- Magnetic Field Effects on and Mechanism of Photoredox Reaction of Aromatic Nitro Group
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Photoredox reaction mechanism of a homologous series p-O2NC6H4O(CH2)nNHPh (1) in acetonitrile and benzene is studied.The major products are p-ONC6H4O(CH2)n-1CHO (3) and aniline derived from intramolecular reaction, but the presence of minor amounts of intermolecular reaction products, p-O2NC6H4O(CH2)n-1CHO (4) and p-ONC6H4O(CH2)nNHPh (5) is confirmed in the reaction mixture.In the presence of an external magnetic field, the yield of 3 is suppressed and those of 4 and 5 are correspondingly increased, while the rates of the disappearance of 1 and of the formation of aniline remain unchanged, suggesting the presence of biradical recombination process accompanied by intersystem crossing in a rate-determining step.On the basis of these observations, two reaction schemes are proposed.The magnetic field effects provide strong evidence for the presence of a transient species with (nitro)N(OH)-O-CHN group generally supposed for nitro oxygen transfer process in this type photoreaction.
- Mutai, Kiyoshi,Nakagaki, Ryoichi,Tukada, Hideyuki
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- Structure and Catalytic Activity of Cr-Doped BaTiO3 Nanocatalysts Synthesized by Conventional Oxalate and Microwave Assisted Hydrothermal Methods
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In the present study synthesis of BaTi1-xCrxO3 nanocatalysts (x = 0.0 ≤ x ≤ 0.05) by conventional oxalate and microwave assisted hydrothermal synthesis methods was carried out to investigate the effect of synthesis methods on the physicochemical and catalytic properties of nanocatalysts. These catalysts were thoroughly characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 physisortion, and total acidity by pyridine adsorption method. Their catalytic performance was evaluated for the reduction of nitrobenzene using hydrazine hydrate as the hydrogen source. Structural parameters refined by Rietveld analysis using XRD powder data indicate that BaTi1-xCrxO3 conventional catalysts were crystallized in the tetragonal BaTiO3 structure with space group P4mm, and microwave catalysts crystallized in pure cubic BaTiO3 structure with space group Pm3μm. TEM analysis of the catalysts reveal spherical morphology of the particles, and these are uniformly dispersed in microwave catalysts whereas agglomeration of the particles was observed in conventional catalysts. Particle size of the microwave catalysts is found to be 20-35 nm compared to conventional catalysts (30-48 nm). XPS studies reveal that Cr is present in the 3+ and 6+ mixed valence state in all the catalysts. Microwave synthesized catalysts showed a 4-10-fold increase in surface area and pore volume compared to conventional catalysts. Acidity of the BaTiO3 catalysts improved with Cr dopant in the catalysts, and this could be due to an increase in the number of Lewis acid sites with an increase in Cr content of all the catalysts. Catalytic reduction of nitrobenzene to aniline studies reveals that BaTiO3 synthesized by microwave is very active and showed 99.3% nitrobenzene conversion with 98.2% aniline yield. The presence of Cr in the catalysts facilitates a faster reduction reaction in all the catalysts, and its effect is particularly notable in conventional synthesized catalysts.
- Srilakshmi, Chilukoti,Saraf, Rohit,Prashanth,Rao, G. Mohan,Shivakumara
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- Pd nanoparticles immobilized on halloysite decorated with a cyclodextrin modified melamine-based polymer: a promising heterogeneous catalyst for hydrogenation of nitroarenes
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For the first time, a hybrid system composed of halloysite (Hal) and a cyclodextrin modified melamine-based polymer is developed and employed for immobilization of Pd(0) nanoparticles. The resulting catalytic hybrid system, Pd@HTMC, was then applied as a
- Sadjadi, Samahe,Akbari, Maryam,Monflier, Eric,Heravi, Majid M.,Leger, Bastien
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- Mesoporous silica supported cobalt catalysts for gas phase hydrogenation of nitrobenzene: role of pore structure on stable catalytic performance
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Highly dispersed cobalt nanoparticles were prepared over mesoporous silica with different pore structures (2D-hexagonal COK-12 and 3D-cubic SBA-16). These catalysts were evaluated for gas phase hydrogenation of nitrobenzene to aniline at atmospheric H2 pressure. A combination of catalytic activity and characterization results were assessed to establish the role of the support pore structure on hydrogenation activity. XRD, N2-physisorption, SEM and TEM analysis confirmed the presence of mesoporous structures in the supported cobalt catalysts. H2-TPR, H2-pulse chemisorption and TEM studies demonstrated higher dispersion of cobalt nanoparticles in Co/SBA-16 than in the Co/COK-12 catalyst. During the time-on-stream study the Co/SBA-16 catalyst experienced a gradual deactivation whereas the Co/COK-12 catalyst exhibited constant catalytic performance with respect to the hydrogenation of nitrobenzene. The interconnected cage type pores in Co/SBA-16 catalyst allowed the product molecules to participate in further reactions. This resulted in the formation of condensed products and coke deposition. The Co/SBA-16 catalyst was rapidly deactivated due to pore blocking through coke deposition. N2-Physisorption, TGA, H2-TPR and CHNS elemental analysis of spent catalysts confirmed the severe coke deposition in the Co/SBA-16 catalyst compared to the Co/COK-12 catalyst.
- Kondeboina, Murali,Enumula, Siva Sankar,Gurram, Venkata Ramesh Babu,Yadagiri, Jyothi,Burri, David Raju,Kamaraju, Seetha Rama Rao
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- Well-dispersed bimetallic nanoparticles confined in mesoporous metal oxides and their optimized catalytic activity for nitrobenzene hydrogenation
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Well-dispersed bimetallic nanoparticles (BMNPs = PtPd/AuPd/AuPt) confined in mesoporous metal oxides (MMOs = TiO2/Al2O 3/SiO2/ZrO2) are synthesized by a general and mild one-step sol-gel strategy. Thi
- Liu, Juanjuan,Zou, Shihui,Xiao, Liping,Fan, Jie
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- Palladium nanoparticles supported on silicate-based nanohybrid material: highly active and eco-friendly catalyst for reduction of nitrobenzene at ambient conditions
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In this study, spent bleaching earth (SBE), a hazardous industrial waste was used as raw material to synthesis carbon/silicate nanohybrid material (CSNH) as support for mono and bimetallic palladium and nickel nanoparticles. The synthesized catalysts were
- Ebadati, Esmat,Aghabarari, Behzad,Bagheri, Mozhgan,Khanlarkhani, Ali,Martinez Huerta, Maria Victoria
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- Efficient reduction catalysis of viologen-bound iron porphyrin and its application to six-electron reduction of nitrobenzene to aniline
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A newly synthesized methylviologen-bound iron porphyrin chloro(5-{4-[3-(1′-methyl-4,4′-bipyridinium)ethylcarboxyamidyl] phenyl}-10,15,20-triphenylporphyrin)iron dichloride, efficiently catalyzes six-electron reduction of nitrobenzene to aniline, a model reaction of NO2- conversion to NH4+ by nitrite reductase. The Royal Society of Chemistry 2000.
- Sakaki, Shigcyoshi,Koga, Hiroaki,Tao, Kou-Ichiro,Yamashita, Takafumi,Iwashita, Tetsuro,Hamada, Taisuke
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- A Modification of the Sheverdina-Kocheshkov Amination: The Use of Methoxyamine-Methyllithium as a Convenient Synthetic Equivalent for NH2+
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Direct stoichiometric amination of organolithiums can be achieved in high yields by methoxyamine and methyllithium in hexane-ether.The synthetic advantages of this approach are noted.
- Beak, Peter,Kokko, Bruce J.
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- Transition Metal Catalyzed Reduction of Azidoarenes to Aminoarenes with Carbon Monoxide-Water System
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Azidoarenes were readily transformed to aminoarenes in good yields under mild conditions with carbon monoxide and water in the presence of a catalytic amount of rhodium(III) complex, which is more catalytically active than rhodium(I) or palladium(II) complexes.
- Shim, Sang Chul,Choi, Kui Nam,Yeo, Young Kuk
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- Pd immobilized on polymeric network containing imidazolium salt, cyclodextrin and carbon nanotubes: Efficient and recyclable catalyst for the hydrogenation of nitroarenes in aqueous media
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A novel polymeric network benefiting from the chemistry of imidazolium salt (IL), cyclodextrin (CD) and carbon nanotube (CNT) is fabricated through a multi-step process, in which silica coated CNTs were vinyl functionalized and polymerized with poly (ethy
- Sadjadi, Samahe,Koohestani, Fatemeh
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- Decolorization of azo dye Orange G by aluminum powder enhanced by ultrasonic irradiation
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In this work, the decolorization of azo dye Orange G (OG) in aqueous solution by aluminum powder enhanced by ultrasonic irradiation (AlP-UI) was investigated. The effects of various operating operational parameters such as the initial pH, initial OG conce
- Cai, Mei Qiang,Wei, Xiao Qin,Song, Zhi Jun,Jin, Mi Cong
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- Synthesis of PVP-stabilized Pt/Ru colloidal nanoparticles by ethanol reduction and their catalytic properties for selective hydrogenation of ortho-chloronitrobenzene
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Stable poly(N-vinyl-2-pyrrolidone)-stabilized Pt/Ru colloidal nanoparticles (PVP-Pt/Ru) were prepared via ethanol reduction of H2PtCl 66H2O and RuCl3nH2O. The average diameters of the nanoparticles with different molar ratio of Pt/Ru were in a range of 2.1-2.8 nm with narrow size distributions. X-ray photoelectron spectroscopy verified that both Pt and Ru were in the metallic state and Ru was rich on the surface. These nanoparticles were employed to selectively hydrogenate ortho-chloronitrobenzene at 298 K and 0.1 MPa hydrogen pressure. They showed high activity [TOF was in the range of 0.8-5.3 × 10 -2 molo-CNB/(molM,surface atom) s] and high selectivity (93-99%) to ortho-chloroaniline (o-CAN) for the reaction, which were composition-dependent. The selectivity to o-CAN monotonously increased, but the activity of the catalyst decreased with the increasing proportion of Ru in Pt/Ru colloidal catalysts. PVP-1Pt/4Ru nanoparticles exhibited the highest selectivity of 99.0% to o-CAN at a complete conversion.
- Liu, Manhong,Zhang, Jin,Liu, Jinqiang,Yu, William W.
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- Direct amination of benzene to aniline with H2O2 and NH3·H2O over Cu/SiO2 catalyst
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The direct amination of benzene to aniline with H2O2 and NH3·H2O was studied using a series of Cu/SiO2 catalysts with mesoporous structures under mild conditions, and an acceptable yield (5.4%) and selectivity (74.0%) to aniline was obtained. Ultraviolet-visible diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated that some of the Cu atoms were incorporated into the mesoporous silica network forming Cu-O-Si species, which enabled the selective activation of the N-H bond of NH 3. The medium-strong acid sites were beneficial for the amination reaction. The concentration of the reactants was found to be another critical factor for aniline formation. The amination of the aromatic ring of substituted benzenes was also investigated under the optimized conditions. the Partner Organisations 2014.
- Yu, Tianhua,Yang, Ruiguang,Xia, Sheng,Li, Guiying,Hu, Changwei
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- Thermolysis of azobenzene
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Thermolysis of azobenzene in a melt and in solution results in the formation of aniline.The possible directions of the reaction are considered.Comparison of the enthalpies of the reaction proves that the cleavage of a ?-bond in the N=N group to form a biradical intermediate is thermodynamically more favorable than that of a C-N ?-bond.
- Budyka, M. F.,Kantor, M. M.
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- Multicomponent Strategy for the Preparation of Pyrrolo[1,2-a]pyrimidine Derivatives under Catalyst-Free and Microwave Irradiation Conditions
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A simple and efficient one-pot procedure has been developed for the construction of pyrrolo[1,2-a]pyrimidines via the three-component domino reaction of 5-aminopyrazoles, acetylenedicarboxylates and malononitrile under catalyst-free, microwave irradiation conditions. The key step in this transformation is the N N bond cleavage reaction of the 5-aminopyrazole substrate, which has been reported in this context for the first time in this study. The advantages of this protocol include readily available starting materials, short reaction times and good regioselectivity.
- Xun, Zhan,Feng, Xian,Wang, Jianjun,Shi, Daqing,Huang, Zhibin
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- Photochemical locking and unlocking of an acyl nitroso dienophile in the Diels-Alder reaction
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Photochromic Diels-Alder cycloadducts consisting of acyl nitroso dienophiles, which are known nitroxyl (HNO) donors, and dithienyldienes are presented. The dithienylethene-type photochromic cycloadducts were found to exhibit reversible electrocyclic ring closing and ring opening reactions to 'lock' or 'unlock' the retro Diels-Alder reaction, respectively. The release of an acyl nitroso dienophile via a retro Diels-Alder reaction at 92 °C was shown to occur only from the open or 'unlocked' form of a photochromic dithienylcyclopentene and not from the closed or 'locked' isomer.
- Schultz, Kevin P.,Spivey, David W.,Loya, E. Kirkbride,Kellon, Jaclyn E.,Taylor, Lisa M.,McConville, Marie R.
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- Square Wave Voltammetry for Two-Step Surface Reductions
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Strongly adsorbed species on an electrode surface are used to create a stable, redox-modified surface. Square wave voltammetry is then used to degrade the surface electrochemically, as evidenced by the resulting voltammetric response. This process can be mathematically modeled as a quasi-reversible surface reaction coupled with a first-order irreversible surface reaction of the product. This is the simplest possible model that can explain a two-step surface reduction. Exemplary calculations for square wave voltammetry show a wide variety of peak shapes depending on rate constants and square wave amplitude. The reduction of Dimethyl Yellow (4-(dimethylamino)azobenzene) adsorbed on mercury is accurately described by this model. Characteristic parameters of the overall surface process are obtained from voltammograms by using the two-step model with nonlinear least-squares analysis (COOL). For Dimethyl Yellow in Britton - Robinson buffer (pH 6.00) at a surface concentration of 17.3 pmol cm-2, these parameters are as follows: standard potential, E10 = -0.397 ± 0.001 V vs SCE; transfer coefficient for the first step, α1 = 0.43 ± 0.02; rate constant for the first step, k10 = 103 ± 8 s-1; transfer coefficient for the second step, α2 = 0.11 ± 0.04; and rate constant for the second step, k20 (referenced to E10) = 11.1 ± 1.7 s-1. Uncertainties are 95% confidence intervals derived from a pool of 11 voltammograms collected at different square wave amplitudes (ESW = 0-100 mV).
- O'Dea, John J.,Osteryoung, Janet G.
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- Oxidation-reduction conversions of derivatives of 1,4-dihydropyridine and 4H-pyran on interaction of alicyclic 1,5-diketones with 4-aminoazobenzene
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The interaction of 2,2′-methylenedicyclohexanone and 2,2′-methylenedicyclopentanone with 4-aminoazobenzene in acetic acid leads to reduction of the azo group of 1,4-dihydropyridine and 4H-pyran derivatives formed as intermediates. The reduction products were isolated as the corresponding pyridinium salts.
- Maslov,Akimova,Kaminski
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- Visible light photocatalytic synthesis of aniline with an Au/LaTiO3 nanocomposites
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An ultrasonic method was used to prepare LaTiO3 nanoparticles and a photo-assisted deposition method was used to loading gold into surface of LaTiO3. The samples obtained were characterized using a photoluminescence emission spectra,
- Mkhalid
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- Methylene blue sensitized photodechlorination of isomeric mono- and dichloroanilines via molecular complex formation mechanism
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The photosensitized dechlorination of isomeric mono- and dichloroanilines has been studied using methylene blue as photosensitizer in alkaline medium. The dechlorination products have been identified and formation of molecular complex between aniline and methylene blue has been observed. The effects of the pH, concentration of the sensitizer, concentration of the substrate, the intensity of the light and the temperature on the rate of the reaction have been studied. The quantum efficiency of the photodechlorination has been evaluated. The mechanism of the photodechlorination has been suggested.
- Pande,Dwivedi
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- Determination of the Carbamate Herbicide Propham by Synchronous Derivative Spectrofluorometry following Fluorescamine Fluorogenic Labeling
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Three methods for the determination of propham by fluorogenic labeling with fluorescamine and synchronous derivative spectrofluorometry are described and discussed.The herbicide is hydrolyzed in 1 M NaOH at 100 deg C for 40 min, and the liberated aniline reacts instantaneously wih fluorescamine in an aqueous buffer solution (pH 4.0).Reaction rates, fluorescence phenomena, and synchronous derivative parameters are investigated.To enhance sensitivity, the analysis of the fluorescamine derivative is used following extraction in ethyl acetate.Linear analytical curves are obtained between 24 and 2000 ng/mL.The minimum detectable quantity is estimated to be 7.2 ng/mL.Wellwater samples containing low concentrations of carbamate are also analyzed.
- Sanchez, F.Garcia,Blanco, C.Cruces
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- Features of the phenylhydroxylamine catalytic hydrogenation in water solutions of 2-propanole on skeletal nickel
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The kinetics of phenylhydroxylamine hydrogenation reaction on skeletal nickel catalyst in 2-propanole aqueous solutions was studied. It was shown that the value of phenylhydroxylamine and aniline adsorption increases with an increase in the molar fraction of water in the binary solvent 2-propanole-water. It was found experimentally that the hydrogenation reaction is of the first order with phenylhydroxilamine and of the zero order with hydrogen. It is noted that the amount of hydrogen absorbed in the reduction of phenylxydroxylamine in the initial phase of the reaction is considerably lower than the stehiometry of the reaction would indicate. The reasons for the effect of solvent on the features of phenylhydroxilamine hydrogenation are discussed.
- Budanov,Lefedova,Ulitin,Kha, Nguen Tkhi Tkhu
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- Synergetic effects of graphene-CoPc/silk fibroin three-dimensional porous composites as catalysts for acid red G degradation
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The disposal of dye wastewater is one of the hotspots of scientific research. Upon combining the ability of graphene to accelerate the hydroxyl radical generation with the Fenton system, it has shown a faster degradation rate and can be recycled, showing greater degradation efficiency than the traditional dye treatment method. Herein, a catalytic system based on the regenerated silk fibroin (SF) gel integrated with cobalt tetraaminophthalocyanine (CoTAPc)-grafted-reduced graphene oxide (RGO) sheets were fabricated, and its catalytic activity was assessed via the degradation of acid red G (ARG) at varying catalyst and H2O2 dosages, pH values, and temperatures. The results revealed that the three-dimensional (3D) porous RGO-CoTAPc/SF gel exhibited a much stronger catalytic behavior than the other arbitrary components due to its high surface area and synergetic hydroxyl radical generation efficiency, with the dye removal ratio by RGO-CoTAPc/SF being higher in an acidic medium than in an alkaline medium. It also increases with the increase in temperature and RGO-CoTAPc/SF and H2O2 dosages. Further, the catalytic oxidation process of ARG was determined, and the possible degradation mechanism of ARG has been discussed. Our results suggest that the composite materials with high catalytic activity can provide a reference for future Fenton-like catalytic systems.
- Ma, Hui,Zhang, Huanxia,Tong, Mingqiong,Cao, Jianda,Wu, Wen
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- Vilsmeier-Haack reagent-promoted formyloxylation of α-chloro-N-arylacetamides by formamide
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In this study, a Vilsmeier-Haack reagent-promoted formyloxylation of α-chloro-N-arylacetamides by formamide was developed. The reaction successfully provided the desired α-formyloxy-N-arylacetamides 4 and 7a-n in moderate to excellent yields (70-96%) by use of 3.0 equivalents of PBr3 at 80-90 °C and was applicable to substrates bearing electron-donating or withdrawing groups at the aryl moiety. For α-chloro-N-(naphthalenyl)acetamide (8a), α-chloro-N-(quinolin-8-yl)acetamide (8b), and α-chloro-N-(thiazol-2-yl)acetamide (8c) possessing the α-chloro group, the reaction also provided the desired formyloxylated products 9a-c in 70-87% yields. A plausible mechanism was proposed through the activation of α-chloroacetamide by the Vilsmeier-Haack reagent to account for the new transformation.
- Huang, Jiann-Jyh,Lu, Shi-Han,Chung, Yu Hsuan,Wong, Fung Fuh
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- Preparation of NiO Nanocatalyst Supported on MWCNTs and Its Application in Reduction of Nitrobenzene to Aniline in Liquid Phase
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In this research NiO nanoparticles supported on multiwalled carbon nanotubes (MWCNTs) and activated carbon were prepared and applied as nanocatalyst in hydrogenation of nitrobenzene (NB) to aniline (AN). The nanocatalysts were prepared via homogenous depo
- Hashemi, Majid,Khodaei, Mohammad Mehdi,Teymouri, Mohammad,Rashidi, Alimorad,Mohammadi, Hadi
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- Preparation, structural characterization of a novel egg-shell palladium sulfide catalyst and its application in selective reductive alkylation reaction
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A novel egg-shell Pd-S catalyst with palladium metal as the core and a membrane of palladium sulfide as the surface has been prepared by sulphidizing Pd/C with H2S. This catalyst is effective for the reductive alkylation of p-amino diphenylamine (PADPA) and methylisobutyl ketone (MIBK) to afford N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenedianine (DBPPD) with conversion up to 99.42% and selectivity to 97.46%. Comparing with the other common palladium sulfide catalysts, the membrane of palladium sulfide on the surface and the core of palladium metal cause the Pd on the surface of the new catalyst in a lower sulfur coordination, which improves its activity. Our result indicates that this new egg-shell Pd-S/C is an efficient hydrogenation catalyst.
- Zhang, Qun Feng,Wu, Jia Chun,Su, Chang,Feng, Feng,Ding, Qiao Ling,Yuan, Zhao Lian,Wang, Hong,Ma, Lei,Lu, Chun Shan,Li, Xiao Nian
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- METAL-ASSISTED REACTIONS. PART 24: THE IMPORTANCE OF SOLVENTS IN LIQUID-PHASE HETEROGENEOUS CATALYTIC TRANSFER REDUCTION
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In liquid-phase catalytic transfer reduction in which a hydrogen donor is used to effect hydrogenation of a substrate, reaction often proceeds sluggishly in single phase solvents but goes rapidly in biphasic solvent systems in which the catalyst usually resides in one or other of the phases.Depending on the nature of the substrate and donor, an excess of either can lead to the catalyst surface becoming saturated with one component, thereby preventing reaction.It is shown that the biphasic solvent system is, in practice, a simple means of controlling access to the catalyst by either the substrate or donor such that both are present on the surface in comparable amounts, leading to optimum or near optimum reaction rates.
- Brigast, Amadeu F.,Johnstone, Robert A. W.
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- Preparation and reactivity of UV light-reduced Pd/α-Fe2O3 catalyst towards the hydrogenation of o-chloronitrobenzene
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A type of Pd/α-Fe2O3 catalyst was synthesized by a convenient UV light-induced reduction in the presence of Fe3+ ions. The synthesized Pd/α-Fe2O3 particles were characterized by X-ray diffraction (XRD), low-resolution transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectrum (XPS), atomic force microscope (AFM), scan electron microscopy with energy dispersion spectra (SEM-EDS), FT-IR and BET. Related characterizations confirm that UV light-induced reduction is a feasible, simply and environment-friendly method for the preparation of supported catalysts containing active metal. Furthermore, hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) by the selected Pd(0.5%)/α-Fe2O3 was investigated systematically. The α-Fe2O3-supported Pd catalyst was found to exhibit good catalytic activity and selectivity for the o-CNB reduction under mild conditions. The hydrogenation of o-CNB over the resulting Pd-based catalyst gave a 100% o-CNB conversion and 91.4% selectivity of o-CAN under the reaction conditions of 50 °C, 2 h, 1 MPa hydrogen pressure, no-CNB/nPd = 6000:1. Moreover, the resulting Pd-based catalyst remained higher hydrogenation reactivity after three runs even if a sharply decrease in activity was observed at the fourth run. The obtained results reveal the as-prepared Pd/α-Fe2O3 is an efficient catalyst for the hydrogenation of o-CNB even at a high level of substrate concentration.
- Jiang, Weidong,Xu, Bin,Xiang, Zhen,Liu, Xiaoqiang,Liu, Fuan
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- NN bond cleavage of azobenzene: Via photocatalytic hydrogenation with Dy-doped Zn(O,S): The progress from hydrogen evolution to green chemical conversion
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Hydrogen-evolved Dy-doped Zn(O,S) photocatalysts with different amounts of Dy precursor have been synthesized, characterized and further utilized for hydrogenation reactions. The Dy catalysts are first examined using electrochemical impedance spectroscopy, photo responsivity, and the hydrogen evolution reaction. Dy-doped Zn(O,S) with 10% Dy precursor shows the best photocatalyst performance with the highest H2 production rate of 8.160 mmol g-1 h-1. This catalyst is chosen for conducting the hydrogenation reaction. It is our intention to confirm the correlation between the photocatalytic H2 production rate and the hydrogenation reactions of 4-nitrophenol to 4-aminophenol and azobenzene to aniline, which is a step further in the hydrogenation reaction to challenge the NN bond cleavage of azobenzene. A 100% photo conversion of 60 ppm azobenzene to aniline in 6 h was confirmed under a low-power UV light illumination in a 10% ethanol solution. Kinetic steps and kinetic mechanisms are proposed, which involve the important reaction steps of solvation, adsorption, pinning, and surface hydrogenation reaction operating together.
- Abdullah, Hairus,Kuo, Dong-Hau,Gultom, Noto Susanto
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- 7-Bromo-5-phenyl-1,2-dihydro-3H-1,3,5-benztriazepin-2-one
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7-Bromo-5-phenyl-1,2-dihydro-3H-1,4-benztriazepin-2-one was obtained by thermolysis of the syn-4-phenylsemicarbazone of 2-aminobenzophenone. Its molecular and crystal structure were established by X-ray crystallography. The nature of the hydrogen bonds be
- Vlasiuk,Pavlovsky,Andronati,Gdaniec,Simonov
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- Direct amination of benzene to aniline by reactive distillation method over copper doped hierarchical TS-1 catalyst
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We report an effective method for the direct amination of benzene to aniline where aqueous ammonia was employed as aminating agent with hydrogen peroxide as oxidant and copper doped hierarchical TS-1 as catalyst, using a reactive distillation reactor under mild conditions. A desirable aniline yield (12.4%) with excellent selectivity (84.7%) was obtained under optimized conditions. A probable catalytic pathway of benzene ammoxidation to aniline over hierarchical TS-1 or metal doped hierarchical TS-1 was proposed.
- Yu, Tianhua,Zhang, Qian,Xia, Sheng,Li, Guiying,Hu, Changwei
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- Study of dehalogenation of halogenoanilines using Raney Al-Ni alloy in aqueous medium at room temperature
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Dehalogenation of halogenated anilines by action of powdered aluminium-nickel alloy in aqueous alkaline solution at room temperature has been studied. The reaction course was monitored by means of1H nuclear magnetic resonance (NMR) spectroscopy. The rates of dehalogenation of 4-bromo-, 4-chloro-, 4-fluoro-and 3-chloroaniline were compared under conditions of minimum necessary excess of Al-Ni alloy as reducing agent in edetane buffer medium at pH 10.9. The dehalogenation rates of halogenated anilines decreased in the following order: 3-chloroaniline > 4-bromoaniline ≥ 4-chloroaniline >4-fluoroaniline. On the basis of the results obtained in buffers, the dehalogenation method of aqueous solutions of halogenoanilines was verified using NaOH as the base. Springer-Verlag 2010.
- Weidlich, Tomas,Krejcova, Anna,Prokes, Lubomir
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- Synthesis, characterization and catalytic activity of copper incorporated and immobilized mesoporous MCM-41 in the single step amination of benzene
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The paper reports the synthesis, surface and textural characterization of copper and amine modified MCM-41 and its application for the single step amination of benzene to aniline at 70 °C. Varying the amount of Cu different Cu/amine modified MCM-41 samples was synthesized by co-condensation and impregnation method. The samples were characterized by nitrogen adsorption-desorption, X-ray powder diffraction, Fourier-transform infrared spectroscopy (FT-IR), 29Si magic-angle spinning (MAS) and 13C Nuclear Magnetic Resonance (NMR) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). X-ray diffraction patterns indicate that the modified materials retain the standard MCM-41 structure. FT-IR and DRS results indicated that Cu and amino groups are incorporated into the Si-O framework and frame wall respectively. NMR showed higher degree of condensation of materials in framework position. Cu-amine-MCM-41 samples showed significant catalytic activity for single step amination of benzene in acetic acid-water medium under mild reaction conditions using hydroxylamine as aminating agent. The Cu-amine-MCM-41 (Si/Cu = 20) showed highest benzene conversion (72.2%) and 100% selectivity for aniline.
- Parida,Rath, Dharitri,Dash
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- Synthesis of palladium nanoparticles over graphite oxide and carbon nanotubes by reduction in ethylene glycol and their catalytic performance on the chemoselective hydrogenation of para-chloronitrobenzene
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Pd nanoparticles have been synthesized over carbon nanotubes (CNT) and graphite oxide (GO) by reduction with ethylene glycol and by conventional impregnation method. The catalysts were tested on the chemoselective hydrogenation of p-chloronitrobenzene and the effect of the synthesis method and surface chemistry on their catalytic performance was evaluated. The catalysts were characterized by N2 adsorption/desorption isotherms at 77 K, TEM, powder X-ray diffraction, thermogravimetry, infrared and X-ray photoelectron spectroscopy and ICP-OES. It was observed that the synthesis of Pd nanoparticles employing ethylene glycol resulted in metallic palladium particles of smaller size compared to those prepared by the impregnation method and similar for both supports. The presence of oxygen groups on the support surface favored the activity and diminished the selectivity. It seems that ethylene glycol reacted with the surface groups of GO, this favoring the selectivity. The activity was higher over the CNT-based catalysts and both catalysts prepared by reduction in ethylene glycol were quite stable upon recycling.
- Dongil,Pastor-Pérez,Fierro,Escalona,Sepúlveda-Escribano
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- Physicochemical properties of 4,5-(aryl,alkyl)-3-substituted 2-aminothiophenes sulfonyl derivatives
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Physicochemical properties of 4,5-(aryl, alkyl)-3-substituted 2-sulfonylaminothiophenes have been studied. The effect of the nature of the substituents in the thiophene ring on acid-base properties, solubility, and chemical stability was investigated.
- Chekanova,Manylova,Pavlov,Vasyanin,Shurov,Maiorova
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- Reactivity of phenyl N-phenylcarbamates in the alkaline hydrolysis reaction
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In the present study, we explore the application of several theoretically estimated indices that characterize the reactivity of a series of phenyl N-phenylcarbamates in the alkaline hydrolysis reaction. The rate constants (at 25°C) for the hydrolysis of several derivatives were spectrophotometrically determined. The obtained kinetic data in this study, combined with literature data for other derivatives, were then correlated with theoretically estimated reactivity indices: Hirshfeld and NBO atomic charges, the Parr electrophilicity index (ω), and the electrostatic potential at the carbon and oxygen atoms of the reaction centre (VC, VO). The predictive ability of these quantities is discussed in a comparative context. Copyright
- Nalbantova, Didi,Cheshmedzhieva, Diana,Hadjieva, Boriana,Ilieva, Sonia,Galabov, Boris
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- Functionalization of a plasmonic Au/TiO2 photocatalyst with an Ag co-catalyst for quantitative reduction of nitrobenzene to aniline in 2-propanol suspensions under irradiation of visible light
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A functionalized plasmonic Au/TiO2 photocatalyst with an Ag co-catalyst was successfully prepared by the combination of two types of photodeposition methods, and it quantitatively converted nitrobenzene and 2-propanol to aniline and acetone under irradiation of visible light.
- Tanaka, Atsuhiro,Nishino, Yuri,Sakaguchi, Satoshi,Yoshikawa, Takayuki,Imamura, Kazuya,Hashimoto, Keiji,Kominami, Hiroshi
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- Kinetics of the hydrogenation of a mixture of nitrobenzene and azoxybenzene on skeletal nickel in an aqueous solution of propan-2-ol
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The sequence of the reduction of nitro and azoxy groups in the combined hydrogenation of nitrobenzene and azoxybenzene on skeletal nickel in an aqueous azeotropic solution of propan-2-ol is considered. The time dependences of the rates and concentrations of the initial compound and reaction product for the hydrogenation of individual compounds (nitrobenzene and azoxybenzene) in the solvent of the indicated composition are discussed for comparative analysis. In all cases, the reactions proceed selectively to aniline without accumulating side products. The reduction of the nitro and azoxy groups involves hydrogen bound by the active sites of the catalyst surface. The competitive character of adsorption between the initial compounds and formed aniline is observed. Nitrobenzene is characterized by the highest adsorbability, whereas azoxybenzene and aniline are less adsorbable.
- Merkin,Latypova,Kha, Nguen Tkhi Tkhu,Lefedova
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- REACTION OF TETRACYANOCOBALTATE(I) WITH ARYL HALIDES. FORMATION OF ?-ARYLPENTACYANOCOBALTATES AND CYANATION TO ARYL CYANIDES
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Tetracyanocobaltate(I), which is formed in strongly alkaline solutions of cyanocobaltate under H2 at Cn:Co 5;1, reacts readily with aryl halides to form ?-arylpentacyanocobaltates(III). 1H and 13C NMR spectra of these new and fairly stable complexes have been determined.In the reactions of some aryl halides, aryl cyanides as well as hydrogenolysis products are formed, and α-bromonaphthalene reacts selectively to give the highest yield of the nitrile.The reactions are explained by a mechanism involving an electron-transfer process.
- Funabiki, Takuzo,Nakamura, Hitoshi,Yoshida, Satohiro
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- Palladated composite of Cu-BDC MOF and perlite as an efficient catalyst for hydrogenation of nitroarenes
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A novel composite of metal-organic framework and perlite is prepared through hydrothermal treatment of terephthalic acid and Cu(NO3)2·3H2O in the presence of perlite. The resulting composite was then utilized as a support for the immobilization of Pd nanoparticles. The obtained compound was characterized via XRD, TGA, ICP, FTIR, TEM, FE-SEM/EDS and elemental mapping analysis and applied as a catalyst for the hydrogenation of nitroarenes under mild reaction condition. The results approved that the catalyst could efficiently promote hydrogenation of various nitroarenes with different electronic densities and steric properties. Moreover, the catalyst showed high selectivity towards hydrogenation of nitro groups. Hot filtration test affirmed heterogeneous nature of catalysis. Furthermore, the present catalytic composite was highly recyclable with low Pd leaching. A comparative study also approved superior activity of the composite compared to palladated perlite and metal-organic framework.
- Koohestani, Fatemeh,Sadjadi, Samahe
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- Nickel Boride Catalyzed Reductions of Nitro Compounds and Azides: Nanocellulose-Supported Catalysts in Tandem Reactions
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Nickel boride catalyst prepared in situ from NiCl2 and sodium borohydride allowed, in the presence of an aqueous solution of TEMPO-oxidized nanocellulose (0.01 wt%), the reduction of a wide range of nitroarenes and aliphatic nitro compounds. Here we describe how the modified nanocellulose has a stabilizing effect on the catalyst that enables low loading of the nickel salt pre-catalyst. Ni-B prepared in situ from a methanolic solution was also used to develop a greener and facile reduction of organic azides, offering a substantially lowered catalyst loading with respect to reported methods in the literature. Both aromatic and aliphatic azides were reduced, and the protocol is compatible with a one-pot Boc-protection of the obtained amine yielding the corresponding carbamates. Finally, bacterial crystalline nanocellulose was chosen as a support for the Ni-B catalyst to allow an easy recovery step of the catalyst and its recyclability for new reduction cycles.
- Proietti, Giampiero,Prathap, Kaniraj Jeya,Ye, Xinchen,Olsson, Richard T.,Dinér, Peter
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supporting information
p. 133 - 146
(2021/11/04)
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- Iron-mediated desulphurization approach: synthesis of cyanamides and their conversions
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The iron-mediated efficient multi-component method has been demonstrated for the synthesis of substituted cyanamides from isothiocyanates under mild reaction conditions. Subsequent nucleophilic addition and desulfurization are involved in this proposed synthetic methodology. All the reactions are rapid, facile, and accomplished at room temperature. A variety of substrates readily underwent the optimized reaction conditions to provide their respective target products in good to excellent yields. Furthermore, we have confirmed that no other by-products could be identified during our experimental reaction process. Graphical abstract: Iron-mediated efficient multi-component method has been demonstrated for the synthesis of substituted cyanamides from isothiocyanates under mild reaction conditions. Subsequent nucleophilic addition and desulfurization are involved in this proposed synthetic methodology.[Figure not available: see fulltext.].
- Nannapaneni, Madhavi,Pendem, Venkata Bhavanarushi,Tamminana, Ramana
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- Scalable and selective deuteration of (hetero)arenes
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Isotope labelling, particularly deuteration, is an important tool for the development of new drugs, specifically for identification and quantification of metabolites. For this purpose, many efficient methodologies have been developed that allow for the small-scale synthesis of selectively deuterated compounds. Due to the development of deuterated compounds as active drug ingredients, there is a growing interest in scalable methods for deuteration. The development of methodologies for large-scale deuterium labelling in industrial settings requires technologies that are reliable, robust and scalable. Here we show that a nanostructured iron catalyst, prepared by combining cellulose with abundant iron salts, permits the selective deuteration of (hetero)arenes including anilines, phenols, indoles and other heterocycles, using inexpensive D2O under hydrogen pressure. This methodology represents an easily scalable deuteration (demonstrated by the synthesis of deuterium-containing products on the kilogram scale) and the air- and water-stable catalyst enables efficient labelling in a straightforward manner with high quality control. [Figure not available: see fulltext.].
- Bartling, Stephan,Beller, Matthias,Bourriquen, Florian,Brückner, Angelika,Junge, Kathrin,Kreyenschulte, Carsten,Lei, Aiwen,Li, Wu,Lund, Henrik,Rabeah, Jabor,Rockstroh, Nils,Surkus, Annette-Enrica,Yang, Dali
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- 2-(4-Nitrophenyl)-1H-indolyl-3-methyl Chromophore: A Versatile Photocage that Responds to Visible-light One-photon and Near-infrared-light Two-photon Excitations
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Due to cell damage caused by UV light, photoremovable protecting groups (PPGs) that are removed using visible or near-infrared light are attracting attention. A 2-(4-nitrophenyl)- 1H-indolyl-3-methyl chromophore (NPIM) was synthesized as a novel PPG. Various compounds were caged using this PPG and uncaged using visible or near-infrared light. Low cytotoxicity of NPIM indicates that it may be applied in physiological studies.
- Abe, Manabu,Guo, Runzhao,Hamao, Kozue,Lin, Qianghua,Takagi, Ryukichi
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supporting information
p. 153 - 156
(2022/02/14)
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- Synthesis, thermal behavior in oxidative and pyrolysis conditions, spectroscopic and DFT studies of some alkaline earth metals p-aminobenzoate complexes using TG-DTA, DSC, PXRD and EGA (TG-FTIR) techniques
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p-aminobenzoic acid is a substance widely used in several areas, such as catalysis, biomarkers, magnetic materials, luminescent materials and biological applications. p-aminobenzoate complexes with alkaline earth metal were synthesized and the thermal and pyrolysis behavior was studied using thermoanalytical and spectroscopic techniques. Based on TG/DTG-DTA and EGA results, the thermal decomposition mechanisms of the compounds were proposed under both atmospheres studied. The main gaseous products identified by EGA in both study conditions were H2O, Aniline, CO and CO2. From DSC analysis, it was possible to measure the enthalpies of dehydration and evaluate the phase transitions of the magnesium complex. FTIR data suggest that metal-ligand coordination occurs through carboxylate group by different ways. The coordination modes suggested by experimental FTIR data were supported by DFT study. The X-ray diffraction powder patterns show that the barium compound was obtained in amorphous state, while the other compounds have a crystalline structure.
- Caires, Flávio J.,Fernandes, Richard P.,Gaspari, Ana P. S.,Ionashiro, Massao,Isquibola, Guilherme,Machado, Antonio E. H.,Teixeira, José Augusto
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- Oxygen-implanted MoS2 nanosheets promoting quinoline synthesis from nitroarenes and aliphatic alcohols via an integrated oxidation transfer hydrogenation-cyclization mechanism
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We herein report that MoS2 with oxygen-implanting modification (O-MoS2) can work as a multifunctional catalyst to achieve the one-pot quinoline synthesis from basic nitroarenes and aliphatic alcohols. Different from common knowledge that the application of MoS2-based catalysts and above quinoline synthesis need anaerobic conditions, we conduct the heterogeneous catalysis under an unusual air atmosphere. Catalyst characterization and experimental results indicate that the MoOx clusters implanted in the MoS2 skeleton, not the coordinatively unsaturated Mo sites (CUS Mo), dominate the generation of quinolines. By overturning the catalysis perception that O2 adsorption on MoSx can deactivate the MoS2-based catalysts using an efficient method for in situ healing of the MoOx structure in O-MoS2 and protecting the O-MoS2 catalyst by inhibiting unwanted MoOx elimination with extra H*, we innovatively introduce O2 into the quinoline synthesis. The robust O-MoS2 can be consecutively used ten times without regeneration and it offers 69-75% yields of 2-methylquinoline from nitrobenzene and ethanol. Furthermore, different from the traditional transfer hydrogenation-condensation mechanism, an integrated oxidation-transfer hydrogenation-cyclization mechanism is proposed over the O-MoS2 catalyst.
- Gao, Zhuyan,Huang, Zhipeng,Lu, Jianmin,Mu, Junju,Ren, Puning,Su, Kaiyi,Wang, Feng,Zhang, Chaofeng,Zhang, Shichao
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p. 1704 - 1713
(2022/03/08)
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- Simultaneous synthesis of aniline and γ-butyrolactone from nitrobenzene and 1,4-butanediol over Cu-CoOx-MgO catalyst via catalytic hydrogen transfer process: Effect of calcination temperature
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This study examined a hydrogen transfer reaction from 1,4-butanediol to nitrobenzene for γ-butyrolactone and aniline simultaneously over Cu-CoOx-MgO catalysts. The catalyst was developed by co-precipitation followed by metal hydroxycarbonate mixing and calcination at three different temperatures (500, 700, and 900 °C). The hydrogenation of nitrobenzene to aniline and the dehydrogenation of 1,4-butanediol to γ-butyrolactone was accomplished in a gas-phase fixed-bed continuous reactor system at 250 °C. The catalyst Cu-CoOx-MgO-500 calcined at 500 °C showed outstanding performance because of the higher copper dispersion and negligible spinel species (CuCo2O4 /MgCo2O4) compared to the other two catalysts. The order of activity decreased with increasing calcination temperature from 500° to 900°C. The activity trend followed the order, Cu-CoOx-MgO-500 > Cu-CoOx-MgO-700 > Cu-CoOx-MgO-900. The effect of calcination on the catalytic properties was analyzed by atomic absorption spectroscopy elemental analysis, Brunauer-Emmett-Teller surface area, N2O pulse chemisorption, temperature-programmed reduction-H2, X-ray diffraction, and X-ray photoelectron spectroscopy. The results showed that Cu-CoO-MgO-500 exhibited more active copper sites (Cu0/Cu+1) and optimal metal-support interactions that decrease the reduction temperature of copper. On the other hand, Cu-Co and Mg-Co spinel (CuCo2O4/MgCo2O4) content, which adversely affects the catalyst activity, increased with increasing calcination temperature. In summary, simultaneous hydrogenation and dehydrogenation reactions via hydrogen transfer reactions have potential commercial applications.
- Kannapu, Hari Prasad Reddy,Park, Young-Kwon,Vaddeboina, Veeralakshmi
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- Biogenic Synthesis of Gold Nanoparticles on a Green Support as a Reusable Catalyst for the Hydrogenation of Nitroarene and Quinoline
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Direct attachment of gold nanoparticles to a green support without the use of an external reducing agent and using it for removing toxic pollutants from wastewater, i. e., reduction of nitroarene to amine, are described. A novel approach involving the reduction of gold by the jute plant (Corchorus genus) stem-based (JPS) support itself to form nanoparticles (AuNPs) to be used as a catalytic system (‘dip-catalyst’) and its catalytic activity for the hydrogenation of series of nitroarenes in aqueous media are presented. AuNPs/JPS catalyst was characterized using SEM, UV-Vis, FTIR, TEM, XPS, and ICP-OES. Confined area elemental mapping exhibits uniform and homogeneous distribution of AuNPs on the support surface. TEM shows multi-faceted AuNPs in the range of 20–30 nm. The reactivity of AuNPs/JPS for the transfer hydrogenation of nitroarene as well as hydrogenation of quinoline under molecular H2 pressure was evaluated. Sodium borohydride, when used as the hydrogen source, demonstrates a high catalytic efficiency in the transfer hydrogenation reduction of 4-nitrophenol (4-NP). Quinoline is quantitatively and chemoselectively hydrogenated to 1,2,3,4-tetrahydroquinoline (py-THQ) using molecular hydrogen. Reusability studies show that AuNPs are stable on the support surface and their selectivity is not affected.
- Adeyeye Nafiu, Sodiq,Aziz, Abdul,Shaheen Shah, Syed,Shaikh, M. Nasiruzzaman
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p. 1956 - 1966
(2021/06/18)
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- Composite of β-cyclodextrin and bentonite clay: a promising support for Pd immobilization and developing a catalyst for hydrogenation of nitroarenes under mild reaction condition
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In attempt to take advantages of naturally occurring compounds for the catalysis, a novel composite composed of β-cyclodextrin, dendrimer and bentonite clay is fabricated and utilized as a support for the stabilization of Pd nanoparticles. To prepare the support, bentonite is amino functionalized and then successively reacted with 2,4,6-trichloro-1,3,5-triazine and ethylenediamine to furnish a dendrimer of generation II on bentonite. Afterwards, the terminal functionalities of the dendrimer were adorned with cyclodextrin. Bentonite played role in the heterogenation of the catalyst and improvement of the stability of the composite while, cyclodextrins served as molecular shuttles and capping agent for the as-prepared Pd nanoparticles. Dendrimer with multi nitrogen atoms, on the other hand, improved Pd anchoring through electrostatic interactions. The catalyst was applied for the hydrogenation of nitroarenes under mild reaction condition in aqueous media in a selective manner. Notably, the catalyst could be recovered and reused repeatedly.
- Koohestani, Fatemeh,Sadjadi, Samahe
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supporting information
(2020/12/21)
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- Palladated composite of MOF and cyclodextrin nanosponge: A novel catalyst for hydrogenation reaction
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In attempt to develop green protocols for organic transformations, a novel catalyst is prepared by combination of the features of metal-organic frameworks and polymers of cyclic carbohydrates. In detail, cyclodextrin nanosponge was synthesized from β-cycl
- Koohestani, Fatemeh,Sadjadi, Samahe
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- Rhodium-terpyridine Catalyzed Transfer Hydrogenation of Aromatic Nitro Compounds in Water
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A rhodium terpyridine complex catalyzed transfer hydrogenation of nitroarenes to anilines with i-PrOH as hydrogen source and water as solvent has been developed. The catalytic system can work at a substrate/catalyst (S/C) ratio of 2000, with a turnover frequency (TOF) up to 3360 h?1, which represents one of the most active catalytic transfer hydrogenation systems for nitroarene reduction. The catalytic system is operationally simple and the protocol could be scaled up to 20 gram scale. The water-soluble catalyst bearing a carboxyl group could be recycled 15 times without significant loss of activity.
- Liu, Yuxuan,Miao, Wang,Tang, Weijun,Xue, Dong,Xiao, Jianliang,Wang, Chao,Li, Changzhi
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p. 1725 - 1729
(2021/06/01)
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- Porous polymeric ligand promoted copper-catalyzed C-N coupling of (hetero)aryl chlorides under visible-light irradiation
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A porous polymeric ligand (PPL) has been synthesized and complexed with copper to generate a heterogeneous catalyst (Cu@PPL) that has facilitated the efficient C-N coupling with various (hetero)aryl chlorides under mild conditions of visible-light irradiation at 80 °C (58 examples, up to 99% yields). This method could be applied to both aqueous ammonia and substituted amines, and is compatible to a variety of functional groups and heterocycles, as well as allows tandem C-N couplings with conjunctive dihalides. Furthermore, the heterogeneous characteristic of Cu@PPL has enabled a straightforward catalyst separation in multiple times of recycling with negligible catalytic efficiency loss by simple filtration, affording reaction mixtures containing less than 1 ppm of Cu residue. [Figure not available: see fulltext.]
- Wang, Erfei,Chen, Kaixuan,Chen, Yinan,Zhang, Jiawei,Lin, Xinrong,Chen, Mao
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- Generation of a Sulfinamide Species from Facile N-O Bond Cleavage of Nitrosobenzene by a Thiolate-Bridged Diiron Complex
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The activation of nitrosobenzene promoted by transition-metal complexes has gained considerable interest due to its significance for understanding biological processes and catalytic C-N bond formation processes. Despite intensive studies in the past decades, there are only limited cases where electron-rich metal centers were commonly employed to achieve the N-O or C-N bond cleavage of the coordinated nitrosobenzene. In this regard, it is significant and challenging to construct a suitable functional system for examining its unique reactivity toward reductive activation of nitrosoarene. Herein, we present a {Fe2S2} functional platform that can activate nitrosobenzene via an unprecedented iron-directed thiolate insertion into the N-O bond to selectively generate a well-defined diiron benzenesulfinamide complex. Furthermore, computational studies support a proposal that in this concerted four-electron reduction process of nitrosobenzene the iron center serves as an important electron shuttle. Notably, compared to the intact bridging nitrosoarene ligand, the benzenesulfinamide moiety has priority to convert into aniline in the presence of separate or combined protons and reductants, which may imply the formation of the sulfinamide species accelerates reduction process of nitrosoarene. The reaction pattern presented here represents a novel activation mode of nitrosobenzene realized by a thiolate-bridged diiron complex.
- Chen, Yifeng,Qu, Jingping,Wang, Baomin,Xu, Sunlin,Yang, Dawei,Ye, Shengfa
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supporting information
p. 17374 - 17387
(2021/10/25)
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- Chemoselective Hydrogenation of Nitroarenes Using an Air-Stable Base-Metal Catalyst
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The reduction of nitroarenes to anilines as well as azobenzenes to hydrazobenzenes using a single base-metal catalyst is reported. The hydrogenation reactions are performed with an air-and moisture-stable manganese catalyst and proceed under relatively mild reaction conditions. The transformation tolerates a broad range of functional groups, affording aniline derivatives and hydrazobenzenes in high yields. Mechanistic studies suggest that the reaction proceeds via a bifunctional activation involving metal-ligand cooperative catalysis.
- Zubar, Viktoriia,Dewanji, Abhishek,Rueping, Magnus
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p. 2742 - 2747
(2021/05/05)
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- NaI/PPh3-Mediated Photochemical Reduction and Amination of Nitroarenes
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A mild transition-metal- and photosensitizer-free photoredox system based on the combination of NaI and PPh3 was found to enable highly selective reduction of nitroarenes. This protocol tolerates a broad range of reducible functional groups such as halogen (Cl, Br, and even I), aldehyde, ketone, carboxyl, and cyano. Moreover, the photoredox catalysis with NaI and stoichiometric PPh3 provides also an alternative entry to Cadogan-type reductive amination when o-nitrobiarenes were used.
- Qu, Zhonghua,Chen, Xing,Zhong, Shuai,Deng, Guo-Jun,Huang, Huawen
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p. 5349 - 5353
(2021/07/21)
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- Manganese Catalyzed Hydrogenation of Azo (N=N) Bonds to Amines
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We report the first example of homogeneously catalyzed hydrogenation of the N=N bond of azo compounds using a complex of an earth-abundant-metal. The hydrogenation reaction is catalyzed by a manganese pincer complex, proceeds under mild conditions, and yields amines, which makes this methodology a sustainable alternative route for the conversion of azo compounds. A plausible mechanism involving metal-ligand cooperation and hydrazine intermediacy is proposed based on mechanistic studies. (Figure presented.).
- Ben-David, Yehoshoa,Das, Uttam Kumar,Diskin-Posner, Yael,Kar, Sayan,Milstein, David
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p. 3744 - 3749
(2021/07/09)
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- A mild and selective Cu(II) salts-catalyzed reduction of nitro, azo, azoxy, N-aryl hydroxylamine, nitroso, acid halide, ester, and azide compounds using hydrogen surrogacy of sodium borohydride
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The first mild, in situ, single-pot, high-yielding well-screened copper (II) salt-based catalyst system utilizing the hydrogen surrogacy of sodium borohydride for selective hydrogenation of a broad range of nitro substrates into the corresponding amine under habitancy of water or methanol like green solvents have been described. Moreover, this catalytic system can also activate various functional groups for hydride reduction within prompted time, with low catalyst-loading, without any requirement of high pressure or molecular hydrogen supply. Notably, this system explores a great potential to substitute expensive traditional hydrogenation methodologies and thus offers a greener and simple hydrogenative strategy in the field of organic synthesis.
- Kalola, Anirudhdha G.,Prasad, Pratibha,Mokariya, Jaydeep A.,Patel, Manish P.
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supporting information
p. 3565 - 3589
(2021/10/12)
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- A Metal-Free Direct Arene C?H Amination
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The synthesis of aryl amines via the formation of a C?N bond is an essential tool for the preparation of functional materials, active pharmaceutical ingredients and bioactive products. Usually, this chemical connection is only possible by transition metal-catalyzed reactions, photochemistry or electrochemistry. Here, we report a metal-free arene C?H amination using hydroxylamine derivatives under benign conditions. A charge transfer interaction between the aminating reagents TsONHR and the arene substrates enables the chemoselective amination of the arene, even in the presence of various functional groups. Oxygen was crucial for an effective conversion and its accelerating role for the electron transfer step was proven experimentally. In addition, this was rationalized by a theoretical study which indicated the involvement of a dioxygen-bridged complex with a “Sandwich-like” arrangement of the aromatic starting materials and the aminating agents at the dioxygen molecule. (Figure presented.).
- Wang, Tao,Hoffmann, Marvin,Dreuw, Andreas,Hasagi?, Edina,Hu, Chao,Stein, Philipp M.,Witzel, Sina,Shi, Hongwei,Yang, Yangyang,Rudolph, Matthias,Stuck, Fabian,Rominger, Frank,Kerscher, Marion,Comba, Peter,Hashmi, A. Stephen K.
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supporting information
p. 2783 - 2795
(2021/04/05)
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- Synthesis of new Copper Catalyst with Pyrazole Based Tridentate Ligand and Study of Its Activity for Azide Alkyne Coupling
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Synthesis of new copper catalyst with pyrazole based tridentate ligand and study of its activity for azide alkyne coupling were investigated by researchers. To a solution of acetyl acetone (2.002 g, 20 mmol), 2- nitrophenylhydrazine in ethanol was added five drops of con. HCl and heated at 50° for 1 hour. After confirming the formation of 3, 5-dimethyl-1-(2-nitrophenyl)- 1H-pyrazole by TLC, ice cooled water was added in to the reaction mixture. The precipitate was filtered, washed with water and then hexane. The product formed as yellow precipitate, that precipitate had been filtered by normal filter paper. The product was recrystallized in ethanol. For synthesis, was suspended in 6 mL of deionized and stirred for 4 h until a clear solution was obtained in 50 ml round bottom flask Cu(OAc) 2. The reaction mixture was diluted with water, filtered, washed sequentially with water, methanol and n-hexane. Then dark greenish blue color crystal were formed and used for the reactions. The solid was crystallized in CH2Cl2 to get crystal whose structure was confirmed by single crystal XRD.
- Rajeswari, Panneer Selvam,Nagarajan, Rajendran,P, Sujith K,Emmanuvel, Lourdusamy
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supporting information
(2020/12/03)
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- Catalytic Hydrogenation of Azobenzene in the Presence of a Cuboidal Mo3S4Cluster via an Uncommon Sulfur-Based H2Activation Mechanism
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Azobenzene hydrogenation is catalyzed under moderate conditions by a cuboidal Mo3(μ3-S)(μ-S)3 diamino complex via a cluster catalysis mechanism. Dihydrogen activation by the molecular [Mo3(μ3-S)(μ-S)3Cl3(dmen)3]+ cluster cation takes place at the μ-S bridging atoms without direct participation of the metals in clear contrast with classical concepts. The reaction occurs with the formation of 1,2-diphenylhydrazine as an intermediate with similar appearance and disappearance rate constants. On the basis of DFT calculations, a mechanism is proposed in which formation of 1,2-diphenylhydrazine and aniline occurs through two interconnected catalytic cycles that share a common reaction step that involves H2 addition to two of the bridging sulfur atoms of the catalyst to form a dithiolate Mo3(μ3-S)(μ-SH)2)(μ-S) adduct. Both catalytic cycles have similar activation barriers, in agreement with the experimental observation of close rate constant values. Microkinetic modeling of the process leads to computed concentration-time profiles in excellent agreement with the experimental ones providing additional support to the calculated reaction mechanism. Slight modifications on the experimental conditions of the catalytic protocol in combination with theoretical calculations discard a direct participation of the metal on the reaction mechanism. The effect of the ancillary ligands on the catalytic activity of the cluster fully agrees with the present mechanistic proposal. The results herein demonstrate the capability of molybdenum sulfide materials to activate hydrogen through an uncommon sulfur based mechanism opening attractive possibilities toward their applications as catalysts in other hydrogenation processes.
- Guillamón, Eva,Oliva, Mónica,Andrés, Juan,Llusar, Rosa,Pedrajas, Elena,Safont, Vicent S.,Algarra, Andres G.,Basallote, Manuel G.
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p. 608 - 614
(2021/01/14)
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- Convenient semihydrogenation of azoarenes to hydrazoarenes using H2
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The high atom-economical and eco-benign nature of hydrogenation reactions make them much more superior to conventional reduction and transfer hydrogenation. Herein, a convenient and highly selective hydrogenation reaction of azoarenes using molecular hydrogen to access diverse hydrazoarenes is reported. The present catalytic method is general and operationally simple, and it operates under exceedingly mild conditions (room temperature and 1 atm of hydrogen pressure). The reusability of catalysts used in this method is also successfully demonstrated.
- Sahoo, Manoj K.,Sivakumar, Ganesan,Jadhav, Sanjay,Shaikh, Samrin,Balaraman, Ekambaram
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p. 5289 - 5293
(2021/06/30)
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- A convenient Hofmann reaction of carboxamides and cyclic imides mediated by trihaloisocyanuric acids
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A simple, efficient and pot-economic approach in a single vessel has been developed for conversion of aromatic and aliphatic carboxamides into primary amines with one fewer carbom atom (Hofmann reaction) in 38–89 % yield by reacting with trichloro- or tribromoisocyanuric acid and sodium hydroxide in aqueous acetonitrile. Under the same reaction conditions, cyclic imides gave amino acids (69–83 %). The role of the trihaloisocyanuric acids is the in situ generation of N-haloamides, key-intermediates for the Hofmann reaction. The scalability of the methodology was demonstrated by a multigram-scale transformation of phthalimide into anthranilic acid in 77 % yield.
- Bastos, Gustavo A.,de Mattos, Marcio C.S.
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- Minimization of Back-Electron Transfer Enables the Elusive sp3 C?H Functionalization of Secondary Anilines
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Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C?H functionalization.
- Zhao, Huaibo,Leonori, Daniele
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supporting information
p. 7669 - 7674
(2021/03/08)
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- Designing of Highly Active and Sustainable Encapsulated Stabilized Palladium Nanoclusters as well as Real Exploitation for Catalytic Hydrogenation in Water
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Abstract: Encapsulated nanoclusters based on palladium, 12-tunstophosphoric acid and silica was designed by simple wet impregnation methodology. The catalyst was found to be very efficient towards cyclohexene hydrogenation up to five catalytic runs with substrate/catalyst ratio of 4377/1 at 50?°C as well as for alkene, aldehyde, nitro and halogen compounds. Graphic Abstract: Silica encapsulated Pd nanoclusters stabilized by 12-tungstophosphoric acid is proved to be sustainable and excellent for water mediated hydrogenation reaction with very high catalyst to substrate ratio as well as TON.[Figure not available: see fulltext.]
- Patel, Anish,Patel, Anjali
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p. 803 - 820
(2020/08/12)
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- Visible-light induced one-pot hydrogenation and amidation of nitroaromatics with carboxylic acids over 2D MXene-derived Pt/N-TiO2/Ti3C2
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Pt nanoparticles supported on N doped titanium dioxide/titanium carbide (MXene) heterojunctions were employed as photocatalysts for the tandem reactions between aromatic nitro compounds and carboxylic acids to produce amide products. The 3%Pt/N-TiO2/Ti3C2 heterojunction was prepared by in situ grew TiO2 on Ti3C2 nanosheets and then N doped TiO2 with melamine, Pt nanoparticles with 3.3 nm mean diameter well dispersed on N-TiO2/Ti3C2. 3%Pt/N-TiO2/Ti3C2 had excellent amidation activity and chemoselectivity under visible-light irradiation. The elevated catalytic performance of 3%Pt/N-TiO2/Ti3C2 was owing to the improvement in photogenerated electron and hole separation efficiency through charge short-range directional transmission caused by the intimate contact between the TiO2 and the conductive Ti3C2. This direct hydrogenation along with amidation between nitroaromatics and carboxylic acids own actual merits in the amides produce with no harmful byproducts. In situ DRIFTS spectra verified that the amidation activation with visible light irradiation at 25 °C was much faster than heating.
- Jiang, Heyan,Hu, Zujie,Gan, Chuan,Sun, Bin,Kong, Shuzhen,Bian, Fengxia
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- Method for catalyzing one-pot hydrogenation and amidation of nitroaromatic hydrocarbon and carboxylic acid by visible light
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The invention discloses a method for catalyzing one-pot hydrogenation and amidation reaction of nitroaromatic hydrocarbon and carboxylic acid by visible light. The method comprises the following steps: preparing Pt nanoparticles uniformly dispersed on an N-doped titanium dioxide/titanium carbide (MXene) heterojunction as a photocatalyst (3% Pt/N-TiO2/Ti3C2), and applying the catalyst to a cascade reaction of an aromatic nitro compound and carboxylic acid to prepare an amide product. The 3% Pt/N-TiO2/Ti3C2 has excellent tandem hydrogenation and amidation activity and chemical selectivity of an aromatic nitro compound and carboxylic acid under the irradiation of visible light. The excellent catalytic performance of 3% Pt/N-TiO2/Ti3C2 is attributed to the close contact of TiO2 and conductive Ti3C2, and the separation efficiency of photo-induced electrons and holes is improved through charge short-range directional transmission. The preparation method of the catalyst is simple and easy to operate, the catalyst can be used for photocatalytic efficient one-pot hydrogenation and amidation reactions, the reaction conditions are mild, and the catalyst is easy to recycle.
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Paragraph 0025
(2021/06/09)
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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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- One-pot synthesis of cyclohexylamine and: N -aryl pyrroles via hydrogenation of nitroarenes over the Pd0.5Ru0.5-PVP catalyst
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The direct synthesis of cyclohexylamine via the hydrogenation of nitrobenzene over monometallic (Pd, Ru or Rh) and bimetallic (PdxRu1-x) catalysts was studied. The Pd0.5Ru0.5-PVP catalyst was the most effective catalyst for this reaction. The catalyst can be reused and applied for the synthesis of N-aryl pyrroles and quinoxalines from nitrobenzenes.
- Chaudhari, Chandan,Sato, Katsutoshi,Ikeda, Yasuyuki,Terada, Kenji,Abe, Naoya,Nagaoka, Katsutoshi
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supporting information
p. 9743 - 9746
(2021/06/15)
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- Ru single atoms for efficient chemoselective hydrogenation of nitrobenzene to azoxybenzene
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Selectivity control of nitrobenzene hydrogenation remains a great challenge, and it is desirable to develop a green and highly efficient catalytic route toward value-added metastable intermediate products. Herein, we reported that isolated Ru single atoms coordinated with oxygen atoms in CeO2(Ru-SAs/CeO2) can achieve chemoselective hydrogenation of nitrobenzene to azoxybenzene with a selectivity of 88.2% in a continuous flow reactor using H2without using any bases or expensive organic reducing agents, while 82.7% aniline selectivity was obtained by Ru nanoparticles. We demonstrated that the unique coordinated structure between Ru single atoms and O atoms preferentially controls the reaction route toward the coupling of nitrosobenzene and phenylhydroxylamine intermediates to form azoxybenzene while greatly suppressing over-hydrogenation. The present work provides an efficient strategy to regulate the reaction pathway of nitrobenzene hydrogenation with a green and industry-friendly process by designing highly dispersed Ru single atoms.
- Huang, Min,Jiang, Zheng,Li, Ji,Lin, Tiejun,Song, Fei,Sun, Fanfei,Sun, Yuhan,Wu, Bo,Yang, Ruoou,Zhang, Huan,Zhong, Liangshu
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supporting information
p. 4753 - 4761
(2021/07/12)
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- Multi-functional aromatic amine compound as well as preparation method and application thereof
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The invention belongs to the technical field of synthesis of aromatic amine compounds, and particularly relates to a multi-functional aromatic amine compound as well as a preparation method and application thereof. The invention provides a multi-functional aromatic amine compound and also provides a preparation method of the multi-functional aromatic amine compound. The amination reaction of aromatic carboxylic acid is catalyzed by DMAP at a relatively low temperature under the condition of no transition metal, and the method can be used for synthesizing a series of multi-functional aromatic amine compounds. The preparation method has not been reported in literature at present. The invention also provides a derivative product of arylamine and a preparation method thereof, and an application of the multi-functional aromatic amine compound in later modification of active molecules. The compound can be used for construction of optical active urea compounds and some important active molecules, and has a development prospect in synthesis of active drugs and natural products.
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- Enhanced strong metal-support interactions between Pt and WO3-xnanowires for the selective hydrogenation ofp-chloronitrobenzene
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WO3-xnanowires with oxygen vacancies synthesized by a hydrothermal method were employed as supports to deposit Pt nanoparticles (NPs)viaa deposition-reduction method with NaBH4. The Pt/WO3-xnanocomposites exhibit an excellent catalytic hydrogenation performance in the selective hydrogenation ofp-chloronitrobenzene due to the interaction between Pt NPs and WO3-xnanowires.
- Yan, Xuedong,Yang, Fan,Yin, Hongfeng,Yu, Hongbo,Yu, Zhiyong
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supporting information
p. 18065 - 18069
(2021/10/12)
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- Catalytic Hydrogenation of Urea Derivatives and Polyureas
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We present herein the catalytic hydrogenation of various urea derivatives to amines and methanol. The reaction is catalyzed by a ruthenium or an iridium Macho pincer complex and produces amine and methanol in very good to excellent yields. Moreover, we also expand this concept to demonstrate the first example of the hydrogenative depolymerization of polyureas to produce diamines and methanol in moderate yields.
- Kumar, Amit,Luk, James
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supporting information
p. 4546 - 4550
(2021/08/30)
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- The benzyl can be selectively removed by visible light or near visible light. Method for protecting allyl and propargyl group
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The invention provides a method for selectively removing benzyl, allyl and propargyl protecting groups by visible light or near visible light, namely a substrate containing benzyl, allyl or propargyl protecting groups. The method has the advantages of simple operation, safe and clean visible light or near visible light as excitation conditions, cheap and easily available reagents, high reaction yield, high reaction chemistry and regional selectivity, and is suitable for selective removal of benzyl, allyl and propargyl protecting groups in various substrates.
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Paragraph 0015
(2021/10/16)
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- Integration of Pd nanoparticles with engineered pore walls in MOFs for enhanced catalysis
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Achieving free-access metal sites with the ability to regulate interactions with substrates is highly desired yet remains a grand challenge in catalysis. Herein, naked Pd nanoparticles were encapsulated inside a metal-organic framework (MOF), giving Pd@MIL-101-NH2. Its activity and selectivity toward de/hydrogenation reactions can be greatly promoted via the MOF pore wall engineering to regulate Pd surrounding microenvironment and substrate adsorption behavior. Creating free-access active sites and regulating their interaction with substrates are crucial for efficient catalysis, yet remain a grand challenge. Herein, naked Pd nanoparticles (NPs) have been encapsulated in a metal-organic framework (MOF), MIL-101-NH2, to afford Pd@MIL-101-NH2. The hydrophobic perfluoroalkyls were post-synthetically modified onto -NH2 group to yield Pd@MIL-101-Fx (x = 3, 5, 7, 11, 15), which engineer the MOF pore walls to regulate Pd surrounding microenvironment and interaction with substrates. As a result, both the dehydrogenation coupling of organosilane and hydrogenation of halogenated nitrobenzenes show that their activity and selectivity can be greatly promoted upon hydrophobic modification due to the favorable substrate enrichment and regulated interactions between Pd and the modified MOF hosts, far surpassing the traditional supported or surfactant-protected Pd NPs. We envision metal NPs@MOF composites would be an ideal platform integrating the inherent activity of well-accessible metal sites with engineered microenvironment via readily tunable MOFs. Regulating the interaction between active sites and substrates is of great importance in catalysis. The common strategy is to modify the surface of active sites (mostly, metal nanoparticles/NPs in heterogeneous catalysts) with diverse molecules, which, unfortunately, is unfavorable to substrate accessibility and, thus, detrimental to activity. Therefore, it is highly desired to develop heterogeneous catalysts featuring naked metal NPs, which are simultaneously able to regulate interaction with substrates. This puts forward long-standing contradictory challenges on metal NP-based catalysts: (1) exposed active sites, requiring naked metal surface, for their good accessibility; (2) functional molecules around active sites, affording tunable interaction with substrates, for enhanced activity and selectivity. To meet the above challenges, we judiciously encapsulate surface-naked metal NPs into MOFs, achieving tunable interaction with substrates by engineering the MOF pore wall microenvironment.
- Li, Luyan,Li, Zhixin,Yang, Weijie,Huang, Yamin,Huang, Gang,Guan, Qiaoqiao,Dong, Yemin,Lu, Junling,Yu, Shu-Hong,Jiang, Hai-Long
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p. 686 - 698
(2021/02/27)
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- Yeast supported gold nanoparticles: an efficient catalyst for the synthesis of commercially important aryl amines
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Candida parapsilosisATCC 7330 supported gold nanoparticles (CpGNP), prepared by a simple and green method can selectively reduce nitroarenes and substituted nitroarenes with different functional groups like halides (-F, -Cl, -Br), olefins, esters and nitriles using sodium borohydride. The product aryl amines which are useful for the preparation of pharmaceuticals, polymers and agrochemicals were obtained in good yields (up to >95%) using CpGNP catalyst under mild conditions. The catalyst showed high recyclability (≥10 cycles) and is a robust free flowing powder, stored and used after eight months without any loss in catalytic activity.
- Krishnan, Saravanan,Patel, Paresh N.,Balasubramanian, Kalpattu K.,Chadha, Anju
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supporting information
p. 1915 - 1923
(2021/02/06)
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- Catalytic Teflon AF-2400 membrane reactor with adsorbed ex situ synthesized Pd-based nanoparticles for nitrobenzene hydrogenation
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Among the unconventional approaches of supporting catalyst nanoparticles, the layer-by-layer assembly of polyelectrolyte multilayers for nanoparticle adsorption represents an easy and convenient method. It enables the deposition of singularly adsorbed nanoparticles and prevents them from aggregating. In this work, polydopamine was grafted onto the internal surface of a Teflon AF-2400 tubular membrane, known for its excellent permeability to light gases and inertness to chemicals. Poly(acrylic acid) and poly(allylamine hydrochloride) were sequentially adsorbed onto the modified surface of the membrane. Ex situ synthesized spherical, cubical, truncated octahedral palladium or dendritic platinum-palladium nanoparticles were then incorporated. The catalytic membranes were assembled in a tube-in-tube configuration and tested over 6 h of continuous nitrobenzene hydrogenation with molecular hydrogen. Stable conversion was observed for the truncated octahedral and dendritic nanoparticles, while a progressive deactivation occurred for the other nanoparticles. Due to their small size, the 3.7 nm spherical nanoparticles exhibited the highest reaction rate, 629molreactant/(molcatalyst?h), while the cubical nanoparticles showed the highest turnover frequency, ～3000 h?1. The reactor concept developed in this work demonstrates how such a design can serve as a platform for conducting continuous multiphase catalytic reactions in flow using singularly adsorbed and finely tuned nanoparticles. The small volume of pressurized gas present in the tube-in-tube reactor offers improved process safety compared to a batch process, while the Teflon AF-2400 membrane provides control over the gas permeation during reaction.
- Venezia, Baldassarre,Panariello, Luca,Biri, Daniel,Shin, Juhun,Damilos, Spyridon,Radhakrishnan, Anand N.P.,Blackman, Chris,Gavriilidis, Asterios
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p. 104 - 112
(2020/04/29)
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- Ligand compound for copper catalyzed aryl halide coupling reaction, catalytic system and coupling reaction
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The invention provides a ligand compound capable of being used for copper catalyzed aryl halide coupling reaction, the ligand compound is a three-class compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group, and the invention also provides a catalytic system for the aryl halide coupling reaction. Thecatalytic system comprises a copper catalyst, a compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group adopted as a ligand, alkali and a solvent, and meanwhile, the invention also provides a system for the aryl halide coupling reaction adopting the catalyst system. The compound containing the 2-(substituted or non-substituted) aminopyridine nitrogen oxygen group can be used as the ligand for the copper catalyzed aryl chloride coupling reaction, and the ligand is stable under a strong alkaline condition and can well maintain catalytic activity when being used for the copper-catalyzed aryl chloride coupling reaction. In addition, the copper catalyst adopting the compound as the ligand can particularly effectively promote coupling of copper catalyzed aryl chloride and various nucleophilic reagents which are difficult to generate under conventional conditions, C-N, C-O and C-S bonds are generated, and numerous useful small molecule compounds are synthesized. Therefore, the aryl halide coupling reaction has a very good large-scale application prospect by adopting the copper catalysis system of the ligand.
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Paragraph 0111-0118
(2021/05/29)
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- METHOD FOR PRODUCING AMINO AROMATIC COMPOUND
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To provide a novel method for producing an amino aromatic compound.SOLUTION: A method for producing a compound (B) having at least one amino group on an aromatic ring, includes at least a step in which a compound (A) at least having an aromatic ring and one group represented by -CR=CH2 [R is a hydrogen atom or a C1-3 alkyl group] on the aromatic ring is reacted with sodium azide in the presence of acid.SELECTED DRAWING: None
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Paragraph 0040-0045
(2021/03/03)
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- Room-temperature copper-catalyzed electrophilic amination of arylcadmium iodides with ketoximes
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We started our study by preparation two ketoximes. Later, there were studies to reveal these ketoximes' effects in the electrophilic amination reaction with organocadmium reagents. Primarily, it was observed that arylcadmium iodides could not be reacted with ketoximes at room temperature in the absence of a catalyst. CuCN was a suitable catalyst for this electrophilic amination reaction of arylcadmium iodides and allowed the preparation of functionalized aniline derivatives in good yields under mild reaction conditions. We obtained the results indicated that the yield of primary arylamines was strongly dependent on the steric and electronic effects of organocadmium reagent and amination agent. In the case of both amination reagents, meta-substituted arylamines were obtained in higher yields than para-substituted arylamines. We observed that acetone O-(4-chlorophenylsulfonyl)oxime, 1, as an aminating agent, was more successful than acetone O-(2-Naphthylsulfonyl)oxime, 2, in the synthesis of functionalized arylamines by electrophilic amination of corresponding aryl cadmium iodides. In this method, there is no cadmium release to the environment.
- Korkmaz, Adem
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p. 3119 - 3125
(2021/05/10)
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- Reductive Formylation of Nitroarenes using HCOOH over Bimetallic C?N Framework Derived from the Integration of MOF and COF
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CoZn embedded C?N framework is prepared by the carbonization of CoZn containing MOF integrated with COF porous architecture in Ar atmosphere. The graphitic nature of porous carbon is confirmed from Raman analysis. The porosity and nanostructure information are retrieved from N2-sorption and transmission electron microscopic analysis, respectively. The incorporation of different metals and their oxidation states and types of nitrogen present in the C?N framework are confirmed from X-ray photoelectron spectroscopy. The basicity of the materials is determined from a CO2-temperature programmed desorption. ZnCo embedded C?N framework exhibits excellent activity in the selective reductive formylation using HCOOH. For comparison, more than 15 materials are prepared, and their activities are compared. Several control experiments are performed to establish a structure-activity relation. The recycling experiment, hot-filtration test, and poisoning experiment demonstrate the metal embedded porous C?N framework‘s recyclability and stability. A reaction mechanism for the reductive N-formylation of nitroaromatics is presented based on structure-activity relationship, control reactions, and physicochemical characterizations. The development of interesting MOF-COF-derived metal nanoclusters embedded C?N framework for selective reductive formylation of nitroaromatics using formic acid will be highly attractive to catalysis researchers and industrialists.
- Kumar Kar, Ashish,Srivastava, Rajendra
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p. 3174 - 3183
(2021/05/27)
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- Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
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The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
- Liu, Xin,Werner, Thomas
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p. 10590 - 10597
(2021/08/20)
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- The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
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An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium. A range of carbon materials has been tested as carbocatalysts. To our surprise, graphite was found to be the best catalyst in terms of the turnover frequency. A broad range of valuable substituted aromatic compounds, i.e., phenols, anilines, nitroarenes, and haloarenes, has been prepared via the functionalization of the C-B bond into C-N, C-O, and many other C-X bonds. The vital role of the aromatic π-conjugation system of graphite in this protocol has been established and was observed via numerous analytic techniques. The heterogeneous nature of graphite facilitates the high recyclability of the carbocatalyst. This effective and easy system provides a multipurpose approach for the production of valuable substituted aromatic compounds without using any metals, ligands, bases, or harsh oxidants.
- Badgoti, Ranveer Singh,Dandia, Anshu,Parewa, Vijay,Rathore, Kuldeep S.,Saini, Pratibha,Sharma, Ruchi
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p. 18040 - 18049
(2021/05/29)
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- High yielding electrophilic amination with lower order and?higher order organocuprates: Application of acetone O-(4-Chlorophenylsulfonyl)oxime in the construction of the C?N bond at room temperature
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Electrophilic amination reaction was performed with lower order and?higher order organocuprates using acetone O-(4-Chlorophenylsulfonyl)oxime (1). It was proceeded smoothly at room temperature in the presence of organocuprates to provide the corresponding primary amines in good yields with 10 and 60 min, respectively. The primary amine yields of the electrophilic amination of bromomagnesium organocyanocuprates and dibromomagnesium diorganocyanocuprates were obtained 52–72% and 58–83%, respectively. We observed that higher order organocuprates were more successful than lower order organocuprates in the synthesis of functionalized arylamines by electrophilic amination.
- Duran, Serdar,Korkmaz, Adem
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p. 2077 - 2087
(2021/05/27)
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- Direct synthesis of imines from nitro compounds and biomass-derived carbonyl compounds over nitrogen-doped carbon material supported Ni nanoparticles
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The selective synthesis of imines from biomass-derived chemicals over heterogeneous non-noble metal catalysts is of great importance for organic transformation. Herein, non-noble heterogeneous nitrogen-doped carbon supported Ni catalysts (abbreviated as Ni/CN-MgO-T, whereTrepresents the pyrolysis temperature) have been facilely prepared from the simple pyrolysis of Ni precursors and biomass, and Ni/CN-MgO-600 with the smallest size of Ni nanoparticles demonstrated the highest catalytic activity. The reductive coupling of nitroarenes and carbonyl compounds could be performed under mild conditions (80 °C, and 10 bar H2), affording structurally-diverse imines with high to excellent yields (84.2-98.1%). Thanks to the mild reaction conditions, the developed method showed good tolerance to other functional groups such as nitriles, halogen and vinyl groups.
- Li, Bo,Wang, Yanxin,Chi, Quan,Yuan, Ziliang,Liu, Bing,Zhang, Zehui
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p. 4464 - 4471
(2021/03/15)
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- Stable Ni catalyst encapsulated in N-doped carbon nanotubes for one-pot reductive amination of nitroarenes with aldehydes
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A novel strategy involving a popping process and carbothermal reduction was developed to create a kind of stable nickel catalyst (Ni-NC). The popping process of the mixture being composed of carbon nitride (C3N4) and nickel nitrate decomposed the nickel nitrate into nickel (oxide) nanoparticles that afterwards functioned as catalyst to grow N-containing carbon nanotubes with carbon nitride as N-containing carbon source. Finally, the nickel catalyst possessed a special structure of nanoparticles encapsulated in N-doped carbon nanotubes. This special structure is helpful to prevent nickel nanoparticles from being oxidized in air for months so that the catalyst exhibits high stability in air atmosphere. As a practical application, this encapsulated nickel catalyst exhibited excellent catalytic activity and stability in one-pot cascade reaction involving nitro-reduction and reductive amination of nitroarenes.
- Cui, Penglei,Gao, Yongjun,Liu, Yaru,Shang, Ningzhao,Wang, Chun,Xu, Yuzhu
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- Photocatalytic one-pot multidirectional N-alkylation over Pt/D-TiO2/Ti3C2: Ti3C2-based short-range directional charge transmission
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Visible-light-induced one-pot, multistep, and chemoselectivity adjustable reactions highlight the economical, sustainable, and green process. Herein, we report Pt nanoparticles dispersed on S and N co-doped titanium dioxide/titanium carbide (MXene) (3%Pt/
- Jiang, Heyan,Sheng, Meilin,Li, Yue,Kong, Shuzhen,Bian, Fengxia
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- Highly Active Ni Nanoparticles on N-doped Mesoporous Carbon with Tunable Selectivity for the One-Pot Transfer Hydroalkylation of Nitroarenes with EtOH in the Absence of H2
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Cost-effective and environmentally friendly conversion of nitroarenes into value-added products is desirable but still challenging. In this work, highly dispersed Ni nanoparticles (NPs) supported on N-doped mesoporous carbon (Ni/NC-x) were synthesized via novel ion exchange-pyrolysis strategy. Their catalytic performance was investigated for one-pot transfer hydroalkylation of nitrobenzene (NB) with EtOH in absence of H2. Interestingly, the catalytic performance could be easily manipulated by tuning the morphology and electronic state of Ni NPs via varying the pyrolysis temperature. It was found that the Ni/NC-650 achieved 100 % nitrobenzene conversion and approx. 90 % selectivity of N,N-diethyl aniline at 240 °C for 5 h, more active than those of homogeneous catalysts or supported Ni catalysts prepared by impregnation (Ni/NC-650-IM, Ni/SiO2). This can be ascribed to the higher dispersion and better reducibility as well as richer surface basicity of the catalyst. More interestingly, the Ni/NC-650 catalyst achieved complete conversion of various nitroarenes, yielding imines, secondary amines, or tertiary amines selectively by simply controlling the reaction temperature at 180, 200 and 240 °C, respectively. The one-pot hydrogen-free process with non-noble metal catalysts, as demonstrated in this work, shows great promise for selective conversion of nitroarenes with ethanol to various anilines at industrial scale, from an economic, environmental, and safety viewpoint.
- Tao, Yuewen,Nie, Yunqing,Hu, Haitao,Wang, Ke,Chen, Yi,Nie, Renfeng,Wang, Jianshe,Lu, Tianliang,Zhang, Yongsheng,Xu, Chunbao Charles
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p. 4243 - 4250
(2021/08/20)
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- Synthesis of Substituted Anilines from Cyclohexanones Using Pd/C-Ethylene System and Its Application to Indole Synthesis
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The synthesis of anilines and indoles from cyclohexanones using a Pd/C-ethylene system is reported. A simple combination of NH4OAc and K2CO3 under nonaerobic conditions was found to be the most suitable to perform this reaction. Hydrogen transfer between cyclohexanone and ethylene generates the desired products. The reaction tolerates a variety of substitutions on the starting cyclohexanones.
- Maeda, Katsumi,Matsubara, Ryosuke,Hayashi, Masahiko
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supporting information
p. 1530 - 1534
(2021/03/08)
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