C:Corrosive;
107-92-6Relevant articles and documents
Aqueous-phase hydrogenation of biomass-derived itaconic acid to methyl-γ-butyrolactone over Pd/C catalysts: Effect of pretreatments of active carbon
Li, Sha,Wang, Xicheng,Liu, Xiaoran,Xu, Guoqiang,Han, Sheng,Mu, Xindong
, p. 92 - 96 (2015)
The effect of active carbon pretreatment on the catalytic performance of Pd/C catalysts in the hydrogenation of itaconic acid was studied. The catalysts were prepared by deposition-precipitation and characterized by XRD, BET, NH3-TPD, TEM and F
CATALYTIC CARBONYLATION OF PROPYLENE WITH CARBON MONOXIDE UNDER PRESSURE IN THE PRESENCE OF A PALLADIUM-ZEOLITE CATALYST
Lapidus, A. L.,Pirozhkov, S. D.,Vellekov, A.,Garanin, V. I.,Slyunyaev, P. I.,Minachev, Kh. M.
, p. 2027 - 2030 (1982)
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A series of crystal structures of a meta-cleavage product hydrolase from Pseudomonas fluorescens IP01 (CumD) complexed with various cleavage products
Fushinobu, Shinya,Jun, So-Young,Hidaka, Masafumi,Nojiri, Hideaki,Yamane, Hisakazu,Shoun, Hirofumi,Omori, Toshio,Wakagi, Takayoshi
, p. 491 - 498 (2005)
Meta-cleavage product hydrolase (MCP-hydrolase) is one of the key enzymes in the microbial degradation of aromatic compounds. MCP-hydrolase produces 2-hydroxypenta-2,4-dienoate and various organic acids, according to the C6 substituent of the substrate. Comprehensive analysis of the substrate specificity of the MCP-hydrolase from Pseudomonas fluorescens IP01 (CumD) was carried out by determining the kinetic parameters for nine substrates and crystal structures complexed with eight cleavage products. CumD preferred substrates with long non-branched C6 substituents, but did not effectively hydrolyze a substrate with a phenyl group. Superimposition of the complex structures indicated that benzoate was bound in a significantly different direction than other aliphatic cleavage products. The directions of the bound organic acids appeared to be related with the kcat values of the corresponding substrates. The Ile139 and Trp143 residues on helix α4 appeared to cause steric hindrance with the aromatic ring of the substrate, which hampers base-catalyzed attack by water.
Sharp et al.
, p. 1802 (1952)
Aerobic oxidation of alcohols to carbonyl compounds catalyzed by N-hydroxyphthalimide (NHPI) combined with Co(acac)3
Iwahama, Takahiro,Sakaguchi, Satoshi,Nishiyama, Yutaka,Ishii, Yasutaka
, p. 6923 - 6926 (1995)
Aerobic oxidation of various alcohols has been accomplished by using a new catalytic system. N-hydroxyphthalimide (NHPI) combined with Co(acac)3. The oxidation of alcohols by NHPI was found to be markedly enhanced by adding a slight amount of Co(acac)3 (0.05 equiv. to NHPI). Thus, secondary alcohols and vic-diols which are difficult to be oxidized by NHPI alone were smoothly oxidized with molecular oxygen (1 atm) to the corresponding carbonyl compounds under relatively mild conditions (65 ~ 75 °C).
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Eccott,Linstead
, p. 911 (1930)
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Lid hinge region of Penicillium expansum lipase affects enzyme activity and interfacial activation
Tang, Lianghua,Su, Min,Yan, Junzhe,Xie, Sheng,Zhang, Wenhuang
, p. 1218 - 1223 (2015)
Saturation mutagenesis at sites displaying the highest B factors in the lid and the hinge regions of Penicillium expansum lipase (PEL) has been employed to improve the efficiency of the lipase in biocatalysis. Replacements of amino acid on beneficial mutants were identified as T66L/D70N, T66V/D70N, E83K, E83H and E83N. In substrate specificity assays, T66L/D70N was significantly more active than wild-type PEL on substrates with medium and long chain lengths. In addition this mutant also displayed a 136.4-fold increase in activity on p-nitrophenyl palmitate. Remarkably, E83K lacked interfacial activation while it was observed in wild-type PEL and the other mutants. Insight into the relation between the mutations and enzymatic properties was gained by modeling and docking studies. All these mutants showed an enhanced catalytic activity, indicating their potential in further application. Therefore, these results indicate the amino acid composition of the lid hinge region plays an extremely important role in the interfacial activation, activity and substrate specificity of PEL. Moreover, the results in this work provide a new clue for selecting critical amino acid residues for the enzyme design.
Effects of diluents on the reaction hazards of tributyl phosphate with nitric acid
Sreekantan, Smitha Velayuthan,Mahadevan, Surianarayanan,Jala, Samuel Vara Kumar,Seshadri, Hariharan,Mandal, Asit Baran
, p. 1821 - 1827 (2014)
A proportion of 30 wt % of tributyl phosphate (TBP) in suitable diluents is the workhorse in the extraction of U and Pu in the plutonium uranium extraction (PUREX) process. Accelerating rate calorimetric (ARC) studies of effects of diluents on TBP behavior reveal a similar thermal behavior irrespective of the nature of diluents. The reactive thermal hazards of 30 wt % of TBP with 4N HNO3 in different diluents show onset temperatures in the range of 105-130 °C with a significant pressure rise. Although the onset points are closer to the operating temperature range of the PUREX process, the heat rates are small. However, the process poses pressurization hazards due to the breakdown of the structure of TBP. Oxidation of butanol to butanoic acid is the main cause for exothermic behavior in all cases.
Adsorption and degradation of Congo red on a jarosite-type compound
Dong, Yu,Wang, Ziting,Yang, Xin,Zhu, Meiying,Chen, Rufen,Lu, Bin,Liu, Hui
, p. 102972 - 102978 (2016)
Natrojarosite particles were prepared by forced hydrolysis. X-ray diffraction and field-emission scanning electron microscopy were used to characterize the resulting products. Degradation of the azo dye Congo red (CR) by natrojarosite was investigated under various conditions, such as in the presence or absence of visible-light irradiation, catalyst loading, H2O2 concentration, and initial pH. Total organic carbon determination, UV-visible spectroscopy, and direct infusion-electrospray ionization mass spectrometry in the negative ion mode provided insight into the nature of the degradation products. Moreover, a complete degradation mechanism of CR on natrojarosite was presented. The degradation of CR in the current system occurred even at neutral pH, and the total degradation rate was close to 99.1% for a 30 mg L-1 CR solution. Approximately 80% of the samples were completely mineralized and the other 20% were degraded to small-molecule products. The novel natrojarosite catalysts are potentially valuable for industrial applications because of their high activity, low iron leaching, and low cost.
Study of monometallic Pd/TiO2 catalysts for the hydrogenation of succinic acid in aqueous phase
Tapin, Benoit,Epron, Florence,Especel, Catherine,Ly, Bao Khanh,Pinel, Catherine,Besson, Michele
, p. 2327 - 2335 (2013)
A series of 2 wt % Pd/TiO2 monometallic catalysts were prepared by varying some parameters, such as the nature of the precursor salt, the titania support, and the preparation method. The structural and textural properties of the catalytic systems were fully characterized by several physical and chemical techniques (inductively coupled plasma optical emission spectrometry, N2 physisorption, H2 chemisorption, transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, powder X-ray diffraction, temperature-programmed reduction, X-ray photoelectron spectroscopy, and gas phase reaction of cyclohexane dehydrogenation). The catalytic performances were further estimated for the hydrogenation of an aqueous solution of succinic acid (SUC) performed in a batch reactor at 160 C and under 150 bar total pressure. The results showed that all the Pd catalysts are very selective to produce γ-butyrolactone, the first hydrogenated product. However, the rate of succinic acid conversion is a function of both the Pd dispersion and the preparation method. The deposition-precipitation method allows one to obtain the highest performing 2 wt % Pd/TiO2 samples during SUC hydrogenation in terms of activity and stability.
Applications of Homogeneous Water-gas-shift Reaction. I. Further Studies of the Hydroformylation of Propene with CO and H2O
Murata, Kazuhisa,Matsuda, Akio
, p. 245 - 248 (1981)
Polar ether solutions prepared in situ from Co2(CO)8 and 1,2-bis(diphenylphosphino)ethane (diphos) are active catalysts for the hydroformylation of propene with CO and H2O.Under the hydroformylation conditions employed, butyl(C4) or isobutyl alcohols, butyric(C4) acids, and dipropyl ketones were found to be formed as by-products.A pronounced formation of C4 alcohols was observed as the reaction temperature was increased; in fact, the catalyst solutions described above actively reduce butyraldehyde to butyl alcohol.The effects of the CO pressure and of the propene concentration on the formation of C4 aldehydes are also examined.It turns out that the water molecule as well as Co2(CO)8 and diphos are essential for the formation of catalytic intermediates, which are themselves responsible for the hydroformylation activity.
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Brady,Sharawy
, p. 4082,4083 (1953)
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Aqueous-phase aerobic oxidation of alcohols by soluble Pt nanoclusters in the absence of base
Wang, Tao,Xiao, Chao-Xian,Yan, Liang,Xu, Lin,Luo, Jie,Shou, Heng,Kou, Yuan,Liu, Haichao
, p. 4375 - 4377 (2007)
A soluble Pt nanocluster catalyst (Pt-GLY) is efficient in the absence of base for aqueous-phase aerobic oxidation of, in particular, non-activated alcohols with high recyclability. The Royal Society of Chemistry.
Electrocatalytic Alcohol Oxidation with TEMPO and Bicyclic Nitroxyl Derivatives: Driving Force Trumps Steric Effects
Rafiee, Mohammad,Miles, Kelsey C.,Stahl, Shannon S.
, p. 14751 - 14757 (2015)
Bicyclic nitroxyl derivatives, such as 2-azaadamantane N-oxyl (AZADO) and 9-azabicyclo[3.3.1]nonane N-oxyl (ABNO), have emerged as highly effective alternatives to TEMPO-based catalysts for selective oxidation reactions (TEMPO = 2,2,6,6-tetramethyl-1-piperidine N-oxyl). Their efficacy is widely attributed to their smaller steric profile; however, electrocatalysis studies described herein show that the catalytic activity of nitroxyls is more strongly affected by the nitroxyl/oxoammonium redox potential than by steric effects. The inexpensive, high-potential TEMPO derivative, 4-acetamido-TEMPO (ACT), exhibits higher electrocatalytic activity than AZADO and ABNO for the oxidation of primary and secondary alcohols. Mechanistic studies provide insights into the origin of these unexpected reactivity trends. The superior activity of ACT is especially noteworthy at high pH, where bicyclic nitroxyls are inhibited by formation of an oxoammonium hydroxide adduct.
Synthesis of nanostructured carbon on Ni catalysts supported on mesoporous silica, preparation of carbon-containing adsorbents, and preparation and study of lipase-active biocatalysts
Kovalenko,Chuenko,Perminova,Rudina
, p. 394 - 403 (2016)
This work continues a series of our studies on the synthesis of nanostructured carbon (NSC) by the pyrolysis of H2 + C3–C4 alkane mixtures on nickel and cobalt metal catalysts supported on chemically diverse inorganic materials (aluminosilicates, alumina, carbon) having different textural characteristics (mesoporous and macroporous supports) and shapes (granules, foamed materials, and honeycomb monoliths). Here, we consider Ni catalysts supported on granular mesoporous silica (SiO2). It has been elucidated how the yield of synthesized carbon depends on the Ni/SiO2 catalyst preparation method (homogeneous precipitation or impregnation) and on the composition of the impregnating solution, including the molar ratio of its components—nickel nitrate and urea. The morphology of catalytic NSC and Ni distribution in the silica granule have been investigated using a scanning electron microscope with an EDX analyzer. Carbon-containing composite supports (NSC/SiO2) have been employed as adsorbents for immobilizing microbial lipase. The enzymatic activity and stability of the resulting biocatalysts have been estimated in transesterification reactions of vegetable (sunflower and linseed) oils involving methyl or ethyl acetate, esterification, and synthesis of capric acid–isoamyl alcohol esters in nonaqueous media.
Reactions of calix[4]resorcinolarene anions with esters of carboxylic acids in H2O-DMF solvent
Mirgorodskaya,Kudryavtseva,Kazakova,Konovalov
, p. 261 - 264 (2000)
Reactions of calix[4]resorcinolarene anions with para-nitrophenyl carboxylates in the H2O-DMF medium were studied. The kinetics of this process was measured by optical spectroscopy and potentiometric titration; the step of formation of acylated calixarene and the subsequent step of its hydrolysis were detected. Self-association of long-chain calixarenes into micelles decreases their reactivity with respect to that of the monomers.
Catalytic oxidation of ethers with H2O2 over zeolites
Sasidharan,Suresh,Sudalai
, p. 9071 - 9072 (1995)
Titanium Silicates (TS-1 and TS-2) catalyzed efficiently the selective oxidation of both linear and cyclic ethers into the corresponding acids and lactones respectively, using dil, H2O2 as the oxidant.
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Merrow,Whitnack
, p. 1224 (1958)
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Synthesis Gas Homologation of Aliphatic Carboxylic Acids
Knifton, John F.
, p. 41 - 43 (1981)
A new preparative route to aliphatic carboxylic acids is described involving a novel homologation using synthesis gas catalysed by soluble ruthenium species coupled with iodide promotors.
Bioreduction of aldehydes and ketones using Manihot species
Machado, Luciana L.,Souza, Joao Sammy N.,de Mattos, Marcos Carlos,Sakata, Solange K.,Cordell, Geoffrey A.,Lemos, Telma L.G.
, p. 1637 - 1643 (2006)
Biocatalysis constitutes an important tool in organic synthesis, especially for the preparation of chiral molecules of biological interest. A series of aliphatic and aromatic aldehydes and two ketones were reduced using plant cell preparations from Manihot esculenta and Manihot dulcis roots. The reduced products were typically obtained in excellent yields (80-96%), and with excellent enantiomeric excess (94-98%), except for vanillin. Esters, a nitrile, and an amide were also examined, but were not reduced. Preliminary conversion rate studies are reported. This is the first attempt to perform the biotransformation of carbonyl compounds using Manihot species.
Selective oxidation of n-butanol using gold-palladium supported nanoparticles under base-free conditions
Gandarias, Inaki,Miedziak, Peter J.,Nowicka, Ewa,Douthwaite, Mark,Morgan, David J.,Hutchings, Graham J.,Taylor, Stuart H.
, p. 473 - 480 (2015)
The base-free selective catalytic oxidation of n-butanol by O2 in an aqueous phase has been studied using Au-Pd bimetallic nanoparticles supported on titania. Au-Pd/TiO2 catalysts were prepared by different methods: wet impregnation, physical mixing, deposition-precipitation and sol immobilisation. The sol immobilisation technique, which used polyvinyl alcohol (PVA) as the stabilizing agent, gave the catalyst with the smallest average particle size and the highest stable activity and selectivity towards butyric acid. Increasing the amount of PVA resulted in a decrease in the size of the nanoparticles. However, it also reduced activity by limiting the accessibility of reactants to the active sites. Heating the catalyst to reflux with water at 90°C for 1 h was the best method to enhance the surface exposure of the nanoparticles without affecting their size, as determined by TEM, X-ray photoelectron spectroscopy and CO chemisorption analysis. This catalyst was not only active and selective towards butyric acid but was also stable under the operating conditions.
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Simmons,Kreuz
, p. 836 (1968)
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Hybrid composites octyl-silica-methacrylate agglomerates as enzyme supports
Fernández, Oscar,Díaz, Isabel,Torres, Carlos F.,Tobajas, Montserrat,Tejedor, Víctor,Blanco, Rosa M.
, p. 204 - 210 (2013)
The use of immobilized enzymes as catalysts may be limited by particle size which must be larger than the mesh that retains them in the reactor. Octyl-silica (OS) beads of 70 μm average size were agglomerated to obtain hybrid organic-inorganic composites with particle sizes between 100 and 200 μm. The agglomeration process has been achieved by polymerization of methacrylate from glycidyl methacrylate and ethylene dimethacrylate in the presence of silica beads and further functionalization of the composite with octyl groups. Methacrylate content of the composite (20%) is high enough to stick OS beads, and low enough to preserve the advantages of these particles as supports. The properties of the octyl silica particles for lipase immobilization have been very closely reproduced with the octyl-silica-methacrylate (OSM) composite. Enzyme loading of 210 mg lipase per gram of support has been achieved on OSM vs 230 mg/g on OS. Also catalytic activity values are close for both catalysts, OSM-lipase remaining fully active and stable after 15 cycles in acetonitrile.
Biotransformation of aromatic and heterocyclic amides by amidase of whole cells of Rhodococcus sp. MTB5: Biocatalytic characterization and substrate specificity
Ismailsab, Mukram,Monisha,Reddy, Pooja V.,Santoshkumar,Nayak, Anand S.,Karegoudar, Timmanagouda B.
, p. 74 - 85 (2017)
In this study, an amidohydrolase activity of amidase in whole cells of Rhodococcus sp. MTB5 has been used for the biotransformation of aromatic, monoheterocyclic and diheterocyclic amides to corresponding carboxylic acids. Benzoic acid, nicotinic acid and pyrazinoic acid are carboxylic acids which have wide industrial applications. The amidase of this strain is found to be inducible in nature. The biocatalytic conditions for amidase present in the whole cells of MTB5 were optimized against benzamide. The enzyme exhibited optimum activity in 50 mM potassium phosphate buffer pH 7.0. The optimum temperature and substrate concentrations for this enzyme were 50 °C and 50 mM, respectively. The enzyme was quite stable for more than 6 h at 30 °C. It showed substrate specificity against different amides, including aliphatic, aromatic and heterocyclic amides. Under optimized reaction conditions, the amidase is capable of converting 50 mM each of benzamide, nicotinamide and pyrazinamide to corresponding acids within 100, 160 and 120 min, respectively, using 5 mg dry cell mass (DCM) per mL of reaction mixture. The respective percent conversion of these amides was 95.02%, 98.00% and 98.44% achieved by whole cells. The amidase in whole cells can withstand as high as 383 mM concentration of product in a reaction mixture and above which it undergoes product feedback inhibition. The results of this study suggest that Rhodococcus sp. MTB5 amidase has the potential for large-scale production of carboxylic acids of industrial value.
Photoactivable heterocyclic cages in a comparative release study of butyric acid as a model drug
Piloto, Ana M.,Hungerford, Graham,Sutter, Jens U.,Soares, Ana M.S.,Costa, Susana P.G.,Gonc?alves, M. Sameiro T.
, p. 44 - 53 (2015)
Aiming: at the improvement of the photorelease of butyric acid - a model carboxylic acid drug, a set of heteroaromatic compounds based on acridine, naphtho[2,1-b]pyran, 3H-benzopyran fused julolidine and thioxo-naphtho[2,1-b]pyran were evaluated as benzyl-type phototriggers, in comparison with the well-known o-nitrobenzyl group. The corresponding ester cages were irradiated in a photochemical reactor at 254, 300, 350 and 419 nm, in two solvent systems (methanol or acetonitrile in 80:20 mixtures with HEPES buffer). Photolysis studies showed that, for some of the cages, the release of the active molecule occurred with short irradiation times using 419 nm. Time-resolved fluorescence was used to elucidate their photophysical properties and determine the decay kinetics. Studies were also carried out to assess the suitability of using two-photon excitation to address these compounds, which is advantageous if their use in biological systems is to be considered.
One-step solvent-free aerobic oxidation of aliphatic alcohols to esters using a tandem Sc-Ru?MOF catalyst
Feng, Tingkai,Li, Conger,Li, Tao,Zhang, Songwei
supporting information, p. 1474 - 1480 (2022/03/08)
Esters are an important class of chemicals in industry. Traditionally, ester production is a multi-step process involving the use of corrosive acids or acid derivatives (e.g. acid chloride, anhydride, etc.). Therefore, the development of a green synthetic protocol is highly desirable. This work reports the development of a metal-organic framework (MOF) supported tandem catalyst that can achieve direct alcohol to ester conversion (DAEC) using oxygen as the sole oxidizing agent under strictly solvent-free conditions. By incorporating Ru nanoparticles (NPs) along with a homogeneous Lewis acid catalyst, scandium triflate, into the nanocavities of a Zr MOF, MOF-808, the compound catalyst, Sc-Ru?MOF-808, can achieve aliphatic alcohol conversion up to 92% with ester selectivity up to 91%. A mechanistic study reveals a unique “via acetal” pathway in which the alcohol is first oxidized on Ru NPs and rapidly converted to an acetal on Sc(iii) sites. Then, the acetal slowly decomposes to release an aldehyde in a controlled manner for subsequent oxidation and esterification to the ester product. To the best of our knowledge, this is the first example of DAEC of aliphatic alcohols under solvent-free conditions with high conversion and ester selectivity.
Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
, p. 803 - 808 (2021/07/20)
Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
A 3D MOF based on Adamantoid Tetracopper(II) and Aminophosphine Oxide Cages: Structural Features and Magnetic and Catalytic Properties
?liwa, Ewelina I.,Nesterov, Dmytro S.,Kirillova, Marina V.,K?ak, Julia,Kirillov, Alexander M.,Smoleński, Piotr
supporting information, p. 9631 - 9644 (2021/06/30)
This work describes an unexpected generation of a new 3D metal-organic framework (MOF), [Cu4(μ-Cl)6(μ4-O)Cu(OH)2(μ-PTAO)4]n·2nCl-EtOH·2.5nH2O, from copper(II) chloride and 1,3,5-triaza-7-phosphaadamantane 7-oxide (PTAO). The obtained product is composed of diamandoid tetracopper(II) [Cu4(μ-Cl)6(μ4-O)] cages and monocopper(II) [Cu(OH)2] units that are assembled, via the diamandoid μ-PTAO linkers, into an intricate 3D net with an nbo topology. Magnetic susceptibility measurements on this MOF in the temperature range of 1.8-300 K reveal a ferromagnetic interaction (J = +20 cm-1) between the neighboring copper(II) ions. Single-point DFT calculations disclose a strong delocalization of the spin density over the tetranuclear unit. The magnitude of exchange coupling, predicted from the broken-symmetry DFT studies, is in good agreement with the experimental data. This copper(II) compound also acts as an active catalyst for the mild oxidation and carboxylation of alkanes. The present study provides a unique example of an MOF that is assembled from two different types of adamantoid Cu4 and PTAO cages, thus contributing to widening a diversity of functional metal-organic frameworks.
