- Chemiluminescence-promoted oxidation of alkyl enol ethers by NHPI under mild conditions and in the dark
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The hydroperoxidation of alkyl enol ethers using N-hydroxyphthalimide and molecular oxygen occurred in the absence of catalyst, initiator, or light. The reaction proceeds through a radical mechanism that is initiated by N-hydroxyphthalimide-promoted autoxidation of the enol ether substrate. The resulting dioxetane products decompose in a chemiluminescent reaction that allows for photochemical activation of N-hydroxyphthalimide in the absence of other light sources.
- Anderson,Andia, Alexander A.,Woerpel
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- One-step hydroxylation of benzene to phenol via a Pd capillary membrane microreactor
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A novel Pd capillary membrane microreactor for one-step hydroxylation of benzene to phenol was synthesized and investigated to showcase the effectiveness of 'Niwa concept'. Reaction parameters including H2/O2 ratio and temperature were systematically studied for their effects on benzene conversion and phenol yield. A detailed examination of different membrane reactors, feed mode and long-term reaction stability was also conducted. Pd capillary membrane displayed good stability for low temperature separation and reaction due to the excellent anchorage of Pd layer into the porous α-alumina support. An optimum H2/O2 ratio was identified at 473 K with the benzene conversion of 19.6% and phenol yield of 18.1%. An increase in reaction temperature caused not only an increase in benzene conversion but also a decrease in phenol selectivity. A comparison between our work and the literature results was also made to discuss the feasibility of the membrane reactor concept. Experimental results proved that narrow flow channels and larger Pd membrane surface area-to-volume ratios provided more effective area of Pd interface and promoted the radial diffusion of reactants, enabling the reactive species more opportunities to react directly with benzene resulting in high benzene conversion. The Royal Society of Chemistry 2013.
- Wang, Xiaobin,Tan, Xiaoyao,Meng, Bo,Zhang, Xiongfu,Liang, Qi,Pan, Hui,Liu, Shaomin
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- Improved Rhodium Hydrogenation Catalysts Immobilized on Oxidic Supports
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Wilkinson-type rhodium hydrogenation catalysts immobilized on oxidic supports via mono-and bidentate phosphine linkers have been studied by 31P solid-state NMR, and their recycling stability and lifetime with respect to hydrogenation of 1-dodecene, 2-cyclohexen-1-one, and 4-bromostyrene have been improved substantially.
- Merckle,Bluemel
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- Synthesis of 1,1′-bishydroperoxydi(cycloalkyl) peroxides by homocoupling of 11-15-membered gem-bis(hydroperoxy)cycloalkanes in the presence of boron trifluoride
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A procedure was developed for the synthesis of 1,1′- bishydroperoxydi(C11-C15-cycloalkyl) peroxides based on homocoupling of geminal 11-15-membered bis(hydroperoxy)cycloalkanes in the presence of BF3·OEt2.
- Terent'ev,Kutkin,Platonov,Starikova,Ogibin,Nikishin
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- Polypyrrole films containing rhodium(I) and iridium(I) complexes: Improvement in their synthesis and electrocatalytic activity in aqueous media
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Functionalized polypyrrole films containing M1(L)(diene)]+ complexes (M = rhodium or iridium, L = substituted 2,2′-bipyridine or 1,10-phenanthroline) have been synthesized by complexation of [M1(diene)CL]2 precu
- Hamar-Thibault, Sylvaine,Moutet, Jean-Claude,Tingry, Sophie
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- Role of keto intermediates in the hydrodeoxygenation of phenol over Pd on oxophilic supports
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The performance of Pd catalysts supported on SiO2, Al2O3 and ZrO2 for the hydrodeoxygenation (HDO) of phenol has been compared in the gas phase, at 300 °C and 1 atm using a fixed bed reactor. While Pd supported on SiO2 and Al2O3 exhibits high selectivity to cyclohexanone, when supported on an oxophilic support such as ZrO2, it favors the selectivity toward benzene, reducing the formation of ring-hydrogenated products, cyclohexanone and cyclohexanol. Diffuse reflectance infrared Fourier transform spectroscopy experiments support the participation of a keto-tautomer intermediate (2,4-cyclohexadienone) in the reaction. This intermediate can be hydrogenated in two different pathways. If the ring is hydrogenated, cyclohexanone and cyclohexanol are dominant products, as in the case of Pd/SiO2 and Pd/Al2O3 catalysts. By contrast, if the carbonyl group of the keto-intermediate tautomer is hydrogenated, benzene is directly formed via rapid dehydration of the unstable cyclohexadienol intermediate. This is observed in the case of Pd/ZrO2 catalyst. These results demonstrate that the selectivity for HDO of phenol can be controlled by using supports of varying oxophilicity. (Chemical Equation Presented).
- De Souza, Priscilla M.,Rabelo-Neto, Raimundo C.,Borges, Luiz E. P.,Jacobs, Gary,Davis, Burtron H.,Sooknoi, Tawan,Resasco, Daniel E.,Noronha, Fabio B.
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- Cobalt immobilized on hydroxyapatite as a low-cost and highly effective heterogeneous catalyst for alkenes epoxidation under mild conditions
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Transition metal Co immobilized on hydroxyapatite with a loading of 0.05 wt% (denoted 0.05 wt% Co/HAP) could catalyze partial oxidation of cyclic alkenes, aromatic alkenes and aliphatic alkenes to yield epoxide products with excellent selectivity at 30 °C with O2 and iso-butyraldehyde as co-oxidant. The TOF value was as high as 6261 h?1 for epoxidation of cyclohexene. In addition, the prepared 0.05 wt% Co/HAP catalyst can be re-used at least 6 times without significant loss of catalytic activity and selectivity.
- Mekrattanachai, Pagasukon,Cao, Changyan,Li, Zhaohua,Li, Huining,Song, Weiguo
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- Catalytic Activity of a Polymerizable tris(β-ketoesterate)Iron(III) Complex towards the Oxidation of Organic Substrates
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The facile oxidation of alkenes, aldehydes, cyclic ketones, alkanes, sulfides and alcohols is achieved by a polymerizable b-ketoesterato complex under Mukaiyama's conditions (atmospheric pressure of molecular oxygen in the presence of a sacrificial aldehyde at room temperature).
- Mastrorilli, Piero,Nobile, Cosimo Francesco
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- "Solvent-free" synthesis of thermally stable and hierarchically porous aluminophosphates (SF-APOs) and heteroatom-substituted aluminophosphates (SF-MAPOs)
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Hierarchically porous aluminophosphates (SF-APOs) and metal substituted aluminophosphates (SF-MAPOs, M = Co, Fe, Cr) have been synthesized via simple grinding and heating in the absence of solvent. Characterization results show that these mesoporous aluminophosphates have a hierarchically microporous/mesoporous structure. In addition, metal atoms can be efficiently incorporated into the walls of mesoporous aluminophosphates, and the SF-CoAPO sample shows high catalytic activity in cyclohexene oxidation compared with microporous samples. Special features of the "solvent-free" synthesis route, such as increasing product yield, saving energy, elimination of pollution, and convenience for incorporation of heterogeneous atoms, ensure its great potential in the synthesis of porous materials. The Royal Society of Chemistry 2011.
- Zhang, Pengling,Wang, Liang,Ren, Limin,Zhu, Longfeng,Sun, Qi,Zhang, Jian,Meng, Xiangju,Xiao, Feng-Shou
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- ORGANOBORANES FOR SYNTHESIS. 4. OXIDATION OF ORGANOBORANES WITH PYRIDINIUM CHLOROCHROMATE. A DIRECT SYNTHESIS OF ALDEHYDES FROM TERMINAL ALKENES VIA HYDROBORATION
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The oxidation of trialkylboranes containing primary alkyl groups with pyridinium chlorochromate (PCC) in methylene chloride provides the corresponding aldehydes in good yields.The stoichiometry for the oxidation of alcohols, borate esters and trialkylboranes with PCC has been examined.In view of the poor regioselectivity (only 94percent primary alkyl groups) and functional group tolerance observed in the hydroboration with borane (BH3*THF or BH3*SMe2), a more selective hydroborating agent, bis(3-methyl-2-butyl)borane (disiamylborane), was utilized for the preparation of aldehydes from terminal alkenes.However, the formation of 3-methyl-2-butanone as a by-product, and the requirement of six moles of PCC per mole of aldehyde are major disadvantages in this method.This difficulty was circumvented by employing monochloroborane-dimethyl sulfide for hydroboration.This reagent exhibits high regioselectivity (> 99percent primary alkyl groups) in the hydroboration of terminal alkenes.Oxidation of the resulting dialkylchloroborane following hydrolysis affords the desired aldehydes in satisfactory yields.Consequently, the hydroboration of terminal alkenes, followed by PCC oxidation, represents a direct convenient method for the transformation of alkenes into the corresponding aldehydes.
- Brown, Herbert C.,Kulkarni, Surendra U.,Rao, C. Gundu,Patil, Vemanna D.
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- Nitrogen-functionalized ordered mesoporous carbons as multifunctional supports of ultrasmall Pd nanoparticles for hydrogenation of phenol
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N-functionalized ordered mesoporous carbons could be readily obtained by post-synthesis treatment with nitrogen containing molecules to achieve materials with a nitrogen loading as high as 8.6 wt % and well preserved mesopore structure. Using NH3/su
- Li, Zelong,Liu, Jianhua,Xia, Chungu,Li, Fuwei
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- Effect of Zirconia Morphology on Hydrodeoxygenation of Phenol over Pd/ZrO2
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This work studies the effect of zirconia structure on the performance of Pd/ZrO2 catalysts for hydrodeoxygenation of phenol at 300 °C and 1 atm using a fixed bed reactor. Benzene was the major product over Pd/t-ZrO2, while significant formation of cyclohexanone was observed over Pd/m-ZrO2. On the other hand, Pd/m,t-ZrO2 exhibited intermediary behavior. DRIFTS of adsorbed pyridine, NH3-TPD, and the dehydration of the cyclohexanol reaction revealed that the Pd/t-ZrO2 catalyst exhibits a higher density of oxophilic sites than Pd/m-ZrO2 and Pd/m,t-ZrO2. This promoted the formation of deoxygenated products. However, a mechanism involving dehydration of cyclohexanol to cyclohexene, followed by dehydrogenation to benzene, may not be ruled out. Pd/ZrO2 catalysts significantly deactivated as a function of time on stream. Results of dehydrogenation of cyclohexane and dehydration of cyclohexanol indicate that the Pd particle size increased and the density of oxophilic sites decreased during the hydrodeoxygenation of the phenol reaction. In addition, the DRIFTS spectra under reaction conditions demonstrated that the coverage of oxophilic sites by phenoxy and intermediate species increased during the reaction. The growth of Pd particles is likely responsible for the losses in the metal-support interface that gradually inhibits the ability of the adsorbed species to turnover at the metal-support boundary.
- De Souza, Priscilla M.,Rabelo-Neto, Raimundo C.,Borges, Luiz E. P.,Jacobs, Gary,Davis, Burtron H.,Graham, Uschi M.,Resasco, Daniel E.,Noronha, Fabio B.
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- Liquid phase cyclohexene oxidation over vanadia based catalysts with tert-butyl hydroperoxide: Epoxidation versus allylic oxidation
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VO2-SiO2 based catalysts with V contents between 5 and 20 wt.% were prepared from inorganic precursors via the sol-gel process and subsequently dried, calcined and reduced at 673 K. Structural characterization of these materials was carried out with X-rays diffraction (XRD), ICP, N 2 adsorption-desorption at 77 K, UV-vis diffused reflectance spectroscopy (DR UV-vis), FTIR and pyridine adsorption followed by FTIR. Their catalytic activities in the cyclohexene epoxidation with TBHP as oxidant and heptane as solvent were also examined. Results of XRD and DR UV-visible spectroscopy revealed that VO2 species are well dispersed on silica. BET analysis showed that the surface area decreases from 390 to 22 m2 g-1 with V content. The results of pyridine adsorption followed by FTIR indicated that the 5 wt.% VO2-SiO2 catalyst displays low acid densities. Experimental results pointed out that the 5 wt.% VO 2-SiO2 catalysts offer excellent activity. The obtained cyclohexene conversion and selectivity toward epoxide are 21% and 84% respectively. A reaction mechanism explaining clearly epoxidation versus allylic oxidation is proposed.
- El-Korso, Sanaa,Khaldi, Ilyes,Bedrane, Sumeya,Choukchou-Braham, Abderrahim,Thibault-Starzyk, Frédéric,Bachir, Redouane
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- Epoxidation of cyclohexene with tert-butyl hydroperoxide catalyzed by mixed oxide V2O5–TiO2
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TiO2 and 20 wt% V2O5–TiO2 catalysts were prepared by the sol–gel route and calcined at 500 °C. The mixed oxide presented the crystalline structures of TiO2 anatase and V2O5 Shcherbinaite phases, with a BET (Brunauer–Emmett–Teller) surface area of 19 m2/g. The catalytic material was tested for the epoxidation of cyclohexene by tert-butyl hydroperoxide at 80 °C. The activity and selectivity were investigated as a function of the reaction time as well as the amounts of the catalyst and solvent. The reaction followed second-order kinetics, and the best catalytic performance was observed after 6 hr of reaction time, with 150 mg of catalyst in n-heptane solvent. The epoxidation selectivity reached 76% at 48% conversion. The catalyst remained stable after two cycles.
- Lahcene, Driss,Choukchou-Braham, Abderrahim
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- o-Nitrobenzyl Alcohol, a Simple and Efficient Reagent for the Photoreversible Protection of Aldehydes and Ketones
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Two independent procedures are described for the preparation of bis-o-nitrobenzyl acetal derivatives of aldehydes and ketones which are shown to be photoremovable in high yield by simple irradiation at 350 nm in an aprotic solvent.
- Gravel, Denis,Murray, Stevens,Ladouceur, Gaetan
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- Synergistic catalysis of nano-Pd and nano rare-earth oxide/AC: Complex nanostructured catalysts fabricated by a photochemical route for selective hydrogenation of phenol
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Cyclohexanone is an important industrial intermediate in the manufacture of polyamides in the chemical industry, but direct selective hydrogenation of phenol to cyclohexanone under mild conditions to achieve both high conversion and selectivity is a chall
- Zhang, Yanji,Zhou, Jicheng,Si, Jiaqi
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- Mild oxidative conversion of nitroalkanes into carbonyl compounds in ionic liquids
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Basic hydrogen peroxide and sodium perborate were found to be cheap and efficient alternatives for the conversion of primary and secondary nitro to carbonyl compounds (Nef reaction) in ionic liquids. Copyright Taylor & Francis Group, LLC.
- Bortolini, Olga,Nino, Antonio De,Garofalo, Angelo,Maiuolo, Loredana,Russo, Beatrice
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- A novel, green 1-glycyl-3-methyl imidazolium chloride-copper(II) complex catalyzed CH oxidation of alkyl benzene and cyclohexane
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A variety of alkyl-arenes and cyclohexane were converted to the corresponding ketones with NaClO as the oxidant in the presence of 1-glycyl-3-methyl imidazolium chloride-copper(II) complex. This method contains simplified product isolation and catalyst recycling, affording benzylic CH oxidation of alkyl-arenes imparting high yield of ketones. Furthermore, complex could be reused seven times without a significant loss of its catalytic activity.
- Karthikeyan, Parasuraman,Bhagat, Pundlik Rambhau,Kumar, S. Senthil
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- Rhodium(iii) complexes with a bidentate N-heterocyclic carbene ligand bearing flexible dendritic frameworks
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Rh(iii) complexes with a bidentate N-heterocyclic carbene ligand bearing flexible dendritic frameworks have been synthesized and fully characterized by X-ray crystallographic analysis, NMR measurements and theoretical calculations. The Royal Society of Chemistry.
- Fujihara, Tetsuaki,Obora, Yasushi,Tokunaga, Makoto,Tsuji, Yasushi
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- Calcium tungstate: A convenient recoverable catalyst for hydrogen peroxide oxidation
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Calcium tungstate was found to be an excellent catalyst for large scale "green" oxidations of organic substrates (amines, alkenes, alcohols, sulfides) with hydrogen peroxide. It displays the unusual dual characteristics of producing a soluble pertungstate species, allowing for homogeneous reaction conditions, but then precipitating, unchanged, at the end of the oxidation. These qualities allow for easy catalyst recovery and minimal waste stream generation for large scale application.
- Tressler, Caitlin M.,Stonehouse, Peter,Kyler, Keith S.
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- On the efficiency of phenol and cyclohexanone electrocatalytic hydrogenation - Effect of conditioning and working pH in acetic acid solution on palladium/fluorine-doped tin dioxide supported catalyst
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The electrocatalytic hydrogenation (ECH) of phenol and cyclohexanone was performed on a conductive Pd/SnO2:F catalyst. The catalyst was obtained by the impregnation method. We studied the influence of the pH of the supporting electrolyte, the conditioning pH, and the quantity of the conditioning charge passed before hydrogenation. Fourier transform infrared spectroscopy analysis showed that the functionalization of the catalyst surface by the acetic acid electrolyte depends on the pH. A direct correlation was observed between the efficiency of the hydrogenation, the pH of the electrolyte, and the electrode conditioning charge. Phenol hydrogenation was favored in acidic media, whereas cyclohexanone hydrogenation needed an acidic medium for conditioning and a basic medium for hydrogenation. The ECH rate appeared to depend on the functionalization of the catalyst surface, the adsorption of the target organic molecule on the catalyst, and its structural modification with the pH.
- Tountian, Dihourahouni,Brisach-Wittmeyer, Anne,Nkeng, Paul,Poillerat, Gerard,Menard, Hugues
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- Dehydrogenation of cyclohexanol on copper containing catalysts: The role of the support and the preparation method
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SiO2 and Al2O3 supported copper catalysts were prepared by "chemisorption-hydrolysis" or incipient wetness impregnation methods and investigated by XRD, TG-TPR, UV-vis diffuse reflectance and FTIR spectroscopy. Formation of finely dispersed copper oxide species was registered for the samples prepared by "chemisorption-hydrolysis" method, while a significant amount of XRD detectable copper oxide phase is registered for the SiO2 impregnated one. The latter materials possess higher catalytic selectivity in cyclohexanol dehydrogenation to cyclohexanone.
- Popova,Dimitrov,Santo, V. Dal,Ravasio,Scotti
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- Cationic Palladium Nitro Complexes as Catalysts for the Oxygen-based Oxidation of Alkenes to Ketones, and for the Oxydehydrogenation of Ketones and Aldehydes to the α,β-Unsaturated Analogues
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Cationic palladium nitro complexes permit more rapid and more selective oxidation of alkenes to ketones than existing metal nitro catalysts; they also oxidatively dehydrogenate ketones and aldehydes to the corresponding α,β-unsaturated analogues under extremely mild conditions.
- Wenzel, Timothy T.
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- Comparison of three enoate reductases and their potential use for biotransformations
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Enoate reductases (ERs) selectively reduce carbon-carbon double bonds in α,β-unsaturated carbonyl compounds and thus can be employed to prepare enantiomerically pure aldehydes, ketones, and esters. Most known ERs, most notably Old Yellow Enzyme (OYE), are biochemically very well characterized. Some ERs have only been used in whole-cell systems, with endogenous ketoreductases often interfering with the ER activity. Not many ERs are biocatalytically characterized as to specificity and stability. Here, we cloned the genes and expressed three non-related ERs, two of them novel, in E. coli: XenA from Pseudomonas putida, KYE1 from Kluyveromyces lactis, and Yers-ER from Yersinia bercovieri. All three proteins showed broad ER specificity and broad temperature and pH optima but different specificity patterns. All three proteins prefer NADPH as cofactor over NADH and are stable up to 40°C. By coupling Yers-ER with glucose dehydrogenase (GDH) to recycle NADP(H), conversion of > 99 % within one hour was obtained for the reduction of 2-cyclohexenone. Upon lowering the loadings of Yers-ER and GDH, we discovered rapid deactivation of either enzyme, especially of the thermostable GDH. We found that the presence of enone substrate, rather than oxygen or elevated temperature, is responsible for deactivation. In summary, we successfully demonstrate the wide specificity of enoate reductases for a range of α,β- unsaturated carbonyl compounds as well as coupling to glucose dehydrogenase for recycling of NAD(P)(H); however, the stability limitations we found need to be overcome to envision large-scale use of ERs in synthesis.
- Chaparro-Riggers, Javier F.,Rogers, Thomas A.,Vazquez-Figueroa, Eduardo,Polizzi, Karen M.,Bommarius, Andreas S.
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- OXIDATION OF OLEFINS TO KETONES IN COMBINATION WITH ELECTROOXIDATION
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In combination with anodic oxidation, 1-alkenes are oxidized to methyl ketones efficiently by the catalyses of Pd(OAc)2 and benzoquinone.Cyclopentene and Cyclohexene are oxidized smoothly to the corresponding ketones in high yields.
- Tsuji, Jiro,Minato, Makoto
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- Copper nanoparticle/carbon quantum dots hybrid as green photocatalyst for high-efficiency oxidation of cyclohexane
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To develop green catalysts for cyclohexane oxidation with high efficiency and high selectivity is a trend in nanotechnology and nanocatalysis. In this work, we demonstrate that copper nanoparticles/carbon quantum dots (Cu/CQDs) hybrid as photocatalyst exh
- Qiao, Shi,Fan, Baohu,Yang, Yanmei,Liu, Naiyun,Huang, Hui,Liu, Yang
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- One-pot synthesis of phenol and cyclohexanone from cyclohexylbenzene catalyzed by N-hydroxyphthalimide (NHPI)
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Synthesis of phenol and cyclohexanone in one pot was examined by means of the NHPI-catalyzed aerobic oxidation of cyclohexylbenzene. The aerobic oxidation of cyclohexylbenzene catalyzed by NHPI followed by treatment with sulfuric acid afforded phenol and
- Aoki, Yasuhiro,Sakaguchi, Satoshi,Ishii, Yasutaka
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- Highly Effective Dehydrogenation of Cyclohexanol to Cyclohexanone over Carbon-Supported Cobalt Catalyst
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The dehydrogenation of cyclohexanol to cyclohexanone has been studied over activated carbon-supported transition metals as catalysts.The Co/carbon catalyst was found to be highly effective for the reaction.Its catalytic behaviors strongly depended on the temperature of hydrogen reduction.Highly dispersed and well-reduced cobalt catalyst showed pronounced activity and stability.
- Uemichi, Yoshio,Shouji, Kiyoshi,Sugioka, Masatoshi,Kanazuka, Takaji
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- Effective hydrodechlorination of 4-chlorophenol over pd deposited on multiwall carbon nanotubes
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Multiwall carbon nanotubes (MWCNTs) supported Pd nanoparticles were prepared by impregnation method and characterized by TEM, XRD, XPS, and FT-IR. The as-prepared catalyst Pd/MWCNTs exhibited excellent catalytic property for the hydrodechlorination (HDC) of 4-chlorophenol (4-CP) in aqueous medium without any additives under mild conditions. The results indicated that the choice of support and the introduction of metal ions played a significant role in the catalytic property for HDC of 4-CP. The high catalytic performance of Pd/MWCNTs was attributed to the highly dispersed Pd nanoparticles on the support MWCNTs and the interaction between support and metal actives. Copyright Taylor & Francis Group, LLC.
- Deng, Hongying,Fan, Guangyin,Wang, Yinhu
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- MECHANISM OF THE SELECTIVE FORMATION OF CYCLOHEXANONE IN THE DECOMPOSITION OF CYCLOHEXYL HYDROPEROXIDE BY CHROMIUM STEARATE
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From a comparison of the rates of formation of cyclohexanone and 2-decanone in cyclohexane solutions of cyclohexyl hydroperoxide or tert-butyl-hydroperoxide in the presence of chromium(III) stearate and a mixture of cyclohexanol and 2-decanol in an atmosphere of argon at 350 K, it is concluded that the direct breakdown of cyclohexyl hydroperoxide by chromium stearate leads to selective formation of cyclohexanone.The contribution of the oxidation of cyclohexanol to ketone formation at a cyclohexanol concentration comparable with the hydroperoxide concentration (ca. 0.1 M) is ca. 10percent.
- Petrov, L. V.,Solyanikov, V. M.
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- Intercalation of a Rhodium Carbonyl into the Layered Vanadyl Phosphate VOPO4.2H2O and its Catalytic Activity
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Evidence for the intercalation of a rhodium carbonyl into the layered vanadyl phosphate, VOPO4.2H2O has been provided from XRD, FTIR and XPS studies.The incorporated rhodium carbonyl has been found to exhibit catalytic activity and shape selectivity in the hydrogenation of olefinic substrates.
- Datta, Arunabha,Bhaduri, Sumit,Kelkar, Ravindra Y.,Khwaja, Hanif I.
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- Study of the deactivation of copper-based catalysts for dehydrogenation of cyclohexanol to cyclohexanone
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Catalytic dehydrogenation of cyclohexanol was carried out in the gas phase in a continuous fixed bed reactor under atmospheric pressure. Two commercial catalysts composed by copper chromite and copper zinc oxide were tested. The activity of the catalysts
- Simón, Ernesto,Rosas, Juana María,Santos, Aurora,Romero, Arturo
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- PALLADIUM CATALYSED OXIDATION OF PRIMARY AND SECONDARY ALCOHOLS UNDER SOLID-LIQUID PHASE TRANSFER CONDITIONS
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Palladium acetate catalysed the oxidation of primary and secondary alcohols to aldehydes and ketones respectively at room temperature and atmospheric pressure under solid-liquid phase transfer conditions.
- Choudary, B. M.,Reddy, N. Prabhakar,Kantam, M. Lakshmi,Jamil, Zafar
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- Highly efficient and metal-free aerobic hydrocarbons oxidation process by an o-phenanthroline-mediated organocatalytic system
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A highly efficient o-phenanthroline-mediated, metal-free catalytic system has been developed for oxidation of hydrocarbons with dioxygen in the presence of N-hydroxyphthalimide; various hydrocarbons were efficiently and high selectively oxidized, e.g., ethylbenzene to acetophenone in 97% selectivity and 76% conversion, under mild conditions.
- Tong, Xinli,Xu, Jie,Miao, Hong
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- Preparation and Characterisation of a Palladium-Copper Heterometallic Complex and its Catalytic Activity towards Oxidation of Alkenes
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Treatment of PdCl2(MeCN)2 and CuCl2 with pyrrolidin-2-one L gives a novel Pd-Cu heterometallic complex having a polymeric structure of n which catalyses the oxidation of cyclohexene in ClCH2CH2Cl-MeOH.
- Hosokawa, Takahiro,Takano, Minoru,Murahashi, Shun-Ichi,Ozaki, Hiroshi,Kitagawa, Yasuyuki,et al.
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- Catalytic synergism in a C;inf;60;/inf;IL;inf;10;/inf;TEMPO;inf;2;/inf; hybrid in the efficient oxidation of alcohols
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A novel fullerene [5:1]hexakisadduct bearing two 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) radicals and ten 1-propyl-3-methylimidazolium bromide moieties has been synthesized and characterized. Such an C;inf;60;/inf;IL;inf;10;/inf;TEMPO;inf;2;/inf; hybrid has been successfully employed as a catalyst in the selective oxidation of a wide series of alcohols and is highly active at just 0.1 mol% loading. Moreover, it can be easily recovered by adsorption onto a multilayered covalently-linked SILP phase (mlc-SILP) through a "release and catch" approach and reused for up to 12 cycles without loss in efficiency. Interestingly, a catalytic synergistic effect of TEMPO and imidazolium bromide moieties combined in the same hybrid has been clearly shown.
- Beejapur, Hazi Ahmad,Campisciano, Vincenzo,Giacalone, Francesco,Gruttadauria, Michelangelo
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- Modeling TauD- J: A high-spin nonheme oxoiron(IV) complex with high reactivity toward C-H bonds
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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
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- TRANSFORMATION OF ORGANOIRON COMPLEXES OF SYNTHETIC AND CHEMICAL INTEREST.
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Cationic organometallic complexes derived by complexation of vinyl ethers with the dicarbonyl cyclopentadienyliron cation (F//p** plus ) are readily prepared, highly reactive reagents. These substances have been shown to function as vinyl cation equivalents for the vinylation of ketones, and for the synthesis of alpha -methylene- gamma -lactones and dihydrofurans. Similar complexation of propiolic esters gives a reactive species, which functions as a beta -acrylic ester cation equivalent and yields cyclobutenes, 1,3-dienes and dihydro- alpha -pyrones with olefins and cinnamic esters with aromatic systems.
- Rosenblum,Bucheister,Chang,Cohen,Marsi,Samuels,Scheck,Sofen,Watkins
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- Efficient and selective oxidation of hydrocarbons with tert-butyl hydroperoxide catalyzed by oxidovanadium(IV) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles
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The catalytic activity of an oxidovanadium(IV) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles, γ-Fe2O3@[VO(salenac-OH)] in which salenac-OH = [9-(2′,4′-dihydroxyphenyl)-5,8-diaza-4
- Ardakani, Mehdi Hatefi,Sabet, Mohammad,Samani, Mahnaz
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- An efficient method for the catalytic aerobic oxidation of cycloalkanes using 3,4,5,6-Tetrafluoro-N-Hydroxyphthalimide (F4-NHPI)
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N-Hydroxyphthalimide (NHPI) is known to be an effective catalyst for the oxidation of hydrocarbons. The catalytic activity of NHPI derivatives is generally increased by introducing an electron-withdrawing group on the benzene ring. In a previous report, two NHPI derivatives containing fluorinated alkyl chain were prepared and their catalytic activity was investigated in the oxidation of cycloalkanes. It was found that the fluorinated NHPI derivatives showed better yields for the oxidation reaction. As a continuation of our work with fluorinated NHPI derivatives, our next aim was to investigate the catalytic activity of the NHPI derivatives by introducing fluorine atoms in the benzene ring of NHPI. In the present research, 3,4,5,6-Tetrafluoro-N-Hydroxyphthalimide (F4-NHPI) is prepared and its catalytic activity has been investigated in the oxidation of two different cycloalkanes for the first time. It has been found that F4-NHPI showed higher catalytic efficiency compared with that of the parent NHPI catalyst in the present reactions. The presence of a fluorinated solvent and an additive was also found to accelerate the oxidation.
- Guha, Samar K.,Ishii, Yasutaka
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p. 327 - 335
(2021/12/13)
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- An alternative route for the preparation of phenol: Decomposition of cyclohexylbenzene-1-hydroperoxide
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In this work, a HPW/ZSM-5 catalyst was prepared by impregnating phosphotungstic acid (HPW) with carrier ZSM-5 zeolite and characterized by XRD, SEM, N2 adsorption/desorption isotherm, NH3-TPD, and FT-IR techniques. The catalytic performance of HPW/ZSM-5 was investigated by using the decomposition reaction of cyclohexylbenzene-1-hydroperoxide (CHBHP) to phenol and cyclohexanone. The conversion rate of CHBHP was up to 97.28%. In addition, the reusability test exhibited that the high durability HPW/ZSM-5 as the conversion rate of CHBHP only decreased by 3.11% after five runs. The kinetic study of the decomposition reaction indicated it was a primary reaction. The apparent activation energy of the decomposition reaction was 102.39?kJ·mol–1 in the temperature range of 45–60℃. All results indicate that the HPW/ZSM-5 catalyst has good performance and promising applications in acid catalyzed organic chemistry.
- Yang, Yufei,Zhang, Yadong
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- Rational synthesis of palladium nanoparticles modified by phosphorous for the conversion of diphenyl ether to KA oil
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Conversion of lignin-derived molecules into value-added chemicals is critical for sustainable chemistry but still challenging. Herein, phosphorus-modified palladium catalyzed the degradation of lignin-derived 4-O-5 linkage to produce KA oil (cyclohexanone-cyclohexanol oil) was reported. The reaction proceeds via a restricted partial hydrogenation-hydrolysis pathway. Phosphorus-modified palladium catalyst suppressed the full hydrogenation of diary ether, which was the key point to produce KA oil selectively. Under the optimized conditions, the 4.5 nm Pd-P NPs could catalyze the conversion of 4-O-5 linkage into KA oil in 83% selectivity with a high production rate of 32.5 mmol·g?1Pd·min?1. This study represented an original method for KA oil production.
- Bai, Hong-Cun,Cao, Jing-Pei,Jiang, Wei,Wei, Yu-Lei,Xie, Jin-Xuan,Zhang, Chuang,Zhao, Liang,Zhao, Ming,Zhao, Xiao-Yan
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- Electrocatalytic hydrogenation of lignin monomer to methoxy-cyclohexanes with high faradaic efficiency
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Developing efficient renewable electrocatalytic processes in chemical manufacturing is of commercial interest, especially from biomass-derived feedstock. Selective electrocatalytic hydrogenation (ECH) of biomass-derived lignin monomers to high-value oxygen-functional compounds is promising towards achieving this goal. However, ECH has to date lacked the satisfied selectivity to upgrade lignin monomers to high-value oxygenated chemicals due to the reduction of vulnerable ?OCH3 that exists in most lignin monomers. Herein we report carbon-felt supported ternary RhPtRu catalysts with a record faradaic efficiency (FE) of 62.8% and selectivity of 91.2% to methoxy-cyclohexanes (2-methoxy-cyclohexanol and 2-methoxy-cyclohexanone) from guaiacol, via a strong inhibition effect on the cleavage of the methoxy group, representing the best performance compared to previous reports. We further conducted a brief TEA to demonstrate a profitable ECH of guaiacol to high-value methoxy-cyclohexanes using our designed RhPtRu ternary catalysts.
- Chen, Henan,Kumar, Mohan,Liang, Baiyao,Peng, Tao,Wang, Miao,Yang, Chenxin,Zhang, Yun,Zhao, Wei
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supporting information
p. 142 - 146
(2022/01/19)
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- From Ring-Expansion to Ring-Contraction: Synthesis of γ-Lactones from Cyclobutanols and Relative Stability of Five- and Six-Membered Endoperoxides toward Organic Bases
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Cyclobutanols undergo ring expansion with molecular oxygen in the presence of Co(acac)2 to afford 1,2-dioxane-hemiperoxyketals. In the course of acylation, we observed that endoperoxides rearranged into ?-lactone in the presence of triethylamine. Thus, a generalization of this ring contraction through a Kornblum DeLaMare rearrangement is here reported. Application of this transformation to monosubstituted 1,2-dioxane derivatives also led to 1,4-ketoaldehydes, in proportions depending on the nature of the substituent. These same conditions applied to five-membered dioxolane analogues led to fragmentation instead, through a retro-aldol type process. This study emphasizes the difference of stability of 1,2-dioxane and 1,2-dioxolane against organic bases, 1,2-dioxolanes having proved to be particularly reactive whereas 1,2-dioxanes showed a relative tolerance under these conditions.
- Ferrié, Laurent,Jamey, Nicolas
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- Titania-supported molybdenum oxide combined with Au nanoparticles as a hydrogen-driven deoxydehydration catalyst of diol compounds
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A heterogenous catalyst for the deoxydehydration (DODH) reaction was developed using less expensive Mo than Re as the active center. The combination of Mo with anatase-rich TiO2 and Au as the support and promoter for H2 activation, respectively, can selectively convert 1,4-anhydroerythritol to 2,5-dihydrofuran, which is a typical DODH model reaction, with H2 as a reducing agent. Loading of Au on TiO2 by the deposition-precipitation method gave the more active MoOx-Au/TiO2 catalyst (MoOx-dpAu/TiO2) than that obtained by the impregnation method (MoOx-impAu/TiO2), and the activity difference is derived from the smaller size of Au particles in MoOx-dpAu/TiO2 (3-5 nm) than that in MoOx-impAu/TiO2 (>25 nm). The MoOx-dpAu/TiO2 catalyst could be applied to the DODH reaction of linear alkyl vicinal diols and cis-1,2-cyclohexanediol. The characterization with XRD, STEM, H2-TPR, XAFS and XPS revealed that the MoIV oxide cluster species on the surface of anatase TiO2 particles are responsible for the DODH reaction.
- Cao, Ji,Gan, Jianxing,Hacatrjan, Schanth,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi,Yabushita, Mizuho
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p. 2146 - 2161
(2022/04/28)
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- Enthalpy-Entropy Compensation Effect in Oxidation Reactions by Manganese(IV)-Oxo Porphyrins and Nonheme Iron(IV)-Oxo Models
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"Enthalpy-Entropy Compensation Effect"(EECE) is ubiquitous in chemical reactions; however, such an EECE has been rarely explored in biomimetic oxidation reactions. In this study, six manganese(IV)-oxo complexes bearing electron-rich and -deficient porphyrins are synthesized and investigated in various oxidation reactions, such as hydrogen atom transfer (HAT), oxygen atom transfer (OAT), and electron-transfer (ET) reactions. First, all of the six Mn(IV)-oxo porphyrins are highly reactive in the HAT, OAT, and ET reactions. Interestingly, we have observed a reversed reactivity in the HAT and OAT reactions by the electron-rich and -deficient Mn(IV)-oxo porphyrins, depending on reaction temperatures, but not in the ET reactions; the electron-rich Mn(IV)-oxo porphyrins are more reactive than the electron-deficient Mn(IV)-oxo porphyrins at high temperature (e.g., 0 °C), whereas at low temperature (e.g., -60 °C), the electron-deficient Mn(IV)-oxo porphyrins are more reactive than the electron-rich Mn(IV)-oxo porphyrins. Such a reversed reactivity between the electron-rich and -deficient Mn(IV)-oxo porphyrins depending on reaction temperatures is rationalized with EECE; that is, the lower is the activation enthalpy, the more negative is the activation entropy, and vice versa. Interestingly, a unified linear correlation between the activation enthalpies and the activation entropies is observed in the HAT and OAT reactions of the Mn(IV)-oxo porphyrins. Moreover, from the previously reported HAT reactions of nonheme Fe(IV)-oxo complexes, a linear correlation between the activation enthalpies and the activation entropies is also observed. To the best of our knowledge, we report the first detailed mechanistic study of EECE in the oxidation reactions by synthetic high-valent metal-oxo complexes.
- Guo, Mian,Zhang, Jisheng,Zhang, Lina,Lee, Yong-Min,Fukuzumi, Shunichi,Nam, Wonwoo
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supporting information
p. 18559 - 18570
(2021/11/22)
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- Trans(Cl)-2,2′-bipyridinedicarbonyldichlororuthenium(II) complex catalyzed oxidation of olefins, aryl hydrocarbons and alcohols in homogeneous phase
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Catalytic oxidation of organic substrates has wide applications in chemical industries due to which huge extensive research work is continuously going on throughout the world. Present study reports efficacious use of Trans (Cl)-2,2′-bipyridinedicarbonyldichlororuthenium(II) complex catalyzed oxidation of internal and terminal olefins, aryl hydrocarbons and alcohols. CH2Cl2–C2H5OH (6:4) was suitable solvent system for these oxidation reactions. The normal pressure oxidation reaction has been carried out at 1 ?atm. Pressure of oxygen and at 300C. The high pressure oxidation reaction was done at 4.48 ?× ?103 KNm3 pressure of oxygen and at 600C. No diminished catalytic activity was observed while checking the recyclability of catalyst up to 6–8 catalytic runs. Catalytic activity was also investigated using tert-butyl hydroperoxide as oxidant inspite of di-oxygen. Effect of different parameters on the rate of oxidation was also studied i.e. extra ligand, temperature, solvents, acids and bases. Kinetic studies have been done and on the basis of kinetics, the mechanism is proposed.
- Sharma, Varsha,Pant, Bhawana,Prakash, Deep,Sagar, Priyanka
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- Facile Peroxidation of Cyclohexane Catalysed by In Situ Generated Triazole-Functionalised Schiff Base Copper Complexes
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A set of facile room temperature catalytic systems for the oxidation of cyclohexane C–H bonds was developed from in situ generated triazole-functionalised Schiff base copper complexes. The combination of a new triazolium-functionalised Schiff base, [(E)-3-methyl-1-propyl-4-(2-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenyl)-1H-1,2,3-triazol-3-ium hexafluorophosphate(V), 2] with a range of bench-top Cu(I) and Cu(II) salts (Cu2O, CuO, Cu(CH3CN)4PF6, CuSO4·5H2O, Cu2(OAc)4·2H2O, CuCl2, Cu(NO3)2·3H2O) as catalysts were screened under varying reaction conditions for the peroxidation of cyclohexane using hydrogen peroxide as a green source of oxygen. High conversions to oxidised products were obtained with up to 80% in 6?h for the 2/CuSO4·5H2O system at 1?mol% catalyst concentration under optimised reaction conditions. All the copper salts yielded the ketone–alcohol (K–A) oil containing varying ratios of cyclohexanol and cyclohexanone. The results also showed that at room temperature, the various in situ generated copper catalysts exclusively yielded only the K–A oil. Furthermore, by changing the reaction temperature to reflux in acetonitrile and depending on the starting substrate (cyclohexane, cyclohexanol or cyclohexanone), 23–100% of adipic acid was also obtained. The kinetics study for the peroxidation reaction reveals activation energy of 12.29 ± 2?kJ/mol following a copper initiated radical mechanism. Graphic Abstract: [Figure not available: see fulltext.]
- Bala, Muhammad D.,Ibrahim, Halliru,Lawal, Nasir S.
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- Cooperative activating effects of metal ion and Br?nsted acid on a metal oxo species
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Metal oxo (MO) complexes are common oxidants in chemical and biological systems. The use of Lewis acids to activate metal oxo species has attracted great interest in recent years, especially after the discovery of the CaMn4O5 cluster in the oxygen-evolvin
- Chen, Gui,Ma, Li,Lo, Po-Kam,Mak, Chi-Keung,Lau, Kai-Chung,Lau, Tai-Chu
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p. 632 - 638
(2021/01/29)
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- Efficient Aliphatic C-H Oxidation and C═C Epoxidation Catalyzed by Porous Organic Polymer-Supported Single-Site Manganese Catalysts
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Bioinspired manganese complexes have emerged over recent decades as attractive catalysts for a number of selective oxidation reactions. However, these catalysts still suffer from oxidative degradation. In the present study, we prepared a series of porous Mn-N4 catalysts in which the catalytic units are embedded in the skeleton of porous organic polymers (POPs). These POP-based manganese catalysts demonstrated high reactivity in the oxidation of aliphatic C-H bonds and the asymmetric epoxidation of olefins. Furthermore, these catalysts could be readily recycled and reused due to their heterogeneous nature. Morphological characterization revealed that the Mn-N4 complex was individually distributed over a porous polymer network. Remarkably, the nature of the single-site catalyst prevented oxidative degradation during the reaction. The present work has thus developed a successful approach for bioinspired single-site manganese catalysts in which the oxidation reaction is confined to a specific channel in an enzyme-like mode.
- Wang, Bingyang,Lin, Jin,Sun, Qiangsheng,Xia, Chungu,Sun, Wei
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p. 10964 - 10973
(2021/09/08)
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- SBA-15 Supported Silver Catalyst for the Efficient Aerobic Oxidation of Toluene Under Solvent-Free Conditions
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The efficient SBA-15 supported silver catalysts(Ag/SBA-15) were prepared and characterized by ICP-OES, XRD, TEM, SEM, XPS and N2 adsorption–desorption techniques. The catalysts exhibited an excellent catalytic activity for the aerobic oxidation of toluene to benzaldehyde under solvent-free conditions. Conversion of toluene and selectivity of benzaldehyde were 50% and 89% respectively over catalyst with 9.1 wt% Ag loading (10Ag/SBA-15). A wide range of substrates were tolerated under the selected reaction conditions. The kinetic study shows that the oxidation of toluene over 10Ag/SBA-15 is pseudo-first-order reaction and the activation energy Ea is 45.1?kJ/mol. A plausible mechanism involving oxygen free radicals was proposed for the aerobic oxidation reaction. Compared with the traditional method, the newly designed heterogeneous catalytic system shows better economic applicability, environmental friendliness and broader application prospects. Graphical abstract: [Figure not available: see fulltext.]
- Chen, Lei,Chen, Yanjiao,Dai, Xuan,Guo, Jiaming,Peng, Xinhua
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- Reduction of α,β-unsaturated carbonyl compounds and 1,3-diketones in aqueous media, using a raney ni-al alloy
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The treatment of α,β-unsaturated carbonyl compounds and 1,3-diketones with Raney Ni-Al alloy in aqueous media yielded as major reaction products the corresponding saturated alcohols and/or the corresponding hydrocarbons, in a complete transformation of the starting material.
- Simion, Cristian,Mitoma, Yoshiharu,Katayama, Yumi,Simion, Alina Marieta
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- Palladium Nanoparticles in Hypercrosslinked Polystyrene: Synthesis and Application in the Hydrogenation of Arenes
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Abstract: A novel method for incorporation of palladium nanoparticles into a poroushypercrosslinked polystyrene matrix has been developed. The composite obtainedby reduction of [Pd(π-allyl)Cl]2 with hydrogen insupercritical CO2 shows high catalytic activity in thehydrogenation of benzene and can be used twelve (12) times in a row without anydecrease in conversion rate. The catalyst is also suitable for quantitativehydrogenation of toluene, tetralin and phenol. The obtained catalytic system iscompared with the palladium composite synthesized by a conventional method basedon hypercrosslinked polystyrene.
- Lyubimov,Zvinchuk,Korlyukov,Davankov,Parenago
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- Bimetallic RuPd nanoparticles in ionic liquids: Selective catalysts for the hydrogenation of aromatic compounds
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Bimetallic RuPd nanoparticles (NPs) immobilized in ionic liquids (ILs) were shown to be a highly active medium for the selective hydrogenation of benzene and phenol under mild conditions (4 bar H2, 60 °C) in a biphasic system (n-heptane/IL). The equimolar combination of Ru and Pd into a bimetallic particle generated a synergistic catalyst that allowed the selective production of cyclohexane (>99% selectivity, 94% conversion) and cyclohexanol (99% selectivity, >98% conversion) from the reduction of benzene and phenol, respectively. Moreover, the catalytic results revealed that the activity and selectivity are dependent on the Ru?:?Pd ratio into the bimetallic NPs.
- Abarca, Gabriel,Goncalves, Wellington D. G.,Albuquerque, Brunno L.,Dupont, Jairton,Prechtl, Martin H. G.,Scholten, Jackson D.
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supporting information
p. 98 - 103
(2021/01/11)
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- Passing the framework skeleton and properties of coordination materials onto organic framework materials
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A practically applicable strategy for transforming fragile metal-organic frameworks (MOFs) into highly stable and ordered organic framework materials (OFMs) is developed by replacing the labile coordination bonds in MOFs with stable covalent bonds in OFMs, which exhibit hypothetically approximated topology, porosity and properties of the parent MOFs by merging the advantages of MOFs and porous organic materials, thus providing a general pathway for the synthesis of highly ordered OFMs with merged advantages of MOFs and organic polymers.
- Wang, Xuan,Dong, Ming-Jie,Chen, Kai,Liu, Zi-Kun,Wu, Chuan-De
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supporting information
p. 1348 - 1351
(2021/02/22)
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- Tunable selectivity of phenol hydrogenation to cyclohexane or cyclohexanol by a solvent-driven effect over a bifunctional Pd/NaY catalyst
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Hydrogenation of phenol is an important strategy to produce cyclohexane or cyclohexanol as both of them are raw materials for the synthesis of nylon-6 and nylon-66. Herein, we report a novel method for the selective hydrogenation of phenol to cyclohexane or cyclohexanol over a bifunctional Pd/NaY catalyst by regulating the solvent polarity. It was found that solvent polarity has a strong influence on the hydrogenation reaction mechanism. Under the identical conditions, 100% selectivity to cyclohexane could be obtained when reacting inn-octane (nonpolar solvent), while 92.3% selectivity to cyclohexanol was achieved in EtOH (polar solvent). The polarity of the solvent not only affects the competitive adsorption capacity but also the adsorption manner of phenol over the acid sites and the Pd nanoparticles in the Pd/NaY catalyst. DFT calculations show that different solvents have an almost negligible effect on the reaction energy barriers but highly affect the hydration reaction of cyclohexanol if the trace amount of water formed could not be timely removed from the catalytic system. This solvent-driven catalysis exhibits good recyclability, showing great promise for industrial applications. These findings not only provide new insights into the hydrogenation mechanism of phenolics, but also might help to develop facile strategies for the selective conversion of other phenolics into desired products.
- Xia, Heng,Tan, Hongzi,Cui, Hongyou,Song, Feng,Zhang, Yuan,Zhao, Rongrong,Chen, Zhe-Ning,Yi, Weiming,Li, Zhihe
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p. 1881 - 1887
(2021/03/29)
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- RhNPs supported onN-functionalized mesoporous silica: effect on catalyst stabilization and catalytic activity
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Amine and nicotinamide groups grafted on ordered mesoporous silica (OMS) were investigated as stabilizers for RhNPs used as catalysts in the hydrogenation of several substrates, including carbonyl and aryl groups. Supported RhNPs on functionalized OMS were prepared by controlled decomposition of an organometallic precursor of rhodium under dihydrogen pressure. The resulting materials were characterized thoroughly by spectroscopic and physical techniques (FTIR, TGA, BET, SEM, TEM, EDX, XPS) to confirm the formation of spherical rhodium nanoparticles with a narrow size distribution supported on the silica surface. The use of nicotinamide functionalized OMS as a support afforded small RhNPs (2.3 ± 0.3 nm), and their size and shape were maintained after the catalyzed acetophenone hydrogenation. In contrast, amine-functionalized OMS formed RhNP aggregates after the catalytic reaction. The supported RhNPs could selectively reduce alkenyl, carbonyl, aryl and heteroaryl groups and were active in the reductive amination of phenol and morpholine, using a low concentration of the precious metal (0.07-0.18 mol%).
- Pulido-Díaz, Israel T.,Serrano-Maldonado, Alejandro,López-Suárez, Carlos César,Méndez-Ocampo, Pedro A.,Portales-Martínez, Benjamín,Gutiérrez-Alejandre, Aída,Salas-Martin, Karla P.,Guerrero-Ríos, Itzel
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p. 3289 - 3298
(2021/03/16)
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- Pt and Ru Catalysts Based on Porous Aromatic Frameworks for Hydrogenation of Lignin Biofuel Components
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Abstract: A platinum catalyst and a ruthenium catalyst were synthesized from a porousaromatic framework, namely PAF-30. The catalyst properties were examined inhydrogenation of phenol and guaiacol at 80–250°C and at a hydrogen pressure of30 atm in the presence of various solvents. Significant effects of the reactionmedium, process conditions, and catalyst morphology on the reaction mechanismwere demonstrated. Reaction conditions optimal for complete conversion of phenoland guaiacol to hydrogenation products were selected for both catalysts. [Figure not available: see fulltext.]
- Cherednichenko, K. A.,Kalinina, M. A.,Karakhanov, E. A.,Kulikov, L. A.,Makeeva, D. A.,Maximov, A. L.
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p. 711 - 720
(2021/08/03)
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- POLITAG-Pd(0) catalyzed continuous flow hydrogenation of lignin-derived phenolic compounds using sodium formate as a safe H-source
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Phenols are aromatic biobased compounds and as they are accessible from lignin depolymerization, they can be a useful platform chemicals to produce value-added products. Herein we report our recent investigations on the definition of an approach to the efficient continuous flow selective hydrogenation of phenols in water. Our protocol is based on the use of sodium formate as a clean and safe hydrogen source in combination with our newly defined heterogeneous POLITAG-Pd(0) catalytic system. POLITAG is a polymeric heterogeneous support decorated with pincer-type ionic ligands proven to be highly efficient for the stabilization of Pd(0) nanoparticles. The results obtained are remarkable in comparison with other protocols that employ sodium formate as H-source. Indeed, our investigation has been extended to a variety of differently substituted phenolic compounds that have been hydrogenated with excellent to good selectivity in continuous flow conditions. Durability of the catalyst has been also tested with a representative continuous processing of over 100 mmol that showed no loss in efficiency and minimal metal leaching.
- Campana, Filippo,Ferlin, Francesco,Silvetti, Matteo,Trombettoni, Valeria,Vaccaro, Luigi,Valentini, Federica
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- Highly Selective Hydrogenation of Phenols to Cyclohexanone Derivatives Using a Palladium@N-Doped Carbon/SiO2Catalyst
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A new palladium-based heterogeneous material was synthesized by means of immobilization of Pd(OAc)2/1,10-phenanthroline on commercially available SiO2and subsequent pyrolysis at 600 °C for 2 h in air, namely, a Pd@N-doped carbon/SiO2catalyst. The obtained catalyst was studied by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) techniques, and was effectively applied in the highly selective hydrogenation of phenols to give the corresponding cyclohexanone derivatives with 93-98% yields at 100 °C under 0.4 MPa H2in EtOH. It was demonstrated that introducing nitrogen could effectively promote the Pd dispersion and enhance the electronic interaction of Pd, both of which facilitate the improvement of the catalytic activity and selectivity. The likely reaction pathway was outlined to elucidate the selective hydrogenation mechanism according to experimental results.
- Sheng, Xueru,Wang, Chao,Wang, Wentao
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supporting information
p. 2425 - 2431
(2021/11/16)
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- Efficient oxidation of cycloalkanes with simultaneously increased conversion and selectivity using O2 catalyzed by metalloporphyrins and boosted by Zn(AcO)2: A practical strategy to inhibit the formation of aliphatic diacids
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The direct sources of aliphatic acids in cycloalkanes oxidation were investigated, and a strategy to suppress the formation of aliphatic acids was adopted through enhancing the catalytic transformation of oxidation intermediates cycloalkyl hydroperoxides to cycloalkanols by Zn(II) and delaying the emergence of cycloalkanones. Benefitted from the delayed formation of cycloalkanones and suppressed non-selective thermal decomposition of cycloalkyl hydroperoxides, the conversion of cycloalkanes and selectivity towards cycloalkanols and cycloalkanones were increased simultaneously with satisfying tolerance to both of metalloporphyrins and substrates. For cyclohexane, the selectivity towards KA-oil was increased from 80.1% to 96.9% meanwhile the conversion was increased from 3.83 % to 6.53 %, a very competitive conversion level with higher selectivity compared with current industrial process. This protocol is not only a valuable strategy to overcome the problems of low conversion and low selectivity lying in front of current cyclohexane oxidation in industry, but also an important reference to other alkanes oxidation.
- Shen, Hai-Min,Wang, Xiong,Ning, Lei,Guo, A-Bing,Deng, Jin-Hui,She, Yuan-Bin
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- Identification of key oxidative intermediates and the function of chromium dopants in PKU-8: catalytic dehydrogenation ofsec-alcohols withtert-butylhydroperoxide
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Catalytic oxidation reaction using green oxidants plays an important role in modern chemical engineering; however, thein situgenerated active species and the related catalytic mechanism need to be understood in depth. For this purpose, Cr-substituted aluminoborate Cr-PKU-8 catalysts were synthesized and applied as recyclable heterogeneous catalysts for the oxidation of aliphatic and aromatic alcohols usingtert-butylhydroperoxide (TBHP). Both high efficiency and selectivity (>99%) were achieved during the dehydrogenation of varioussec-alcohols into acetone in H2O solvent medium. From the analyses using isotopic tracer, molecular probe and cyclic voltammetry strategies, the chromium ions were observed to undergo a Cr3+-Cr2+-Cr3+redox cycle. DFT calculations suggest thatt-BuOO* is more energetically favourable for hydrogen abstraction fromsec-alcohol thant-BuO*, and probably acts as the key active species. Accordingly, the reaction scheme was proposed to interpret the catalytic process based on the observed results.
- Wang, Weilu,He, Yang,He, Junkai,Dang, Yanliu,Kankanmkapuge, Tharindu,Gao, Wenliang,Cong, Rihong,Suib, Steven L.,Yang, Tao
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p. 1365 - 1374
(2021/03/14)
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- Rapid, chemoselective and mild oxidation protocol for alcohols and ethers with recyclable N-chloro-N-(phenylsulfonyl)benzenesulfonamide
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Chlorine is the 20th most abundant element on the earth compared to bromine, iodine, and fluorine, a sulfonimide reagent, N-chloro-N-(phenylsulfonyl)benzenesulfonamide (NCBSI) was identified as a mild and selective oxidant. Without activation, the reagent was proved to oxidize primary and secondary alcohols as well as their symmetrical and mixed ethers to corresponding aldehydes and ketones. With recoverable PS-TEMPO catalyst, selective oxidation over chlorination of primary and secondary alcohols and their ethers with electron-donating substituents was achieved. The reagent precursor of NCBSI was recovered quantitatively and can be reused for synthesizing NCBSI.
- Badani, Purav,Chaturbhuj, Ganesh,Ganwir, Prerna,Misal, Balu,Palav, Amey
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supporting information
(2021/06/03)
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- Chemoselective Hydrogenation of Olefins Using a Nanostructured Nickel Catalyst
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The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth-abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N-doped carbon layer on the active carbon support.
- Klarner, Mara,Bieger, Sandra,Drechsler, Markus,Kempe, Rhett
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supporting information
p. 2157 - 2161
(2021/05/21)
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- Method for preparing ketone compound from olefin
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The invention belongs to the technical field of organic chemical synthesis, and discloses a method for preparing a ketone compound from olefin by using an iron catalyst. According to the invention, the ligand and the iron salt form an iron catalyst in the on-site reaction, the raw materials in the formula are easy to obtain, and the synthesis is simple. By using the catalyst, olefin can be efficiently converted into ketone compounds, and compared with a palladium catalyst, the price is very low, and the catalyst is suitable for industrial application.
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Paragraph 0038-0040
(2021/08/19)
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- Catalytic Oxidation of Ethylene in Solutions of Palladium(II) Cationic Complexes in Binary and Ternary Aqueous Organic Solvents
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Abstract: The effect of organic solvents on the rate of ethylene oxidation with p-benzoquinone to acetaldehyde in aqueous organic solutions of palladium cationic complexes has been studied. It was found that the reaction rate increased when the acceptor number of the solvent increased and the donor number decreased. The oxidation of ethylene and cyclohexene in binary (N-methylpyrrolidone–H2O) and ternary (acetonitrile–N-methylpyrrolidone–H2O) solvents was studied in more detail. In contrast to the acetonitrile–Н2О system, in the N-methylpyrrolidone–Н2О binary solvent hydrogen peroxide oxidizes ethylene to acetaldehyde in the presence of Pd(II) cationic complexes. The use of a solvent N-methylpyrrolidone acceptable for cyclohexene (CH) oxidation technology leads to a decrease in the rate and selectivity of cyclohexanone synthesis.
- Oshanina, I. V.,Pestunova, U. V.,Podtyagina, A. V.,Rusnak, I. N.,Temkin, O. N.
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p. 734 - 743
(2022/01/13)
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- Tailoring the electron density of cobalt oxide clusters to provide highly selective superoxide and peroxide species for aerobic cyclohexane oxidation
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The catalytic aerobic cyclohexane oxidation to cyclohexanol and cyclohexanone (KA oil) is an industrially relevant reaction. This work is focused on the synthesis of tailor-made catalysts based on the well-known Co4O4 core in order to successfully deal with cyclohexane oxidation reaction. The catalytic activity and selectivity of the synthesized catalysts can be correlated with the electronic density of the cluster, modulated by changing the organic ligands. This is not trivial in cyclohexane oxidation. Furthermore, the reaction mechanism is discussed on the basis of kinetics and spin trapping experiments, confirming that the electronic density of the catalyst has a clear influence on the distribution of the reaction products. In addition, in situ Raman spectroscopy was used to characterize the oxygen species formed on the cobalt cluster during the oxidation reaction. Altogether, it can be concluded that the catalyst with the highest oxidation potential promotes the formation of peroxide and superoxide species, which is the best way to oxidize inactivated CH bonds in alkanes. Finally, based on the results of the mechanistic studies, the contribution of these cobalt oxide clusters in each single reaction step of the whole process has been proposed.
- Gaona-Miguélez, José,Gutiérrez-Tarri?o, Silvia,O?a-Burgos, Pascual
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supporting information
p. 15370 - 15379
(2021/11/17)
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- Selective Aerobic Oxidation of Secondary C (sp3)-H Bonds with NHPI/CAN Catalytic System
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Abstract: The direct aerobic oxidation of secondarty C(sp3)-H bonds was achieved in the presence of N-hydroxyphthalimide (NHPI) and cerium ammonium nitrate (CAN) under mild conditions. Various benzylic methylenes could be oxidized to carbonyl compounds in satisfied selectivity while saturated cyclic alkanes could be further oxidized to the corresponding lactones with the catalytic system. Remarkably, 25% of isochroman was converted to corresponding ketone with a selectivity of 96%. The reaction was initiated by hydrogen atom abstraction from NHPI by cerium and nitrates under oxygen atmosphere to form PINO radicals. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) addition experiments showed that the oxidation proceeded via a complex radical chain mechanism and an ion pathway. Graphic Abstract: [Figure not available: see fulltext.]
- Wang, Lingyao,Zhang, Yuanbin,Yuan, Haoran,Du, Renfeng,Yao, Jia,Li, Haoran
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p. 1663 - 1669
(2020/10/21)
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- Selective hydrogenation of phenol to cyclohexanone over Pd nanoparticles encaged hollow mesoporous silica catalytic nanoreactors
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Pd nanoparticles (NPs) encaged hollow mesoporous silica nanoreactors (Pd?HMSNs) are prepared for hydrogenations of phenol, cresols and chlorophenols to cyclohexanone derivatives. Pd?HMSNs feature ～ 4 nm Pd NPs in ～ 16 nm hollow cavities of ～ 30 nm HMSNs. Such Pd?HMSNs are highly thermally and catalytically stable. At mild reaction conditions, Pd?HMSNs efficiently catalyze hydrogenations of phenol and m-cresol to cyclohexanone derivatives with ≥ 98.3 % selectivity at ≥ 99.0 % conversions. Hydrogenations of o- and m-chlorophenol over Pd?HMSNs give cyclohexanone with ≥ 97.3 % selectivity at 100.0 % conversions, demonstrating a beneficial effect of such HMSNs for consecutive reactions. The confinement of Pd NPs inside hollow cavities of mesoporous nanoreactors greatly promotes collision times of reactant molecules with Pd NPs, resulting in an enhanced catalytic efficiency, while the residence of Pd NPs inside cavities provides a protecting effect for Pd NPs and is beneficial to thermal and catalytic stabilities.
- Li, Kaijie,Wang, Junyou,Yang, Caoping,Zhou, Shenghu
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- Aliphatic C–H hydroxylation activity and durability of a nickel complex catalyst according to the molecular structure of the bis(oxazoline) ligands
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Applicability of the oxazoline-based compounds, bis(2-oxazolynyl)methane (BOX) and 2,6-bis(2-oxazolynyl)pyridine (PyBOX), as supporting ligands of nickel(II) complexes for the catalysis of aliphatic C–H hydroxylation with m-CPBA (meta-chloroperoxybenzoic acid) was explored. Substituent groups at the fourth and fifth positions of oxazoline rings and the bridgehead carbon atom of the BOX derivatives affected the catalytic performances toward cyclohexane hydroxylation. Presence of dioxygen led to a reduced catalytic performance of the nickel complexes, except in the case of a fully substituted BOX ligand complex.
- Hikichi, Shiro,Izumi, Takashi,Matsuba, Naki,Nakazawa, Jun
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- Application of an immobilized ionic liquid for the preparation of hydroxylamine via hydrolysis of cyclohexanone oxime
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Preparation of hydroxylamine via hydrolysis of cyclohexanone oxime was studied over porous SiO2 supported acid ionic liquid catalyst. The catalyst [SPIPTES]CF3SO3@SiO2 was prepared through sol-gel method and characterized by elemental analysis, IR and TG, etc. Various parameters such as reaction temperature and time, catalyst amount were investigated systematically. The optimized reaction conditions investigated were catalyst:cyclohexanone oxime (mass ratio) 4 : 1, conducted at 60 °C for 1 h. Since the present hydrolysis reaction is controlled by thermodynamics, the conversion of cyclohexanone oxime could not be very high. However, reasonable result was achieved under the optimized reaction conditions. Cyclohexanone oxime conversion was 38.41 % and NH2OH yield was 37.65 %. Additionally, combining experiments with density functional theory calculations, a possible catalyst structure and reaction pathway involved protonated cyclohexanone oxime mechanism was proposed for the present hydrolysis in this study.
- Wang, Shuangyu,Liu, Jiaqi,Cheng, Peng,Li, Zhihui,Zhang, Dongsheng,Yang, Qiusheng,Zhao, Xinqiang,Wang, Yanji
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p. 742 - 750
(2021/02/05)
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- Chromium-Catalyzed Production of Diols From Olefins
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Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
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Paragraph 0111
(2021/03/19)
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- Enhancing Chemo- And Stereoselectivity in C-H Bond Oxygenation with H2O2by Nonheme High-Spin Iron Catalysts- And Role of Lewis Acid and Multimetal Centers
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Spin states of iron often direct the selectivity in oxidation catalysis by iron complexes using hydrogen peroxide (H2O2) on an oxidant. While low-spin iron(III) hydroperoxides display stereoselective C-H bond hydroxylation, the reactions are nonstereoselective with high-spin iron(II) catalysts. The catalytic studies with a series of high-spin iron(II) complexes of N4 ligands with H2O2 and Sc3+ reported here reveal that the Lewis acid promotes catalytic C-H bond hydroxylation with high chemo- and stereoselectivity. This reactivity pattern is observed with iron(II) complexes containing two cis-labile sites. The enhanced selectivity for C-H bond hydroxylation catalyzed by the high-spin iron(II) complexes in the presence of Sc3+ parallels that of the low-spin iron catalysts. Furthermore, the introduction of multimetal centers enhances the activity and selectivity of the iron catalyst. The study provides insights into the development of peroxide-dependent bioinspired catalysts for the selective oxygenation of C-H bonds without the restriction of using iron complexes of strong-field ligands.
- Das, Abhishek,Jana, Rahul Dev,Paine, Tapan Kanti
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p. 5969 - 5979
(2021/05/04)
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- Preparation method of cyclohexanone oxime
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The invention relates to a preparation method of cyclohexanone oxime. The method comprises the following steps: carrying out partial oxidation reaction on cyclohexylamine and molecular oxygen under the action of a catalyst to obtain an oxidation reaction product consisting of cyclohexanone oxime, a byproduct and possibly unconverted cyclohexylamine; and then treating the oxidation reaction product in one of the following modes: (i) carrying out hydrogenation amination reaction with H2 and NH3 at the same time or carrying out hydrogenation and amination reaction in sequence under the action of a catalyst without separation or after part or all of water in the oxidation reaction product is separated, and then carrying out separation to obtain cyclohexanone oxime; and (ii) carrying out hydrogenation reaction with H2 under the action of a catalyst without separation or after part or all of water is separated out, and then carrying out separation to obtain the cyclohexanone oxime. The method disclosed by the invention has the characteristics of short process flow, small occupied area and investment, low material consumption and energy consumption (low cost), simplicity and convenience in operation, environment friendliness and the like.
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Paragraph 0067-0071
(2021/06/13)
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- CdS/BiOBr Nanocomposite with Enhanced Activity under Visible Light for Photocatalytic Reduction of CO2 in Cyclohexanol
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Abstract: The CdS/BiOBr nanocomposites were synthesized through a hydrothermal deposition method. The structure and properties of the as-prepared nanocomposites were characterized by XRD, SEM, TEM, UV–Vis DRS, and PL. The characterizations indicated that the CdS/BiOBr nanocomposites exhibited flower-like microsphere morphologies with good crystallinity, and showed strong photoabsorption both UV and visible light. The photocatalytic activities were investigated in photocatalytic CO2 reduction in cyclohexanol under visible light irradiation. The CdS/BiOBr nanocomposites showed much better photocatalytic activity than the pristine BiOBr sample. The highest yields of the expected products (cyclohexyl formate and cyclohexanone were obtained over 5% CdS/BiOBr composite. A plausible mechanism for photocatalytic CO2 reduction was proposed suggesting that the formation of heterojunction in the composite can facilitate charge transfer, which led to an improved photocatalytic activity.
- Song, G.,Wu, X.
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- Synergy of carbon defect and transition metal on tungsten carbides for boosting the selective cleavage of aryl ether C[sbnd]O bond
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Transition-metal carbides are attractive heterogeneous catalysts for the transformation of lignin-derived compounds. However, the effects of the surface carbon defect (C-defect) remain unclear due to coke deposition and exposed C terminations. Herein, we transform inert tungsten carbides (WC) into active catalysts via surficial C-etching using transition metals in the presence of H2. An optimized 1% Pt–WC catalyst with synergy of Pt and C-defects can perform a 78.6% conversion in the selective hydrogenolysis of guaiacol to phenol with 89.0% selectivity at 300 °C, while the intact WC only gives a 7.1% guaiacol conversion with 51.0% phenol selectivity under the same conditions. As a result, the 1% Pt–WC catalyst exhibits 19-fold higher reaction rate and 12.6-fold higher turnover frequency than those of WC. Moreover, no substantial loss of catalytic performance has been observed with 1% Pt–WC for 50 h on stream. A rational reaction pathway is accordingly proposed through in-depth characterizations.
- Fang, Huihuang,Wu, Lijie,Chen, Weikun,Yuan, Youzhu
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- Direct C(sp3)?H Trifluoromethylation of Unactivated Alkanes Enabled by Multifunctional Trifluoromethyl Copper Complexes
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A mild and operationally simple C(sp3)?H trifluoromethylation method was developed for unactivated alkanes by utilizing a bench-stable CuIII complex, bpyCu(CF3)3, as the initiator of the visible-light photoinduced reaction, the source of a trifluoromethyl radical as a hydrogen atom transfer reagent, and the source of a trifluoromethyl anion for functionalization. The reaction was initiated by the generation of reactive electrophilic carbon-centered CF3 radical through photoinduced homolytic cleavage of bpyCu(CF3)3, followed by hydrogen abstraction from an unactivated C(sp3)?H bond. Comprehensive mechanistic investigations based on a combination of experimental and computational methods suggested that C?CF3 bond formation was enabled by radical–polar crossover and ionic coupling between the resulting carbocation intermediate and the anionic CF3 source. The methylene-selective reaction can be applied to the direct, late-stage trifluoromethylation of natural products and bioactive molecules.
- Choi, Geunho,Lee, Geun Seok,Park, Beomsoon,Kim, Dongwook,Hong, Soon Hyeok
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supporting information
p. 5467 - 5474
(2021/01/20)
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- Palladium-catalyzed synthesis of 4-cyclohexylmorpholines from reductive coupling of aryl ethers and lignin model compounds with morpholines
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This work describes the highly efficient Pd-catalyzed direct coupling of aryl ethers (including the typical lignin model compounds) and morpholines to produce 4-cyclohexylmorpholines, a useful class of fine chemicals. Without employing any acidic additives, various 4-cyclohexylmorpholines could be synthesized with good yields from a variety of aryl ethers using H2 as a hydrogen resource. A mechanism study revealed that the desired product was formed via the cleavage of the C(Ar)-O bonds to generate the corresponding cyclohexanones and subsequent reductive amination. This journal is
- Zheng, Bingxiao,Song, Jinliang,Wu, Haihong,Han, Shitao,Zhai, Jianxin,Zhang, Kaili,Wu, Wei,Xu, Caiyun,He, Mingyuan,Han, Buxing
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supporting information
p. 268 - 273
(2021/01/28)
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- Preparation of Nickel Nanocatalysts and Application to the Hydrodechlorination of 3-Chlorophenol under Liquid Phase
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Nickel nanoparticles were successfully synthesized via the reduction of nickel salt using ethylene glycol (EG) and sodium borohydride (NaBH4) as reducing agents. These nickel nanoparticles were then loaded on the supports as Ni-X (X = vanadium phosphorus
- Co, Thanh Thien,Tran, Thi Kim Anh,Doan, Thi Huong Ly,Diep, Thi Duyen
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- A Zr-Based Metal-Organic Framework with a DUT-52 Structure Containing a Trifluoroacetamido-Functionalized Linker for Aqueous Phase Fluorescence Sensing of the Cyanide Ion and Aerobic Oxidation of Cyclohexane
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A zirconium (Zr) metal-organic framework having a DUT-52 (DUT stands for Dresden University of Technology) structure with face-centered cubic topology and bearing the rigid 1-(2,2,2-trifluoroacetamido) naphthalene-3,7-dicarboxylic acid (H2NDC-NHCOCF3) ligand was prepared, and its solid structure was characterized with the help of the X-ray powder diffraction (XRPD) technique. Other characterization methods like thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy were applied to verify the phase purity of the compound. In order to get the solvent-free compound (1′), 1 was stirred with methanol for overnight and subsequently heated at 100 °C overnight under vacuum. As-synthesized (1) and activated (1′) compounds are thermally stable up to 300 °C. The Brunsuer Emmett-Teller (BET) surface area of 1′ was found to be 1105 m2 g-1. Fluorescence titration experiments showed that 1′ exhibits highly selective and sensitive fluorescence turn-on behavior toward cyanide (CN-) anion. The interference experiments suggested that other anions did not interfere in the detection of CN-. Moreover, a very short response time (2 min) was shown by probe 1′ for CN- detection. The detection limit was found to be 0.23 μM. 1′ can also be effectively used for CN- detection in real water samples. The mechanism for the selective detection of CN- was investigated systematically. Furthermore, the aerobic oxidation of cyclohexane was performed with 1′ under mild reaction conditions, observing higher activity than the analogous DUT-52 solid under identical conditions. These experiments clearly indicate the benefits of hydrophobic cavities of 1′ in achieving higher conversion of cyclohexane and cyclohexanol/cyclohexanone selectivity. Catalyst stability was proved by two consecutive reuses and comparing the structural integrity of 1′ before and after reuses by the XRPD study.
- Gogoi, Chiranjib,Nagarjun, Nagarathinam,Roy, Shubasis,Mostakim,Volkmer, Dirk,Dhakshinamoorthy, Amarajothi,Biswas, Shyam
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supporting information
p. 4539 - 4550
(2021/04/06)
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- Ordered macroporous Co3O4-supported Ru nanoparticles: A robust catalyst for efficient hydrodeoxygenation of anisole
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A three-dimensional ordered macroporous Co3O4 (OM-Co3O4) supported Ru catalyst was developed for the efficient hydrodeoxygenation (HDO) of anisole. It is revealed that small-sized Ru nanoparticles evenly distributed over the surface of OM-Co3O4 with large quantities of oxygen vacancies could strongly capture Ru0 species, thereby resulting in strong Ru-Co3O4 interactions. Compared with commercial Co3O4 supported Ru catalyst, Ru/OM-Co3O4 displays a better catalytic HDO performance, with a high cyclohexane yield of 92.4% at 250 °C and 0.5 MPa hydrogen pressure after 5 h on stream. Such a significant efficiency of Ru/OM-Co3O4 is mainly attributed to both high dispersion of Ru0 species and an enhanced formation of surface defects, as well as the unique macroporous framework of OM-Co3O4 support.
- Wang, An,Shi, Yisheng,Yang, Lan,Fan, Guoli,Li, Feng
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- Method for catalyzing non-tension non-polar carbon-carbon single bond hydrogenolysis of dicarbonyl compound
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The invention belongs to the technical field of chemical engineering, and particularly relates to a method for catalyzing non-tension non-polar carbon-carbon single bond hydrogenolysis of a dicarbonyl compound. According to the method, in a rare earth catalysis system, a secondary alcohol (amine) compound or hydrosilyane is used as a hydrogen source, and non-tension carbon-carbon single bonds of diketone and ketone ester are subjected to hydrogenolysis to form monoketone (ester). The method is a first carbon-carbon bond hydrogenolysis reaction of ketone, and the reaction has the advantages of good atom economy, high position selectivity and chemical selectivity, mild conditions, simplicity and convenience in operation, strong functional group tolerance and the like. Diketone and ketone ester are wide in source, and application is wide when diketone and ketone ester are converted into monoketone (ester).
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Paragraph 0064-0068
(2021/08/06)
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- Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
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An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
- Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
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supporting information
p. 8413 - 8418
(2021/11/01)
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- Method for preparing aldehyde/ketone by breaking C-C key
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The invention discloses a method for preparing aldehyde/ketone by breaking C-C bonds, and the method comprises the following steps of anaerobic condition. In an organic solvent system, an alcohol is used as a reaction raw material, and the C-C bond is selectively broken under the common action of an iron catalyst, an organic base and an additive to obtain aldehyde/ketone. The method is low in cost, easy to obtain, wide in substrate range, simple and product in post-treatment and high in purity, a new synthetic route and a method are developed for an aldehyde ketone compound, and the method has good application potential and research value.
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Paragraph 0103-0106
(2021/11/19)
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- Synthesis of cyclohexanol and ethanol via the hydrogenation of cyclohexyl acetate with Cu2Znx/Al2O3catalysts
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Cyclohexanol (CHOL), as a value-added chemical, has attracted much attention due to its huge application market. The hydrogenation of cyclohexyl acetate (CHA), derived from the esterification of acetic acid and cyclohexene, not only provides a novel route to yield CHOL and ethanol (EtOH), but also rationally utilizes excess acetic acid. In this work, a series of Zn-promoted Cu/Al2O3 catalysts were prepared via a deposition-precipitation method for the liquid-phase hydrogenation of CHA to yield CHOL and EtOH. As a result, the addition of Zn species with an optimal amount greatly improved the activity and selectivity to CHOL and EtOH. A Cu2Zn1.25/Al2O3 catalyst, which contained 16.2 wt% Cu and 9.6 wt% Zn, exhibited superior catalytic performance with 93.9% conversion of CHA and 97.2% selectivity to EtOH along with 97.1% selectivity to CHOL in a batch reactor. The Cu2Zn1.25/Al2O3 catalyst also showed excellent stability and there was no deactivation after five runs. Based on detailed characterization, it was revealed that the addition of Zn species increased the dispersion of Cu particles, adjusted the strength and amount of acid sites, and changed the electronic properties of Cu species and thus the ratio of Cu+/(Cu0 + Cu+).
- Li, Kefan,Li, Xiaohong,Qi, Yuanyuan,Song, Tongyang,Wu, Peng,Zhu, Zhirong
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p. 7035 - 7046
(2021/11/16)
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- Revisiting Alkane Hydroxylation with m-CPBA (m-Chloroperbenzoic Acid) Catalyzed by Nickel(II) Complexes
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Mechanistic studies are performed on the alkane hydroxylation with m-CPBA (m-chloroperbenzoic acid) catalyzed by nickel(II) complexes, NiII(L). In the oxidation of cycloalkanes, NiII(TPA) acts as an efficient catalyst with a high yield and a high alcohol selectivity. In the oxidation of adamantane, the tertiary carbon is predominantly oxidized. The reaction rate shows first-order dependence on [substrate] and [NiII(L)] but is independent on [m-CPBA]; vobs=k2[substrate][NiII(L)]. The reaction exhibited a relatively large kinetic deuterium isotope effect (KIE) of 6.7, demonstrating that the hydrogen atom abstraction is involved in the rate-limiting step of the catalytic cycle. Furthermore, NiII(L) supported by related tetradentate ligands exhibit apparently different catalytic activity, suggesting contribution of the NiII(L) in the catalytic cycle. Based on the kinetic analysis and the significant effects of O2 and CCl4 on the product distribution pattern, possible contributions of (L)NiII?O. and the aroyloxyl radical as the reactive oxidants are discussed.
- Itoh, Mayu,Itoh, Shinobu,Kubo, Minoru,Morimoto, Yuma,Shinke, Tomoya,Sugimoto, Hideki,Wada, Takuma,Yanagisawa, Sachiko
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p. 14730 - 14737
(2021/09/29)
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- Role of Catalyst Support's Physicochemical Properties on Catalytic Transfer Hydrogenation over Palladium Catalysts
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Catalytic transfer hydrogenation (CTH) is a promising reaction for valorisation of bio-based feedstocks via hydrogenation without needing to use H2. Unlike standard hydrogenation, CTH occurs via dehydrogenation (DHD) of a hydrogen donor (H-donor) and hydrogenation (HYD) of a substrate. Therefore, the “ideal” CTH catalyst must balance the catalysis of both reactions to maximize the hydrogen transfer between H-donor and substrate with minimal H2 loss to gas (high atom efficiency). Additionally, the H-donor must be highly stable to prevent secondary reactions with the substrate. Herein we study the impact of the catalyst's properties on CTH of guaiacol using bicyclohexyl, a liquid organic hydrogen carrier, as a H-donor. The reaction was promoted by palladium dispersed on three typical support materials (γ-Al2O3, MgO, and SiO2). The performance of these catalysts in the conversion of bicyclohexyl and guaiacol was evaluated, allowing to estimate the H-transfer efficiency, as well as the potential for recycling the spent H-donor (bicyclohexyl). The apparent activation energies for DHD of bicyclohexyl and HYD of guaiacol revealed that slow DHD combined with fast HYD, as is the case with Pd/MgO, favours hydrogen transfer efficiency and selectivity towards hydrogenated products. In addition, an investigation of the DHD of bicyclohexyl and HYD of guaiacol independently showed that the affinity between the organic molecules and the support significantly impacts CTH. Indeed, Pd/SiO2 was highly active for both reactions individually and almost inactive for CTH. Consequently, these findings highlight the importance of the interaction between solvent-substrate-support in designing catalysts for transfer hydrogenation.
- Batalha, Nuno,Fraga, Gabriel,Hasan, M. D.,Konarova, Muxina,Laycock, Bronwyn,Pratt, Steven,Santos, Mirella S.
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p. 5191 - 5202
(2021/10/29)
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