Highly active organosilane-based N-heterocyclic carbene-palladium complex immobilized on silica particles for the Suzuki reaction

1-Methyl-3-(3-trimethoxysilylpropyl)imidazolium chloride, [TMSPIM][Cl-], was synthesized as a precursor of N-heterocyclic carbene (NHC), which can be coordinated with palladium to give an organosilane-based bidentic NHC-Pd complex. The organosilane-based NHC-Pd complex was immobilized covalently on silica particles (NHC-Pd/silica) and then characterized by field emission/scanning electron microscopy (FE/SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIRS), and inductively coupled plasma/atomic emission spectroscopy (ICP/AES). The Suzuki reaction was performed as a model reaction to examine the catalytic activity of NHC-Pd/silica. NHC-Pd/silica exhibited excellent performance in the Suzuki reaction of various aryl halide derivatives (except for aryl chloride derivatives) with phenylboronic acid under mild conditions (room temperature and short reaction time). Moreover, the catalyst was recycled several times without any significant loss of catalytic activity in the Suzuki reaction.

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Environmentally benign and effective syntheses of N-substituted carbamates via alcoholysis of disubstituted ureas over TiO2/SiO2 catalyst

Pure and Applied Chemistry ◽

10.1351/pac-con-11-05-06 ◽

2011 ◽

Vol 84 (3) ◽

pp. 461-471 ◽

Cited By ~ 2

Author(s):

Liguo Wang ◽

Jianpeng Shang ◽

Shimin Liu ◽

Lequan Liu ◽

Shiguo Zhang ◽

...

Keyword(s):

Electron Microscopy ◽

Catalytic Activity ◽

Inductively Coupled Plasma ◽

Atomic Emission ◽

Tetrabutyl Titanate ◽

Impregnation Method ◽

Inductively Coupled ◽

Strong Acidity ◽

Temperature Programmed ◽

Halogen Free

Catalytic syntheses of cyclohexyl carbamates via alcoholysis of dicyclohexyl urea (DCU), which can be synthesized from CO2 and amines, were first investigated with low-molecular-weight alcohols, i.e., methanol, ethanol, butan-1-ol. TiO2/SiO2 catalyst was prepared by wet impregnation method using tetrabutyl titanate as titanium source. The catalyst was characterized by inductively coupled plasma/atomic emission spectroscopy (ICP/AES), N2 adsorption, X-ray diffraction (XRD), field emission/scanning electron microscopy (FE/SEM), transmission electron microscopy TEM), and NH3/temperature-programmed desorption (TPD) in detail. TiO2/SiO2 with 5 wt % loadings and calcination at 600 °C exhibited better catalytic activity, and excellent yields of >95 % with 98 % selectivities for desired carbamates were achieved. Accordingly, the strong acidity was considered to be responsible for its superior activity. Moreover, the catalytic activity can essentially be preserved during the recycling tests. The scope was also expanded to synthesize other alkyl or aryl carbamates via alcoholysis of the corresponding disubstituted ureas, and 94 % yields with 96 % selectivities can be achieved. It provided a good candidate for the organic carbamates syntheses via a phosgene/halogen-free and effective route.

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Improved Catalytic Durability of Pt-Particle/ABS for H2O2 Decomposition in Contact Lens Cleaning

Nanomaterials ◽

10.3390/nano9030342 ◽

2019 ◽

Vol 9 (3) ◽

pp. 342 ◽

Cited By ~ 1

Author(s):

Yuji Ohkubo ◽

Tomonori Aoki ◽

Satoshi Seino ◽

Osamu Mori ◽

Issaku Ito ◽

...

Keyword(s):

Catalytic Activity ◽

Surface Charge ◽

Contact Lens ◽

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Pt Nanoparticles ◽

Acrylonitrile Butadiene Styrene ◽

Atomic Emission ◽

Cross Sectional ◽

H2o2 Decomposition

In a previous study, Pt nanoparticles were supported on a substrate of acrylonitrile–butadiene–styrene copolymer (ABS) to give the ABS surface catalytic activity for H2O2 decomposition during contact lens cleaning. Although the Pt-particle/ABS catalysts exhibited considerably high specific catalytic activity for H2O2 decomposition, the catalytic activity decreased with increasing numbers of repeated usage, which meant the durability of the catalytic activity was low. Therefore, to improve the catalytic durability in this study, we proposed two types of pretreatments, as well as a combination of these treatments before supporting Pt nanoparticles on the ABS substrate. In the first method, the ABS substrate was etched, and in the second method, the surface charge of the ABS substrate was controlled. A combination of etching and surface charge control was also applied as a third method. The effects of these pretreatments on the surface morphology, surface chemical composition, deposition behavior of Pt particles, and Pt loading weight were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), cross-sectional SEM, and inductively coupled plasma atomic emission spectroscopy (ICP-AES), respectively. Both etching and controlling the surface charge effectively improved the catalytic durability for H2O2 decomposition. In addition, the combination treatment was the most effective.

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Facile Green Preparation of Rhodium Nanoclusters Supported Nano-Scaled Graphene Platelets for Sonogashira Coupling Reaction and Reduction of p-Nitrophenol

Catalysts ◽

10.3390/catal9110908 ◽

2019 ◽

Vol 9 (11) ◽

pp. 908 ◽

Cited By ~ 2

Author(s):

Gopiraman Mayakrishnan ◽

Saravanamoorthy Somasundaram ◽

Sana Ullah ◽

Ilangovan Andivelu ◽

Kim Ick Soo ◽

...

Keyword(s):

Catalytic Activity ◽

Electron Microscope ◽

Inductively Coupled Plasma ◽

Coupling Reaction ◽

Significant Loss ◽

Sonogashira Coupling ◽

Inductively Coupled ◽

Sonogashira Coupling Reaction ◽

Graphene Platelets ◽

Means Of Transmission

Rhodium nanoclusters were uniformly dispersed on nano-scaled graphene platelets by a simple ‘mix and heat’ method without using any toxic reagents. Distilled water was used to obtain the homogenous dispersion of Rh-nanoclusters on graphene platelets. The morphology of the resultant catalyst (Rh(0)NCs/GNPs) was studied by means of transmission electron microscope (TEM) and atomic force microscope (AFM) analyses. The X-ray photoemission spectroscope (XPS) result confirmed the metallic form of Rh-nanoclusters in Rh(0)NCs/GNPs. The crystalline property and the interaction between Rh-nanoclusters and graphene platelets (GNPs) were studied by means of XRD and Raman analysis. The Rh-loading in Rh(0)NCs/GNPs was confirmed by scanning electron microscope and energy dispersive spectroscope (SEM-EDS) and inductively coupled plasma-mass spectroscope (ICP-MS) analysis. After being optimized, the Rh(0)NCs/GNPs used as catalyst for the reduction of 4-nitrophenol with NaBH4 and the Sonogashira coupling reaction between iodobenzene with phenylacetylene. To our delight, the Rh(0)NCs/GNPs showed excellent catalytic activity towards the reduction of 4-nitrophenol with an excellent turnover frequency (TOF) value of 112.5 min−1. The kapp and k’ values were calculated to be 62.07 × 10−3 min−1(0.002 mg of Rh(0)NCs/GNPs) and 31035 × 10−3 mg−1 min−1,respectively. Alike, under the optimal conditions, the Rh(0)NCs/GNPs gave the desired product, diphenylacetylene, in a good yield of 87% with 91% selectivity. The Rh(0)NCs/GNPs can be reused without significant loss in its catalytic activity.

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Treatment of fly ash from power plants using thermal plasma

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.8.105 ◽

2017 ◽

Vol 8 ◽

pp. 1043-1048 ◽

Cited By ~ 4

Author(s):

Sulaiman Al-Mayman ◽

Ibrahim AlShunaifi ◽

Abdullah Albeladi ◽

Imed Ghiloufi ◽

Saud Binjuwair

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Fly Ash ◽

Thermal Plasma ◽

Inductively Coupled Plasma ◽

Power Plants ◽

Plasma Reactor ◽

Atomic Emission ◽

Inductively Coupled ◽

Scanning Electron

Fly ash from power plants is very toxic because it contains heavy metals. In this study fly ash was treated with a thermal plasma. Before their treatment, the fly ash was analyzed by many technics such as X-ray fluorescence, CHN elemental analysis, inductively coupled plasma atomic emission spectroscopy and scanning electron microscopy. With these technics, the composition, the chemical and physical proprieties of fly ash are determined. The results obtained by these analysis show that fly ash is mainly composed of carbon, and it contains also sulfur and metals such as V, Ca, Mg, Na, Fe, Ni, and Rh. The scanning electron microscopy analysis shows that fly ash particles are porous and have very irregular shapes with particle sizes of 20–50 μm. The treatment of fly ash was carried out in a plasma reactor and in two steps. In the first step, fly ash was treated in a pyrolysis/combustion plasma system to reduce the fraction of carbon. In the second step, the product obtained by the combustion of fly ash was vitrified in a plasma furnace. The leaching results show that the fly ash was detoxified by plasma vitrification and the produced slag is amorphous and glassy.

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Photocatalytic Oxidation of Alcohols Over Magnetically Recoverable Gold Supported Iron Oxide Nanoparticles

Science of Advanced Materials ◽

10.1166/sam.2019.3608 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1731-1738 ◽

Cited By ~ 2

Author(s):

Ma Hui ◽

Wu Juzhen ◽

Zhao Li ◽

Zhou Zheng ◽

Guo Jiahu

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Photocatalytic Oxidation ◽

Organic Dyes ◽

Atomic Emission ◽

One Pot ◽

X Ray ◽

Inductively Coupled ◽

Oxidation Of Alcohols

A one-pot simple and efficient synthetic route for the synthesis of Au-loaded Fe2O3 nanoparticles was developed, and this material's photocatalytic activity for visible light assisted oxidation of alcohols and degradation of organic dye were studied. As-synthesized nanostructured catalyst was characterised by powder X-ray diffraction (XRD), transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), SEM-mapping, X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption isotherm (BET), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). It was observed that 5–10 nm Au-nanoparticles supported on 10–80 nm Fe2O3 shows boomerang-shaped nanoparticle. Gold loading of 1 wt% shows high conversion and selectivity towards the target product aldehyde. The synthesized nanomaterial also proved to be an excellent photocatalyst for degradation of organic dyes such as methylene blue (MB) and rhodamine B (RhB). The catalyst proved to be noteworthy as it does not loss in its catalytic activity even after five cycles of reuse.

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Antiphotocorrosive photocatalysts containing CdS nanoparticles and exfoliated TiO2 nanosheets

Journal of Materials Research ◽

10.1557/jmr.2010.0007 ◽

2010 ◽

Vol 25 (1) ◽

pp. 182-188 ◽

Cited By ~ 32

Author(s):

Xiaoxia Yan ◽

Gang Liu ◽

Lianzhou Wang ◽

Yong Wang ◽

Xianfang Zhu ◽

...

Keyword(s):

Electron Microscopy ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Self Assembly ◽

Inductively Coupled Plasma ◽

Atomic Emission ◽

Cds Nanoparticles ◽

Visible Absorption ◽

X Ray ◽

Tio2 Nanosheets

Aimed at designing an efficient visible light active photocatalyst and suppressing the self-corrosion tendency of CdS nanoparticles, a novel composite consisting of CdS nanoparticles and exfoliated two-dimensional (2D) TiO2 nanosheets was successfully fabricated using a simple self-assembly process. The prepared samples were characterized using various techniques including x-ray diffraction, ultraviolet–visible absorption spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. It was found that the exfoliated 2D nanosheets played an important role as an ultrathin coating to suppress the photocorrosion of CdS nanoparticles, evidenced by inductively coupled plasma-atomic emission spectrometer analysis. The resultant CdS/TiO2 composites exhibited enhanced photocatalytic activity in the oxidation of Rhodamine B in water under visible light irradiation (λ > 420 nm).

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Study of Deactivation in Suzuki Reaction of Polymer-Stabilized Pd Nanocatalysts

Processes ◽

10.3390/pr8121653 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1653

Author(s):

Linda Nikoshvili ◽

Elena S. Bakhvalova ◽

Alexey V. Bykov ◽

Alexander I. Sidorov ◽

Alexander L. Vasiliev ◽

...

Keyword(s):

Catalytic Activity ◽

Catalyst Deactivation ◽

Phenylboronic Acid ◽

Suzuki Reaction ◽

Cross Coupling ◽

Catalyst Stability ◽

Separation Procedure ◽

Amino Groups ◽

Highly Active ◽

Hydrophobic Nature

This work is addressed to the phenomenon of catalyst deactivation taking place during the repeated uses in the reaction of Suzuki-Miyaura (S-M) cross-coupling, which is widely applied in industry for C-C bond formation. Ligandless catalysts based on Pd(0) NPs supported on hyper-cross-linked polystyrene (HPS) of two types (non-functionalized and bearing tertiary amino groups) were studied in a model S-M reaction between 4-bromoanisole and phenylboronic acid. Synthesized catalysts were shown to be highly active under mild reaction conditions. HPS allows stabilization of Pd(0) NPs and prevents their agglomeration and detectable Pd leaching. However, the loss of catalytic activity was observed during recycling. The deactivation issue was assigned to the hydrophobic nature of non-functionalized HPS, which allowed a strong adsorption of cross-coupling product during the catalyst separation procedure. A thorough washing of Pd/HPS catalyst by hydrophobic solvent was found to improve to the big extent the observed catalytic activity, while the replacement of non-functionalized HPS by a one containing amino groups increased the catalyst stability at the expense of their activity.

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QuadraPure-Supported Palladium Nanocatalysts for Microwave-Promoted Suzuki Cross-Coupling Reaction under Aerobic Condition

The Scientific World JOURNAL ◽

10.1155/2014/796196 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 7

Author(s):

Kin Hong Liew ◽

Poh Lee Loh ◽

Joon Ching Juan ◽

Mohd Ambar Yarmo ◽

Rahimi M. Yusop

Keyword(s):

Catalytic Activity ◽

Mechanical Stability ◽

Physical Adsorption ◽

Phenylboronic Acid ◽

Reduction Process ◽

Cross Coupling ◽

Aerobic Condition ◽

Significant Loss ◽

Coupling Reactions ◽

Palladium Nanocatalysts

Cross-linked resin-captured palladium (XL-QPPd) was readily prepared by simple physical adsorption onto the high loading QuadraPure macroporous resin and a subsequent reduction process. To enhance the mechanical stability, entrapped palladium nanocatalysts were cross-linked with succinyl chloride. Both transmission electron microscopy images and X-ray diffraction analysis revealed that the palladium nanoparticles were well dispersed with diameters ranging in 4–10 nm. The catalyst performed good catalytic activity in microwave-promoted Suzuki cross-coupling reactions in water under aerobic condition with mild condition by using various aryl halides and phenylboronic acid. In addition, the catalyst showed an excellent recyclability without significant loss of catalytic activity.

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INFLUENCE OF THE AROMATIC POLYMERIC MATRIX TYPE ON STABILITY OF NANOSIZED PALLADIUM CATALYSTS IN SUZUKI REACTION

Physical and Chemical Aspects of the Study of Clusters Nanostructures and Nanomaterials ◽

10.26456/pcascnn/2020.12.775 ◽

2020 ◽

pp. 775-783

Author(s):

Елена Сергеевна Бахвалова ◽

Алексей Владимирович Быков ◽

Александр Иванович Сидоров ◽

Линда Жановна Никошвили ◽

Lioubov Kiwi-Minsker

Keyword(s):

Palladium Catalysts ◽

Aryl Halide ◽

Phenylboronic Acid ◽

Suzuki Reaction ◽

Cross Coupling ◽

Polymeric Matrix ◽

Catalyst Stability ◽

Water Mixture ◽

Strong Adsorption ◽

Crosslinked Polystyrene

Данная работа посвящена исследованию влияния типа полимерной матрицы сверхсшитого полистирола на активность и стабильность палладиевых катализаторов кросс-сочетания Сузуки. Показано, что применение сверхсшитого полистирола, функционализированного третичными аминогруппами, может быть перспективным с точки зрения обеспечения стабильности катализатора при рециклах, однако для достижения 100 % конверсии арилгалогенида (4 - броманизола) требуется применение сильного избытка фенилбороновой кислоты и основания. Катализатор на основе нефункционализированного сверхсшитого полистирола обладает более высокой активностью и позволяет, используя полуторакратный избыток фенилбороновой кислоты, достичь полной конверсии 4 - броманизола за 60 мин реакции в мягких условиях (70 °С, растворитель - смесь этанола и воды в соотношении 5:1). Недостатком такой системы является сильная адсорбция продукта кросс-сочетания в гидрофобной полимерной матрице. This work is devoted to the study of the influence of the type of polymeric matrix of hyper-crosslinked polystyrene on activity and stability of palladium catalysts of Suzuki cross-coupling. The use of the hyper-crosslinked polystyrene functionalized with tertiary amino groups was shown to be promising in terms of ensuring of the catalyst stability during recycles, but in order to achieve 100 % conversion of aryl halide (4 - bromanisole) the use of strong excess of phenylboronic acid and of a base is required. The catalyst based on non-functionalized hyper-crosslinked polystyrene had higher activity and allowed achieving complete conversion of 4 - bromanisole during the reaction under mild conditions (70 °C, ethanol and water mixture is in the ratio of 5 : 1 as a solvent) while using 1,5 - fold excess of phenylboronic acid. However, strong adsorption of the cross-coupling product in a hydrophobic polymeric matrix was found to be a disadvantage of such a system.

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Y-Modified MCM-22 Supported PdOx Nanocrystal Catalysts for Catalytic Oxidation of Toluene

Catalysts ◽

10.3390/catal9110902 ◽

2019 ◽

Vol 9 (11) ◽

pp. 902 ◽

Cited By ~ 3

Author(s):

Zhu Chen ◽

Danna Situ ◽

Jie Zheng ◽

Zhen Cheng ◽

Zhuo Wang ◽

...

Keyword(s):

Electron Microscopy ◽

Catalytic Oxidation ◽

Inductively Coupled Plasma ◽

Atomic Emission ◽

Catalytic Performance ◽

High Dispersion ◽

X Ray ◽

Practical Applications ◽

Inductively Coupled ◽

Chlorine Poisoning

A series of rare earth elements (REEs)-modified and Mobil Composition of Matter (MCM)-22-supported Pd nanocrystal catalysts were synthesized via a high-temperature solution-phase reduction method and tested for toluene complete oxidation. These catalytic materials were systematically characterized by N2 adsorption/desorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), temperature-programmed surface reaction of toluene (toluene-TPSR) and X-ray photoelectron spectroscopic (XPS) techniques in order to investigate the structure–catalytic property relationship. Moreover, catalysts with an appropriate yttrium content greatly improved the catalytic activity of 0.2%Pd/MCM-22. PdOx (x = 0, 1) nanoparticles, ranging from 3.6 to 6.8 nm, which were well distributed on the surface of MCM-22. Efficient electron transfer from the Pd2+/Pd0 redox cycle facilitated the catalytic oxidation process, and the formation of Pd (or Y) –O–Si bonds improved the high dispersion of the PdOx and Y2O3 particles. Toluene–TPSR experiments suggested that the addition of Y2O3 improved the physical/chemical adsorption of 0.2%Pd/MCM-22, thus increasing the toluene adsorption capacity. Then, 0.2%Pd/7.5%Y/MCM-22 exhibited the highest catalytic performance. In addition, this catalyst maintained 95% conversion with high resistance to water and chlorine poisoning, even after toluene oxidation at 210 °C for 100 h, making it more valuable in practical applications.

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