- A novel iron(iii)-based heterogeneous catalyst for aqueous oxidation of alcohols using molecular oxygen
-
A novel silica supported iron(iii)-based heterogeneous catalyst (FeCl3-imine@SiO2) has been synthesized and characterized by several techniques, such as FTIR, nitrogen adsorption analysis (BET), SEM-EDX, XRD, EPR, AAS and XPS analyses. The catalyst showed excellent activity for selective oxidation of alcohols to corresponding carbonyl compounds in water under atmospheric pressure of oxygen without using any additive. Notably, the heterogeneous catalyst showed remarkable improvement over its homogeneous counterpart, which might be attributable to the synergic effect between the metal and the supported ligand. The catalyst could be easily recovered by simple filtration and reused several times without compromising its activity. A wide range of primary and secondary alcohols including heterocyclic alcohols are tolerated as substrates.
- Sahu, Debojeet,Silva, Ana Rosa,Das, Pankaj
-
-
Read Online
- Correlation of 1-octen-3-one with antixenotic resistance in subterranean clover cotyledons to red-legged earth mite, halotydeus destructor (acarina: penthaleidae)
-
Artificially damaged cotyledons of subterranean clover (Trifolium subterraneum L.) released several volatile metabolites, including 1-octen-3-one, arising from lipid peroxidation. The amount of 1-octen-3-one produced was negatively correlated with feeding damage caused by the red-legged earth mite (Halotydeus destructor) in nine out of 10 resistant and susceptible T. subterraneum varieties tested. The EC50 of this compound in deterring mites from feeding in a membrane bioassay was 50 ppm. Cotyledon toughness was also involved in resistance. The resistant variety, S3615D, which has the lowest toughness value among the resistant varieties, produced the highest amount of 1-octen-3-one recovered from the headspace in 1 hr. Artificially damaged cotyledons of both susceptible Dalkeith and resistant DGI007, growing in shade, showed lower toughness, but had enhanced production of C8 volatile compounds and were avoided by mites during a 3-hr feeding test. When both 1-octen-3-one content and cotyledon toughness value were taken as cofactors in resistance, the resultant multiplication value yielded a more significantly negative correlation with mite feeding damage scores within the 10 varieties than either factor alone. We conclude that 1-octen-3-one has a role in resistance of subclover cotyledon to the mite.
- Jiang,Ghisalberti,Ridsdill-Smith
-
-
Read Online
- Activation of nitrous oxide and selective oxidation of alcohols and alkylarenes catalyzed by the [PV2MO10O40]5- polyoxometalate ion
-
A vanadium-substituted polyoxomolybdate ion ([PV2Mo10O40]5-, top right) can activate nitrous oxide to promote the highly selective catalytic oxidation of primary and secondary alcohols to aldehydes and ketones, and the oxidation of various alkylaromatic substrates (see scheme).
- Ben-Daniel, Revital,Neumann, Ronny
-
-
Read Online
- Copper-Catalyzed Asymmetric Hydrosilylation of β-Nitroethyl Aryl Ketones
-
A copper-catalyzed asymmetric hydrosilylation of β-nitroethyl aryl ketones has been disclosed, and the corresponding chiral alcohols could be obtained in high yields (up to 99% yield) and excellent enantioselectivities (up to 96% ee). Moreover, the reaction worked well on a gram scale with 0.3 mol % of ligand loading, indicating that our protocol has potential applications in the synthesis of important pharmaceuticals such as Tranylcypromine and Ticagrelor.
- Zeng, Weijun,Tan, Xuefeng,Yu, Yang,Chen, Gen-Qiang,Zhang, Xumu
-
supporting information
p. 858 - 862
(2020/01/31)
-
- Gold nanoparticles onto cerium oxycarbonate as highly efficient catalyst for aerobic allyl alcohol oxidation
-
Au nanoparticles, generated by the metal vapor synthesis technique, were supported onto cerium oxycarbonate monohydrate (Ce2O(CO3)2·H2O) giving Au@Ce2O(CO3)2·H2O. The obtained heterogeneous catalyst was used in the aerobic allyl alcohol oxidation reaction performed in toluene, showing a notably higher catalytic substrate conversion and isomerization activity compared to Au onto ceria, which is the reference catalyst for this type of catalysis. Results originating from catalytic recycling experiments and PXRD, HRTEM and XPS measurements carried out on recovered Au@Ce2O(CO3)2·H2O, confirmed the stability of the catalyst under aerobic oxidation reaction conditions and hence its recyclability, without the need of a regeneration step.
- Oberhauser, Werner,Evangelisti, Claudio,Marelli, Marcello,Santo, Vladimiro Dal,Cepek, Cinzia,Bellini, Marco
-
-
- Palladium-catalyzed regioselective synthesis of B(4,5)-or B(4)-substituted: O-carboranes containing α,β-unsaturated carbonyls
-
With the help of a carboxylic acid directing group, Pd-catalyzed regioselective synthesis of B(4,5)-or B(4)-substituted o-carboranes containing α,β-unsaturated carbonyls has been reported. The-COOH, removed during the course of the reaction, is responsible for controlling the regioselectivity. The desired products could be obtained in moderate to good yields.
- Li, Jiaoyi,Lu, Jian,Tian, Song,Wang, Qian,Zhang, Chuyi,Zhang, Jianwei,Zhou, Ling
-
p. 4723 - 4727
(2020/07/13)
-
- Solvent-free, microwave assisted oxidation of alcohols with 4-hydroxypyridinium chlorochromate functionalized silica gel
-
4-Hydroxypyridinium chlorochromate functionalized silica gel was found to be an efficient and reusable oxidant for the very fast oxidation of primary and secondary alcohols to the corresponding carbonyl compounds under solventfree conditions and microwave irradiation in excellent yields.
- AHMADI, Sayed Ali,GHALEHBANDI, Shermineh Sadat,GHAZANFARI, Dadkhoda,SHEIKHHOSSEINI, Enayatollah
-
p. 283 - 289
(2020/10/06)
-
- Heck Reactions of Acrolein or Enones and Aryl Bromides – Synthesis of 3-Aryl Propenals or Propenones and Consecutive Application in Multicomponent Pyrazole Syntheses
-
3-(Hetero)aryl propenals or propenones are efficiently prepared by a Heck reaction of (hetero)aryl bromides and acrolein or vinyl ketones using Beller's CataCXium Ptb ligand under Jeffery's and Fu's conditions. The formation of these three-carbon building blocks is embedded into consecutive three- and pseudo-four-component syntheses of 3-(hetero)aryl and 3,5-diarylpyrazoles with a broad substitution pattern in moderate to excellent yield.
- Stephan, Marvin,Panther, Jesco,Wilbert, Fabio,Ozog, Pauline,Müller, Thomas J. J.
-
supporting information
p. 2086 - 2092
(2020/03/23)
-
- A General One-Pot Methodology for the Preparation of Mono- and Bimetallic Nanoparticles Supported on Carbon Nanotubes: Application in the Semi-hydrogenation of Alkynes and Acetylene
-
A facile and straightforward methodology for the preparation of monometallic (copper and palladium) and bimetallic nanocatalysts (NiCu and PdCu) stabilized by a N-heterocyclic carbene ligand is reported. Both colloidal and supported nanoparticles (NPs) on carbon nanotubes (CNTs) were prepared in a one-pot synthesis with outstanding control on their size, morphology and composition. These catalysts were evaluated in the selective hydrogenation of alkynes and alkynols. PdCu/CNTs revealed an efficient catalytic system providing high selectivity in the hydrogenation of terminal and internal alkynes. Moreover, this catalyst was tested in the semi-hydrogenation of acetylene in industrially relevant acetylene/ethylene-rich model gas feeds and showed excellent stability even after 40 h of reaction.
- Lomelí-Rosales, Diego A.,Delgado, Jorge A.,Díaz de los Bernardos, Miriam,Pérez-Rodríguez, Sara,Gual, Aitor,Claver, Carmen,Godard, Cyril
-
supporting information
p. 8321 - 8331
(2019/06/04)
-
- Tandem Acyl Substitution/Michael Addition of Thioesters with Vinylmagnesium Bromide
-
A tandem reaction of thioesters with vinylmagnesium bromide is reported. The initial acyl substitution provides an α,β-unsaturated ketone which further reacts with the liberated thiolate. This transition-metal-free synthesis of β-sulfanyl ketones takes place under mild reaction conditions, whereas the addition of a second Grignard molecule is almost completely suppressed. The carefully chosen parameters enabled the transformation of different substrates in moderate to good yields.
- Hirschbeck, Vera,B?ldl, Marlene,Gehrtz, Paul H.,Fleischer, Ivana
-
p. 2578 - 2582
(2019/04/17)
-
- Manganese-Catalyzed Ring-Opening Coupling Reactions of Cyclopropanols with Enones
-
A manganese-catalyzed ring-opening coupling reaction of cyclopropanols with enones for the facile and efficient preparation of 1,6-diketones is described. A wide array of synthetically important 1,6-diketones bearing manifold functional groups are obtained with up to 93% yield. These reactions feature broad substrate scopes, environmentally benign conditions, inexpensive catalyst, and operational simplicity.
- Zhang, Yong-Hui,Zhang, Wen-Wei,Zhang, Ze-Yu,Zhao, Kai,Loh, Teck-Peng
-
p. 5101 - 5105
(2019/07/03)
-
- Highly Selective and Catalytic Oxygenations of C?H and C=C Bonds by a Mononuclear Nonheme High-Spin Iron(III)-Alkylperoxo Species
-
The reactivity of a mononuclear high-spin iron(III)-alkylperoxo intermediate [FeIII(t-BuLUrea)(OOCm)(OH2)]2+(2), generated from [FeII(t-BuLUrea)(H2O)(OTf)](OTf) (1) [t-BuLUrea=1,1′-(((pyridin-2-ylmethyl)azanediyl)bis(ethane-2,1-diyl))bis(3-(tert-butyl)urea), OTf=trifluoromethanesulfonate] with cumyl hydroperoxide (CmOOH), toward the C?H and C=C bonds of hydrocarbons is reported. 2 oxygenates the strong C?H bonds of aliphatic substrates with high chemo- and stereoselectivity in the presence of 2,6-lutidine. While 2 itself is a sluggish oxidant, 2,6-lutidine assists the heterolytic O?O bond cleavage of the metal-bound alkylperoxo, giving rise to a reactive metal-based oxidant. The roles of the urea groups on the supporting ligand, and of the base, in directing the selective and catalytic oxygenation of hydrocarbon substrates by 2 are discussed.
- Ghosh, Ivy,Banerjee, Sridhar,Paul, Satadal,Corona, Teresa,Paine, Tapan Kanti
-
p. 12534 - 12539
(2019/08/07)
-
- Selective catalytic oxidation of alkenes employing homobinuclear manganese(II) catalysts with TBHP
-
The two novel homobinuclear compounds [Mn2(II,II) (μ1,1-4-CH3-C6H4COO)2(phen)4](ClO4)2 (1) and [Mn2(II,II) (μ1,3-4-CH3-C6H4COO)2(bipy)4](ClO4)2 (2), where bipy = 2,2-bipyridine and phen = 1,10-phenanthroline, have been synthesized and characterized by elemental analyses and spectral methods (UV–Vis, FTIR, and X-ray). A single-crystal X-ray diffraction structure analysis of the compounds revealed that the manganese atom is octahedrally coordinated. In compound 1, the binuclear(II) structure is monodentate, bridged with one oxygen atom of carboxylate ligand in μ1,1 mode, and each Mn(II) center is coordinated with two phen ligands. In compound 2, the binuclear(II) structure is syn–anti bidentate, bridged with two oxygen atoms of carboxylate ligand in μ1,3 mode, and each Mn(II) center is coordinated with two bipy ligands. The Mn–Mn separation is 3.441 (1) ? and 4.450 (1) ? for 1 and 2, respectively. The catalytic potentials of these compounds have been tested for the oxidation reaction of various olefins (i.e., styrene, cyclohexene, ethyl benzene, 1-hexene, 1-octene). The oxidation reactions were carried out in the presence of catalytic amounts of 1 and 2 with a peroxide oxygen donor (TBHP = tert-Butyl hydroperoxide) in acetonitrile at 70 °C. On comparing the catalytic activities of 1 and 2, both catalysts showed good activity (~100% conv. in 24 h) in the oxidation of studied alkenes, and excellent conversion was obtained for cyclohexene (~100% conv. in 3 h; TON = 265 and TON = 257, respectively, for 1 and 2).
- K?l??, Yal??n,Kani, ?brahim
-
p. 352 - 359
(2018/01/10)
-
- A carboxylate-bridged Mn(II) compound with 6-methylanthranilate/bipy: oxidation of alcohols/alkenes and catalase-like activity
-
A novel manganese compound, [Mn2(μ1,3-6-CH3-2-NH2C6H4COO)2(bipy)4](ClO4)2 (bipy?=?2,2′-bipyridine), was synthesized and used as a catalyst precursor in the oxidation of alkenes and primary alcohols to corresponding aldehydes, ketones, and acids. The six-coordinate compound has a binuclear structure in which two Mn(II) ions adopt a syn-anti μ1,3-bridging mode with two carboxylate groups and two chelated bipy ligands. The compound exhibits good activity in the oxidation of cyclohexene to 2-cyclohexene-1-one as the major product (93% conv. in 3?h, 79.3% selectivity) and of cinnamyl alcohol to cinnamaldehyde as the major product with 46% selectivity (100% conv. in 1.5?h) with tert-butyl hydroperoxide (TBHP) in acetonitrile at 70?°C. Furthermore, the catalase-like activity of the compound was studied in different solvents (acetonitrile, methanol, Tris-HCl buffer; TOF?=?29,910?h?1 in Tris-HCl buffer).
- Kilic, Yalcin,Bolat, Serkan,Kani, Ibrahim
-
p. 2293 - 2303
(2018/05/14)
-
- One-Step Bioconversion of Fatty Acids into C8-C9 Volatile Aroma Compounds by a Multifunctional Lipoxygenase Cloned from Pyropia haitanensis
-
The multifunctional lipoxygenase PhLOX cloned from Pyropia haitanensis was expressed in Escherichia coli with 24.4 mg·L-1 yield. PhLOX could catalyze the one-step bioconversion of C18-C22 fatty acids into C8-C9 volatile organic compounds (VOCs), displaying higher catalytic efficiency for eicosenoic and docosenoic acids than for octadecenoic acids. C20:5 was the most suitable substrate among the tested fatty acids. The C8-C9 VOCs were generated in good yields from fatty acids, e.g., 2E-nonenal from C20:4, and 2E,6Z-nonadienal from C20:5. Hydrolyzed oils were also tested as substrates. The reactions mainly generated 2E,4E-pentadienal, 2E-octenal, and 2E,4E-octadienal from hydrolyzed sunflower seed oil, corn oil, and fish oil, respectively. PhLOX showed good stability after storage at 4 °C for 2 weeks and broad tolerance to pH and temperature. These desirable properties of PhLOX make it a promising novel biocatalyst for the industrial production of volatile aroma compounds.
- Zhu, Zhu-Jun,Chen, Hai-Min,Chen, Juan-Juan,Yang, Rui,Yan, Xiao-Jun
-
p. 1233 - 1241
(2018/02/19)
-
- Enantioselective addition of selenosulfonates to α,β-unsaturated ketones
-
An organo-catalyzed enantioselective addition of selenosulfonates to α,β-unsaturated ketones was developed for the first time. With a chiral squaramide as an efficient catalyst, the desired α-selenylated ketones were obtained in a good yields with high enantioselectivity up to 89% ee, and good results could be obtained on a gram scale. The products could also be efficiently transformed into useful building blocks with a propenylic stereocenter; the strategy presented in this study may find further applications in organic synthesis.
- Luo, Shilong,Zhang, Nan,Wang, Zhen,Yan, Hailong
-
p. 2893 - 2901
(2018/05/03)
-
- Synthesis of γ-keto sulfones by copper-catalyzed oxidative sulfonylation of tertiary cyclopropanols
-
Tertiary cyclopropanols undergo ring-opening oxidative sulfonylation to afford γ-keto sulfones when reacting with sulfinate salts in the presence of a copper(ii) acetate catalyst and an oxidant (tert-butyl hydroperoxide or atmospheric oxygen). Various fluoroalkyl, aryl and alkyl sulfinate salts are successfully employed as sulfonylation reagents, affording the corresponding sulfones in up to 94% yields. The experimental protocol is mild and tolerates a number of functionalities in the cyclopropanol substrate. The reaction proceeds via a one-pot oxidation-Michael addition mechanism and can serve as a useful addition to the existing methods for the preparation of γ-keto sulfones based on the sulfa-Michael reaction.
- Konik, Yulia A.,Elek, Gábor Zoltán,Kaabel, Sandra,J?rving, Ivar,Lopp, Margus,Kananovich, Dzmitry G.
-
p. 8334 - 8340
(2017/10/23)
-
- 2,2-Diiododimedone: A mild electrophilic iodinating agent for the selective synthesis of α-iodoketones from allylic alcohols
-
2,2-Diiodo-5,5-dimethylcyclohexane-1,3-dione is reported as a new electrophilic iodinating agent that selectively iodinates electron-rich aromatics. In contrast to other common electrophilic iodinating reagents, its mild nature allows it to be used for the selective synthesis of α-iodinated carbonyl compounds from allylic alcohols through a 1,3-hydrogen shift/iodination process catalyzed by iridium(iii) complexes.
- Martinez-Erro, Samuel,Bermejo Gómez, Antonio,Vázquez-Romero, Ana,Erbing, Elis,Martín-Matute, Belén
-
p. 9842 - 9845
(2017/09/11)
-
- Base free transfer hydrogenation using a covalent triazine framework based catalyst
-
Isomerisation of allylic alcohols to saturated ketones can be efficiently catalysed by a heterogeneous molecular system resulting from IrIIICp? anchoring to a covalent triazine framework. The obtained catalysts are active, selective, and fully recyclable.
- Bavykina,Mautscke,Makkee,Kapteijn,Gascon,Llabrési Xamena
-
p. 4166 - 4170
(2017/08/04)
-
- Efficient acceptorless dehydrogenation of secondary alcohols to ketones mediated by a PNN-Ru(II) catalyst
-
Four types of ruthenium(II) complexes, [fac-PNN]RuH(PPh3)(CO) (A), [fac-PNHN]RuH(η1-BH4)(CO) (B), [fac-PNHN]RuCl2(PPh3) (C) and [fac-PNHN]RuH(η1-BH4)(PPh3) (D) (where PNHN and PNN are N-(2-(diphenylphosphino)ethyl)-5,6,7,8-tetrahydroquinoline-8-amine and its deprotonated derivative), have been synthesized and assessed as catalysts for the acceptorless dehydrogenation of secondary alcohols to afford ketones. It was found that C, in combination with t-BuOK, proved the most effective and versatile catalyst allowing aromatic-, aliphatic- and cycloalkyl-containing alcohols to be efficiently converted to their corresponding ketones with particularly high values of TON achievable. Furthermore, the mechanism for this PNN-Ru mediated process been proposed on the basis of a number of intermediates that have been characterized by EI-MS and NMR spectroscopy. These catalysts show great potential for applications in atom-economic synthesis as well as in the development of organic hydride-based hydrogen storage systems.
- Wang, Zheng,Pan, Bing,Liu, Qingbin,Yue, Erlin,Solan, Gregory A.,Ma, Yanping,Sun, Wen-Hua
-
p. 1654 - 1661
(2017/07/13)
-
- Selective oxidation of styrene catalyzed by cerium-doped cobalt ferrite nanocrystals with greatly enhanced catalytic performance
-
The rare earth metal Ce-doped cobalt ferrite samples CexCo1?xFe2O4 (x?=?0.1, 0.3, 0.5) were prepared by the sol–gel autocombustion route. The as-prepared samples were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, ICP–atomic emission spectroscopy, and N2 physisorption. Their catalytic performance was evaluated in oxidation of styrene using hydrogen peroxide (30%) as oxidant. Compared with pristine CoFe2O4, the Ce-doped samples were found to be more efficient catalysts for the oxidation of styrene to benzaldehyde, with greatly enhanced catalytic performance. Especially, when Ce0.3Co0.7Fe2O4 was used as catalyst, 90.3% styrene conversion and 91.5% selectivity for benzaldehyde were obtained at 90?°C for 9?h reaction. The catalyst can be magnetically separated easily for reuse, and no obvious loss of activity was observed when it was reused in five consecutive runs.
- Tong, Jinhui,Li, Wenyan,Bo, Lili,Wang, Huan,Hu, Yusen,Zhang, Zhixia,Mahboob, Abdulla
-
p. 474 - 481
(2016/11/18)
-
- Fungal mediated kinetic resolution of racemic acetates to (R)-alcohols using Fusarium proliferatum
-
Fungal mediated kinetic resolution of seven acyclic/aromatic acetates was achieved using Fusarium proliferatum to furnish (R)-alcohols in high enantiomeric excess (>95%). The kinetic resolution was established as one-pot two-step de-esterification/oxidation biocatalytic process. Further, the preparative scale synthesis of (R)-(+)-1-phenylethanol was accomplished through de-esterification/oxidation of (±)-1-phenylethyl acetate using the whole cell of F. proliferatum NCIM 1105.
- Jadhav, Dipesh D.,Patil, Harshal S.,Chaya, Patil S.,Thulasiram, Hirekodathakallu V.
-
p. 4563 - 4567
(2016/09/23)
-
- Visible-Light-Induced Efficient Selective Oxidation of Nonactivated Alcohols over {001}-Faceted TiO2 with Molecular Oxygen
-
In the presence of molecular oxygen, a {001}-faceted nanocrystalline anatase TiO2 catalyst enabled the selective oxidation of nonactivated aliphatic alcohols to the corresponding aldehydes or ketones under visible light. The reaction shows excellent conversion and selectivity towards the formation of the carbonyl products without over-oxidation to the corresponding carboxylic acids. The exceptional reactivity of the catalyst is possibly due to the absorption of visible light originating from a stronger interaction of alcohol with the {001} facet, which facilitates the modification of the band structure of TiO2, thus facilitating the photogenerated hole transfer and subsequent oxidation processes. The experimental results have also been corroborated by first-principles quantum chemical DFT calculations.
- Vadakkekara, Raji,Biswas, Abul Kalam,Sahoo, Tapan,Pal, Provas,Ganguly, Bishwajit,Ghosh, Subhash Chandra,Panda, Asit Baran
-
supporting information
p. 3084 - 3089
(2016/11/13)
-
- Highly efficient Au hollow nanosphere catalyzed chemo-selective oxidation of alcohols
-
Micelles of poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-PVP-PEO) with core-shell-corona structures have been used as a scaffold for the fabrication of gold (Au) hollow nanospheres of particle size 26 ± 2 nm using HAuCl4 and NaBH4 as metal precursor and reducing agent, respectively. The PS core acts as a template for hollow void, the PVP shell serves as reaction sites for inorganic precursors, and PEO corona stabilizes the composite particles. Under acidic conditions, the PVP shell domain becomes positively charged pyridinum-species that electrostatically interacts with negatively charged AuCl4- ions. On reduction of these composite particles and subsequent solvent extraction leads to the formation of Au hollow nanospheres. Various analytical tools such as powder X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetric analyses (TG/DTA), dynamic light scattering of (DLS) have been employed to characterize the polymeric micelles and hollow nanoparticles. The TEM and XRD studies confirmed the formation of highly crystalline Au hollow nanospheres. The Au hollow nanosphere/H2O2 system efficiently catalyzes the chemoselective oxidation of allylic-type unsaturated alcohols into aldehydes and ketones under mild liquid-phase conditions. The versatility of present catalytic system for the oxidation of other substrates like aliphatic-, acylic-, aromatic-, and heteroaromatic alcohols to their respective keto compounds has also been reported.
- Sasidharan, Manickam,Anandhakumar, Sundaramurthy,Bhanja, Piyali,Bhaumik, Asim
-
-
- Direct Synthesis of γ-Keto Sulfones from Allylic Alcohols: One-Pot Palladium(II)-Catalyzed Generation of Enones Followed by Water-Mediated 1,4-Addition of Organosulfinates
-
Allylic alcohols were exploited as synthetic precursors of γ-keto sulfones. The reaction involved the one-pot generation of α,β-enones in situ from the allylic alcohols by using a PdII–dioxygen catalytic system and subsequent sulfa-Michael addition in the presence of water. Importantly, water was identified as a sustainable substitute for a toxic copper salt to promote organosulfonyl addition. Diverse examples of aromatic and aliphatic γ-keto sulfones were prepared. Specially, Ar–X (X = Br, Cl) bonds were tolerated, which indicated a chemoselective catalytic system for the preparation of halogen-bearing γ-keto sulfones. This one-pot method does not require an acid, a base, or isolation of any intermediate. Control experiments indicated that the active catalyst of the first step also promoted the subsequent C–S bond-formation reaction. Water was found to accelerate the reaction rate and to be involved in the protonolysis of the σ-alkylpalladium complex, as corroborated by deuterium incorporation.
- Vellakkaran, Mari,Andappan, Murugaiah M. S.,Nagaiah, Kommu,Nanubolu, Jagadeesh Babu
-
supporting information
p. 3575 - 3583
(2016/07/28)
-
- 1H-pyrrole-2,4-dicarbonyl-derivatives and their use as flavoring agents
-
The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
- -
-
-
- Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
-
The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
- -
-
-
- Crystal Structure and Catalytic Behavior in Olefin Epoxidation of a One-Dimensional Tungsten Oxide/Bipyridine Hybrid
-
The tungsten oxide/2,2′-bipyridine hybrid material [WO3(2,2′-bpy)]·nH2O (n = 1-2) (1) has been prepared in near quantitative yield by the reaction of H2WO4, 2,2′-bpy, and H2O in the mole ratio of ca. 1:2:700 at 160°C for 98 h in a rotating Teflon-lined digestion bomb. The solid-state structure of 1 was solved and refined through Rietveld analysis of high-resolution synchrotron X-ray diffraction data collected for the microcrystalline powder. The material, crystallizing in the orthorhombic space group Iba2, is composed of a one-dimensional organic-inorganic hybrid polymer, ∞1[WO3(2,2′-bpy)], topologically identical to that found in the previously reported anhydrous phases [MO3(2,2′-bpy)] (M = Mo, W). While in the latter the N,N′-chelated 2,2′-bpy ligands of adjacent corner-shared {MO4N2} octahedra are positioned on the same side of the 1D chain, in 1 the 2,2′-bpy ligands alternate above and below the chain. The catalytic behavior of compound 1 for the epoxidation of cis-cyclooctene was compared with that for several other tungsten- or molybdenum-based (pre)catalysts, including the hybrid polymer [MoO3(2,2′-bpy)]. While the latter exhibits superior performance when tert-butyl hydroperoxide (TBHP) is used as the oxidant, compound 1 is superior when aqueous hydrogen peroxide is used, allowing near-quantitative conversion of the olefin to the epoxide. With H2O2, compounds 1 and [MoO3(2,2′-bpy)] act as sources of soluble active species, namely, the oxodiperoxo complex [MO(O2)2(2,2′-bpy)], which is formed in situ. Compounds 1 and [WO(O2)2(2,2′-bpy)] (2) were further tested in the epoxidation of cyclododecene, trans-2-octene, 1-octene, (R)-limonene, and styrene. The structure of 2 was determined by single-crystal X-ray diffraction and found to be isotypical with the molybdenum analogue.
- Amarante, Tatiana R.,Antunes, Margarida M.,Valente, Anabela A.,Paz, Filipe A. Almeida,Pillinger, Martyn,Gon?alves, Isabel S.
-
p. 9690 - 9703
(2015/11/03)
-
- Desulfonylative Methenylation of β-Keto Sulfones
-
A one-step strategy for the synthesis of α-methenyl ketones from β-keto sufones is reported. Success of the methodology is elaborated for the synthesis of chromanones and isoflavanones in one-step.
- Pandey, Ganesh,Vaitla, Janakiram
-
supporting information
p. 4890 - 4893
(2015/10/12)
-
- Modeling TauD- J: A high-spin nonheme oxoiron(IV) complex with high reactivity toward C-H bonds
-
High-spin oxoiron(IV) species are often implicated in the mechanisms of nonheme iron oxygenases, their C-H bond cleaving properties being attributed to the quintet spin state. However, the few available synthetic S = 2 FeIV=O complexes supported by polydentate ligands do not cleave strong C-H bonds. Herein we report the characterization of a highly reactive S = 2 complex, [FeIV(O)(TQA)(NCMe)]2+ (2) (TQA = tris(2-quinolylmethyl)amine), which oxidizes both C-H and C=C bonds at -40 °C. The oxidation of cyclohexane by 2 occurs at a rate comparable to that of the oxidation of taurine by the TauD-J enzyme intermediate after adjustment for the different temperatures of measurement. Moreover, compared with other S = 2 complexes characterized to date, the spectroscopic properties of 2 most closely resemble those of TauD-J. Together these features make 2 the best electronic and functional model for TauD-J to date.
- Biswas, Achintesh N.,Puri, Mayank,Meier, Katlyn K.,Oloo, Williamson N.,Rohde, Gregory T.,Bominaar, Emile L.,Münck, Eckard,Que, Lawrence
-
supporting information
p. 2428 - 2431
(2015/03/04)
-
- A highly efficient palladium(ii)/polyoxometalate catalyst system for aerobic oxidation of alcohols
-
A simple catalyst system composed of Pd(OAc)2, phosphomolybdic acid and tetrabutylammonium acetate oxidises a range of alcohols efficiently, with turnover numbers (TONs) of up to 10000.
- Dornan, Laura M.,Muldoon, Mark J.
-
p. 1428 - 1432
(2015/04/14)
-
- Bismuth-substituted "sandwich" type polyoxometalate catalyst for activation of peroxide: Umpolung of the peroxo intermediate and change of chemoselectivity
-
The epoxidation of alkenes with peroxides by WVI, MoVI, VV, and TiIV compounds is well established, and it is well accepted that the active intermediate peroxo species are electrophilic toward nucleophilic substrates. Polyoxotungstates, for example, those of the "sandwich" structure, [WZn(TM-L)2(ZnW9O34)2]q- in which TM = transition metal and L = H2O, have in the past been found to be excellent epoxidation catalysts. It has now been found that substituting the Lewis basic BiIII into the terminal position of the "sandwich" polyoxometalate structure to yield [Zn2BiIII2(ZnW9O34)2]14- leads to an apparent umpolung of the peroxo species and formation of a nucleophilic peroxo intermediate. There are two lines of evidence that support the formation of a reactive nucleophilic peroxo intermediate: (1) More electrophilic sulfoxides are more reactive than more nucleophilic sulfides, and (2) nonfunctionalized aliphatic alkenes and dienes showed ene type reactivity rather than epoxidation pointing toward "dark" formation of singlet oxygen from the nucleophilic intermediate peroxo species. Allylic alcohols reacted much faster than alkenes but showed chemoselectivity toward C-H bond activation of the alcohol and formation of aldehydes or ketones rather than epoxidation. This explained via alkoxide formation at the BiIII center followed by oxidative β-elimination.
- Amanchi, Srinivasa Rao,Khenkin, Alexander M.,Diskin-Posner, Yael,Neumann, Ronny
-
p. 3336 - 3341
(2015/06/16)
-
- Highly efficient oxidation of alcohols catalyzed by a porphyrin-inspired manganese complex
-
A novel strategy for catalytic oxidation of a variety of benzylic, allylic, propargylic, and aliphatic alcohols to the corresponding aldehydes or ketones by an in situ formed porphyrin-inspired manganese complex in excellent yields (up to 99%) has been successfully developed.
- Dai, Wen,Lv, Ying,Wang, Lianyue,Shang, Sensen,Chen, Bo,Li, Guosong,Gao, Shuang
-
supporting information
p. 11268 - 11271
(2015/07/07)
-
- Building MOF bottles (MIL-101 family as heterogeneous single-site catalysts) around Fe3O4 ships: A highly efficient and magnetically separable catalyst for oxidation of alcohols
-
Fe3O4 supported on chromium-based metal-organic framework (MOF), MIL-101(Cr), has emerged as highly efficient and heterogeneous catalyst for selective oxidation of alcohols because of its high specific surface area, tuneable pore size, and unique structure. MIL-101 and its Fe3O4 composite (Fe3O4@MIL-101) was prepared via the impregnation of the Fe3O4 in MIL-101. The surface properties of the functionalized catalyst were analyzed by a series of characterization techniques like FTIR, XRD, N2 adsorption-desorption, and TEM. XRD and adsorption-desorption analysis show that the mesostructure of MIL-101 remains intact after Fe3O4 modifications, while spectral technique show the successful immobilizing of the neat Fe3O4 inside the MIL-101 support. Fe3O4@MIL-101 can be reused several times although they get less active.
- Naghdi, Zahra,Farzaeli, Razieh,Aliyan, Hamid
-
p. 1343 - 1350
(2015/12/01)
-
- Oxygen as single oxidant for two steps: Base-free one-pot Pd(ii)-catalyzed alcohol oxidation & arylation to halogen-intact β-aryl α,β-enones
-
Using oxygen as the sole oxidant for two steps, we developed a new method to synthesize β-aryl α,β-enones by fine-tuning the Pd(ii)-catalyzed oxidation of allyl alcohol to subsequent arylation with arylboronic acids, arylboronic ester and aryltrifluoroborate salt. This one-pot green method does not require copper salt, base, and intermediate isolation. Halogen-bearing chalcones, dibenzylideneacetones and arylalkyl enones were synthesized in good yields. This journal is
- Vellakkaran, Mari,Andappan, Murugaiah M. S.,Nagaiah, Kommu
-
p. 45490 - 45494
(2014/12/10)
-
- Arachidonic acid-dependent carbon-eight volatile synthesis from wounded liverwort (Marchantia polymorpha)
-
Eight-carbon (C8) volatiles, such as 1-octen-3-ol, octan-3-one, and octan-3-ol, are ubiquitously found among fungi and bryophytes. In this study, it was found that the thalli of the common liverwort Marchantia polymorpha, a model plant species, emitted high amounts of C8 volatiles mainly consisting of (R)-1-octen-3-ol and octan-3-one upon mechanical wounding. The induction of emission took place within 40 min. In intact thalli, 1-octen-3-yl acetate was the predominant C8 volatile while tissue disruption resulted in conversion of the acetate to 1-octen-3-ol. This conversion was carried out by an esterase showing stereospecificity to (R)-1-octen-3-yl acetate. From the transgenic line of M. polymorpha (des6KO) lacking arachidonic acid and eicosapentaenoic acid, formation of C8 volatiles was only minimally observed, which indicated that arachidonic and/or eicosapentaenoic acids were essential to form C8 volatiles in M. polymorpha. When des6KO thalli were exposed to the vapor of 1-octen-3-ol, they absorbed the alcohol and converted it into 1-octen-3-yl acetate and octan-3-one. Therefore, this implied that 1-octen-3-ol was the primary C8 product formed from arachidonic acid, and further metabolism involving acetylation and oxidoreduction occurred to diversify the C8 products. Octan-3-one was only minimally formed from completely disrupted thalli, while it was formed as the most abundant product in partially disrupted thalli. Therefore, it is assumed that the remaining intact tissues were involved in the conversion of 1-octen-3-ol to octan-3-one in the partially disrupted thalli. The conversion was partly promoted by addition of NAD(P)H into the completely disrupted tissues, suggesting an NAD(P)H-dependent oxidoreductase was involved in the conversion.
- Kihara, Hirotomo,Tanaka, Maya,Yamato, Katsuyuki T.,Horibata, Akira,Yamada, Atsushi,Kita, Sayaka,Ishizaki, Kimitsune,Kajikawa, Masataka,Fukuzawa, Hideya,Kohchi, Takayuki,Akakabe, Yoshihiko,Matsui, Kenji
-
-
- Surface functionalization of supported Mn clusters to produce robust Mn catalysts for selective epoxidation
-
A robust heterogeneous Mn catalyst for selective epoxidation was prepared by the attachment of a Mn4 oxonuclear complex [Mn4O 2(CH3COO)7(bipy)2](ClO 4)·3H2O (1) on SiO2 and the successive stacking of SiO2-matrix overlayers around a supported Mn cluster. The structures of supported Mn catalysts were characterized by means of FT-IR spectroscopy, diffuse-reflectance UV/vis spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and Mn K-edge X-ray absorption fine structure. A ligand exchange reaction between the CH3COO ligand of 1 and surface silanol group produced a SiO2-supported Mn cluster (2), whose coordination structure was similar to 1. Subsequent heating of 2 under vacuum yielded supported Mn clusters (3, 4) through the partial elimination of CH 3COO ligands. The surface-attached Mn clusters of 2, 3, and 4 were easily released to a reaction solution under epoxidation conditions (Mn leaching: approximately 50%), although they were active for epoxidation of trans-stilbene (the conversion of trans-stilbene, 99%, and the selectivity of trans-stilbene epoxid, 96%, for 6 h on 3). We found that the functionalization of the supported Mn cluster on 2 with surface SiO2-matrix overlayers altered the reactivity of the supported Mn cluster. Dimeric Mn species (5c) with reduced Mn oxidation state and coordination numbers was formed together with a reaction nanospace surrounded by the SiO2-matrix overlayers. By optimizing the stacking manner of the SiO2-matrix overlayers, the durability of the Mn catalyst was remarkably improved from leaching (the Mn leaching reached the minimum value of 0.01%), and active and stable epoxidation performances were successfully achieved in the heterogeneous phase (the conversion of trans-stilbene, 97%, and the selectivity of trans-stilbene epoxide, 91%, for 31 h on 5c).
- Muratsugu, Satoshi,Weng, Zhihuan,Tada, Mizuki
-
p. 2020 - 2030
(2013/09/24)
-
- Selective aerobic oxidation of activated alkanes with MOFs and their use for epoxidation of olefins with oxygen in a tandem reaction
-
MOFs with Cu2+ centers linked to four nitrogen atoms from azaheterocyclic compounds, i.e., pyrimidine [Cu(2-pymo)2] and imidazole [Cu(im)2], are active catalysts for aerobic oxidation of activated alkanes, such as tetralin, cumene and ethylbenzene. Differences in activity among the two MOFs appear to be related to differences in their ability to decompose the hydroperoxide and to coordinate to the resulting radical OH species. Copper ions in [Cu(im)2] can coordinate by expanding their coordination sphere from 4 to 5 in a reversible way, while in the case of [Cu(2-pymo)2] it results in a displacement of one of the pyrimidine ligands. The MOFs can be used in combination with a silylated Ti-MCM-41 to catalyze the epoxidation of olefins with oxygen by means of a tandem reaction in which the MOF produces cumene hydroperoxide, which is used by Ti-MCM-41 to epoxidize the olefin. The Royal Society of Chemistry 2013.
- Luz,Leon,Boronat,Llabres I Xamena,Corma
-
p. 371 - 379
(2013/03/14)
-
- Highly stereoselective cyclopropanation of α,β-unsaturated carbonyl compounds with methyl (diazoacetoxy)acetate catalyzed by a chiral ruthenium(II) complex
-
Tantalizing triangles: The title reaction gives bicarbonyl cyclopropane products that can lead to versatile intermediates with high yields and stereoselectivities. This system was also applied to the enantioselective total synthesis of spiro cyclopropane oxindole, an HIV-1 nonnucleoside reverse transcriptase inhibitor. Copyright
- Chanthamath, Soda,Takaki, Suguru,Shibatomi, Kazutaka,Iwasa, Seiji
-
supporting information
p. 5818 - 5821
(2013/07/11)
-
- Iron-catalyzed aerobic oxidation of allylic alcohols: The issue of C=C bond isomerization
-
An aerobic oxidation of allylic alcohols using Fe(NO3) 3·9H2O/TEMPO/NaCl as catalysts under atmospheric pressure of oxygen at room temperature was developed. This eco-friendly and mild protocol provides a convenient pathway to the synthesis of stereodefined α,β-unsaturated enals or enones with the retention of the C-C double-bond configuration.
- Liu, Jinxian,Ma, Shengming
-
supporting information
p. 5150 - 5153
(2013/11/06)
-
- OXIDATION OF PRIMARY ALIPHATIC ALCOHOLS WITH A NOBLE METAL POLYOXOMETALATE COMPLEX
-
A process of oxidizing primary alcohols to their corresponding aldehydes is disclosed. The process is effected in the presence of noble metal polyoxometalate complexes. A novel process for preparing noble metal polyoxometalate complexes, and novel noble metal polyoxometalate complexes are also disclosed.
- -
-
Page/Page column 10-11
(2012/08/08)
-
- L-Proline-derived ligands to mimic the '2-His-1-carboxylate' triad of the non-haem iron oxidase active site
-
Non-haem iron(II) oxidases (NHIOs) catalyse a variety of oxidative transformations in biology. The iron-binding environment of the NHIO active site typically incorporates a '2-His-1-carboxylate' facial triad of amino acid side-chains, a motif that has emerged as a defining feature of the enzyme family. Towards the goal of biomimetic, iron-mediated C-H activation we have synthesized a series of peptidomimetic ligands from l-proline. By coupling l-proline to 2,6-bis(bromomethyl)pyridine, 2-(bromomethyl)-6-((tert- butyldimethylsilyloxy)methyl)pyridine and picolinic acid, we have generated several new ligand architectures designed to complex with iron(II) and mimic the NHIO active site. The resulting iron complexes promote modest levels of alkene dihydroxylation and allylic oxidation using hydrogen peroxide as oxidant.
- Dungan, Victoria J.,Wong, Shwo Mun,Barry, Sarah M.,Rutledge, Peter J.
-
experimental part
p. 3231 - 3236
(2012/06/01)
-
- The dual role of cis-[RuCl2(dmso)4] in the synthesis of new water-soluble Ru(II)-phosphane complexes and in the catalysis of redox isomerization of allylic alcohols in aqueous-organic biphasic systems
-
New air-stable, water-soluble Ru(II)-phosphane complexes were synthesized in high purity by the reaction of cis-[RuCl2(dmso)4] with 2 equivalents of 1,3,5-triaza-7-phosphaadamantane (pta) and its N-methyl and N-benzyl derivatives (pta-Me and pta-Bn, respectively). All new complexes were characterized by elementary analysis and spectroscopic methods (NMR, ESI-MS) and the molecular structures of cis-cis-trans-[RuCl2(dmso) 2(pta)2], cis-cis-trans-[RuCl2(dmso) 2(pta-H)2]Cl2 (obtained in acidic solutions) and that of cis-cis-trans-[RuCl2(dmso)2(pta-Me) 2](CF3SO3)2 were determined by single crystal X-ray diffraction. Under mild conditions, cis-[RuCl 2(dmso)4] actively catalyzed the transformation of allylic alcohols into the corresponding ketones with 100% selectivity while in the same reaction the new Ru(II)-pta complexes showed moderate activity and selectivity.
- Udvardy, Antal,Bényei, Attila Csaba,Kathó, ágnes
-
p. 116 - 122
(2012/11/06)
-
- Highly dispersed palladium nanoparticles on mesocellular foam: An efficient and recyclable heterogeneous catalyst for alcohol oxidation
-
The preparation of palladium nanoparticles in mesocellular foam (MCF) was reported and these nanoparticles were demonstrated as excellent catalyst for racemization of amines . Palladium was immobilized on siliceous mesocellular foam (MCF) through the use of amine ligands. The Pd 3d core level was deconvoluted into two spin-orbit split components found at 335.5 and 338.2 eV binding energy. From the results with the benzylic substrates, it is we found that the overall presence of substituents on the phenyl ring affects the course of the reaction. The turnover number (TON) based on palladium approaches 135 000 with a high turnover frequency (TOF) of 3750 h-1. The Pd catalyst does not need any additives or extra base, and is able to efficiently catalyze alcohol oxidation under an air atmosphere.
- Johnston, Eric V.,Verho, Oscar,Kaerkaes, Markus D.,Shakeri, Mozaffar,Tai, Cheuk-Wai,Palmgren, Pal,Eriksson, Kristofer,Oscarsson, Sven,Baeckvall, Jan-E.
-
supporting information
p. 12202 - 12206
(2012/11/07)
-
- Ir-catalysed formation of C-F bonds. From allylic alcohols to α-fluoroketones
-
A novel iridium-catalysed tandem isomerisation/C-F bond formation from allylic alcohols and Selectfluor to prepare α-fluorinated ketones as single constitutional isomers is reported.
- Ahlsten, Nanna,Martin-Matute, Belen
-
scheme or table
p. 8331 - 8333
(2011/09/12)
-
- Palladium containing periodic mesoporous organosilica with imidazolium framework (Pd@PMO-IL): An efficient and recyclable catalyst for the aerobic oxidation of alcohols
-
The application of a novel palladium containing ionic liquid based periodic mesoporous organosilica (Pd@PMO-IL) catalyst in the aerobic oxidation of primary and secondary alcohols under molecular oxygen and air atmospheres is investigated. It was found that the catalyst is quite effective for the selective oxidation of several activated and non-activated alcoholic substrates. The catalyst system could be successfully recovered and reused several times without any significant decrease in activity and selectivity. Moreover, the hot filtration test, atomic absorption spectroscopy (AA) and kinetic study with and without selective catalyst poisons showed that the catalyst works in a heterogeneous pathway without any palladium leaching in reaction solution. Furthermore, nitrogen-sorption experiment and transmission electron microscopy (TEM) image proved the superior stability of high-ordered PMO-IL mesostructure during reaction process. TEM image also confirmed the presence of well-distributed Pd-nanoparticles in the uniform mesochannels of the material. These observations can be attributed to the ionic liquid nature of PMO-IL mesostructure which facilitates the reaction through production, chemical immobilization and stabilization of active palladium nanoparticles, as well as preventing Pd-agglomeration during overall process.
- Karimi, Babak,Elhamifar, Dawood,Clark, James H.,Hunt, Andrew J.
-
supporting information; experimental part
p. 7420 - 7426
(2011/11/30)
-
- Aerobic oxidation of primary aliphatic alcohols to aldehydes catalyzed by a palladium(II) polyoxometalate catalyst
-
A hexadecyltrimethylammonium salt of a "sandwich" type polyoxometalate has been used as a ligand to attach a palladium(II) center. This Pd-POM compound was an active catalyst for the fast aerobic oxidation of alcohols. The unique property of this catalyst is its significant preference for the oxidation of primary versus secondary aliphatic alcohols. Since no kinetic isotope effect was observed for the dehydrogenation step, this may be the result of the intrinsically higher probability for oxidation of primary alcohols attenuated by steric factors as borne out by the higher reactivity of 1-octanol versus 2-ethyl-1-hexanol. The reaction is highly selective to aldehyde with little formation of carboxylic acid; autooxidation is inhibited. No base is required to activate the alcohol. The fast reactions appear to be related to the electron-acceptor nature of the polyoxometalate ligand that may also facilitate alcohol dehydrogenation in the absence of base.
- Barats, Delina,Neumann, Ronny
-
scheme or table
p. 293 - 298
(2010/04/28)
-
- Synthesis of water-tolerant indium homoenolate in aqueous media and its application in the synthesis of 1,4-dicarbonyl compounds via palladium-catalyzed coupling with acid chloride
-
The first water-tolerant, ketone-type indium homoenolate was synthesized via the oxidative addition of In/InCl3 to enones. The reaction proceeds exclusively in aqueous media. Both indium and indium(III) chloride are necessary for the smooth conversion of the reaction. Similar results were obtained when InCl or InCl2 was used in place of In/InCl3. The synthetic utility of the indium homoenolate was demonstrated through the synthesis of 1,4-dicarbonyl compounds via palladium-catalyzed coupling of indium homoenolate with acid chloride.
- Shen, Zhi-Liang,Goh, Kelvin Kau Kiat,Cheong, Hao-Lun,Wong, Colin Hong An,Lai, Yin-Chang,Yang, Yong-Sheng,Loh, Teck-Peng
-
supporting information; experimental part
p. 15852 - 15855
(2011/01/10)
-
- A cascade aerobic epoxidation of alkenes over Au/CeO2 and Ti-mesoporous material by "in situ" formed peroxides
-
The one-pot epoxidation of alkenes with O2 is performed with nano-particulated Au/CeO2 and Ti-MCM-41 silylated materials in the presence of a hydrocarbon and azobis-iso-butyronitrile (AIBN) as a promoter. This initiator is able to fo
- Aprile, Carmela,Corma, Avelino,Domine, Marcelo E.,Garcia, Hermenegildo,Mitchell, Chris
-
experimental part
p. 44 - 53
(2009/09/29)
-
- Aerobic oxidation of alcohols using various types of immobilized palladium catalyst: The synergistic role of functionalized ligands, morphology of support, and solvent in generating and stabilizing nanoparticles
-
Preparation and characterization of a variety of immobilized palladium catalyst, based on either ligand functionalized amorphous or ordered mesoporous silica, is described. The resulting Pd-loaded materials act as efficient catalyst for the oxidation of a variety of alcohols using molecular oxygen and air. Our studies show that in the case of supported palladium catalyst on hybrid amorphous silica, the nature of ligand and the solvent could effectively control the generation of nanoparticles. Furthermore, we have found that nanoparticles with smaller size and higher activity were generated from the anchored palladium precursor when the aerobic oxidation of alcohols was carried out in α,α,α-trifluorotoluene (TFT) instead of toluene. On the other hand, in the case of aerobic oxidation reactions by using supported palladium catalyst on hybrid SBA-15, the combination of organic ligand and ordered mesoporous channels resulted in an interesting synergistic effect that led to enhanced activity, prevention of Pd nanoparticles agglomeration, and finally generation of a durable catalyst.
- Karimi, Babak,Zamani, Asghar,Abedi, Sedigheh,Clark, James H.
-
experimental part
p. 109 - 119
(2010/04/22)
-
- A green and efficient oxidation of alcohols by supported gold catalysts using aqueous H2O2 under organic solvent-free conditions
-
The use of supported gold nanoparticles as an efficient, green and reusable catalyst for the oxidation of various alcohols to the corresponding carbonyl compounds using aqueous hydrogen peroxide as an environmentally benign oxidant is presented. The reaction proceeds with good to excellent yields in particular for nonactivated alcohols under base-free conditions.
- Ni, Ji,Yu, Wen-Jian,He, Lin,Sun, Hao,Cao, Yong,He, He-Yong,Fan, Kang-Nian
-
supporting information; experimental part
p. 756 - 759
(2010/04/23)
-
- METHOD AND CATALYSTS FOR THE EPOXIDATION OF OLEFINIC COMPOUNDS IN THE PRESENCE OF OXYGEN
-
The invention relates to a method for the epoxidation of an olefinic compound , which is characterized in that it comprises an oxidation reaction of at least one olefinic compound containing one or more double bonds C=C with oxygen in the presence of one or more reaction initiating agents, at least one catalyst containing at least one metal that is selected from a noble metal, a transition metal and mixtures of same , and al least one hydrocarbon that is selected from one or more branched alkanes, one or more alkyl cyclic or cyclic hydrocarbons, one or more alkyl aromatic or aromatic compounds and mixtures of same.
- -
-
Page/Page column 9
(2008/06/13)
-