• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2644-2648
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• 2010

Catalytic conversion of structurally different epoxides to the corresponding 1,2-diacetoxy esters was carried out readily with phosphomolybdic acid alone or its supported on $SiO_2$. The reactions were carried out under solvolytic or solvent free conditions within 5-15 min at room temperature. The product 1,2-diacetates were obtained in high to excellent yields. Supporting of phosphomolybdic acid on $SiO_2$ showed the better catalytic activity than $Al_2O_3$. Conversion of optically pure R-(+)-styrene oxide to S-(+)-1,2-diacetoxy-1-phenylethane was carried with phosphomolybdic acid in high yield and stereospecificity.

• Bulletin of the Korean Chemical Society
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• 제30권3호
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• pp.551-555
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• 2009

The ytterbium catalyst immobilized on the cross-linked poly(4-vinylpyridine/styrene) copolymer (P/S-Yb) was applied in the Mannich-type, three component one-pot synthesis of $\beta$-aminoketones. This catalytic system showed excellent catalytic activity and selectivity which resulted in the exclusive formation of $\beta$-aminoketone. The applicability of this immobilized catalyst system was shown by the reusability test and again highlighted by the synthesis of a $\beta$-aminoketone library using a broad range of substrates.

• Bulletin of the Korean Chemical Society
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• 제12권1호
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• pp.17-22
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• 1991

Fourier transform infrared spectroscopy has been applied to the characterization of titania supported molybdena. The equilibrium adsorption method seemed to produce molybdena species homogeneously dispersed on the support. Even under an oxidizing environment, molybdena species appeared to be able to possess coordinatively unsaturated $Mo^{5+}$ ions owing to the natures of TiO$_2$, i.e. oxygen deficiency and permeability toward oxygen diffusion. At the initial stage of reduction, the terminal double bond oxygen ( Mo=O ) seemed to be removed, generating presumably $Mo^{4+}$. The carbonyl bands at 2198 and 2190 $cm^{-1}$ observed after CO exposure were attributed to the $Mo^{5+}{\cdots}CO\;and\;Mo^{4+}\;{\cdots}CO$ complexes, respectively, while the band pair at 2136 and 2076 $cm^{-1}$ to $Mo^{4+}(CO)_2$.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.380-386
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• 2018

A sustainable method was developed for the upgrade of biomass derived vanillin (a typical model compound of lignin) into the potential liquid biofuels over a layered double hydroxide supported Pd catalyst (abbreviated as CoAl-LDH/Pd). The CoAl-LDH/Pd catalyst showed high catalytic activity towards the hydrodeoxygenation of vanillin into 2-methoxy-4-methylphenol (MMP) under mild conditions in aqueous media. High MMP yield up to 86% was produced at $120^{\circ}C$ after 4 h. Kinetic studies revealed that the rate-determining step for the hydrodeoxygenation of vanillin was the hydrogenolysis of vanillyl alcohol. More importantly, the CoAl-LDH/Pd catalyst was highly stable without the loss of activity.

• Journal of Electrochemical Science and Technology
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• 제14권3호
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• pp.243-251
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• 2023

Developing oxygen evolution reaction (OER) electrocatalysts is essential to accomplish viable CO₂ and water electrolysis. Herein, we report the fabrication and OER performance of Ni-foam (NF)-immobilized Ni₆ nanoclusters (NCs) (Ni₆/NF) prepared by a dip-coating process. The Ni₆/NF electrode exhibited a high current density of 500 mA/cm² for the OER at an overpotential as low as 0.39 V. Ni₆/NF exhibited high durability in an alkaline solution without corrosion. Electrokinetic studies revealed that OER can be easily initiated on Ni6 NC with fast electron-transfer rates. Finally, we demonstrated stable CO₂-to-CO electroreduction using an NC-based zero-gap CO₂ electrolyzer operated at a current density of 100 mA/cm² and a full-cell potential of 2.0 V for 12 h.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1887-1890
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• 2010

Cross-linked polystyrene supported aluminium triflate (Ps-Al(OTf)$_3$) was found to be an efficient and chemoselective heterogeneous Lewis acid catalyst for the direct conversion of arenes to sulfones using sulfonic acids as sulfonylating agents. The solid acid catalyst is stable (as a bench top catalyst) and can be easily recovered and reused without appreciable change in its efficiency.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3156-3158
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• 2010

Stable and non-hygroscopic polystyrene supported aluminium triflate (Ps-$Al(OTf)_3$), which is prepared easily from cheap and commercially available compounds was found to be an environmentally friendly heterogeneous catalyst for Friedel-Crafts acylation of arenes using acid chlorides in the absence of solvent under mild reaction conditions. The catalyst can be reused up to five times after simple washing with dichloromethane.

• 대한화학회지
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• 제27권5호
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• pp.376-381
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• 1983

540$^{\circ}C$에서 탄소에 분산된 니켈 입자를 제조하여 니켈 덩어리 및 산화 마그네슘에 지지된 니켈 입자의 자기 특성과 상호 비교 검토하였다. 환원대기에 무관하게 니켈은 탄소와 반응함을 알 수 있었다. 또한 니켈-탄소간의 상호작용 가능성에 관하여 논의하였다.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1979-1984
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• 2014

We have developed an efficient method to generate highly active Pd and PdO nanoparticles (NPs) dispersed on graphene and graphene oxide (GO) by an impregnation method combined with thermal treatments in $H_2$ and $O_2$ gas flows, respectively. The Pd NPs supported on graphene (Pd/G) and the PdO NPs supported on GO (PdO/GO) demonstrated excellent carbon-carbon cross-coupling reactions under a solvent-free, environmentally-friendly condition. The morphological and chemical structures of PdO/GO and Pd/G were fully characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). We found that the remarkable reactivity of the Pd/G and PdO/GO catalysts toward the cross-coupling reaction is attributed to the high degree of dispersion of the Pd and PdO NPs while the oxidative states of Pd and the oxygen functionalities of graphene oxide are not critical for their catalytic performance.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.311-317
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• 2003

Vanadium oxides supported on zirconia and modified with MoO₃were prepared by adding Zr(OH)₄powder into a mixed aqueous solution of ammonium metavanadate and ammonium molybdate followed by drying and calcining at high temperatures. The characterization of prepared catalysts was performed using FTIR, Raman spectroscopy and solid-state $^{51}V$ NMR. In the case of a calcination temperature of 773 K, for samples containing low loading of $V_2O_5$, below 15 wt %, vanadium oxide was in a highly dispersed state, while for samples containing high loading of $V_2O_5$, equal to or above 15 wt %, vanadium oxide was well crystallized because the $V_2O_5$ loading exceeded the formation of a monolayer on the surface of $ZrO_2$. The $ZrV_2O_7$ compound was formed through the reaction of $V_2O_5\;and\;ZrO_2$ at 873 K and the compound decomposed into $V_2O_5\;and\;ZrO_2$ at 1073 K, which were confirmed by FTIR spectroscopy and solid-state $^{51}V$ NMR. IR spectroscopic studies of ammonia adsorbed on $V_2O_5-MoO_3/ZrO_2$ showed the presence of both Lewis and Bronsted acids.