cas 78-98-8, Methylglyoxal | Articles data

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Degradation of oligosaccharides in nonenzymatic browning by formation of α-dicarbonyl compounds via a peeling off mechanism
The formation of α-dicarbonyl-containing substances and Amadori rearrangement products was studied in the glycine-catalyzed (Maillard reaction) and uncatalyzed thermal degradation of glucose, maltose, and maltotriose using o-phenylenediamine as trapping agent. Various degradation products, especially α-dicarbonyl compounds, are formed from carbohydrates with differing degrees of polymerization during nonenzymatic browning. The different Amadori rearrangement products, isomerization products, and α-dicarbonyls produced by the used carbohydrates were quantified throughout the observed reaction time, and the relevance of the different degradation pathways is discussed. In the Maillard reaction (MR) the amino-catalyzed rearrangement with subsequent elimination of water predominated, giving rise to hexosuloses with α-dicarbonyl structure, whereas under caramelization conditions more sugar fragments with an α-dicarbonyl moiety were formed. For the MR of oligosaccharides a mechanism is proposed in which 1,4-dideoxyosone is formed as the predominating α-dicarbonyl in the quasi-water-free thermolysis of di- and trisaccharides in the presence of glycine.
Hollnagel, Anke,Kroh, Lothar W.
p. 6219 - 6226
(2000)
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NiO-doped Au/Ti-powder: A catalyst with dramatic improvement in activity for gas-phase oxidation of alcohols
An active and stable NiO@Au/Ti-powder catalyst, which can be obtained by doping Au/Ti-powder (Au: 35-40 nm) with NiO, has been developed for the gas-phase oxidation of alcohols. Gold particles are found to be partially covered with tiny NiO segments to form specific NiO@Au ensembles thereby leading to a dramatic conversion improvement from only ～5% (without NiO doping) to ～94% for the benzyl alcohol oxidation at 280 C. Additionally, the selective oxidation of cyclopropyl carbinol can proceed over this catalyst at 280 C with a selectivity of 94% and a conversion of 72-80% throughout the entire 300 h test. The hybrid active-sites, Ni2O3-Au+, on the NiO@Au ensemble are identified using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS).
Zhao, Guofeng,Hu, Huanyun,Jiang, Zheng,Zhang, Shuo,Lu, Yong
p. 171 - 177
(2013)
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Methylglyoxal synthetase, enol-pyruvaldehyde, glutathione and the glyoxalase system
enol-Pyruvaldehyde (ePY or 2-hydroxypropenal, O=C(H)-C(OH)=CH2) a transient intermediate in the alkaline decomposition of the triosephosphates to methylglyoxal is now observed by UV and 1H NMR spectroscopy as the immediate product of the methylglyoxal synthetase (MGS) reaction: dihydroxyacetone-P → Pi + ePY → methylglyoxal (MG). Analysis of ePY formed from 1-13C- and (1R, 3S)-[1,3-2H]-DHAP establishes the stereochemical course of its formation by MGS. Its rate of ketonization is much too slow to be in the sequence required for the assay of MGS by coupling of the MG produced to glyoxalase I (Glx I): MG + glutathione (GSH) → (S)-lactylglutathione (D-LG). Instead, ketonization occurs by way of the hemithioacetal (HTA) formed between ePY and GSH, and could be either an enzymatic function of Glx I or occur nonenzymatically at an activated rate. Enzymatic ketonization was ruled out because the methyl group of D-LG formed from specifically labeled ePY is achiral. Chemical ketonization of ePY is activated by general bases, such as acetate, and by thiols such as GSH and 2-mercaptoethanol, which disrupt its stabilizing double bond conjugation as hemithioacetal (HTA) adducts. 2-Mercaptoacetate combines both functions, acting as the HTA adduct of ePY with the appended carboxylate group presumably positioned to promote abstraction of the enol proton and protonation of the enolate carbon at an accelerated rate. In the MGS-Glx I system (dihydroxyacetone-P → ePY, ePY + GSH → GS-ePY, GS-ePY → GS-MG, GS-MG → D-LG), the nonenzymatic 2nd and 3rd steps describe the catalytic role of GSH in the critical ketonization process and set the stage for its participation in the glyoxalase system.
Rose, Irwin A.,Nowick, James S.
p. 13047 - 13052
(2002)
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Neuberg,Kobel
p. 243
(1929)
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Formation of pyruvaldehyde (2-oxopropanal) by oxidative dehydrogenation of hydroxyacetone
Various mixed oxides were tested as catalysts for oxidative dehydrogenation of hydroxyacetone to form pyruvaldehyde (2-oxopropanal). The best results were obtained from an iron phosphate with a P/Fe atomic ratio of 1.05. The yield of pyruvaldehyde reached 88%. The next best results were obtained from a supported heteropoly acid (H3PMo12O40). The other molybdenum- and vanadium-based oxide catalysts were not suitable. The effects of the composition and structure of iron phosphate and the effects of reaction variables on the formation of pyruvaldehyde were also studied.
Ai, Mamoru,Ohdan, Kyoji
p. 2143 - 2148
(1999)
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Kinetics, Mechanism, and Thermodynamics of the Reversible Reaction of Methylglyoxal (CH3COCHO) with S(IV)
At pH =/-, SO32-) is obtained: d/dt = (((k0α1+>/Ka0) + k1α1 + k2α2)0)/(1 + Kd + Kd+>/Ka0), where α1 and α2 are the fractional concentrations of HSO3- and SO32-, respectively; k0 is the rate constant for the reaction of HSO3- with the carbocation aldehyde species (CH3COC+HOH); k1 and k2 are the rate constants for the reaction of unhydrated MG with HSO3- and SO32-, respectively; kd is the dehydration constant of hydrated MG; and Ka0 is the acid dissociation constant of the carbocation.At pH =/>4 the rate of formation of HAMS is determined by the rate of dehydration of the diol form of (hydrated) MG: d/dt = kd/(1 + Kd + Kd+>/Θa0), where kd = kw + kH+> + kOH-> + kA + kB, and kw is the intrinsic (water) rate constant; kH and kOH are the specific acid and base rate constants; and kA and kB are the general acid (A) and base (B) rate constants.Between pH 2 and 4, biexponential kinetics are observed because, under our conditions, the rates of dehydration and of S(IV) addition become comparable.Over the pH range 0.7-7.0, the dissociation of HAMS follows the rate law: d/dt = ((k-0+> + k-1 + k-2Ka3/+>)Ka4+>)/(+>2 + Ka4+> + Ka3Ka4), where k-0, k-2 are the reverse of the analogous forward rate constants defined above and Ka3 and Ka4 are the acid dissociation constants of the sulfonate anion and the sulfonic acid, respectively.Experiments to determine the effect of temperature on the rate (and equilibrium) constants indicate a marked effect of ΔS(excit.) (and ΔS298) on the relative magnitude of these constants.
Betterton, Eric A.,Hoffmann, Michael R.
p. 3011 - 3020
(1987)
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Raveux
p. 157
(1946)
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Reactions of aminoguanidine with a-dicarbonyl compounds studied by electrospray ionization mass spectrometry
Aminoguanidine possesses extensive pharmacological properties. This drug is recognized as a powerful a-dicarbonyl scavenger. In order to better elucidate the reactivity of aminoguanidine with a-dicarbonyls, aminoguanidine was reacted with several aldehydic and diketonic a-dicarbonyls. Electrospray ionization mass spectrometry is a suitable technique to study chemical and biochemical processes and was selected for the purpose. In aminoguanidine reactions, triazines were detected and other compounds that have never been reported before were identified. Triazine precursor forms were detected, namely tetrahydrotriazines and singly dehydrated tetrahydrotriazines. Moreover, species with bicyclic ring structures and dehydrated forms were also identified in aminoguanidine reactions. These species appear to result from tetrahydrotriazines and triazines reactions with one dicarbonyl molecule. Experiments revealed that these bicyclic species, in particular the ones resulting from triazines reactivity, could exist in solution, since they were both identified in the reactions of aminoguanidine and of a selected triazine with the dicarbonyls studied. The results obtained with regard to aminoguanidine/triazines reactivities appear to support the capability of triazines to condensate and form polycyclic ring structures and also to support literature mechanistic data for dihydroimidazotriazines formation via dihydroxyimidazolidine-triazines. The data obtained in this study may prove to be valuable to complement solution information concerning the reactivity of amines with a-dicarbonyls, in particular.
Saraiva, Marco A.,Borges, Carlos M.,Florencio, M. Helena
p. 385 - 397,13
(2012)
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Neuberg,Scheuer
p. 1031
(1929)
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Aminoacetone Metabolism by Semicarbazide-Sensitive Amine Oxidase in Rat Aorta
High speed (105,000/60 min) membrane fractions from rat aorta homogenates mobilized the aliphatic amine aminoacetone (AA) to methylglyoxal (MG) with a Km of 19 +/- 3 μM, and Vmax of 510 +/- 169 nmol MG/hr/mg protein. This deaminating activity appears to be due to a semicarbazide-sensitive amine oxidase (SSAO), which is associated with smooth muscle cells in blood vessels of the rat and other species. AA was a competitive inhibitor (Ki of 28 +/- 6 μM) of the metabolism of benzylamine, a synthetic amine often used as an assay substrate for SSAO. AA is produced endogenously from mitochondrial metabolism of threonine and glycine, and thus could be a physiological substrate for SSAO, whereas the production of MG by SSAO could have cytotoxic implications for cellular function.
Lyles, Geoffrey A.,Chalmers, Janette
p. 416 - 419
(1995)
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Kostytschew,Jegorowa
p. 279
(1929)
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Aerobic oxidation of aminoacetone, a threonine catabolite: Iron catalysis and coupled iron release from ferritin
Aminoacetone (AA) is a threonine and glycine catabolite long known to accumulate in cridu-chat and threoninemia syndromes and, more recently, implicated as a contributing source of methylglyoxal (MG) in diabetes mellitus. Oxidation of AA to MG, NH4+, and H2O2 has been reported to be catalyzed by a copper-dependent semicarbazide sensitive amine oxidase (SSAO) as well as by Cu(II) ions. We here study the mechanism of AA aerobic oxidation, in the presence and absence of iron ions, and coupled to iron release from ferritin. Aminoacetone (1-7 mM) autoxidizes in Chelex-treated phosphate buffer (pH 7.4) to yield stoichiometric amounts of MG and NH4+. Superoxide radical was shown to propagate this reaction as indicated by strong inhibition of oxygen uptake by superoxide dismutase (SOD) (1-50 units/mL; up to 90%) or semicarbazide (0.5-5 mM; up to 80%) and by EPR spin trapping studies with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), which detected the formation of the DMPO-·OH adduct as a decomposition product from the DMPO-O2·- adduct. Accordingly, oxygen uptake by AA is accelerated upon addition of xanthine/xanthine oxidase, a well-known enzymatic source of O2·- radicals. Under Fe(II)EDTA catalysis, SOD (· enoyl radical. In the presence of iron, simultaneous (two) electron transfer from both Fe(II) and AA to O2, leading directly to H2O2 generation followed by the Fenton reaction is thought to take place. Aminoacetone was also found to induce dose-dependent Fe(II) release from horse spleen ferritin, putatively mediated by both O2·- and AA· enoyl radicals, and the co-oxidation of added hemoglobin and myoglobin, which may be viewed as the initial step for potential further iron release. It is thus tempting to propose that AA, accumulated in the blood and other tissues of diabetics, besides being metabolized by SSAO, may release iron and undergo spontaneous and iron-catalyzed oxidation with production of reactive H2O2 and O2·-, triggering pathological responses. It is noteworthy that noninsulin-dependent diabetes has been frequently associated with iron overload and oxidative stress.
Dutra,Knudsen,Curi,Bechara
p. 1323 - 1329
(2001)
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Formation of arginine modifications in a model system of N α- Tert -butoxycarbonyl (Boc)-arginine with methylglyoxal
The present study deals with the mechanistic reaction pathway of the α-dicarbonyl compound methylglyoxal with the guanidino group of arginine. Eight products were formed from the reaction of methylglyoxal with N α-tert-butoxycarbonyl (Boc)-arginine under physiological conditions (pH 7.4 and 37 °C). Isolation and purification of substances were achieved using cation-exchange chromatography and preparative high-performance liquid chromatography (HPLC). Structures were verified by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry. 2-Amino-5-(2-amino-4- hydro-4-methyl-5-imidazolinone-1-yl)pentanoic acid (3) was determined as the key intermediate precursor within the total reaction scheme. Kinetic studies identified N--(5-methyl-4-oxo-5-hydroimidazolinone-2-yl)-l-ornithine and N7-carboxyethylarginine as thermodynamically more stable products from compound 3. Further mechanistic investigations revealed an acidic hydrogen at C-8 of compound 3 to trigger aldol condensations. This reactivity of compound 3 allowed for the addition of another molecule of methylglyoxal to form products, such as N--(4-carboxy-4,6-dimethyl-5,6-dihydroxy-1,4,5,6- tetrahydropyrimidine-2-yl)-l-ornithine and argpyrimidine.
Kloepfer, Antje,Spanneberg, Robert,Glomb, Marcus A.
p. 394 - 401
(2011)
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Neuberg,Kobel
p. 1987
(1930)
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Oxidations of Primary Alcohols with a Copper(II) Complex as a Possible Galactose Oxidase Model
N,N'-(2-Hydroxy-propane-1,3-diyl)bis(salicylaldiminato)copper(II) was found to be an effective catalyst for the oxidation of ethanol, n-propanol, or hydroxyacetone in the presence of KOH under O2; the X-ray crystal structure shows that the co-ordination geometry of the copper is significantly distorted toward tetrahedral from square planar with two oxygens and two nitrogens from salicylaldimine moieties.
Kitajima, Nobumasa,Whang, Kaehong,Moro-oka, Yoshihiko,Uchida, Akira,Sasada, Yoshio
p. 1504 - 1505
(1986)
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Suthers,Walker
p. 320
(1932)
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Reactions of a modified lysine with aldehydic and diketonic dicarbonyl compounds: An electrospray mass spectrometry structure/activity study
The phenomenon known as non-enzymatic glycation is described as the reaction of reducing sugars with basic amino groups of proteins and nucleic acids, as well as with simple amines, without enzyme mediation. Non-enzymatic model glycation reactions that make use of low-molecular-weight compounds make an important contribution in the elucidation of glicated processes in vitro and in vivo. Four α-dicarbonyl compounds, aldehydic (glyoxal, methylglyoxal and phenylglyoxal) and ketonic (diacetyl), were reacted with the modified amino acid Na-acetyl-L-lysine (AcLys) in an attempt to establish structure/activity relationships for the reactivity of α-dicarbonyls with the amine compound. Electrospray ionization mass spectrometry (ESI-MS) combined with tandem mass spectrometry (MS/MS) and collision-induced dissociation (CID) was used to identify and characterize reagents, intermediates and reaction products. The formation of dicarbonyl-derived lysine dimers was observed exclusively. Especially, attention is drawn to alkyl-(asymmetrical dicarbonyl systems) and carboxyl-(glyoxal system) substituted imidazolium ions, at ring position 2. The main differences observed in the reactions studied were related to the reactivity with the diimine intermediate. This intermediate can react either with a non-hydrated dicarbonyl molecule at the aldehydic carbonyl, or with a mono-hydrated one at the ketonic carbonyl, particularly for asymmetrical dicarbonyls. For 2-carboxyl-substituted imidazolium ion (glyoxal reaction), besides the usual keto-enol rearrangement from the diol group, an alternative reaction pathway (proton abstraction) appears to contribute also for the imidazolium ring-closure process. Moreover, the formation of imidazolium ring structures can depend on several factors, namely, the presence (or absence) of electron donor substituents at the formed diol, the degree of stability of the new electrophile generated and/or the equilibrium concentration of the non- and mono-hydrated dicarbonyl forms in solution, the last being particularly important for asymmetrical dicarbonyls. The results reported reveal the complexity of reactivity as well as the diversity of imidazolium molecular structures. Copyright
Saraiva, Marco A.,Borges, Carlos M.,Florencio, M. Helena
p. 216 - 228
(2006)
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Yamasaki
p. 130
(1930)
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Evans,Hockett
p. 4384
(1931)
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OH radical-initiated reaction of 3-hexene-2,5-dione: Formation of methylglyoxal
3-Hexene-2,5-dione [CH3C(O)CH=CHC(O)CH3] and other unsaturated 1,4-dicarbonyls are formed from the atmospheric photooxidations of aromatic hydrocarbons. We have reinvestigated the formation of methylglyoxal from the gas-phase reaction of OH radicals with 3-hexene-2,5-dione in the presence of NO at room temperature and atmospheric pressure of air using in situ Fourier transform infrared spectroscopy. No evidence for the formation of methylglyoxal was obtained, with the IR spectra showing that methylglyoxal is, at most, a minor reaction product with a molar formation yield of 3C(O)CH(OH)CHO and CH3C(O)CH(OH)CH(ONO2)C(O)CH3 observed by Bethel et al. (Environ. Sci. Technol. 2001, 35, 4477) are the major first-generation reaction products.
Tuazon, Ernesto C.,Atkinson, Roger
p. 3339 - 3341
(2003)
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Catalytic wet air oxidation of D-glucose by perovskite type oxides (Fe, Co, Mn) for the synthesis of value-added chemicals
The conversion of common biomasses derived, as D-glucose, into value-added chemicals has received highest attention in the last few years. Among all processes, the catalytic wet air oxidation (CWAO) of derived biomasses using noble metal-based heterogeneo
Geobaldo, Francesco,Pirone, Raffaele,Russo, Nunzio,Scelfo, Simone
(2022/03/15)

Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
De Bruin, Bas,De Zwart, Felix J.,Li, Zirui,Mathew, Simon,Wolzak, Lukas A.,Zhou, Minghui
supporting information
p. 20501 - 20512
(2021/12/03)

Designed sol-gel precursors for atomically dispersed Nb and Pb within TiO2as catalysts for dihydroxyacetone transformation
The ‘bottom-up’ synthesis of homogeneously doped metal oxide nanoparticles (NPs) with precision at the atomic/molecular level offers many advantages. We report here the synthesis, structural characterization and hydrolytic behavior of newN-methyldiethanol
Neto, Antonio de Brito Santiago,Alves da Cruz, Márcia Gabriely,Jeanneau, Erwann,Oliveira, Alcineia Concei??o,Essayem, Nadine,Mishra, Shashank
supporting information
p. 1604 - 1609
(2021/02/16)

Maillard Browning Inhibition by Ellagic Acid via Its Adduct Formation with the Amadori Rearrangement Product
The Maillard reaction performed under a stepwise increase of temperature was applied for researching the inhibition of Maillard browning caused by ellagic acid. Ellagic acid was found effective for the inhibition of melanoidin formation in the xylose-glycine Maillard reaction but depended on its dosage and the point of time it was added in the reaction system. The lightest color of the Maillard reaction products was observed when ellagic acid was added at the 90th min, which was the point of time when the Amadori rearrangement product (ARP) developed the most. LC-ESI-MS/MS analysis results showed a significant tendency of the ellagic acid hydrolysis product to react with the predominant intermediate ARP to yield an adduct. The adduct stabilized the ARP and delayed its decomposition and inhibited the downstream reactions toward browning. After the ARP was depleted, ellagic acid also showed an effect on scavenging some short-chain dicarbonyls which contributed to the inhibition of Maillard browning.
Cui, Heping,Hayat, Khizar,Ho, Chi-Tang,Ma, Mengyu,Wang, Ziyan,Xu, Yan,Zhang, Qiang,Zhang, Xiaoming
p. 9924 - 9933
(2021/09/11)

Tin, molybdenum and tin-molybdenum oxides: Influence of Lewis and Bronsted acid sites on xylose conversion
In this study, tin oxide (SnO2), molybdenum oxide (MoO3) and a mixed oxide based on tin and molybdenum (respectively, Sn100, Mo100 and SnMo25, synthesized by the impregnation method) were applied in xylose conversion. The best results were obtained employing Mo100 and SnMo25. In the presence of SnMo25, after 0.5 h, xylose conversions of 39.5%, 34.1% and 63.4% were obtained, respectively, at 110, 130 and 150 °C. For Mo100, conversions of 49.6%, 71.8% and 85.3% were attained under the same reaction conditions, showing that Mo100 provided the best conversion results. However, with the use of this catalyst there was an increase in the amount of soluble and insoluble polymeric material. In terms of the soluble products formed from xylose, depending on the reaction condition were detected xylulose (X), lyxose (L) and furfural (FUR), glyceraldehyde (GL), pyruvaldehyde (PYR), glycoaldehyde (GLYC), dihydroxyacetone (DHA), lactic acid (AL), levulinic acid (LA) and acetic acid (AA). However, with the use of Sn100 or without a catalyst (systems with low conversions) there was mainly the formation of lyxose. The use of Mo100 and SnMo25 (systems which exhibit high acidity) leads mainly to isomerization, epimerization and dehydration reactions, as in the case of the retro-aldol pathway and furfural conversion, highlighting the importance of Lewis and Bronsted acid sites in relation to modulating the selectivity of the systems.
Meneghetti, Mario R.,Meneghetti, Simoni M. P.,Pryston, Dhara B. A.,da Silva Avelino, Débora Olimpio,dos Santos, Thatiane V.
(2021/11/16)

PROCESSES FOR PREPARING C-4 SUGARS AND KETOSE SUGARS
Various processes for preparing C4 aldoses and/or ketones thereof are described. Various processes are described for preparing C4 aldoses and/or ketones thereof from feed compositions comprising glycolaldehyde. Also, various processes for preparing useful downstream products and intermediates, such as erythritol and erythronic acid, from the C4 aldoses and/or ketones thereof are described.
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(2021/11/20)

PROCESSES FOR THE PYROLYSIS OF CARBOHYDRATES
Various processes for the pyrolysis of carbohydrates to prepare products such as glycolaldehyde are described. Also, various catalysts and processes for preparing catalysts useful for carbohydrate pyrolysis are described.
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Page/Page column 13-27

(2021/11/20)

Simultaneous generation of acrylamide, β-carboline heterocyclic amines and advanced glycation ends products in an aqueous Maillard reaction model system
The simultaneous formation of acrylamide; β-carboline heterocyclic amines (HAs): harmane and norharmane; and advanced glycation end products (AGEs) (Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL)) was analyzed based on an aqueous model system. The model systems included lysine–glucose (Lys/Glu), asparagine–glucose (Asn/Glu), tryptophan–glucose (Trp/Glu), and a mixture of these amino acids (Mix/Glu). Only AGEs were generated when heated at 100 °C, Asn and Trp competed with Lys for glucose and methylglyoxal (MGO), and glyoxal (GO) decreased AGE content. The k value of CML, CEL, and acrylamide decreased when heated at 130 °C, whereas that of harmane increased in the Mix/Glu, owing to the competition between Lys and Asn for glucose, GO, and MGO. Harmane preferably formed via the Pictet–Spengler condensation between Trp and acetaldehyde, which further reduced acrylamide formation via the acrolein pathway.
Chen, Jie,He, Zhiyong,Jiao, Ye,Li, Yong,Liu, Guoping,Qin, Fang,Quan, Wei,Wang, Zhaojun,Xue, Chaoyi,Zeng, Maomao
(2020/07/06)

Method for preparing pyruvic aldehyde by catalyzing sugar
The invention relates to a method for preparing pyruvic aldehyde by catalyzing sugar. The method comprises the following steps: contacting sugar with a catalyst in a reactor in the presence of alcohol, and reacting to obtain a pyruvic aldehyde-containing product, wherein the molar ratio of the sugar to the alcohol is 1:(50-600), the reaction temperature is 100 DEG C or above and lower than 150 DEGC, the reaction time is 10-50 hours, the catalyst contains a tin-titanium-silicon molecular sieve, and the weight ratio of the sugar to the tin-titanium-silicon molecular sieve based on dry basis weight is 1:(1-6). The method provided by the invention has high sugar conversion rate and high pyruvic aldehyde yield.
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Paragraph 0164-0191; 0200-0207

(2020/06/30)

Method for preparing pyruvic aldehyde
The invention relates to a method for preparing pyruvic aldehyde. The method comprises the following steps of: contacting sugar with a catalyst in a reactor in the presence of alcohol, and reacting toobtain a pyruvic aldehyde-containing product, wherein the molar ratio of the sugar to the alcohol is 1:1, the reaction temperature is 100 DEG C or above and lower than 150 DEG C, the reaction time is10-50 h, the catalyst contains a mixture of a titanium-silicon molecular sieve and a tin-silicon molecular sieve, and the weight ratio of the sugar to the mixture of the titanium-silicon molecular sieve and the tin-silicon molecular sieve based on the dry basis weight is 1:(0.1-6). The method provided by the invention has high sugar conversion rate and high pyruvic aldehyde yield.
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Paragraph 0072-0083; 0092-0093; 0096-0101

(2020/06/30)

Catalytic conversion of fructose to 1,3-dihydroxyacetone under mild conditions
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
(2020/07/13)

Bi-Functional Magnesium Silicate Catalyzed Glucose and Furfural Transformations to Renewable Chemicals
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
p. 4807 - 4816
(2020/08/24)

Stanosilicates based on Sn-magadiites applied in conversion of fructose at moderate temperatures
Sn-Magadiite stanosilicates were successfully synthesized by the hydrothermal method. They were found to be efficient in fructose conversion, particularly at 130, 150 and 170 °C. The temperature of 150 °C was ideal for the formation of retro-aldol fragmen
Dos Santos, Tiago Gomes,Da Silva, Antonio Osimar Sousa,Plentz Meneghetti, Simoni Margareti
p. 6111 - 6115
(2020/11/03)

Silica-supported chromia-titania catalysts for selective formation of lactic acid from a triose in water
A variety of silica-supported metal oxide catalysts were prepared by the incipient wetness impregnation method and were used for the conversion of dihydroxyacetone to lactic acid. A titanium oxide catalyst with Br?nsted acid sites was selective to an intermediate, pyruvaldehyde and a chromium oxide catalyst with Lewis acid sites was selective to lactic acid. The co-impregnation of chromium- and titanium oxides with different ratios accelerated the reaction rate and improved the lactic acid yield up to 80% at 130 °C. Pyridine-adsorbed Fourier-transform infrared spectroscopy indicated that the silica-supported mixed oxides had both Br?nsted acid and Lewis acid sites and the trend of the Lewis/Br?nsted ratio was close to that of selectivity to lactic acid. Diffuse reflectance UV–vis spectroscopy showed that the silica-supported chromia-titania catalyst composed of isolated Cr and Ti species in tetrahedral coordination. Kinetic analysis revealed that the two critical rate constants, pyruvaldehyde formation and lactic acid formation, for the chromia-titania catalyst were much higher than those of the titania and chromia catalysts.
Takagaki, Atsushi,Goto, Hiroshi,Kikuchi, Ryuji,Oyama, S. Ted
p. 200 - 208
(2018/12/02)

Preparation method of furanone
The invention discloses a preparation method of furanone. The preparation method includes the steps that an acetone aldehyde solution is prepared, a 3,4-dihydroxy-2,5-hexanedione solution is prepared,3,4-dihydroxy-2,5-hexanedione is purified, semi-finished furanone is prepared, and finished furanone is prepared. The preparation method has the advantages that 1, the yield of the intermediate 3,4-dihydroxy-2,5-hexanedione and the total yield of the furanone can be increased through composite catalyst zinc powder, iron powder and manganese powder, 2, purity of the intermediate 3,4-dihydroxy-2,5-hexanedione is obviously increased by adding anhydrous sodium sulphate and sodium chloride composite powder, and 3, purity of the furanone can be obviously improved by combining extractant ethanol andethyl acetate.
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Paragraph 0017; 0022; 0027

(2019/11/12)

Aerobic oxidation of glycerol catalyzed by M salts of PMo12O403-(M = K+, Zn2+, Cu2+, Al3+, Cr3+, Fe3+)
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
p. 52 - 57
(2019/05/01)

The cooperative effect of Lewis and Br?nsted acid sites on Sn-MCM-41 catalysts for the conversion of 1,3-dihydroxyacetone to ethyl lactate
Lactic acid and alkyl lactates are widely applied in the production of food, cosmetics, pharmaceuticals, organic synthesis and biodegradable polymers. They can be prepared via one-pot synthesis from renewable trioses, such as dihydroxyacetone (DHA). Br?nsted-Lewis bifunctional solid acids (BAS & LAS) can promote the reaction via a two-step cascade reaction mechanism. BAS catalyses the dehydration of DHA, resulting in the formation of pyruvaldehyde (PA) via the rearrangement of the enol form. Upon alcohol addition, PA can be converted to the desired alkyl lactates at LAS or to pyruvaldehyde hemiacetal (PAHA) at strong BAS. The density and strength control of Br?nsted acid sites (BAS) and Lewis acid sites (LAS) and the optimization of their cooperation are essential for the efficient conversion of trioses to the target products. Here, we prepared a series of Sn-containing mesoporous MCM-41 catalysts with various BAS/LAS ratios by room temperature techniques. Sn-doped [Si]MCM-41 having a lower BAS/LAS ratio in this research shows a high initial selectivity to ethyl lactate (EL) and similar EL yield in 6 hours as the reported best Sn catalyst Sn-grafted [Si]MCM-41/carbon network materials in DHA conversion. A relatively large density of LAS in Sn-doped [Si]MCM-41 causes a fast conversion of PA to EL, while the overall yield has been limited by the BAS density for the DHA conversion. New H-form [Sn]MCM-41, having a suitable density of LAS and weak BAS and an optimized BAS/LAS ratio, provides a 100% yield of ethyl lactate in the catalytic conversion of DHA in ethanol within 30 min, showing a superior performance hitherto.
Kim, Kyung Duk,Wang, Zichun,Jiang, Yijiao,Hunger, Michael,Huang, Jun
supporting information
p. 3383 - 3393
(2019/06/24)

CuO/CeO2 catalysts for glycerol selective conversion to lactic acid
Ceria supported copper oxide catalysts were produced by a deposition-precipitation method, at a high copper loading (up to >25 wt%). These materials demonstrated excellent properties for glycerol selective conversion to lactic acid, with a conversion reaching up to 87% with a selectivity to lactic acid of 74% (8 h reaction, 220 °C, under N2 pressure). These catalysts also exhibited high stability upon 5 successive reaction cycles. The formation of a crystalline CuO phase was demonstrated in the nanocomposites at a high Cu loading, with elongated shaped particles formed on the cerium oxide surface. Such particles were however, not observed at low Cu loadings. XPS analysis revealed that Cu(ii) was the main Cu species on the fresh catalyst, and that this species was reduced to Cu(i) during the reaction. Complementary characterization over the spent catalyst clearly showed the morphological modifications of the CuO phase, however, did not impact significantly either glycerol conversion or selectivity to lactic acid upon recycling. For instance, apparently, the catalytic activity of CuO largely depends on the Cu(ii) species.
Palacio, Ruben,Torres, Sebastian,Royer, Sébastien,Mamede, Anne Sophie,López, Diana,Hernández, Diana
p. 4572 - 4582
(2018/04/03)

Transformation of cellulose and related carbohydrates into lactic acid with bifunctional Al(III)-Sn(II) catalysts
The catalytic transformation of cellulose into valuable chemicals such as lactic acid under mild conditions represents a promising route for the efficient utilization of renewable biomass. Here, we report that the combination of Al(iii) and Sn(ii) cations can efficiently catalyse the conversion of cellulose and related carbohydrates into lactic acid in water. Al(iii)-Sn(ii) is the most efficient combination for lactic acid formation among the many dual cations investigated. Al(iii) and Sn(ii) with a molar ratio of 1/1 work cooperatively, providing lactic acid with yields of 90%, 81% and 65% in the conversions of fructose, glucose and cellulose, respectively. The formation of lactic acid involves a series of tandem steps including the hydrolysis of cellulose to glucose, the isomerisation of glucose to fructose, the retro-aldol fragmentation of fructose to C3 intermediates and the subsequent conversion of the C3 intermediates to lactic acid. Our experimental and computational studies suggest that Al(iii) mainly catalyses the isomerisation of glucose or the C3 intermediates, whereas Sn(ii) is primarily responsible for the retro-aldol fragmentation. The combination of the two cations enables the reaction to proceed smoothly with few side reactions, providing outstanding catalytic performances for lactic acid production from cellulose or the related carbohydrates.
Deng, Weiping,Wang, Pan,Wang, Binju,Wang, Yanliang,Yan, Longfei,Li, Yanyun,Zhang, Qinghong,Cao, Zexing,Wang, Ye
supporting information
p. 735 - 744
(2018/02/14)

PRODUCTION OF GLYCOLALDEHYDE BY THERMOLYTIC FRAGMENTATION
The present invention relates to a process for the production of glycolaldehyde by thermolytic fragmentation of a carbohydrate feedstock comprising mono- and/or di-saccharide(s) and a system suitable for performing the process. The process and the system are suitable for industrial application, and the process may be performed in a continuous process.
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Page/Page column 19-10

(2018/06/30)

Prebiotic synthesis of aminooxazoline-5′-phosphates in water by oxidative phosphorylation
RNA is essential to all life on Earth and is the leading candidate for the first biopolymer of life. Aminooxazolines have recently emerged as key prebiotic ribonucleotide precursors, and here we develop a novel strategy for aminooxazoline-5′-phosphate synthesis in water from prebiotic feedstocks. Oxidation of acrolein delivers glycidaldehyde (90%), which directs a regioselective phosphorylation in water and specifically affords 5′-phosphorylated nucleotide precursors in upto 36% yield. We also demonstrated a generational link between proteinogenic amino acids (Met, Glu, Gln) and nucleotide synthesis.
Fernández-García,Grefenstette,Powner
supporting information
p. 4919 - 4921
(2017/07/11)

Kinetic study of the ethyl lactate synthesis from triose sugars on Sn/Al2O3 catalysts
The reaction kinetics of the liquid-phase synthesis of ethyl lactate from dihydroxyacetone and ethanol was studied on Sn-promoted alumina catalysts. Yields of ≈70% were obtained at 353?K after 7?h of reaction. The effect of the catalyst Sn loading (1–8?wt.%) and reaction temperature (343–373?K) on the reaction kinetics was investigated. The reaction is promoted by Lewis acid sites provided by surface Sn species. A kinetic model based on a pseudohomogeneous mechanism was postulated to describe the reaction network comprising a sequence of consecutive and parallel reaction steps. The kinetic rate constant associated to ethyl lactate formation increases with the number of Lewis acid sites confirming that surface Sn species participate in the kinetically relevant reaction steps. Catalysts were prepared by impregnation and characterized by N2 physisorption, X-ray diffraction, UV-vis-DRS, FTIR of pyridine and TPD of NH3.
Pighin,Díez,Di Cosimo
p. 29 - 37
(2017/05/16)

FePO4/SiO2 Catalysts for Propylene Glycol Oxidation
FePО4/SiO2 supported catalysts with a different content of iron phosphate are prepared. The properties of the catalyst are changed by the introduction of alkali metal compounds (Na or Cs) on its surface. The samples obtained are characterized by X-ray diffraction, low-temperature nitrogen adsorption, temperatureprogrammed reduction by hydrogen, and temperature-programmed desorption of ammonia. The catalytic properties are investigated in the reaction of gas-phase propylene glycol oxidation. It is shown that the selectivity of methylglyoxal formation on the unmodified catalysts is determined by the state of the supported active component and by its reduction–oxidation ability under the action of a reaction mixture.
Ebert, D. Yu.,Savel’eva,Dorofeeva,Vodyankina
p. 720 - 725
(2018/03/08)

Synthesis of ethyl lactate from triose sugars on Sn/Al2O3 catalysts
Sn-promoted alumina catalysts with different Sn loadings (1-8 wt.%) were prepared by impregnation and characterized by N2 physisorption, X-ray diffraction, UV-vis-DRS, FTIR of pyridine and TPD of NH3. Surface Sn species present Lewis acid properties different from those of the alumina support; the number and strength of the surface Lewis centers increase with the Sn loading. These materials exhibit good catalytic performance for conversion of triose sugars, such as dihydroxyacetone, toward ethyl lactates at mild conditions. The catalyst preparation conditions, Sn content and reaction conditions affect the final ethyl lactate yield. Yields of ≈70% were obtained at 353 K after 7 h of reaction. Surface Sn species participate in the kinetically relevant reaction steps.
Pighin,Díez,Di Cosimo
p. 151 - 160
(2016/03/22)

Catalytic Deoxygenation of Bio-Oil Model Compounds over Acid-Base Bifunctional Catalysts
An acid-base bifunctional catalyst was synthesized by treating a natural mixed-metal oxide, serpentine, with sulfuric acid. Catalyst characterization revealed that the number of acidic and basic sites increased after the acid treatment largely due to an increase in surface area. However, stronger acid sites were also introduced by the formation of bridged hydroxyl groups between a Si atom and a heteroatom, as inferred by H NMR and NH3-TPD analysis. Results from SEM-EDS and 1H NMR suggested that the acid and base sites were in close proximity. Catalytic conversions of carbohydrate-derived bio-oil model compounds were performed over different acid/base catalysts. Eight single bio-oil model compounds and two binary mixtures were used. The reactivity of the model compounds was found to be strongly correlated to the number of oxygen-containing functional groups in the reactant. The results from the binary mixtures showed that the acid-base bifunctional catalyst had the highest activity in aldol condensation reactions. The best deoxygenation performance was also observed with the bifunctional catalyst for the model compounds. Reaction pathways were proposed on the basis of an isotope labeling study. Deoxygenation reactions were found to be promoted by the cooperative catalysis between closely located acid and base sites.
Zhang, Jing,Wang, Kaige,Nolte, Michael W.,Choi, Yong S.,Brown, Robert C.,Shanks, Brent H.
p. 2608 - 2621
(2016/04/26)

Tailoring nano-catalysts: Turning gold nanoparticles on bulk metal oxides to inverse nano-metal oxides on large gold particles
Highly active/stable inverse catalysts of nano-oxides on large gold particles are designed and tailored. For the gas-phase oxidation of alcohols as a model reaction, the experimental and theoretical results verify that the catalyst activity depends on the gold-oxide interface, and the anti-sintering feature of such an inverse structure endows the catalyst with high stability.
Zhao, Guofeng,Wu, Xin-Ping,Chai, Ruijuan,Zhang, Qiaofei,Gong, Xue-Qing,Huang, Jun,Lu, Yong
supporting information
p. 5975 - 5978
(2015/03/30)

Fructose conversion in the presence of Sn(iv) catalysts exhibiting high selectivity to lactic acid
The catalytic performance of a series of Sn(iv)-based organometallic complexes in fructose conversion was studied under several reaction conditions, and the conversion, yields, and selectivity measurements of this transformation have been evaluated. The results were compared to those obtained from non-catalysed reactions and those in the presence of a conventional catalyst (H2SO4). These organometallic Sn(iv)-based catalysts demonstrated the ability to fully convert fructose into valuable chemicals. Under particular reaction conditions, lactic acid is obtained in good yields and selectivity.
Dos Santos, Jailma Barros,De Albuquerque, Nilson José Araújo,De Paiva E Silva Zanta, Carmen Lúcia,Meneghetti, Mario Roberto,Meneghetti, Simoni Margareti Plentz
p. 90952 - 90959
(2015/11/11)

Governing chemistry of cellulose hydrolysis in supercritical water
At extremely low reaction times (0.02 s), cellulose was hydrolyzed in supercritical water (T=400°C and P=25 MPa) to obtain a sugar yield higher than 95 wt %, whereas the 5-hydroxymethylfurfural (5-HMF) yield was lower than 0.01 wt %. If the reaction time was increased to 1 s, the main product was glycolaldehyde (60 wt %). Independently of the reaction time, the yield of 5-HMF was always lower than 0.01 wt %. To evaluate the reaction mechanism of biomass hydrolysis in pressurized water, several parameters (temperature, pressure, reaction time, and reaction medium) were studied for different biomasses (cellulose, glucose, fructose, and wheat bran). It was found that the H+ and OH- ion concentration in the reaction medium as a result of water dissociation is the determining factor in the selectivity. The reaction of glucose isomerization to fructose and the further dehydration to 5-HMF are highly dependent on the ion concentration. By an increase in the pOH/pH value, these reactions were minimized to allow control of 5-HMF production. Under these conditions, the retroaldol condensation pathway was enhanced, instead of the isomerization/dehydration pathway. Just add water: A reaction mechanism for cellulose hydrolysis that can explain the huge selectivity of biomass hydrolysis in supercritical water is presented. The model of the reaction mechanism has been validated by several experiments carried out in a continuous pilot plant capable at various conditions. It was found that the proton and hydroxide anion concentration in the medium due to water dissociation (represented by the ionic product of water, Kw) is the determining factor in the selectivity of the process.
Cantero, Danilo A.,Bermejo, M. Dolores,Cocero, M. José
p. 1026 - 1033
(2015/03/30)

Lactic acid production from hydroxyacetone on dual metal/base heterogeneous catalytic systems
Oxidative aqueous-phase catalytic conversion of hydroxyacetone to lactic acid was investigated under mild and green reaction conditions. Dual metal/base catalyst systems were applied to replace the alkali hydroxide and address the separation requirements and corrosiveness issues usually involved in similar processes. Pt/Al2O3 was taken as the supported metal catalyst while Mg-Al layered double hydroxides (LDH) and their derived 3D mixed oxides were exploited as basic solid catalysts. The anion embedded within the LDH interlamellar domain (nitrate or hydroxyl) and the LDH topology (lamellar or exfoliated 2D nanosheets) were also examined. Activity and chemoselectivity of the dual system were shown to be tailored by the decisive to the catalyst performance; the proximity of metal and basic centres on the same surface rendered highly selective bifunctional catalysts. A remarkable 100% selectivity to lactic acid was reached and the undesired cascade oxidation of lactic to pyruvic acid was hindered.
Albuquerque, Elise M.,Borges, Luiz E. P.,Fraga, Marco A.
p. 3889 - 3899
(2015/07/15)

Unexplored reactivity of 2-oxoaldehydes towards Pictet-Spengler conditions: Concise approach to β-carboline based marine natural products
Novel reactions under Pictet-Spengler conditions between tryptophan methyl ester/tryptamine and 2-oxoaldehydes have been developed and successfully utilized for the total synthesis of Merinacarboline (A and B), Eudistomin Y1, Pityriacitrin B, Pityriacitrin, Fascaplysin and analogues.
Battini, Narsaiah,Padala, Anil K.,Mupparapu, Nagaraju,Vishwakarma, Ram A.,Ahmed, Qazi Naveed
p. 26258 - 26263
(2014/07/08)

Lewis acid properties of some metal salts for lactic acid formation in water: 31P NMR spectroscopy with trimethylphosphine oxide as a molecular probe
31P NMR spectroscopy was applied to the evaluation of water-tolerant Lewis acid catalysis of various metal triflates and chlorides in water using trimethylphosphine oxide (TMPO) as a probe molecule. Direct interaction of the TMPO molecule with the Lewis acid in water changes the original 31P NMR chemical shift and line width. ScCl3, Sc(OTf)3 and In(OTf)3 exhibit larger changes in the 31P chemical shift by the formation of a Lewis acid-TMPO complex than other triflates and chlorides. This is due to strong interaction between the Lewis acid and TMPO, which leads to the slow exchange between TMPO and H 2O in ScCl3, Sc(OTf)3 and In(OTf)3. Lewis acids with large change in the 31P chemical shift exhibit high catalytic activities for lactic acid formation from 1,3-dihydroxyacetone (1.3-DHA) and pyruvic aldehyde in water: Strong interaction with TMPO on the Lewis acid is a dominant factor for lactic acid formation.
Koito, Yusuke,Nakajima, Kiyotaka,Hasegawa, Ryota,Kobayashi, Hisayoshi,Kitano, Masaaki,Hara, Michikazu
p. 198 - 203
(2014/03/21)

An efficient and reusable vanadium based catalytic system for room temperature oxidation of alcohols to aldehydes and ketones
A simple and efficient vanadium based catalyst system for the oxidation of primary and secondary alcohols to aldehydes or ketones is reported using tert-butyl hydroperoxide as oxidizing agent and vanadyl sulfate as catalyst at room temperature. The versatility of the catalytic protocol is studied with wide variety of substrates.
Sarmah, Gayatri,Bharadwaj, Saitanya K.,Dewan, Anindita,Gogoi, Ankur,Bora, Utpal
p. 5029 - 5032
(2015/01/08)

Influence of acid-base sites on ZnO-ZnCr2O4 catalyst during dehydrocyclization of aqueous glycerol and ethylenediamine for the synthesis of 2-methylpyrazine: Kinetic and mechanism studies
The physicochemical characteristics of ZnO-ZnCr2O4 (Zn-Cr-O) mixed oxides were determined by adsorption and spectroscopic methods. The catalytic activities of Zn-Cr-O was investigated for dehydrocyclization of ethylenediamine and aqu
Venugopal, Akula,Sarkari, Reema,Anjaneyulu, Chatla,Krishna, Vankudoth,Kumar, Mandari Kotesh,Narender, Nama,Padmasri, Aytam Hari
p. 398 - 409
(2013/11/19)

Products of the OH radical-initiated reactions of furan, 2- and 3-methylfuran, and 2,3- and 2,5-dimethylfuran in the presence of NO
Products of the gas-phase reactions of OH radicals with furan, furan-d 4, 2- and 3-methylfuran, and 2,3- and 2,5-dimethylfuran have been investigated in the presence of NO using direct air sampling atmospheric pressure ionization tandem mass spectrometry (API-MS and API-MS/MS), and gas chromatography with flame ionization and mass spectrometric detectors (GC-FID and GC-MS) to analyze samples collected onto annular denuders coated with XAD solid adsorbent and further coated with O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine for derivatization of carbonyl-containing compounds to their oximes. The products observed were unsaturated 1,4-dicarbonyls, unsaturated carbonyl-acids and/or hydroxy-furanones, and from 2,5-dimethylfuran, an unsaturated carbonyl-ester. Quantification of the unsaturated 1,4-dicarbonyls was carried out by GC-FID using 2,5-hexanedione as an internal standard, and the measured molar formation yields were: HC(O)CH=CHCHO (dominantly the E-isomer) from OH + furan, 75 ± 5%; CH3C(O)CH=CHCHO (dominantly the E-isomer) from OH + 2-methylfuran, 31 ± 5%; HC(O)C(CH3)=CHCHO (a E-/Z-mixture) from OH + 3-methylfuran, 38 ± 2%; and CH 3C(O)C(CH3)=CHCHO from OH + 2,3-dimethylfuran, 8 ± 2%. In addition, a formation yield of 3-hexene-2,5-dione from OH + 2,5-dimethylfuran of 27% was obtained from a single experiment, in good agreement with a previous value of 24 ± 3% from GC-FID analyses of samples collected onto Tenax solid adsorbent without derivatization.
Aschmann, Sara M.,Nishino, Noriko,Arey, Janet,Atkinson, Roger
p. 457 - 466
(2014/02/14)

PROCESS FOR PREPARING KETENE IN THE PRESENCE OF A FLUIDIZED BED MATERIAL WITH A SURFACE AREA OF UP TO 600 M2/G
A Process for preparing ketene in the presence of a fluidized bed material with a surface area of up to about 600 m2/g. The process is further defined as a process for preparing ketene from a sugar or glycolaldehyde feedstock.
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(2014/09/16)

Atmospheric aqueous phase radical chemistry of the isoprene oxidation products methacrolein, methyl vinyl ketone, methacrylic acid and acrylic acid-kinetics and product studies
Kinetic and mechanistic studies were conducted on the isoprene oxidation products methacrolein, methyl vinyl ketone, methacrylic and acrylic acid reacting with hydroxyl and nitrate radicals and sulfate radical anions in aqueous solution by use of the laser flash photolysis technique and a reversed-rate method for kinetics. High-performance liquid chromatography/mass spectrometry was applied for product analysis. The kinetic investigations show the highest reactivity of the hydroxyl radical followed by sulfate and nitrate radicals. For methacrolein and methyl vinyl ketone the following rate constants have been determined at 298 K: k(OH+methacrolein) = (9.4 ± 0.7) × 109 M-1 s-1, k (OH+methylvinylketone) = (7.3 ± 0.5) × 109 M-1 s-1, k(NO3+methacrolein) = (4.0 ± 1.0) × 107 M-1 s-1, k(NO 3+methylvinylketone)= (9.7 ± 3.4) × 106 M-1 s-1, k (SO4-+methacrolein) = (9.9 ± 4.9) × 107 M-1 s-1 and k (SO4-+methylvinylketone) = (1.0 ± 0.2) × 108 M-1 s-1. Temperature and pH dependencies of the reactions of OH, NO3 and SO4 - with methacrolein, methyl vinyl ketone, methacrylic and acrylic acid as well as Arrhenius parameters have been obtained and discussed. Product studies were performed on the OH radical induced oxidation of methacrolein and methyl vinyl ketone. In the reaction of methacrolein + OH methylglyoxal and hydroxyacetone were identified as first oxidation products with yields of 0.099 and 0.162. Methylglyoxal was primarily produced in the oxidation of methyl vinyl ketone with a yield of 0.052. For both precursor compounds the formation of glycolaldehyde was observed for the first time with yields of 0.051 and 0.111 in the oxidation of methacrolein and methyl vinyl ketone, respectively. Furthermore, highly functionalised C4 compounds were determined from the oxidation of both precursor compounds, but for the first time for methyl vinyl ketone. Reaction schemes were developed based on known peroxyl radical reaction mechanisms. The aqueous phase conversion of the first generation isoprene oxidation products can potentially contribute to tropospheric aqueous phase budgets of important carbonyl and dicarbonyl components which are expected to be conducive to the formation of aqSOA. This journal is
Schoene, Luisa,Schindelka, Janine,Szeremeta, Edyta,Schaefer, Thomas,Hoffmann, Dirk,Rudzinski, Krzysztof J.,Szmigielski, Rafal,Herrmann, Hartmut
p. 6257 - 6272
(2014/04/03)

Base free, one-pot synthesis of lactic acid from glycerol using a bifunctional Pt/Sn-MFI catalyst
Under base free and mild reaction conditions, 80.5% selectivity of lactic acid (LA) was achieved at 89.8% conversion of glycerol using a bifunctional Pt/Sn-MFI catalyst. In the tandem reaction pathway, selective oxidation of glycerol to glyceraldehyde (GLA) and dihydroxyacetone (DHA) was cascaded with Lewis acid catalyzed isomerization of GLA/DHA into LA. This journal is the Partner Organisations 2014.
Cho, Hong Je,Chang, Chun-Chih,Fan, Wei
supporting information
p. 3428 - 3433
(2014/07/08)

METHOD FOR PRODUCING ALPHA-KETOALDEHYDE COMPOUND
An object of the present invention is to provide a new method for producing an ALPHA-ketoaldehyde compound from a 2-oxo-primary alcohol compound. The present invention provides a method for producing an ALPHA-ketoaldehyde compound including a step of oxidizing a 2-oxo-primary alcohol compound in the presence of platinum, a platinum compound, iron or an iron compound. The 2-oxo-primary alcohol compound is preferably a compound represented by the formula (1a), and the ALPHA-ketoaldehyde compound is preferably a compound represented by the formula (2a), wherein Ra is a C1-C6 alkyl group which may have a substituent or a C6-C20 aryl group which may have a substituent.
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Paragraph 0068

(2013/03/26)

Microstructured Au/Ni-fiber catalyst: Galvanic reaction preparation and catalytic performance for low-temperature gas-phase alcohol oxidation
The highly active and selective gold catalysts were successfully prepared by galvanically depositing Au onto a thin-sheet microfibrous structure consisting of 5 vol.% 8-μm Ni-fiber and 95 vol.% voidage, with high heat conductivity and good stability for the gas-phase oxidation of alcohols. The best catalyst was Au-4/Ni-fiber-300 (Au-loading: 4 wt%; calcined at 300 °C in air), being effective for oxidizing acyclic, benzylic, and polynary (1,2-propanediol) alcohols. For benzyl alcohol, the conversion of 95% was achieved with 99% selectivity to benzaldehyde within 660 h test at 250 °C, while a low ΔT of 2 formed at Au galvanic deposition step into NiO was identified along with the low-temperature activity promotion. This suggests a special synergistic effect between NiO and Au particles, of which comprehensive understanding is particularly desirable.
Zhao, Guofeng,Deng, Miaomiao,Jiang, Yifeng,Hu, Huanyun,Huang, Jun,Lu, Yong
p. 46 - 53
(2013/05/21)

Rate Constants for the Reactions of Oh Radicals with 1,2,4,5- Tetramethylbenzene, Pentamethylbenzene, 2,4,5-Trimethylbenzaldehyde, 2,4,5-Trimethylphenol, and 3-Methyl-3-Hexene-2,5-Dione and Products of OH + 1,2,4,5-tetramethylbenzene
Using a relative rate method, rate constants have been measured for the reactions of OH radicals with 1,2,4,5-tetramethylbenzene, pentamethylbenzene, 2,4,5-trimethylbenzaldehyde, 2,4,5-trimethylphenol and 3-methyl-3-hexene-2,5- dione at 298 ± 2 K and atmospheric pressure of air. The rate constants obtained (in units of 10-11 cm3 molecule-1 s-1) were: 1,2,4,5-tetramethylbenzene, 5.55 ± 0.34; pentamethylbenzene, 10.3 ± 0.8; 2,4,5-trimethylbenzaldehyde, 4.27 ± 0.39; 2,4,5-trimethylphenol, 9.75 ± 0.98; and 3-methyl-3-hexene-2,5-dione, 9.4 ± 1.1. The following first-generation products were identified from the OH + 1,2,4,5-tetramethylbenzene reaction in the presence of NO: biacetyl, methylglyoxal, 3-methyl-3-hexene-2,5-dione, and 2,4,5-trimethylbenzaldehyde. The measured molar formation yields for 3-methyl-3-hexene-2,5-dione and 2,4,5-trimethylbenzaldehyde were 45 ± 9% and 3.3 ± 0.7%, with that for 3-methyl-3-hexene-2,5-dione being extrapolated to low NO2 concentrations where the OH-1,2,4,5- tetramethylbenzene adducts react only with O2. Biacetyl appeared to be formed as both a first- and second-generation product, and a first-generation formation yield of 9 ± 3% was derived. The relative formation yield of methylglyoxal was ～0.8 of that for 3-methyl-3-hexene-2,5-dione, indicating that methylglyoxal and 3-methyl-3-hexene-2,5-dione are coproducts. H-atom abstraction from OH + 1,2,4,5-tetramethylbenzene is estimated to account for 3.7 ± 0.8% of the overall OH radical reaction. On the basis of the current understanding of the mechanism of the OH-aromatic adduct + O2 reaction, the observed formation of biacetyl indicates that some ipso addition of OH occurs for OH + 1,2,4,5-tetramethylbenzene.
Aschmann, Sara M.,Arey, Janet,Atkinson, Roger
p. 2556 - 2568
(2013/06/26)

2-alkoxypropenals as synthetic equivalents of methylglyoxal in the synthesis of heterocycles
One-pot synthesis of 2-methylquinoxaline, 3-hydroxy-2-methylimidazo[1,2-a] pyridine, and 2-methyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one via cycloaddition of N,N-binucleophilic o-phenylenediamine, 2-aminopyridine, and 2-aminopyrazine, respectively, to methylglyoxal generated in situ by hydrolysis of 2-alkoxypropenals is reported for the first time. Thus 2-alkoxypropenals in weakly acidic medium (25-80 C, 1-4 h) are convenient synthetic equivalents of methylglyoxal in the synthesis of heterocyclic compounds.
Keiko,Vchislo,Larina
p. 428 - 431
(2013/07/26)

The mechanism of 2-furaldehyde formation from d-xylose dehydration in the gas phase. A tandem mass spectrometric study
The mechanism of reactions occurring in solution can be investigated also in the gas phase by suited mass spectrometric techniques, which allow to highlight fundamental mechanistic features independent of the influence of the medium and to clarifying controversial hypotheses proposed in solution studies. In this work, we report a gas-phase study performed by electrospray triple stage quadrupole mass spectrometry (ESI-TSQ/MS) on the dehydration of d-xylose, leading mainly to the formation of 2-furaldehyde (2-FA). It is generally known in carbohydrate chemistry that the thermal acid catalyzed dehydration of pentoses leads to the formation of 2-FA, but several aspects on the solution-phase mechanism are controversial. Here, gaseous reactant ions corresponding to protonated xylose molecules obtained from ESI of a solution containing d-xylose and ammonium acetate as protonating reagent were allowed to undergo collisionally activated decomposition (CAD) into the triple stage quadrupole analyzer. The product ion mass spectra of protonated xylose are characterized by the presence of ionic intermediates arising from xylose dehydration, which were structurally characterized by their fragmentation patterns. As expected, the xylose triple dehydration leads to the formation of the ion at m/z 97, corresponding to protonated 2-FA. On the basis of mass spectrometric evidences, we demonstrated that in the gas phase, the formation of 2-FA involves protonation at the OH group bound to the C1 atom of the sugar, the first ionic intermediate being characterized by a cyclic structure. Finally, energy resolved product ion mass spectra allowed to obtain information on the energetic features of the d-xylose→2-FA conversion.
Ricci, Andreina,Piccolella, Simona,Pepi, Federico,Garzoli, Stefania,Giacomello, Pierluigi
p. 1082 - 1089
(2013/07/26)

Reactivity of thermally treated α-dicarbonyl compounds
The degradation reaction of thermally treated 3-deoxy-d-erythro-hexos-2- ulose and methylglyoxal, both key intermediates in Maillard chemistry, was investigated. Different analytical strategies were accomplished to cover the broad range of formed products and their different chemical behavior. These involved HPLC-DAD and accordingly LC/MS analysis of the quinoxaline derivates, GC/MS analysis of the acetylated quinoxalines, and GC-FID analysis of the decyl ester of acetic acid. As a main degradation product of 3-deoxy-d-erythro-hexos- 2-ulose, 5-(hydroxymethyl)furfural could be identified. At alkaline pH values, 3-deoxy-d-erythro-hexos-2-ulose generated various acids but no colored products. In contrast, thermal treatment of methylglyoxal yielded high molecular weight, brownish products. A dimer of methylglyoxal, first precursor for aldol-based polymerization of methylglyoxal, could be clearly identified by GC/MS.
Pfeifer, Yvonne V.,Haase, Paul T.,Kroh, Lothar W.
p. 3090 - 3096
(2013/08/25)

Chemical conversion of sugars to lactic acid by alkaline hydrothermal processes
Some like it hot: Lactic acid is an important commodity chemical that is mainly used in the food industry or for the manufacture of biodegradable plastics. A highly efficient strategy for the conversion of carbohydrates from biomass to lactic acid through alkaline hydrolysis in superheated water is presented. Copyright
Esposito, Davide,Antonietti, Markus
p. 989 - 992
(2013/07/27)

High selective oxidation of alcohols based on trivalent ion (Cr 3+ and Co3+) complexes anchored on MCM-41 as heterogeneous catalysts
Cr(III) and Co(III) complexes with acetylacetonate were anchored onto a mesoporous MCM-41 through Schiff condensation. The materials were characterized by XRD, FT-IR, BET, CHN and ICP techniques. Elemental analysis of samples revealed that one C=N bond was formed through Schiff condensation on MCM-41 surface. The catalysts were tested for the alcohol oxidations using t-butyl hydroperoxide (TBHP) and H2O2 as oxidant. The catalytic experiments were carried out at both room temperature and reflux condition. Various solvents such as dichloromethane, acetonitrile and water were examined in the oxidation of alcohols. Among the different solvents, catalytic activity is found more in acetonitrile. Further, the catalysts were recycled three times in the oxidation of alcohols and no major change in the conversion and selectivity is observed, which shows that the immobilized metal-acetylacetonate complexes are stable under the present reaction conditions.
Shojaei, Abdollah Fallah,Rafie, Mahboubeh Delavar,Loghmani, Mohammad Hassan
p. 2748 - 2752
(2012/10/29)

Direct conversion of glycerol to acrylic acid via integrated dehydration-oxidation bed system
Acrylic acid can be successfully produced in a single reactor via subsequent oxidation of the glycerol-dehydrated products. Selective dehydration of glycerol to acrolein was studied at 275-400 °C over HZSM-5, HBeta, HMordenite and HY. The V-Mo oxides (15-70 mol%V) on silicic acid support (20-100 wt% mixed oxides loading) were then included as a second bed for subsequent oxidation of the dehydrated products. Over the acid zeolites, acrolein and acetol are mainly generated, together with acetaldehyde, propionaldehyde, pyruvaldehyde and other oxygenates as secondary products. A complete conversion of glycerol with high selectivity to acrolein (up to 81 mol%) can be obtained when medium pore zeolites (HZSM-5) and low glycerol concentration (10-30 wt%) was used at 300 °C. A separated-sequential bed system provides high selectivity for acrylic acid with small amount of acetic acid and acetaldehyde (～15 mol%). The catalyst with high V content promotes total oxidation of the dehydrated products to CO while that with highly dispersed V-Mo-O phases affords 98% selectivity to acrylic acid with 48% acrolein conversion.
Witsuthammakul, Ayut,Sooknoi, Tawan
scheme or table
p. 109 - 116
(2012/04/10)

Catalyst System and Process for Converting Glycerol to Lactic Acid
A process for producing lactic acid from glycerol using a reaction mixture comprising glycerol, a dehydrogenation catalyst (preferably a copper-based catalyst), an alkaline component, and water.
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Page/Page column 6-7

(2012/10/08)

Methylglyoxal bis-(N,N-dimethylhydrazone): Synthesis and some reactions
Methods were proposed for the synthesis of the methylglyoxal 1,2-bis-(N,N-dimethylhydrazone). A possibility was shown for the first time of its participation in the Diels-Alder reaction with maleic anhydride as an electron-rich diene. The second reaction of these reagents, which is observed in a wet media, is the formation of the hydrazinium salt of the initial diene with maleic acid. The most probable structure of the protonated diene among the four possible forms was revealed by the quantum-chemical calculations of the energy of the molecules and by the analysis of the 13C NMR chemical shifts.
Keiko,Vchislo,Larina,Chernyshev
experimental part
p. 77 - 81
(2012/06/04)