• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.128-134
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• 2016

Due to the great development made in converting the shale gas into the more valuable products, research and commercialization for production technology of olefins like propylene, butenes, butadiene from light alkanes have been intensively investigated. Especially the technology using oxygen like oxidative dehydrogenation or selective hydrogen combustion to overcome thermodynamic limit of direct dehydrogenation conversion has been extensively studied and some cases of applying this technology to the plant scale was reported. In this review, we have categorized the technology into two parts; gas phase oxygen utilization technology and lattice oxygen utilization technology. The trends, results and future direction of the technology are discussed.

• Journal of the Korean Chemical Society
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• v.19 no.6
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• pp.423-427
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• 1975

Changes in the electrical conductivity of gallium doped zinc oxide during the dehydrogenative oxidation of ethanol between 250 and $350^{\circ}C$ have been studied. Both dehydrogenation and dehydration of ethanol takes place on ZnO. At $300^{\circ}C$ and above formation of $CO_2$ was observed accompanied by an increase in the electrical conductivity. This seems to be due to oxidation of CO formed by the decomposition of acetaldehyde. Addition of oxygen to ethanol increases the amount of acetaldehyde formed, while no change is observed in ethylene formation. It may be that oxygen which is present primarily as $O^-$ provides a favorable site for the adsorption of ethanol and for subsequent hydrogen substraction.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.401-410
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• 2016

The $Pt-Sn/Al_2O_3$ catalysts mixed with metal oxides for propane dehydrogenation were studied. $Cu-Mn/{\gamma}-Al_2O_3$, $Ni-Mn/{\gamma}-Al_2O_3$, $Cu/{\alpha}-Al_2O_3$ was prepared and mixed with $Pt-Sn/Al_2O_3$ to measure the activity for propane dehydrogenation. As standard sample, $Pt-Sn/Al_2O_3$ catalyst mixed with glassbead was adopted. In the case of catalytic activity test after non-reductive pretreatment of catalyst and metal oxide, $Pt-Sn/Al_2O_3$ mixed with $Cu-Mn/{\gamma}-Al_2O_3$ showed higher conversion of 15% and similar selectivity at $576.5^{\circ}C$, compared to conversion of 8% in standard sample. In the case of catalytic activity test after reductive pretreatment of catalyst and metal oxde, $Cu/{\alpha}-Al_2O_3$ showed higer yield than standard sample. But, increase of yield of most of samples after reductive pretreatment was not significant, so it was found that lattice oxygen of $Cu-Mn/{\gamma}-Al_2O_3$ is effective to propane dehydrogenation.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.81-85
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• 2011

$V_{0.9}Sb_{0.1}O_x$ systems, bulk and deposited on different supports (five types of $\gamma$-aluminas, $\alpha$-alumina, silica-alumina, silica gel, magnesium oxide), have been tested in the oxidative dehydrogenation (ODH) of iso-butane. Catalytic performance of VSb oxides has shown to be highly dependent on the support and the nature of the support decreasing in a series: $\gamma$-$Al_2O_3$ > $\alpha$-$Al_2O_3$ > Si-Al-O > $SiO_2$ $\approx$ MgO $\gg$ unsupported. Variation of the V-Sb-O-loading in the studied range of coverage (0.5-2 theoretical monolayer) only slightly influences the catalysts' activity and selectivity. The best catalytic performance of $\gamma$-alumina-supported $V_{0.9}Sb_{0.1}O_x$ systems can be explained by the optimal surface interaction between support and supported components resulting in the formation of well-spread amorphous active $VO_x$-component with vanadium in a high oxidation state.

• Clean Technology
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• v.20 no.3
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• pp.330-336
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• 2014

Mg-Al mixed oxides with molar ratio of Mg/Al = 1-3 were prepared by co-precipitation and characterized by using X-ray diffraction, scanning electron microscopy, BET surface area and pore volume measured by $N_2$ sorption analysis, and temperature programmed desorption of iso-propanol. As Al content in Mg-Al mixed oxide increased, the acidity and BET surface area proportionally increased. This increase of acidity directly influenced the catalytic activity of iso-propanol conversion and selectivity to propylene.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.722-729
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• 1992

Mg-and Zn-ferrites having spinel structure, a kind of complex oxides showing the advantageous properties of constituently single metal oxides, were selected to find a relationship between their catalytic activities in the dehydrogenation of ethylbenzene to styrene and the catalytic properties. For the structural and physical analyses of ferrites, XRD, BET, DTA, XPS, TEM and TPD methods were employed. Potassium added to the catalyst played a role of bifunctional promoter which brought the electronic effect as well as the structural one for the increment of particle dispersion. K-addition decreased acid strength of the catalyst by neutralization and increased its acidity. In the dehydrogenation of ethylbenzene, K-addition let the selectivity to styrene be constant throughout the reaction by the proper acid strength of the ferrite for the reaction, which could be obtained from the neutralization of strong acid sites by potassium.

• Journal of the Korean Chemical Society
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• v.24 no.4
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• pp.315-321
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• 1980

A steady-state kinetic study on a dye-coupled cytoplasmic polyol dehydrogenase from G. melanogenus was carried by the initial velocity measurements in the direction of the polyol oxidation and the product inhibition by D-fructose. For the initial rate experiments, D-mannitol and D-sorbitol were employed as the specific polyol substrates and 2,6-dichlorophenolin-dophenol (DPIP) as the specific cofactor substrate for the enzyme. When the polyol and DPIP were examined by varying one of substrates and by fixing the second, the corresponding reciprocal plots showed the typical parallel pattern. This suggests that the enzyme from G. melanogenus proceeds by a Ping Pong Bi-Bi mechanism in which the polyol may account as the first reactant-in, and the ketose formed as the first product-out, respectively. The product inhibition patterns obtained by D-fructose (one no-inhibition, one non-competitive, and two competitive) may also provide an additional conformatory evidence for the above mechanism. Based on the kinetic parameters obtained, it was also suggested that the rate-limiting step in the direction of polyol oxidation is associated with the release of the ketose from the Enzyme${\cdot}$Polyol complex.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.663-669
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• 1992

Chromium oxide/zirconia catalysts were prepared by dry impregnation of $Zr(OH)_4$ powder with aqueous solution of $(NH_4)_2CrO_4$ followed by calcining in air. The redox behavior of prepared catalysts were investigated by reacting cumene as test material over catalysts. As a result it was found that $Cr^{6+}$ species(as chromate) on the surface of catalyst was responsible for the formation of strong acid site and the catalytic activity for the dealkylation of cumene. However, much of the $Cr^{6+}$ species was reduced to $Cr^{3+}$ species by $H_2$ formed during the catalytic reaction of cumene and the reduced $Cr^{3+}$ species was an active site for dehydrogenation of cumene to form ${\alpha}$-methyl styrene. The reduced $Cr^{3+}$ species was also reoxidized to a $Cr^{6+}$ species after treatment with $O_2$ and consequently the deoxidized catalyst exhibited catalytic activity for the dealkylation reaction of cumene.

• Applied Chemistry for Engineering
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• v.2 no.3
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• pp.279-288
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• 1991

Mg- and Zn-ferrites having spinel structure, a kind of complex oxides showing the advantageous properties of constituent single metal oxides, were selected to find a relationship between their catalytic activities in the dehydrogenation of ethylbenzene to styrene and the catalytic properties. For the structural and physical analyses of ferrites, XRD, BET, TG/DTA, ESCA, TEM, and TPD methods were employed. The effects of Cr-substitution were intensively studied by the experimental methods mentioned above. Chromium which showed a preferential tendency to diffuse to the surface acted as a structural promoter by increasing surface area and stability of catalyst structure. In the dehydrogenation of ethylbenzene, catalytic activity, and the effects of Cr-substitution were investigated. Oxygen mobility was decreased with the amount of Cr-substitution in $MgCr_xFe_{2-x}O_4$, which resulted in the increase of selectivity to styrene and the suppression of total oxidation.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.129-134
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• 1998

Conversion of propane to acrylonitrile via ammoxidation was studied using physically mixed catalysts composed of $Nb_2O_5(10{\sim}30wt%)$ and $V_{0.4}Mo_1Te_{0.1}$. Catalytic activities of ammoxidation were improved by adding strong acidic niobium oxide to $V_{0.4}Mo_1Te_{0.1}$, the selectivities to acrylonitrile+propylene being remained constant. The maximum activity was obtained at the mixing ratio 25wt% niobium oxide in $Nb_2O_5-V_{0.4}Mo_1Te_{0.1}$. Niobium oxide was found to be a selective catalyst for the oxidative dehydrogenation of propane.