124-13-0Relevant articles and documents
Rhodium thiolate hydroformylation complexes tethered to delamellated γ-zirconium phosphate
Rojas,Murcia-Mascaros,Terreros,Garcia Fierro
, p. 1430 - 1437 (2001)
Rhodium thiolate complexes intercalated in crystalline γ-zirconium phosphate or tethered to SiO2-modified γ-zirconium phosphate have been synthesised. It was observed that the addition of a solution of organic silicates to a colloidal suspension of γ-zirconium phosphate yielded amorphous substrates, which displayed very high specific areas (160-650 m2 g-1). Incorporation of a mercaptocarbonyl rhodium complex resulted in a highly selective and active catalyst precursor for the hydroformylation of 1-heptene in the liquid phase. Elemental analysis and photoelectron spectroscopy of the fresh and used samples revealed that some metal leaching occurs during the reaction, this being mainly confined to the outer layers of the solid particles. This observation, together with the high selectivity towards linear aldehydes, makes SiO2-modified γ-zirconium phosphate a good support candidate for immobilised Rh catalysts. Spectroscopic data obtained from the crystalline precursor and also from the amorphous catalyst showed that the interaction between the rhodium complex and the acid support was achieved via hydrogen bonds, forming NH groups.
Heterogeneous selective oxidation of fatty alcohols: Oxidation of 1-tetradecanol as a model substrate
Corberán, Vicente Cortés,Gómez-Avilés, Almudena,Martínez-González, Susana,Ivanova, Svetlana,Domínguez, María I.,González-Pérez, María Elena
, p. 49 - 53 (2014)
s Selective oxidation of fatty alcohols, i.e., linear long-chain alkanols, has been scarcely investigated to date, despite its potential application in high value chemical's production. We report for the first time the liquid phase heterogeneous oxidation of 1-tetradecanol, used as a model molecule for fatty alcohols, according to green chemistry principles by using a Au/CeO2-Al2O3 catalyst and O2 as oxidant at normal pressure. High selectivity to tetradecanal (ca. 80%) or to tetradecanoic acid (60-70%) are reached at medium conversion (up to 38%), depending on the reaction conditions used. Comparison with similar tests of 1-octanol oxidation shows that the increase of the carbon chain length decreases the alcohol conversion and the formation of ester, probably due to a greater steric effect.
Coprecipitated gold-trieobalt tetraoxide catalyst for heterogeneous hydroformylation of oleflns
Liu, Xiaohao,Haruta, Masatake,Tokunaga, Makoto
, p. 1290 - 1291 (2008)
The combination of gold (Au0) and tricobalt tetraoxide (CO 3O4) prepared by coprecipitation gives high-performance heterogeneous catalysts for hydroformylation reaction with selectivity above 85% in desired aldehydes, alth
Synthesis of two new Mo(II) organometallic catalysts immobilized on POSS for application in olefin oxidation reactions
Vieira, Eduardo Guimar?es,Dal-Bó, Alexandre Gon?alves,Frizon, Tiago Elias Allievi,Dias Filho, Newton Luiz
, p. 73 - 82 (2017)
The purpose of this work was the preparation and characterization of two new catalysts POSS-ATZAc-[Mo(η3-C3H5)Br(CO)2] (POSS-Mo-I) and POSS-ATZAc-[Mo(CO)3Br2] (POSS-Mo-II). The new heterogeneous catalysts were characterized by several techniques and used as catalysts for the epoxidation of olefins, presenting high catalytic activity. To study and optimize the syntheses of the heterogeneous catalysts, immobilization experiments of the [Mo(η3-C3H5)Br(CO)2(NCMe)2] and [Mo(CO)3Br2(NCMe)2] organometallic complexes on the modified polyhedral oligomeric silsesquioxane were performed. The sorption properties of the modified silsesquioxane showed to be dependent of the contact time, concentration and temperature. Catalysts were tested in the epoxidation of six olefins and compared with homogeneous species [Mo(η3-C3H5)Br(CO)2(ATZAc)] (Mo-I) and [Mo(CO)3Br2(ATZAc)] (Mo-II). To the best of our knowledge, this paper is the first that has reported the preparation and characterization of two new heterogeneous catalysts, as well as the comparison with homogeneous species for catalytic epoxidation of olefins.
Readily Accessible 12-I-5 Oxidant for the Conversion of Primary and Secondary Alcohols to Aldehydes and Ketones
Dess, D. B.,Martin, J. C.
, p. 4155 - 4156 (1983)
Periodinane 2 is a mild, selective reagent for the oxidation of primary and secondary alcohols to aldehydes and ketones.
REDOX REACTIONS IN MICELLAR SYSTEMS. COMMUNICATION 1. REDUCTION OF METHYL VIOLOGEN BY KETYL RADICAL
Burbo, E.M.,Gasanova, L.V.,Dzhabiev, T.S.
, p. 2246 - 2251 (1984)
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Au/TiO2 catalysts promoted with Fe and Mg for n-octanol oxidation under mild conditions
Kotolevich,Kolobova,Mamontov,Khramov,Cabrera Ortega,Tiznado,Farías,Bogdanchikova,Zubavichus, Ya.,Mota-Morales,Cortés Corberán,Zanella,Pestryakov
, p. 104 - 112 (2016)
This work aims to further the understanding of gold-based catalytic oxidation of n-octanol in liquid phase. Modification of catalysts with metal oxides additives (Fe or Mg) was used as a tool for transforming and stabilizing gold species. Structural, electronic and catalytic properties of gold catalysts were systematically investigated by means of DRS, H2, CO FTIR, SBET, EDS and SEM, HRTEM, SR-XRD, XANES, XPS and liquid phase n-octanol oxidation. Addition of modifiers affects Au electronic properties, but not the structural ones. Characterization results allow excluding Au3+ ions as candidates for active sites in n-octanol oxidation. In Au/Mg/TiO2, gold exhibited more reduced states while in Au/Fe/TiO2 gold was more oxidized; Au/TiO2 for intermediate oxidized states was found. The proper balance of oxidation states in the gold surface of Au/Mg/TiO2 can be responsible for its higher activity compared with Au/Fe/TiO2 and Au/TiO2 towards n-octanol oxidation. Finally our approach shed light on the nature of active sites for n-octanol oxidation on gold and furthers the development of green base-free catalytic oxidation of alcohols.
Room temperature liquid salts of Cr and Mo as self-supported oxidants
Noguera, Gladys,Mostany, Jorge,Agrifoglio, Giuseppe,Dorta, Romano
, p. 231 - 234 (2005)
Room temperature liquid salts of Cr and Mo were synthesized and fully characterized including cyclic voltammetry of the neat Mo salt. These liquid salts were used as self-supported reagents for the oxidation of alcohols (under solvent-free and biphasic conditions) and their potential for biphasic self-supported catalytic applications was demonstrated.
ACTIVATION AND SYNTHETIC APPLICATIONS OF THIOSTANNANES. CHEMICAL MODIFICATION OF HYDROXY FUNCTION UNDER PROTECTION
Sato, Tsuneo,Tada, Tatsushi,Otera, Junzo,Nozaki, Hitosi
, p. 1665 - 1668 (1989)
Tetrahydropyranyl ethers are converted in one-pot into benzyl and α-methoxyethoxymethyl ethers, benzoates, tosylates, and aldehydes on treatment with thiostannanes in the presence of BF3*OEt2 followed by exposure of the resulting alkoxystannanes to electrophiles or PCC.
The effect of support properties on n-octanol oxidation performed on gold – silver catalysts supported on MgO, ZnO and Nb2O5
Kaskow, Iveta,Sobczak, Izabela,Ziolek, Maria,Corberán, Vicente Cortés
, (2020)
Catalytic behaviour of supported nanometal catalysts for alcohols selective oxidation depends on the nature of the support and its surface. To identify the main feature that could explain these effects, supported mono- (Au) and bimetallic (AuAg) catalysts were prepared by using pure MgO, ZnO and Nb2O5, representative of three different types of oxides (basic, amphoteric and acidic, respectively), to get homogeneous metal-support interaction for each catalyst. The catalysts were characterized by XRD, N2 physisorption, TEM, UV–vis, XPS and 2-propanol decomposition as test reaction. It was found that the catalytic activity is influenced by the electron mobility between the gold nanoparticles and the support, which in turns depends on the intermediate electronegativity of the support. Selectivity in n-octanol oxidation was determined by redox properties of the gold species, the acid-base properties of the supports and the catalyst pretreatment. Silver addition modified the acid-base properties of the catalytic system, thus influencing the selectivity in n-octanol oxidation. Pretreatment of the catalyst (drying in air or thermal treatment in hydrogen flow) had a significant impact on its activity and selectivity.
Hydroformylation of 1-hexene over rhodium supported on active carbon catalyst
Li, Baitao,Li, Xiaohong,Asami, Kenji,Fujimoto, Kaoru
, p. 378 - 379 (2003)
Hydroformylation of 1-hexene on rhodium catalyst was studied under mild reaction conditions (P = 3.0 MPa, CO/H2 = 1/1, T = 403 K). Its hydroformylation performances were investigated in a variety of solvent. It was found that the excellent activity for the heterogeneous catalyst was showed in the n-octane solvent, while poor activity in the alcoholic and H2O solvent.
Pyridinium chlorochromate: An improved method for its synthesis and use of anhydrous acetic acid as catalyst for oxidation reactions
Agarwal, Seema,Tiwari,Sharma
, p. 4417 - 4420 (1990)
An improved procedure for the preparation of Corey's reagent - Pyridinium chlorochromate has been described. The method is less hazardous and gives better yield. Synthetic utility of the reagent has been shown to increase in the presence of anhydrous acetic acid, used for the first time as catalyst, for the oxidation of alcohols.
Not as easy as π: An insertional residue does not explain the π-helix gain-of-function in two-component FMN reductases
McFarlane, Jeffrey S.,Hagen, Richard A.,Chilton, Annemarie S.,Forbes, Dianna L.,Lamb, Audrey L.,Ellis, Holly R.
, p. 123 - 134 (2019)
The π-helix located at the tetramer interface of two-component FMN-dependent reductases contributes to the structural divergence from canonical FMN-bound reductases within the NADPH:FMN reductase family. The π-helix in the SsuE FMN-dependent reductase of the alkanesulfonate monooxygenase system has been proposed to be generated by the insertion of a Tyr residue in the conserved α4-helix. Variants of Tyr118 were generated, and their X-ray crystal structures determined, to evaluate how these alterations affect the structural integrity of the π-helix. The structure of the Y118A SsuE π-helix was converted to an α-helix, similar to the FMN-bound members of the NADPH:FMN reductase family. Although the π-helix was altered, the FMN binding region remained unchanged. Conversely, deletion of Tyr118 disrupted the secondary structural properties of the π-helix, generating a random coil region in the middle of helix 4. Both the Y118A and Δ118 SsuE SsuE variants crystallize as a dimer. The MsuE FMN reductase involved in the desulfonation of methanesulfonates is structurally similar to SsuE, but the π-helix contains a His insertional residue. Exchanging the π-helix insertional residue of each enzyme did not result in equivalent kinetic properties. Structure-based sequence analysis further demonstrated the presence of a similar Tyr residue in an FMN-bound reductase in the NADPH:FMN reductase family that is not sufficient to generate a π-helix. Results from the structural and functional studies of the FMN-dependent reductases suggest that the insertional residue alone is not solely responsible for generating the π-helix, and additional structural adaptions occur to provide the altered gain of function.
Triruthenium dodecacarbonyl/triphenylphosphine catalyzed dehydrogenation of primary and secondary alcohols
Meijer,Ligthart,Meuldijk,Vekemans,Hulshof,Mills,Kooijman,Spek
, p. 1065 - 1072 (2004)
Dehydrogenation of alcohols into aldehydes and ketones by Ru 3(CO)12/PPh3 based homogeneous catalysis has been investigated as an alternative for the classical Oppenauer oxidation. Several catalytic systems have been screened in the Oppenauer-like oxidation of alcohols. A systematic study of various combinations of Ru3(CO) 12, mono- and bidentate ligands and hydride acceptors was performed to enable dehydrogenation of primary alcohols to stop at the aldehyde stage. Among many H-acceptors screened, diphenylacetylene (tolane) proved the most suitable judged from its smooth reduction. Electron rich and deficient analogues of tolane have been synthesized and, based on competition experiments between these H-acceptors, a tentative catalytic cycle for the Ru 3(CO)12/PPh3-catalyzed dehydrogenations has been proposed.
Asymmetric synthesis of (-)-acaterin
Kandula, Subba Rao V.,Kumar, Pradeep
, p. 6149 - 6151 (2003)
The asymmetric synthesis of (-)-acaterin, an inhibitor of acyl-CoA cholesterol acyl transferase has been achieved starting from the commercially available starting materials, octan-1-ol and methyl (R)-lactate. The key steps are a Sharpless asymmetric dihydroxylation and a Wittig olefination.
One-Pot Bioelectrocatalytic Conversion of Chemically Inert Hydrocarbons to Imines
Chen, Hui,Tang, Tianhua,Malapit, Christian A.,Lee, Yoo Seok,Prater, Matthew B.,Weliwatte, N. Samali,Minteer, Shelley D.
, p. 4047 - 4056 (2022/02/10)
Petroleum hydrocarbons are our major energy source and an important feedstock for the chemical industry. With the exception of combustion, the deep conversion of chemically inert hydrocarbons to more valuable chemicals is of considerable interest. However, two challenges hinder this conversion. One is the regioselective activation of inert carbon-hydrogen (C-H) bonds. The other is designing a pathway to realize this complicated conversion. In response to the two challenges, a multistep bioelectrocatalytic system was developed to realize the one-pot deep conversion from heptane to N-heptylhepan-1-imine under mild conditions. First, in this enzymatic cascade, a bioelectrocatalytic C-H bond oxyfunctionalization step based on alkane hydroxylase (alkB) was applied to regioselectively convert heptane to 1-heptanol. By integrating subsequent alcohol oxidation and bioelectrocatalytic reductive amination steps based on an engineered choline oxidase (AcCO6) and a reductive aminase (NfRedAm), the generated 1-heptanol was successfully converted to N-heptylhepan-1-imine. The electrochemical architecture provided sufficient electrons to drive the bioelectrocatalytic C-H bond oxyfunctionalization and reductive amination steps with neutral red (NR) as electron mediator. The highest concentration of N-heptylhepan-1-imine achieved was 0.67 mM with a Faradaic efficiency of 45% for C-H bond oxyfunctionalization and 70% for reductive amination. Hexane, octane, and ethylbenzene were also successfully converted to the corresponding imines. Via regioselective C-H bond oxyfunctionalization, intermediate oxidation, and reductive amination, the bioelectrocatalytic hydrocarbon deep conversion system successfully realized the challenging conversion from inert hydrocarbons to imines that would have been impossible by using organic synthesis methods and provided a new methodology for the comprehensive conversion and utilization of inert hydrocarbons.
Expanding the Biocatalytic Toolbox with a New Type of ene/yne-Reductase from Cyclocybe aegerita
Karrer, Dominik,Gand, Martin,Rühl, Martin
, p. 2191 - 2199 (2021/02/26)
This study introduces a new type of ene/yne-reductase from Cyclocybe aegerita with a broad substrate scope including aliphatic and aromatic alkenes/alkynes from which aliphatic C8-alkenones, C8-alkenals and aromatic nitroalkenes were the preferred substrates. By comparing alkenes and alkynes, a ~2-fold lower conversion towards alkynes was observed. Furthermore, it could be shown that the alkyne reduction proceeds via a slow reduction of the alkyne to the alkene followed by a rapid reduction to the corresponding alkane. An accumulation of the alkene was not observed. Moreover, a regioselective reduction of the double bond in α,β-position of α,β,γ,δ-unsaturated alkenals took place. This as well as the first biocatalytic reduction of different aliphatic and aromatic alkynes to alkanes underlines the novelty of this biocatalyst. Thus with this study on the new ene-reductase CaeEnR1, a promising substrate scope is disclosed that describes conceivably a broad occurrence of such reactions within the chemical landscape.
Visible light-induced photodeoxygenation of polycyclic selenophene Se-oxides
Chintala, Satyanarayana M.,Throgmorton, John C.,Maness, Peter F.,McCulla, Ryan D.
, (2020/10/02)
Photodeoxygenation of dibenzothiophene S-oxide (DBTO) is believed to produce ground-state atomic oxygen [O(3P)] in solution. Compared with other reactive oxygen species (ROS), O(3P) is a unique oxidant as it is potent and selective. Derivatives of DBTO have been used as O(3P)-precursors to oxidize variety of molecules, including plasmid DNA, proteins, lipids, thiols, and other small organic molecules. Unfortunately, the photodeoxygenation of DBTO requires ultraviolet irradiation, which is not an ideal wavelength range for biological systems, and has a low quantum yield of approximately 0.003. In this work, benzo[b]naphtho[1,2-d]selenophene Se-oxide, benzo[b]naphtho[2,1-d]selenophene Se-oxide, dinaphtho[2,3-b:2’,3’-d]selenophene Se-oxide, and perylo[1,12-b,c,d]selenophene Se-oxide were synthesized, and their ability to utilize visible light for generating O(3P) was interrogated. Benzo[b]naphtho[1,2-d]selenophene Se-oxide produces O(3P) upon irradiation centered at 420 nm. Additionally, benzo[b]naphtho[1,2-d]selenophene Se-oxide, benzo[b]naphtho[2,1-d]selenophene Se-oxide, and dinaphtho[2,3-b:2’,3’-d]selenophene Se-oxide produce O(3P) when irradiated with UVA light and have quantum yields of photodeoxygenation ranging from 0.009 to 0.33. This work increases the utility of photodeoxygenation by extending the range of wavelengths that can be used to generate O(3P) in solution.