141-46-8Relevant articles and documents
A FT IR Study of a Transitory Product in the Gas-Phase Ozone-Ethylene Reaction
Niki, H.,Maker, P. D.,Savage, C. M.,Breitenbach, L. P.
, p. 1024 - 1027 (1981)
Further kinetic and spectroscopic characterization was made with the FT IR method for the transistory species (compound X) detected originally by Heath et al. and more recently Su et al. in the gas-phase reaction between O3 and C2H4.The results obtained support the earlier suggestion of Su et al. that compound X is HOCH2OCHO formed by the secondary reaction of the thermally stabilized CH2OO entity with CH2O.
Pyrolysis of inulin, glucose, and fructose
Ponder, Glenn R.,Richards, Geoffrey N.
, p. 341 - 360 (1993)
The pyrolytic behavior of inulin, a (2->1)-linked fructofuranan, is described.Parallel investigations of the pyrolysis of glucose and of fructose were conducted to supplement the inulin results and to aid comparison with previous results from glucans.Effects of neutral and basic additives are emphasized.As with glucans, the addition of such additives (especially basic) increases the yields of the one-, two-, and three-carbon products (as well as of hexosaccharinolactones), while generally decreasing the yields of anhydro sugar and furan derivatives.The former products include glycolaldehyde, acetol, dihydroxyacetone, acetic acid, formic acid, and lactic acid.Mechanistic speculations are made regarding the origins of these compounds, as well as of furan derivatives and saccharinic acid lactones.Parallels with alkaline degradation are considered.
KINETICS AND MECHANISM OF THE OXIDATION OF SOME DIOLS BY CHROMIUM(VI) IN PERCHLORIC ACID MEDIUM
Gupta, Kalyan Kali Sen,Samanta, Tapashi,Basu, Samarendra Nath
, p. 5707 - 5714 (1986)
Chromic acid oxidations of some diols have been studied in perchloric acid medium.The reactions are firstorder with respect to the diols and acid chromate ion.The rate increases with the increase in acidity but the orders with respect to perchloric acid are different (1.25-2.0).The rate of the oxidation reactions at = 1.0 M and temperature = 35 deg C, follow the order pinacol > 2.3-butane diol > ethylene glycol.The activation parameters of the oxidation reactions have been calculated.Plausible reaction mechanisms have been suggested.
Catalytic conversion of xylose to furfural over the solid acid SO 42-/ZrO2-Al2O3/SBA-15 catalysts
Shi, Xuejun,Wu, Yulong,Li, Panpan,Yi, Huaifeng,Yang, Mingde,Wang, Gehua
, p. 480 - 487 (2011)
Al-promoted SO42--/ZrO2/SBA-15 catalysts were prepared and characterized by XRD, BET, ICP and NH3-TPD techniques. The influence of introducing aluminum on the structure and surface properties of the catalyst and the catalytic activity for dehydration of xylose to furfural has been investigated. The introduction of the Al stabilizes the tetragonal phase of the ZrO2 and thus increases the number and intensity of acid sites. Based on the characterization of the deactivated catalyst, the accumulation of byproducts is the main reason for the deactivation of the catalyst. Regeneration with H2O2 can completely recover the catalytic activity of the deactivated catalyst.
Kinetics and mechanisms of OH-initiated oxidation of small unsaturated alcohols
Takahashi, Kenshi,Hurley, Michael D.,Wallington, Timothy J.
, p. 151 - 158 (2010)
Smog chamber relative rate techniques were used to measure rate coefficients of (5.00 ± 0.54) × 10-11, (5.87 ± 0.63) × 10-11, and (6.49 ± 0.82) × 10 -11 cm3 molecule-1 s-1 in 700 Torr air at 296 ± 1 K for reactions of OH radicals with allyl alcohol, 1-buten-3-ol, and 2-methyl-3-buten-2-ol, respectively; the quoted uncertainties encompass the extremes of determinations using two different reference compounds. The OH-initiated oxidation of allyl alcohol in the presence of NOx gives glycolaldehyde in a molar yield of 0.85 ± 0.08; the quoted uncertainty is two standard deviations. Oxidation of 2-methyl-3-buten-2- ol gives acetone and glycolaldehyde in molar yields of 0.66 ± 0.06 and 0.56 ± 0.05, respectively. The reaction of OH radicals with allyl alcohol, 1-buten-3-ol, and 2-methyl-3-buten-2-ol proceeds predominately via addition to the >C=CH2 double bond with most of the addition occurring to the terminal carbon.
Catalytic fast pyrolysis of cellulose using nano zeolite and zeolite/matrix catalysts in a GC/micro-pyrolyzer
Lee, Kyong-Hwan
, p. 4631 - 4637 (2016)
Cellulose, as a model compound of biomass, was catalyzed over zeolite (HY, HZSM-5) and zeolite/matrix (HY/Clay, HM/Clay) in a GC/micro-pyrolyzer at 500 °C, to produce the valuable products. The catalysts used were pure zeolite and zeolite/matrix including 20 wt% matrix content, which were prepared into different particle sizes (average size; 0.1 mm, 1.6 mm) to study the effect of the particle size of the catalyst for the distribution of product yields. Catalytic pyrolysis had much more volatile products as light components and less content of sugars than pyrolysis only. This phenomenon was strongly influenced by the particle size of the catalyst in catalytic fast pyrolysis. Also, in zeolite and zeolite/matrix catalysts the zeolite type gave the dominant impact on the distribution of product yields.
Effects of B group vitamins on reactions of various α-hydroxyl- containing organic radicals
Lagutin,Shadyro
, p. 3797 - 3800 (2005)
Effects of vitamins B1, B2, B6, and pyridoxal phosphate (PPh) on final product formation in radiolysis of aqueous solutions of ethanol, ethylene glycol, α-methylglycoside, and maltose were studied. It has been found that vitamin B2 and PPh effectively oxidize R.CHOH species, while suppressing their recombination and fragmentation reactions, thereby increasing the yields of the respective oxidation products. Vitamins B1 and B2 are capable of reducing alcohol radicals to the respective initial molecules, decreasing the yields of the radical transformation products.
Convergent Functional Groups: Catalysis of Hemiacetal Cleavage in a Synthetic Molecular Cleft
Wolfe, J.,Nemeth, D.,Costero, A.,Rebek, J. Jr.
, p. 983 - 984 (1988)
-
Separating Thermodynamics from Kinetics—A New Understanding of the Transketolase Reaction
Marsden, Stefan R.,Gjonaj, Lorina,Eustace, Stephen J.,Hanefeld, Ulf
, p. 1808 - 1814 (2017)
Transketolase catalyzes asymmetric C?C bond formation of two highly polar compounds. Over the last 30 years, the reaction has unanimously been described in literature as irreversible because of the concomitant release of CO2 if using lithium hydroxypyruvate (LiHPA) as a substrate. Following the reaction over a longer period of time however, we have now found it to be initially kinetically controlled. Contrary to previous suggestions, for the non-natural conversion of synthetically more interesting apolar substrates, the complete change of active-site polarity is therefore not necessary. From docking studies it was revealed that water and hydrogen-bond networks are essential for substrate binding, thus allowing aliphatic aldehydes to be converted in the charged active site of transketolase.
The Enhancement of Formose Formation with 2-Hydroxyacetophenone. A mechanism Involving Aldol and Retro-aldol Reactions
Sakai, Tomoya,Ishizaki, Masahiko,Goto, Masafumi
, p. 2409 - 2414 (1982)
The rapid aldol addition of formaldehyde to 2-hydroxyacetophenone (HAP), an efficient accelerator for formose formation, took place to yield addition products of HAP with one and two molecules of formaldehyde at 35 deg C in an aqueous 40percent methanol mixture of formaldehyde, HAP, and Ca(OH)2.No further addition product with more than two molecules of formaldehyde attached to HAP was detected throughout the reaction.On the contrary, benzaldehyde and benzoic acid were formed, accompanied by formose sugars.The initial molar amount of HAP corresponded to the sum of the compounds substituted with the phenyl group including benzaldehyde and benzoic acid.The retro-aldol reaction of the HAP derivatives is likely to be involved in the overall reaction to yield glycolaldehyde or trioses, which are good accelerators for formose formation.
Manganese(III) oxidation of L-serine in aqueous sulfuric acid medium: Kinetics and mechanism
Chandraju,Rangappa,Made Gowda
, p. 525 - 530 (1999)
Kinetics and mechanism of oxidation of L-serine by manganese(III) ions have been studied in aqueous sulfuric acid medium at 323 K. Manganese(III) sulfate was prepared by an electrolytic oxidation of manganous sulfate in aqueous sulfuric acid. The dependencies of the reaction rate are: an unusual one and a half-order on [Mn(III)], first-order on [ser], an inverse first-order on [H+], and an inverse fractional-order on [Mn(II)]. Effects of complexing agents and varying solvent composition were studied. Solvent isotope studies in D2O medium were made. The dependence of the reaction rate on temperature was studied and activation parameters were computed from Arrhenius-Eyring plots. A mechanism consistent with the observed kinetic data has been proposed and discussed.
Catalysis and Stability Effect of Solvent Alcohol on the C6 Aldose Conversion toward Tetrose
Hou, Wenrong,Yan, Yueer,Li, Gang,Zhan, Yulu,Feng, Lei,Zhang, Ruohong,Hua Li, Zhen,Zhang, Yahong,Tang, Yi
, p. 4182 - 4188 (2019)
Conversions of biomass feedstock into various valuable chemicals are of great significance. As a typical route, retro-aldol condensation of monosaccharide greatly expands the variety of biomass-derived platform chemicals via a selective C?C splitting. Herein, we describe a solvent-catalysed strategy to high-selectively accumulate tetrose (four-carbon platform chemical) from C6 aldoses via the retro-aldol/aldol process. We find that alcohol solvents with Lewis acidity facilitate the C?C splitting process of hexose under the catalyst-free condition. The conversion is the fastest in methanol while it is the slowest in isopropanol. The product distribution is greatly influenced by the alcohols through shifting the equilibrium between tetrose and glycolaldehyde (GA). The addition of catalyst only accelerates the reaction rate, and does not change the product distribution. On the one hand, the acetalization of GA with methanol or ethanol shifts the equilibrium from tetrose toward GA, which results in a low yield of tetrose in methanol or ethanol solvent. On the other hand, tetrose can be well accumulated in isopropanol or n-butanol, and the yield of tetrose in isopropanol is higher than in n-butanol because tetrose can be well solvated and stabilized in it. This solvent-dependent reaction strategy provides a new possibility which contributes to the conversion of biomass feedback into valuable platform chemicals and accumulation of target products by utilizing the solvation effect.
Products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO
Atkinson,Tuazon,Aschmann
, p. 577 - 587 (1998)
The products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO have been investigated at room temperature and 740 torr total pressure of air by gas chromatography with flame ionization detection, in situ Fourier transform infrared absorption spectroscopy, and direct air sampling atmospheric pressure ionization tandem mass spectrometry. The products identified and quantified by GC-FID and in situ FT-IR absorption spectroscopy were HCHO, 2-methylpropanal, acetone, glycolaldehyde, and methacrolein, with formation yields of 0.70±0.06, 0.58±0.08, 0.17±0.02, 0.18±0.03, and 0.033±0.007, respectively. In addition, IR absorption bands due to organic nitrates were observed, consistent with API-MS observations of product ion peaks attributed to the β-hydroxynitrates (CH3)2CHCH(ONO2)CH2OH and/or (CH3)2CHCH(OH)CH2ONO2 formed from the reactions of the corresponding β-hydroxyalkyl peroxy radicals with NO. A formation yield of ca. 0.15 for these nitrates was estimated using IR absorption band intensities for known organic nitrates. These products account for essentially all of the reacted 3-methyl-1-butene. Analysis of the potential reaction pathways involved shows that H-atom abstraction from the allylic C-H bond in 3-methyl-1-butene is a minor pathway which accounts for 5-10% of the overall OH radical reaction.
Transformations of formaldehyde and glycolaldehyde during the hydroformylation of formaldehyde in the presence of rhodium catalysts
Ezhova, N. N.,Korneeva, G. A.,Slivinsky, E. V.,Aronovich, R. A.
, p. 69 - 73 (1995)
Hydroformylation of formaldehyde to give glycolaldehyde (GA) in the presence of RhCl(PPh3)3, RhCl(CO)(PPh3)2, or the RhCl3 + PPh3 system in N,N-dimethylacetamide was studied.The hydroformylation is accompanied by the Cannizzaro-Tishchenko reaction, condensation of CH2O with GA to give C3-C16 polyoxyladehydes (POA), and dimerization of GA.THe formation of POA, which probably occurs through coordination of GA with a Rh atom, predominates among the side reactions.The optimum conditions for hydroformylation of CH2O were found to be: RhCl3 + PPh3 as the catalyst, T CO+H2 >/= 12 MPa, -1, -3 g-at.L-1, and -1.At a substrate conversion of 62 - 67percent, the selectivity of GA formation reaches 96percent, and the yield is 60 - 65percent. - Key words: formaldehyde, hydroformylation; glycolaldehyde; rhodium catalysts.
Governing chemistry of cellulose hydrolysis in supercritical water
Cantero, Danilo A.,Bermejo, M. Dolores,Cocero, M. José
, p. 1026 - 1033 (2015)
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.
Revealing the chemistry of biomass pyrolysis by means of tunable synchrotron photoionisation-mass spectrometry
Dufour, Anthony,Weng, Junjie,Jia, Liangyuan,Tang, Xiaofeng,Sirjean, Baptiste,Fournet, Rene,Gall, Herve Le,Brosse, Nicolas,Billaud, Francis,Mauviel, Guillain,Qi, Fei
, p. 4786 - 4792 (2013)
Imaging biomass conversion: pyrolysis is the first reaction involved in all thermal processes for biofuels and green chemicals production. Synchrotron light ionisation and mass spectrometry is used for the first time to investigate biomass pyrolysis. The soft and tunable ionisation source coupled with ab initio calculations reveals chemical mechanisms and new major intermediate species. This methodology could be extended to the thermal and catalytic conversion of all other materials. Primary volatile products are analysed online as a function of photon energy, biomass composition (cellulose, xylan, lignin), reactor temperature and time of conversion. Hydroxyacetaldehyde was detected at very minor yields for cellulose pyrolysis confirming that it is a secondary product. The effect of cellulose structure and ash content on primary tar formation was also studied. The mechanism of levoglucosan dissociative photoionisation is depicted. A new major intermediate product which could be a precursor of furanone-based species from cellulose is evidenced thanks to the soft ionisation and MSMS structural analysis of ions. Different lignin markers and evolutions upon time of conversion are shown for miscanthus and oak pyrolysis.
Borate-Stabilized Transformation of C6 Aldose to C4 Aldose
Yan, Yueer,Feng, Lei,Li, Gang,Lin, Shaoying,Sun, Zhen,Zhang, Yahong,Tang, Yi
, p. 4473 - 4478 (2017)
Highly efficient transformations of biomass-derived sugars into various valuable chemicals are of topical interest. Tetrose with a four-carbon bone is the root of most of biomass-derived C4 products, but its extreme instability obstructs the blossoming of C4 products presently. Herein, we describe a borate-stabilized catalytic strategy to accumulate erythrose from C6 aldose in a highly selective manner via retro-aldol and aldol processes in alcohol solvent. In our proposed mechanism, borate can stabilize erythrose and avoid its further retro-aldol splitting or isomerization, and induce the production of erythrose again via the aldol condensation of the above-generated glycolaldehyde.
Products from the gas-phase reaction of some unsaturated alcohols with nitrate radicals
Noda,Hallquist,Langer,Ljungstroem
, p. 2555 - 2564 (2000)
Five structurally similar unsaturated alcohols, 2-propene-1-ol (allyl alcohol), 3-butene-2-ol, 2-methyl-3-butene-2-ol (MBO232), 2-butene-1-ol (crotyl alcohol) and 3-methyl-2-butene-1-ol (MBO321), were examined to clarify their atmospheric degradation pathways via oxidation initiated by NO3 radicals. The reactions were investigated using a 0.153 m3 static glass reactor equipped with long-path FTIR spectroscopy. The experiments were performed at a pressure of 1020 ± 5 mbar and at a temperature of 297 ± 2 K in air or nitrogen as the bath gas. The identified and quantified gas phase products were small carbonyl compounds such as acetone, formaldehyde, acetaldehyde, glycolaldehyde and 2-nitrooxy acetaldehyde. The specific products and their yields varied for the five studied alcohols as follows: formaldehyde 37(±1)% and 2-nitrooxy acetaldehyde 41(±7)% from allyl alcohol; acetaldehyde 28(±6)%, formaldehyde 2(±1)% and 2-nitrooxy acetaldehyde 33(±4)% from 3-butene-2-ol; acetone 63(±6)% and 2-nitrooxy acetaldehyde 67(±8)% from MBO232; acetaldehyde 12(±2)%, formaldehyde 10(±3)% and glycolaldehyde 7(±2)% from 2-butene-1-ol; acetone 21(±6)%, formaldehyde 11(±3)% and glycolaldehyde 29(±10)% from MBO321. In addition, yields were estimated for total organic nitrates using an average integrated absorption cross section of unspecified organic nitrates. Tentative reaction schemes were proposed from the yielded products. The distribution between bond breakage and other processes such as abstraction of a hydrogen atom from the alkoxy radical, formed in the degradation process, was estimated. The small carbonyl compounds were produced by the bond breakage mechanisms. Large multi-functional organic compounds e.g. 1-hydroxy-3-nitrooxy-3-methyl-2- butanone from MBO321 were proposed to be formed by hydrogen abstraction. From the product distribution, the contribution of the number of methyl group substituents at the α and γ carbon atoms, influencing the bond breakage pattern, is discussed. The observed bond cleavage trends are correlated to a substitution pattern where electron donating methyl substituents increase the stability of the leaving radical groups.
A point mutation converts dihydroneopterin aldolase to a cofactor-independent oxygenase
Wang, Yi,Scherperel, Gwynyth,Roberts, Kade D.,Jones, A. Daniel,Reid, Gavin E.,Yan, Honggao
, p. 13216 - 13223 (2006)
Dihydroneopterin aldolase (DHNA) catalyzes the conversion of 7,8-dihydroneopterin (1) to 6-hydroxymethyl-7,8-dihydropterin (4) in the folate biosynthetic pathway. Substitution of a conserved tyrosine residue at the active site of DHNA by phenylalanine converts the enzyme to a cofactor-independent oxygenase, which generates mainly 7,8-dihydroxanthopterin (6) rather than 4. 6 is generated via the same enol intermediate as in the wild-type enzyme-catalyzed reaction, but this species undergoes an oxygenation reaction to form 6. The conserved tyrosine residue plays only a minor role in the formation of the enol reaction intermediate but a critical role in the protonation of the enol intermediate to form 4.
Reactions of the peroxo intermediate of soluble methane monooxygenase hydroxylase with ethers
Beauvais, Laurance G.,Lippard, Stephen J.
, p. 7370 - 7378 (2005)
Soluble methane monooxygenase (sMMO) isolated from Methylococcus capsulatus (Bath) utilizes a carboxylate-bridged diiron center and dioxygen to catalyze the conversion of methane to methanol. Previous studies revealed that a di(μ-oxo)diiron(IV) intermediate termed Q is responsible for the catalytic activity with hydrocarbons. In addition, the peroxodiiron(III) intermediate (Hperoxo) that precedes Q formation in the catalytic cycle has been demonstrated to react with propylene, but its reactivity has not been extensively investigated. Given the burgeoning interest in the existence of multiple oxidants in metalloenzymes, a more exhaustive study of the reactivity of Hperoxo was undertaken. The kinetics of single turnover reactions of the two intermediates with ethyl vinyl ether and diethyl ether were monitored by single- and double-mixing stopped-flow optical spectroscopy. For both substrates, the rate constants for reaction with Hperoxo are greater than those for Q. An analytical model for explaining the transient kinetics is described and used successfully to fit the observed data. Activation parameters were determined through temperature-dependent studies, and the kinetic isotope effects for the reactions with diethyl ether were measured. The rate constants indicate that Hperoxo is a more electrophilic oxidant than Q. We propose that Hperoxo reacts via two-electron transfer mechanisms, and that Q reacts by single-electron transfer steps.
Selective Reductive Dimerization of CO2into Glycolaldehyde
Zhang, Dan,Jarava-Barrera, Carlos,Bontemps, Sébastien
, p. 4568 - 4575 (2021/05/04)
The selective dimerization of CO2 into glycolaldehyde is achieved in a one-pot two-step process via formaldehyde as a key intermediate. The first step concerns the iron-catalyzed selective reduction of CO2 into formaldehyde via formation and controlled hydrolysis of a bis(boryl)acetal compound. The second step concerns the carbene-catalyzed C-C bond formation to afford glycolaldehyde. Both carbon atoms of glycolaldehyde arise from CO2 as proven by the labeling experiment with 13CO2. This hybrid organometallic/organic catalytic system employs mild conditions (1 atm of CO2, 25 to 80 °C in less than 3 h) and low catalytic loadings (1 and 2.5%, respectively). Glycolaldehyde is obtained in 53% overall yield. The appealing reactivity of glycolaldehyde is exemplified (i) in a dimerization process leading to C4 aldose compounds and (ii) in a tri-component Petasis-Borono-Mannich reaction generating C-N and C-C bonds in one process.
PROCESSES FOR PREPARING C-4 SUGARS AND KETOSE SUGARS
-
Page/Page column 13-27, (2021/11/20)
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.
