- Formate to Oxalate: A Crucial Step for the Conversion of Carbon Dioxide into Multi-carbon Compounds
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The efficient conversion of formate into oxalate could enable the industrial-scale synthesis of multi-carbon compounds from CO2 by C?C bond formation. We found conditions for the highly selective catalytic conversion of molten alkali formates into pure solid oxalate salts. Nearly quantitative conversion was accomplished by calcination of sodium formates with sodium hydride. A catalytic mechanism proceeding through a carbonite intermediate, generated upon H2 evolution, was supported by density functional theory calculations, Raman spectroscopy, and the observed changes in the catalytic performance upon changing the nature of the base or the reaction conditions. Whereas the conversion of formate into oxalate by using a hydroxide ion catalyst was previously studied, hydride ion catalysis and the chain reaction mechanism for the conversion involving a carbonite ion intermediate are reported herein for the first time.
- Lakkaraju, Prasad S.,Askerka, Mikhail,Beyer, Heidie,Ryan, Charles T.,Dobbins, Tabbetha,Bennett, Christopher,Kaczur, Jerry J.,Batista, Victor S.
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Read Online
- Homogeneous Reforming of Aqueous Ethylene Glycol to Glycolic Acid and Pure Hydrogen Catalyzed by Pincer-Ruthenium Complexes Capable of Metal–Ligand Cooperation
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Glycolic acid is a useful and important α-hydroxy acid that has broad applications. Herein, the homogeneous ruthenium catalyzed reforming of aqueous ethylene glycol to generate glycolic acid as well as pure hydrogen gas, without concomitant CO2 emission, is reported. This approach provides a clean and sustainable direction to glycolic acid and hydrogen, based on inexpensive, readily available, and renewable ethylene glycol using 0.5 mol % of catalyst. In-depth mechanistic experimental and computational studies highlight key aspects of the PNNH-ligand framework involved in this transformation.
- Zou, You-Quan,von Wolff, Niklas,Rauch, Michael,Feller, Moran,Zhou, Quan-Quan,Anaby, Aviel,Diskin-Posner, Yael,Shimon, Linda J. W.,Avram, Liat,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 4715 - 4722
(2021/02/20)
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- Overcoming Crystallinity Limitations of Aluminium Metal-Organic Frameworks by Oxalic Acid Modulated Synthesis
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A modulated synthesis approach based on the chelating properties of oxalic acid (H2C2O4) is presented as a robust and versatile method to achieve highly crystalline Al-based metal-organic frameworks. A comparative study on this method and the already established modulation by hydrofluoric acid was conducted using MIL-53 as test system. The superior performance of oxalic acid modulation in terms of crystallinity and absence of undesired impurities is explained by assessing the coordination modes of the two modulators and the structural features of the product. The validity of our approach was confirmed for a diverse set of Al-MOFs, namely X-MIL-53 (X=OH, CH3O, Br, NO2), CAU-10, MIL-69, and Al(OH)ndc (ndc=1,4-naphtalenedicarboxylate), highlighting the potential benefits of extending the use of this modulator to other coordination materials.
- Canossa, Stefano,Gonzalez-Nelson, Adrian,Shupletsov, Leonid,Van der Veen, Monique A.,del Carmen Martin, Maria
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- Countercations and Solvent Influence CO2 Reduction to Oxalate by Chalcogen-Bridged Tricopper Cyclophanates
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One-electron reduction of Cu3EL (L3- = tris(β-diketiminate)cyclophane, and E = S, Se) affords [Cu3EL]-, which reacts with CO2 to yield exclusively C2O42- (95% yield, TON = 24) and regenerate Cu3EL. Stopped-flow UV/visible data support an A→B mechanism under pseudo-first-order conditions (kobs, 298K = 115(2) s-1), which is 106 larger than those for reported copper complexes. The kobs values are dependent on the countercation and solvent (e.g., kobs is greater for [K(18-crown-6)]+ vs (Ph3P)2N+, and there is a 20-fold decrease in kobs in THF vs DMF). Our results suggest a mechanism in which cations and solvent influence the stability of the transition state.
- Cook, Brian J.,Di Francesco, Gianna N.,Abboud, Khalil A.,Murray, Leslie J.
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supporting information
p. 5696 - 5700
(2018/05/14)
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- Non-caking salt composition, preparation process and use thereof
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The present invention relates to a sodium chloride composition comprising an iron complex of tartaric acid wherein between 55 and 90% by weight of the tartaric acid is meso-tartaric acid. The present invention furthermore relates to a process to prepare such a sodium chloride composition and to the use of such a sodium chloride composition.
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Page/Page column 11-12
(2015/01/06)
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- Oxidation of glyoxylic acid by a mononuclear manganese(IV) complex of 1,8-bis(2-hydroxybenzamido)-3,6-diazaoctane: A kinetics and mechanistic study
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The oxidation of glyoxylic acid (HGl) by MnIVL {L4- = tetra deprotonated 1,8-bis(2-hydroxybenzamido)-3,6-diazaoctane} was investigated in the pH range 1.67-10.18, at 25-45 °C and 0.5 M ionic strength. The reaction exhibited biphasic kinetics with MnIIIL - as the reactive intermediate. MnIV was reduced to MnII. The products of oxidation of HGl were identified as formic acid and CO2 in acidic medium, and oxalate in basic medium, consistent with the stoichiometry: -Δ[MnIV]/-Δ[HGl] = 1. In acidic medium, both MnIVL and MnIIIL- formed outer-sphere adducts with the neutral HGl {HC(OH)2COOH} molecule, with an association constant Qav of 28 and 70 M-1, respectively. A similar adduct formation was not observed for the glyoxylate mono anion {Gl-, CH(OH)2(CO2-)} and glyoxylate dianion {Gl2-, CH(OH)(O-)CO2 -}. The rate and activation parameters for the various paths are reported and an outer-sphere electron transfer mechanism is suggested.
- Nayak, Suprava,Brahma, Gouri S.,Reddy, K. Venugopal,Reddy, K. Veera,Dash, Anadi C.
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scheme or table
p. 1637 - 1645
(2011/07/31)
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- Synthesis and characterization of Pt(II) complexes with amine and carboxylato ligands. Crystal structure of (1,1-cyclobutanedicarboxylato)di(ethylamine)platinum(II)·H2O
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Two methods for the synthesis of compounds of the type cis-PtA2X2 (A2 = bidentate amine or two monodentate amines and X2 = bidentate or two monodentate carboxylato ligands) were evaluated. The compounds were characterized by multinuclear NMR and IR spectroscopies. The 195PT NMR chemical shifts were in the range - 1615 to - 1976 ppm, the higher field values corresponding to the complexes containing bidentate ligands. The coupling constants 3J(195Pt-1H) are approximately 35 Hz, while the 2J(195Pt-1HN) are about 70 Hz. One coupling constant 2J(195Pt-13C) (53 Hz) was also measured. The crystal structure of the compound, cis-Pt(1,1-cyclobutanedicarboxylato)(C2H5NH2)2·H2O belongs to the P21/n space group with a=9.468(5), b =9.365(4), c = 16.473(7) A?, β = 105.08(3)°, Z = 4 and R1 = 0.0576. The Pt-N bond distances are 1.992(5) and 2.020(5) A?, while the Pt-O bonds are 2.000(4) and 2.015(4) A?. The molecules are held together by intermolecular H-bonds involving the lattice water molecules and the two free carbonyl O atoms and between the amino H atoms and the Pt-bonded C-O groups. (C) 2000 Elsevier Science S.A.
- Rochon, Fernande D.,Gruia, Letitia M.
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p. 193 - 204
(2008/10/08)
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- Novel Synthesis of Oxalate from Carbon Dioxide and Carbon Monoxide in the Presence of Caesium Carbonate
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In the presence of caesium carbonate 1, the direct reaction of CO2 (110 atm) with CO (20 atm) results in reductive capture of CO2 to give caesium oxalate 2 in good yield at elevated temperature (380 deg C).
- Kudo, Kiyoshi,Ikoma, Futoshi,Mori, Sadayuki,Komatsu, Koichi,Sugita, Nobuyuki
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p. 633 - 634
(2007/10/02)
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- Process to prepare amino carboxylic acid salts
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An improved process is disclosed to prepare an carboxylic acid salt. According to the process, an aqueous solution of an alcohol is contacted with an alkali metal hydroxide in the presence of an effective amount of a copper catalyst that contains from about 50 parts per million to about 10,000 parts per million of an element selected from the group consisting of chromium, titanium, niobium, tantalum, zirconium, vanadium, molybdenum, manganese, tungsten, cobalt, nickel and mixtures thereof. Raney copper is preferred.
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- Kinetics and mechanism of oxidation by metal ions: Part XV-Oxidation of glyoxalate ion by alkaline osmium tetroxide
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The kinetics of oxidation of glyoxalate ion by alkaline osmium (VIII) is studied with stopped-flow in the presence of excess of glyoxalate ion.A linear correlation between (a) k-1obs and ->, and (b) kobs and -> is observed where kobs is the observed pseudo-first order rate constant.The rate determining step is the decomposition of, probably, an inner sphere complex 3- formed between 2- and (OH)2CH.COO-.The formation of the complex is inferred by the rapid scanning of the spectrum of the reaction mixture.The kinetically deducted value of the equilibrium constant Kha, for the deprotonation of the hydrated glyoxalate ion at 25 deg C is 3.54+/-0.34 dm3mol-1.Using this value of Kha, the pKa value of the gem-diol of glyoxalate ion is calculated to be 13.4 which is in good agreement with the pKa value of 13.6 for formaldehyde.The thermodynamic parameters and activation enthalpy and entropy values are reported.
- Vishnoi, Minakshi,Prakash, Aditya,Mehrotra, Raj N
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p. 788 - 793
(2007/10/02)
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- MOSSBAUER STUDY OF THE THERMAL DECOMPOSITION OF ALKALI TRIS(OXALATO)FERRATES(III).
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The thermal decomposition of alkali (Li,Na,K,Cs,NH//4) tris(oxalato)ferrates(III) has been studied at different temperatures up to 700 degree C using Mossbauer, infrared spectroscopy, and thermogravimetric techniques. The formation of different intermedia
- Brar,Randhawa
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p. 153 - 156
(2008/10/08)
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- Enantiospecific syntheses of leukotrienes C4, D4 and E4 and [14,15-3H2]leukotriene E4 dimethyl ester
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A 'chiral-pool' approach was employed to synthesize various leukotrienes (slow-reacting substance of anaphylaxis, SRS-A) enantiospecifically. The pivotal (S,S)-trans-epoxy alcohol 9 was prepared by efficient and facile routes starting from erythorbic acid (D-araboascorbic acid, 13). This epoxide could also be produced starting from D-glucose. The epimeric (S,R)-cis-epoxide 38 was obtained utilizing L-tartaric acid as the chiral starting material. Elaboration of 9 into leukotriene A4 methyl ester (5) and the potassium salts of leukotrienes C4 (4a), D4 (4b), and E4 (4c) was accomplished by standard methods. These salts exhibited potent contractile activities in the in vitro guinea pig ileum assay. Reduction of 14,15-dehydroleukotriene A4 methyl ester (44) with tritium gas gave [14,15-3H2]-5 and subsequently the dimethyl ester of [14,15-3H2]leukotriene E4 having a high specific activity of 40 Ci/mmol.
- Cohen,Banner,Lopresti,et al.
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p. 3661 - 3672
(2007/10/02)
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- Process for making an acrylic monomer
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The invention relates to a novel process for making phenyl fluoroacrylate monomer. The monomer is obtained by reaction of a fluoroacrylic salt with an halogenating agent, followed by condensation of the fluoroacryloyl halogenide with phenol and recovery of the phenyl fluoroacrylate. The obtained monomer is applicable to the manufacture of transparent polymers of high thermal stability.
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- Unsymmetrical tertiary-aliphatic azoalkanes
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Unsymmetrical azo compounds (R")3 C--N=N--R' where (R")3 C-- is tert.-aliphatic and R' is --C(R1)(R2)(Z) or STR1 e.g., 1-t-butylazo-1-chlorocyclohexane, their use as vinyl polymerization initiators and polyester resin curing agents, and methods for preparing same from t-aliphatic hydrazones and t-aliphatic α-halo-substituted azoalkanes.
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