyl-5-carbonyl-1,3-dioxane (PDO) by an oxidizing agent under the action of a liquid catalyst and auxiliary agent sodium bromide; hydrolysis reaction, to be more specific, the 2-phenyl-5-carbonyl-1,3-dioxane (PDO) is subjected to hydrolysis reaction under the action of a liquid acid catalyst to obtain a target product. The synthetic process route takes the glycerol as a raw material, the selectivity and the yield are higher than that of the direct oxidation method, the target product is simple in separation, the purity of the product is up to 99%, and industrial production is facilitated.
- -
-
Paragraph 0025; 0028; 0029; 0032; 0033; 0036; 0037; 0040
(2019/04/18)
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- A Polyoxometalate-Based Microfluidic Device for Liquid-Phase Oxidation of Glycerol
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Peroxidation of glycerol has been carried out in a polyoxometalate (POM)-based microfluidic reactor, which was fabricated on a capillary by using a layer-by-layer strategy. Lactic acid (LA) is produced selectively in high yield with a TOF as high as 20 000 h?1, compared to a TOF of 200 h?1 in batch mode. This POM microfluidic reactor is readily prepared, scalable, highly stable, reusable, and also potentially applicable to selective oxidation of other bio-wastes.
- Tao, Meilin,Li, Yiming,Zhang, Xueyan,Li, Zonghang,Hill, Craig L.,Wang, Xiaohong
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p. 2550 - 2553
(2019/06/24)
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- Efficient and stable platinum nanocatalysts supported over Ca-doped ZnAl2O4 spinels for base-free selective oxidation of glycerol to glyceric acid
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In the work, highly dispersed platinum nanocatalysts supported over undoped and Ca-doped zinc aluminate spinels were developed and applied for aqueous-phase selective oxidation of glycerol to produce glyceric acid under base-free conditions. As-fabricated Pt-based catalyst with the incorporation of an appropriate Ca/(Ca + Zn) molar ratio of 0.1 into the spinel exhibited a higher catalytic activity, along with a selectivity to glyceric acid (>81%) and a high turnover frequency of 1160 h?1, compared with other supported Pt-based ones over zinc aluminates, as well as most of supported Pt catalysts previously reported. The structural characterizations and catalytic experiments showed that surface synergy between highly dispersed metallic Pt0 species and medium-strength basic sites mainly contributed to its enhanced catalytic efficiency for base-free glycerol oxidation. Moreover, the present Pt catalyst also presented high structural stability and good reusability. The work opens an alternative approach for constructing highly efficient and stable metal-base bifunctional catalysts for a wide range of heterogeneous oxidation processes without the addition of liquid alkalis.
- Han, Zhengya,Xie, Renfeng,Song, Yihui,Fan, Guoli,Yang, Lan,Li, Feng
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- Microwave-assisted green oxidation of alcohols with hydrogen peroxide catalyzed by iron complexes with nitrogen ligands
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Oxidation of primary and secondary alcohols, including two diols and glycerol, with H2O2 was catalyzed by the iron(II) complexes [FeL3](OTf)2 (L = 2,2′-bipyridine, 2,2′-bipyrimidine, 1,10-phenanthroline and substituted derivatives) and [FeL2](OTf)2 (L = bis(2-pyridinylmethyl)amine, 2,6-di(2-pyridyl)pyridine). The reactions were performed in acetonitrile, water or mixed solvent (typically water/acetonitrile 4:1) in a microwawe reactor at low power. Effect of addition of a cocatalyst, which in some cases improved the yields of the catalytic reaction, was investigated by means of NMR and UV–Visible techniques.
- Cozzi, Irene Sofia,Crotti, Corrado,Farnetti, Erica
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- Pd-Catalyzed Aerobic Oxidation Reactions: Strategies to Increase Catalyst Lifetimes
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The palladium complex [(neocuproine)Pd(μ-OAc)]2[OTf]2 (1, neocuproine = 2,9-dimethyl-1,10-phenanthroline) is an effective catalyst precursor for the selective oxidation of primary and secondary alcohols, vicinal diols, polyols, and carbohydrates. Both air and benzoquinone can be used as terminal oxidants, but aerobic oxidations are accompanied by oxidative degradation of the neocuproine ligand, thus necessitating high Pd loadings. Several strategies to improve aerobic catalyst lifetimes were devised, guided by mechanistic studies of catalyst deactivation. These studies implicate a radical autoxidation mechanism initiated by H atom abstraction from the neocuproine ligand. Ligand modifications designed to retard H atom abstractions as well as the addition of sacrificial H atom donors increase catalyst lifetimes and lead to higher turnover numbers (TON) under aerobic conditions. Additional investigations revealed that the addition of benzylic hydroperoxides or styrene leads to significant increases in TON as well. Mechanistic studies suggest that benzylic hydroperoxides function as H atom donors and that styrene is effective at intercepting Pd hydrides. These strategies enabled the selective aerobic oxidation of polyols on preparative scales using as little as 0.25 mol % of Pd, a major improvement over previous work.
- Ho, Wilson C.,Chung, Kevin,Ingram, Andrew J.,Waymouth, Robert M.
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supporting information
p. 748 - 757
(2018/01/26)
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- Regulating Cofactor Balance In Vivo with a Synthetic Flavin Analogue
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A novel strategy to regulate cofactor balance in vivo for whole-cell biotransformation using a synthetic flavin analogue is reported. High efficiency, easy operation, and good applicability were observed for this system. Confocal laser scanning microscopy was employed to verify that the synthetic flavin analogue can directly permeate into Escherichia coli cells without modifying the cell membrane. This work provides a promising intracellular redox regulatory approach to construct more efficient cell factories.
- Tan, Zhuotao,Zhu, Chenjie,Fu, Jingwen,Zhang, Xiaowang,Li, Ming,Zhuang, Wei,Ying, Hanjie
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supporting information
p. 16464 - 16468
(2018/11/23)
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- Late-stage deuteration of 13C-enriched substrates for: T 1 prolongation in hyperpolarized 13C MRI
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A robust and selective late-stage deuteration methodology was applied to 13C-enriched amino and alpha hydroxy acids to increase spin-lattice relaxation constant T1 for hyperpolarized 13C magnetic resonance imaging. For the five substrates with 13C-labeling on the C1-position ([1-13C]alanine, [1-13C]serine, [1-13C]lactate, [1-13C]glycine, and [1-13C]valine), significant increase of their T1 was observed at 3 T with deuterium labeling (+26%, 22%, +16%, +25% and +29%, respectively). Remarkably, in the case of [2-13C]alanine, [2-13C]serine and [2-13C]lactate, deuterium labeling led to a greater than four fold increase in T1. [1-13C,2-2H]alanine, produced using this method, was applied to in vitro enzyme assays with alanine aminotransferase, demonstrating a kinetic isotope effect.
- Taglang, Céline,Korenchan, David E.,Von Morze, Cornelius,Yu, Justin,Najac, Chloé,Wang, Sinan,Blecha, Joseph E.,Subramaniam, Sukumar,Bok, Robert,Vanbrocklin, Henry F.,Vigneron, Daniel B.,Ronen, Sabrina M.,Sriram, Renuka,Kurhanewicz, John,Wilson, David M.,Flavell, Robert R.
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supporting information
p. 5233 - 5236
(2018/05/28)
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- The Role of Mg(OH)2 in the So-Called “Base-Free” Oxidation of Glycerol with AuPd Catalysts
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Mg(OH)2- and Mg(OH)2-containing materials can provide excellent performance as supports for AuPd nanoparticles for the oxidation of glycerol in the absence of base, which is considered to be a result of additional basic sites on the surface of the support. However, its influence on the reaction solution is not generally discussed. In this paper, we examine the relationship between the basic Mg(OH)2 support and AuPd nanoparticles in detail using four types of catalyst. For these reactions, the physical interaction between Mg(OH)2 and AuPd was adjusted. It was found that the activity of the AuPd nanoparticles increased with the amount of Mg(OH)2 added under base-free conditions, regardless of its interaction with the noble metals. In order to investigate how Mg(OH)2 affected the glycerol oxidation, detailed information about the performance of AuPd/Mg(OH)2, physically mixed (AuPd/C+Mg(OH)2) and (AuPd/C+NaHCO3) was obtained and compared. Furthermore, NaOH and Mg(OH)2 were added during the reaction using AuPd/C. All these results indicate that the distinctive and outstanding performance of Mg(OH)2 supported catalysts in base-free condition is in fact directly related to its ability to affect the pH during the reaction and as such, assists with the initial activation of the primary alcohol, which is considered to be the rate determining step in the reaction.
- Fu, Jile,He, Qian,Miedziak, Peter J.,Brett, Gemma L.,Huang, Xiaoyang,Pattisson, Samuel,Douthwaite, Mark,Hutchings, Graham J.
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supporting information
p. 2396 - 2402
(2018/02/06)
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- POLYMERIC DHA-CONTAINING BIODEGRADABLE COMPOSITIONS AND SURGICAL BARRIER DEVICES MADE THEREOF
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Polymer compositions having the following chemical structure: wherein L1 represents a polymeric linker having the structure shown connecting ethylene oxide oligomers and their use in surgical devices containing the above composition is also described.
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-
Paragraph 0032; 0033
(2017/11/04)
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- The ketol compound
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PROBLEM TO BE SOLVED: To provide a method for producing from alcohol having at least a primary hydroxyl group and a secondary hydroxyl group a corresponding ketol compound selectively at a high yield using a heterogeneous catalyst capable of being easily separated and recovered from a reaction product and being reused.SOLUTION: In a method for producing a ketol compound, alcohol having at least a primary hydroxyl group and a secondary hydroxyl group is oxidized in the presence of a copper catalyst supported on a carrier to produce a corresponding ketol compound. Glycerol is preferable as the alcohol having at least a primary hydroxyl group and a secondary hydroxyl group, and dihydroxyacetone is preferable as the corresponding ketol compound.
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-
Paragraph 0051
(2017/05/20)
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- Pd-Ce nanoparticles supported on functional Fe-MIL-101-NH2: An efficient catalyst for selective glycerol oxidation
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Metal organic framework Fe-MIL-101-NH2 was prepared at different reaction time. The morphology of the Fe-MIL-101-NH2 slightly changed following a longer reaction time; the crystal structure remained. Neocuproine ligand coordinating palladium complex has demonstrated high activity in selective glycerol oxidation towards 1,3-dihydroxyacetone (DHA). Neocuproine ligand was attached to MOF Fe-MIL-101-NH2 by forming an amide (CO[sbnd]NH) bond in this work. The functional Fe-MIL-101-NH2 was used as catalyst supports to hold palladium and cerium nanoparticles. The resulting composite of the Pd-Ce/Fe-MIL-101[sbnd]N[dbnd]CHNeocuproine was found to be a high efficient catalyst in the selective oxidation conversion of glycerol to dihydroxyacetone in comparison with catalysts Pd/Fe-MIL-101[sbnd]N[dbnd]CHNeocuproine and Pt-Bi/C. The catalysts and products were analyzed by FT-IR, XRD, SEM, TEM and 1H, 13C NMR spectroscopy. In addition, the supported catalyst is recyclable with sustainable activity.
- Li, Xinhang,Tjiptoputro, Adrian Kaizen,Ding, Jun,Xue, Jun Min,Zhu, Yinghuai
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- Method for preparing 1,3-dihydroxyacetone through formaldehyde condensation reaction catalyzed by ionic liquid
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The invention discloses a method for preparing 1,3-dihydroxyacetone through a formaldehyde condensation reaction catalyzed by an ionic liquid. The ionic liquid is taken as a catalyst, and 1,3-dihydroxyacetone is prepared from formaldehyde by condensation in a solvent under the synergistic effect of a catalyst promoter. Formaldehyde is taken as a reaction raw material and is cheap and available, reaction conditions are mild, and a reaction process is simple and easy to control.
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Paragraph 0028-0037
(2017/12/28)
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- BIOLOGICAL FERMENTATION USING DIHYDROXYACETONE AS A SOURCE OF CARBON
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The present invention relates to the use of hydrocarbons derived from natural gas in the fermentative production of biochemicals including biofuels. More specifically, the present invention provides the method for manufacturing dihydroxyacetone ("DHA") from natural gas, biogas, biomass and CO2 released from industrial plants including electricity-generating plants, steel mills and cement factories and the use of DHA as a source of organic carbon in the fermentative production of biochemicals including biofuels. The present invention comprises three stages. In the first stage of the present invention, syngas and formaldehyde are produced from natural gas, biogas, biomass and CO2 released from industrial plants. In the second stage of the present invention, formaldehyde and syngas are condensed to produce DHA. In the third stage of the present invention, biochemicals including biofuels are produced from DHA using fermentation process involving wild type or genetically modified microbial biocatalysts.
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Paragraph 0235
(2017/09/05)
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- Au/CuMgAl-hydrotalcite catalysts promoted by Cu+ and basic sites for selective oxidation of glycerol to dihydroxyacetone
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CuMgAl-hydrotalcite-supported Au catalysts were prepared and tested in the selective conversion of glycerol to dihydroxyacetone. The electron density of Au was decreased by Cu embedded in the supports, arising from the electron transfer from Au to Cu sites. The valence state (+?1) of Cu ions was detected. Both Cu+ and basic sites (Mg–O) affected the catalytic activity of Au catalysts. The Cu+ sites promoted the selective oxidation of glycerol to dihydroxyacetone, while basic sites boosted the selectivity oxidation of glycerol to glyceric acid. The synergy of Cu+ sites and basic sites could effectively promote the activity and selectivity of Au catalysts in the selectively conversion of glycerol to dihydroxyacetone. A 53% conversion of glycerol and 72% of dihydroxyacetone selectivity were obtained under optimum reaction conditions.
- Yin, Yanrui,Tang, Tian,Xu, Chunli
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p. 319 - 326
(2017/12/12)
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- Method for preparing 1,3-dihydroxyacetone from 1,3-dichloroacetone
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The invention discloses a method for preparing 1,3-dihydroxyacetone from 1,3-dihydroxyacetone. The method comprises the following steps: by taking 1,3-dichloroacetone and ethylene glycol as raw materials and taking p-toluenesulfonic acid as a catalyst, reacting at the temperature of 0-110 DEG C so as to produce 1,3-dichloroacetone ethylene ketal; adding sodium hydroxide of a certain mass fraction, and hydrolyzing under alkaline conditions so as to obtain 1,3-dihydroxyacetone ethylene ketal; and finally, adding sulfuric acid for acidifying so as to enable the solution to be acidic, obtaining a mixture containing dihydroxyacetone and ethylene glycol, desalting the mixture, evaporating, concentrating, recrystallizing, and filtering, thereby obtaining the dihydroxyacetone crystal, wherein the filtrate is a mixed solution containing sodium sulfate, and the yield of the dihydroxyacetone can reach 60% or higher. The method disclosed by the invention can be used for an industrial production path of dihydroxyacetone, and has the advantages of high yield, low cost, simplicity in operation and separation and the like compared with a biological method, and is convenient for industrial production.
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Paragraph 0036; 0040; 0051
(2017/08/29)
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- Metal-Free Oxidation of Glycerol over Nitrogen-Containing Carbon Nanotubes
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Nitrogen rich carbon nanotubes have been used as a metal free catalyst for the conversion of glycerol into dihydroxyacetone using tert-butyl hydroperoxide as an oxidant. Pyridine nitrogen groups embedded in a carbon matrix are identified as active sites for the reaction. Computational studies have demonstrated that oxidation of pyridine groups to pyridine oxime followed by hydrogen abstraction from secondary alcohol is likely responsible for the oxidation process.
- Gupta, Neeraj,Khavryuchenko, Oleksiy,Villa, Alberto,Su, Dangsheng
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p. 3030 - 3034
(2017/08/18)
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- Making H2 from light and biomass-derived alcohols: The outstanding activity of newly designed hierarchical MWCNT/Pd@TiO2 hybrid catalysts
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Hydrogen evolution is among the most investigated catalytic processes given the importance of H2 from an industrial and an energy perspective. Achieving H2 production through green routes, such as water splitting or more realistically photoreforming of alcohols, is particularly desirable. In this work, we achieve a remarkable H2 productivity through photoreforming of either ethanol or glycerol as a sacrificial electron donor by employing a hybrid nanocatalyst where the properties of multi-walled carbon nanotubes (MWCNTs), Pd nanoparticles and crystalline TiO2 are optimally merged through appropriate engineering of the three components and an optimised synthetic protocol. Catalysts were very active both under UV (highest activity 25 mmol g-1 h-1) and simulated solar light (1.5 mmol h-1 g-1), as well as very stable. Critical to such high performance is the intimate contact of the three phases, each fulfilling a specific task synergistically with the other components.
- Beltram,Melchionna,Montini,Nasi,Fornasiero,Prato
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supporting information
p. 2379 - 2389
(2017/07/15)
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- PRODUCTION OF ALPHA-HYDROXY CARBOXYLIC AIDS AND ESTERS FROM HIGHER SUGARS USING TANDEM CATALYST SYSTEMS
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The present disclosure is directed to methods and composition used in the preparation of alpha-hydroxy carboxylic acids and esters from higher sugars using a tandem catalyst system comprising retro-aldol catalysts and Lewis acid catalysts. In some embodiments, these alpha-hydroxy carboxylic acids may be prepared from pentoses and hexoses. The retro-aldol and Lewis catalysts may be characterized by their respective ability to catalyze a 1,2-carbon shift reaction and a 1,2-hydride shift reaction on an aldose or ketose substrate.
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Page/Page column 2; 13-14
(2017/02/09)
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- Keggin heteropolyacids supported on TiO2 used in gas-solid (photo)catalytic propene hydration and in liquid-solid photocatalytic glycerol dehydration
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(Photo)catalytic propene hydration to 2-propanol and glycerol dehydration to acrolein were carried out by using Keggin heteropolyacids (HPAs) supported on TiO2. Binary materials have been prepared by impregnation of H3PW12O40, H3PMo12O40 and H4SiW12O40, on TiO2 Evonik P25. Moreover, a binary material consisting of H4SiW12O40 and TiO2 was prepared via a hydrothermal treatment and tested for the same reactions. All the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with energy dispersive X-ray (EDX) measurements, diffuse reflectance spectroscopy (DRS), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). The supported Keggin HPA species played a key role both for the catalytic and for the photo-assisted catalytic reactions due to their strong acidity and ability to form strong oxidant species under UV irradiation.
- Marcì, Giuseppe,García-López, Elisa,Vaiano, Vincenzo,Sarno, Giuseppe,Sannino, Diana,Palmisano, Leonardo
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- Selective glycerol oxidation using platinum nanoparticles supported on multi-walled carbon nanotubes and nitrogen-doped graphene hybrid
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Selective oxidation of glycerol is a hot topic. Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied. However, Pt catalysts suffer from deactivation because of weak metal-support interactions. In this study, multi-walled carbon nanotube (MWCNTs)-pillared nitrogen-doped graphene (NG) was prepared by direct pyrolysis of melamine on MWCNTs, and the synthesized NG-MWCNT composite was used as the support for Pt. Characterization results showed that the surface area (173 m2/g) and pore volume of the NG-MWCNT composite were greater than those of bare MWCNTs and the separated melamine pyrolysis product (CNx). Pt (1.4 ± 0.4 nm) dispersion on the NG-MWCNTs was favorable and the Pt/NG-MWCNT catalyst was highly active and selective in the oxidation of glycerol to glyceric acid (GLYA) in base-free aqueous solution. For example, the conversion of glycerol reached 64.4% with a GLYA selectivity of 81.0%, whereas the conversions of glycerol over Pt/MWCNTs and Pt/CNx were 29.0% and 31.6%, respectively. The unique catalytic activity of the Pt/NG-MWCNTs is attributed to well-dispersed Pt clusters on the NG-MWCNTs and the electron-donating effect of the nitrogen dopant in the NG-MWCNTs.
- Zhang, Mengyuan,Sun, Yanyan,Shi, Juanjuan,Ning, Wensheng,Hou, Zhaoyin
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p. 537 - 544
(2017/04/04)
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- Selective oxidation of glycerol in base-free conditions over N-doped carbon film coated carbon supported Pt catalysts
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A series of N-doped carbon film coated active carbon (NxC-XC-72) was prepared via direct pyrolysis of mixed XC-72 (a commercial activated carbon), polyvinyl pyrrolidone and urea. Characterizations indicated that the specific area of synthesized N2.5C-XC-72 reached 281 m2/g and uniform meso pore channels (sized in 4.0 nm) formed. It was found that NxC-XC-72 was an excellent support for the evenly dispersion of Pt compared with raw XC-72. Pt/NxC-XC-72 was active and stable for the selective oxidation of glycerol to glyceric acid in a base-free aqueous solution. The calculated turnover frequency on the basis of surface Pt increased from 573 (in Pt/XC-72) to 706 h? 1 (in Pt/N2.5C-XC-72) at 60 °C.
- Yang, Lihua,Li, Xuewen,Sun, Yanyan,Yue, Linhai,Fu, Jie,Lu, Xiuyang,Hou, Zhaoyin
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p. 107 - 110
(2017/08/14)
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- The Role of Ruthenium on Carbon-Supported PtRu Catalysts for Electrocatalytic Glycerol Oxidation under Acidic Conditions
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A series of binary PtRu catalysts with different Pt/Ru atomic ratios (from 7:3 to 3:7) were synthesized on a carbon support using the colloidal method; they were then used for electrooxidation of glycerol in acid media. X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy analyses were used to investigate particle size, size distribution, and structural and electronic properties of the prepared catalysts. Ru added to the Pt-based catalysts caused structural and electronic modifications over the PtRu alloy catalyst formation. The electrocatalytic activities of PtRu/C series catalysts were investigated using cyclic voltammetry. The Pt5Ru5/C catalyst shows enhanced catalytic activity at least 40 % higher than that of the Pt/C catalyst, with improved stability for glycerol electrooxidation; these improvements are attributed to structural and electronic modifications of the Pt catalysts. Using an electrocatalytic batch reactor, product analysis after the oxidation reaction was performed by high-performance liquid chromatography to determine and compare the reaction pathways on the Pt/C and PtRu/C catalysts. To understand different catalytic activities of glycerol oxidation on the PtRu alloy surfaces, density functional calculations were performed.
- Kim, Youngmin,Kim, Hyun Woo,Lee, Seonhwa,Han, Jisu,Lee, Daewon,Kim, Jeong-Rang,Kim, Tae-Wan,Kim, Chul-Ung,Jeong, Soon-Yong,Chae, Ho-Jeong,Kim, Beom-Sik,Chang, Hyunju,Kim, Won Bae,Choi, Sung Mook,Kim, Hyung Ju
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p. 1683 - 1690
(2017/05/15)
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- Preparation method of 1,3-dihydroxyacetone
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The invention relates to the technical field of organic synthesis, and discloses a preparation method of 1, 3-dihydroxyacetone. The preparation method of 1,3-dihydroxyacetone comprises the following steps: (1) carrying out contact reaction between glycerol and halogenated reagents in presence of a catalyst to prepare 1,3-dichloro-2-propanol; (2) carrying out oxidative dehydrogenation reaction on the 1,3-dichloro-2-propanol to obtain an intermediate product 1,3-dichloro-2 acetone; (3) contacting the 1,3-dichloro-2 acetone with alkali substances in a water-containing medium for hydrolysis reaction to obtain the 1,3-dihydroxyacetone, wherein a hydrolysis reaction temperature is 25 to 60 DEG C. According to the preparation method of the 1,3-dihydroxyacetone, the conversion rate of the glycerol and the yield of the 1,3-dihydroxyacetone are higher; by taking zirconium oxide as the catalyst, the preparation method disclosed by the invention is high-efficient, is low in cost and has industrial application prospect.
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Paragraph 0050
(2017/10/26)
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- Method for producing 1,3-dihydroxyacetone through catalytic oxidation with supported gold catalyst
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The invention discloses a method for producing 1,3-dihydroxyacetone through catalytic oxidation with a supported gold catalyst. According to the method, a glycerin aqueous solution and oxygen are used as raw materials, ZnO, Cu-Al hydrotalcite or spinel supported gold is used as the catalyst, and high selectivity conversion from glycerin to the 1,3-dihydroxyacetone in an oxidation manner is realized in the absence of alkali. The method is performed in the absence of alkali, has low requirement for reaction equipment and is low in investment; the catalyst preparation technology is simple, reaction raw materials are easy to obtain, the reaction process is mild, the method is environment-friendly and free of pollution, the catalyst has advantages of convenience in recovery, long service life and the like, and the industrial prospect is bright.
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Paragraph 0014; 0015
(2016/10/17)
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