- Entrapment of a Pseudo-Tetrahedral CoII Center by Thioether Sulfur Bound {Co2(μ-L)} Fragments: Synthesis, Field-Induced Single-Ion Magnetism and Catechol Oxidase Mimicking Activity
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Simultaneous incorporation of both CoII and CoIII ions within a new thioether S-bearing phenol-based ligand system, H3L (2,6-bis-[{2-(2-hydroxyethylthio)ethylimino}methyl]-4-methylphenol) formed [Co5] aggregates [CoIICoIII 4L2(μ-OH)2(μ1,3-O2CCH3)2](ClO4)4?H2O (1) and [CoIICoIII 4L2(μ-OH)2(μ1,3-O2CC2H5)2](ClO4)4?H2O (2). The magnetic studies revealed axial zero-field splitting (ZFS) parameter, D/hc=?23.6 and ?24.3 cm?1, and E/D=0.03 and 0.00, respectively for 1 and 2. Dynamic magnetic data confirmed the complexes as SIMs with Ueff/kB=30 K (1) and 33 K (2), and τ0=9.1×10?8 s (1), and 4.3×10?8 s (2). The larger atomic radius of S compared to N gave rise to less variation in the distortion of tetrahedral geometry around central CoII centers, thus affecting the D and Ueff/kB values. Theoretical studies also support the experimental findings and reveal the origin of the anisotropy parameters. In solutions, both 1 and 2 which produce {CoIII 2(μ-L)} units, display solvent-dependent catechol oxidation behavior toward 3,5-di-tert-butylcatechol in air. The presence of an adjacent CoIII ion tends to assist the electron transfer from the substrate to the metal ion center, enhancing the catalytic oxidation rate.
- Das, Manisha,Basak, Dipmalya,Trávní?ek, Zdeněk,Van?o, Ján,Ray, Debashis
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- A method for preparing sodium acrylate-d3, a useful and stable precursor for deuterated acrylic monomers
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A convenient and economical method for converting propiolic acid to sodium acrylate-d3 is described. Successive D/H exchange of the alkyne proton of sodium propiolate (prepared from propiolic acid) using D2O affords sodium propiolate-d having up to 99 at.% D. Sodium propiolate-d can be partially reduced to sodium acrylate-d3 with 90% conversion and 89% yield using D2 and the Lindlar catalyst, with control of reaction parameters to maximize conversion while minimizing over-reduction. Copyright 2011 John Wiley & Sons, Ltd. A three-step synthetic route for preparing sodium acrylate-d3 in high yield and high isotopic purity from propiolic acid is described. Copyright
- Yang, Jun,Hong, Kunlun,Bonnesen, Peter V.
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- Biopropionic acid production via molybdenum-catalyzed deoxygenation of lactic acid
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As the search for non-fossil based building blocks for the chemical industry increases, new methods for the deoxygenation of biomass-derived substrates are required. Here we present the deoxygenation of lactic acid to propionic acid, using a catalyst based on the non-noble and abundant metal molybdenum under relatively mild reactive distillation conditions (200-270°C). Good yields of sodium propionate (up to 41%) can be obtained with either triethylene glycol dimethyl ether or water as the solvent in the presence of one equivalent of sodium hydroxide, without an external reductant, and using an industrially relevant feedstock of 44% lactic acid in water. Mechanistic studies show that several reactions occur simultaneously, including decarboxylation and decarbonylation of lactic acid, dehydration, and deoxygenation. The major pathway of propionic acid formation was determined with isotopic labeling studies to proceed via direct C-O cleavage, and to a lesser extent via the dehydration/hydrogenation pathway involving acrylic acid.
- Korstanje, Ties J.,Kleijn, Hendrik,Jastrzebski, Johann T. B. H.,Klein Gebbink, Robertus J. M.
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- PROCESS FOR PREPARATION OF TERT-BUTYLAMINE AND PROPIONIC ACID SALTS FROM N-TERTIARY BUTYL ACRYLAMIDE
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Disclosed is a process (100) for conversion of N-tertiary butyl acrylamide to tert-butylamine and salts of propionic acid. The process comprises of first selectively reducing the vinylic double bond in N-tertiary butyl acrylamide by catalytic hydrogenation of an alcoholic solution of N-tertiary butyl acrylamide to provide N-tertiary buyl propanamide; recovering the hydrogenation catalyst by filtering the solution and treating the solution with an alkali to produce N-tertiary butylamine and corresponding alkali salt of propionic acid. The process converts of N-tertiary butyl acrylamide into value added products at milder reaction conditions, without producing any hazardous byproducts and effluents.
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Page/Page column 16-17
(2021/11/13)
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- METHODS FOR THE SYNTHESIS OF DEUTERATED ACRYLATE SALTS
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A method for synthesizing a deuterated acrylate of the Formula (1), the method comprising: (i) deuterating a propiolate compound of Formula (2) to a methyne-deuterated propiolate compound of Formula (3) in the presence of a base and D2O: and (ii) reductively deuterating the methyne-deuterated propiolate compound of Formula (3) in a reaction solvent in the presence of deuterium gas and a palladium-containing catalyst to afford the deuterated acrylate of the Formula (1). The resulting deuterated acrylate compounds, derivatives thereof, and polymers derived therefrom are also described.
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Paragraph 0057-0064
(2013/04/10)
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- Products formed at intermediate stages of electrochemical perfluorination of propionyl and n-butyryl chlorides. Further evidence in support of NiF 3 mediated free radical pathway
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The partially fluorinated HF soluble intermediates formed during the electrochemical perfluorination of propionyl chloride (PC) and n-butyryl chloride (n-BC) were analyzed after passing 0%, 25%, 50%, 75% and 100% of theoretical charge required for the fluorination of PC and n-BC. The acid fluorides formed were converted to their corresponding sodium salt by alkali treatment and were separated by methanol extraction. The methanol was subsequently removed from the extract by vacuum distillation and the residue containing partially fluorinated sodium carboxylates was analyzed using 19F and 1H NMR spectra. Initial perfluorination on activated electrode surface indicates the operation of 'zipper-mechanism'. Formation of partially fluorinated product mixture, initial selectivity towards primary and secondary carbon, carbon chain isomerization and formation of cleaved and coupled products support the general operation of free radical pathway in the overall electrochemical process.
- Rangarajan,Sathyamoorthi,Velayutham,Noel,Singh,Brahma, Raju
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experimental part
p. 107 - 113
(2011/03/23)
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- Selective formation of lactate by oxidation of 1,2-propanediol using gold palladium alloy supported nanocrystals
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The use of bio-renewable resources, such as glycerol, a by-product from bio-diesel manufacture, can provide a viable way to make valuable products using greener technology. In particular, glycerol can be reduced to give 1,2-propanediol that can then be se
- Dimitratos, Nikolaos,Lopez-Sanchez, Jose Antonio,Meenakshisundaram, Sankar,Anthonykutty, Jinto Manjaly,Brett, Gemma,Carley, Albert F.,Taylor, Stuart H.,Knight, David W.,Hutchings, Graham J.
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experimental part
p. 1209 - 1216
(2010/05/17)
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- Simple and Rapid Determination of the Activation Parameters of Organic Reactions by Temperature-Dependent NMR Spectroscopy I. Application to Irreversible Reactions
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A rapid and convenient method for the evaluation of activation enthalpies and entropies of reactions in solutions was contrived. This was realized by the stepwise elevation of the temperature of a reaction system using a variable temperature apparatus of NMR spectrometer. A repetition of rapid collection of FIDs (Free Inductive Decays) at every plateau part of temperature at regular intervals allows us to determine the time-conversion curve, from which the rates at various temperatures were obtained as the first derivatives. Several examples of applications are shown.
- Satoh, Masahiro,Hirota, Minoru
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p. 2031 - 2038
(2007/10/03)
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- Hyaluronic acid-urea pharmaceutical compositions and uses
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This invention includes a pharmaceutical composition including a pharmaceutically acceptable carrier, urea, and hyaluronic acid or a pharmaceutically salt thereof. The invention also includes a method of treating disease of the cutis which includes applying to cutis tissues in need of such treatment a therapeutically effective amount of a composition comprising a pharmaceutically acceptable carrier, urea, and hyaluronic acid or a pharmaceutically acceptable salt thereof, said disease having symptoms selected from the group consisting of inflammation, erythema, edema, papules, vesicles, macules, pustules, scaling, cracking, crusting, and lesions. The invention further includes methods for the treatment of psoriasis, eczema, dermatitis, herpetic conditions, acne, skin ulcers, genital herpes lesions and anorectal disease, which includes applying to tissues in need of such treatment a therapeutically effective amount of a composition including a pharmaceutically acceptable carrier, urea and hyaluronic acid or a pharmaceutically acceptable salt thereof.
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- Thermal Stability of Phosphinoacetic Acids
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Phosphinoacetic acids decarboxylate smoothly in toluene solution at 99 deg C and the corresponding alkylphosphine is formed in quantitative yields.Electron-withdrawing substituents at the α position of the carboxylic acid lead to a large increase in the reaction rate.In contrast, electron-withdrawing substituents at the phosphorus atom lead to a small decrease in the rate.We have concluded from the substituent effects, solvent effects, and the influence of bases and acids that both the lone pair of the phosphorus atom and the carboxylate hydrogen atom play a crucial role in the reaction.A mechanism is proposed that proceeds via an ylide.Sodium phosphinocarboxylates do not decarboxylate in an aqueous solution at 95 deg C.Instead a carbon-phosphorus bond cleavage occurs probably by an intramolecular nucleophilic substitution.
- Doorn, Johannes A. van,Meijboom, Nico
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p. 1309 - 1314
(2007/10/02)
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- The Stereoselective Retardation of the Alkaline Hydrolysis of Organic Esters by Binuclear Cu(II) Complexes with Cyclodextrins
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The alkaline hydrolysis of p-nitrophenyl acetate (p-NPA) in 1.0 mol dm-3 NaOH at 25 deg C was almost completely retarded by the addition of a binuclear Cu(II) complex with α-cyclodextrin Cu2α-CD).The dissociation constant for an inclusion complex of Cu2α-CD with p-NPA was determined to be 0.059 mmol dm-3, which is about one 200th that for an inclusion complex of α-CD with p-NPA.The alkaline hydrolysis of o- and m-nitrophenyl acetates was also retarded by Cu2α-CD, though the extent of retardation was much less than that for p-NPA.A binuclear Cu(II) complex with β-cyclodextrin (Cu2β-CD) also caused a stereoselective deceleration of the alkaline hydrolysis of the esters.However, the stereoselectivity of Cu2β-CD was not so remarkable as that of Cu2α-CD.Dissociation constants for inclusion complexes of Cu2α-CD with several alcohols and other organic substrates were determined by the kinetic examination of the competitive inhibition effect of the substrates on the association of Cu2α-CD with p-NPA.Cu2α-CD formed stable inclusion complexes with such disk-like molecules as cyclohexanol, cycloheptanol, and p-nitrobenzyl alcohol.The geometry of a Cu2α-CD-p-NPA inclusion complex was presumed on the basis of these results.
- Matsui, Yoshihisa,Suemitsu, Daisuke
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p. 1658 - 1662
(2007/10/02)
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- Characterisation of the citrate synthase reaction with propionyl-CoA.
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Experiments with propionyl-CoA stereoselectively deuteriated in the propionyl moiety demonstrate that the formation of (2S,3S)-methylcitric acid (1) catalysed by citrate (si)-synthase occurs with inversion of configuration in the propionyl moiety; the absolute configurations of the methylcitric acids 1 and 2 indicate a si attack on oxaloacetate. Deuterium in the pro-S position is exchanged for protium 60 times faster than deuterium in the pro-R position. Experiments with (R,S)-(2-2H1)propionyl-CoA allowed the determination of isotope effects. For the enzymatic formation of 1, a primary deuterium isotope effect kH/kD = 1.8 and a secondary alpha-deuterium isotope effect kH/kD = 0.99 were calculated; both are effects on Vmax/KM.
- Brand?nge,Josephson,M?hlén,M?rch
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p. 695 - 700
(2007/10/02)
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- Relationship between the Electronic Structure of Acrylic and Methacrylic Acid and the Rates of Hydrogenation of Their Salts on Pt Black
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We have studied the hydrogenation of the alkali metal salt of acrylic and methacrylic acid on platinum black.The relative reactivities, which are interest in calculations of the electronic structure of acids, have been determined by the CNDO/2 method.
- Volkova, L. D.,Vyaznikovtseva, O. V.,Gabdrakipov, V. Z.,Sokol'skii, D. V.
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p. 1650 - 1652
(2007/10/02)
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