• Journal of Korean Society for Atmospheric Environment
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• v.11 no.1
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• pp.77-84
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• 1995

To prevent or reduce air pollutant from methanol fueled vehicles, methanol oxidation reaction was carried out using a heteropoly acid catalysts. Catalytic activities of catalysts have been experimented at atmospheric pressure in a fixed bed flow reactor. Catalysts were characterized by XRD, IR, thermal analysis, N $H_{3}$-TPD and GC pulse technique. Acidities of catalysts were highly affected by poly-atoms. Methanol conversion was much higher on catalyst with W than on catalyst with Mo as a poly-atoms. With the increase of copper content(X) in C $u_{x}$ $H_{{3-2x}}$PMo catalyst, acidity was decreased and oxidation ability was increased. Methanol conversion and product distribution were affected by the acidity and oxidation ability of catalyst. Especially, supported PdSiW(1wt%) catalyst has a very good methanol conversion and C $O_{2}$ selectivity as high as a commertial 3-way catalyst.t.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.366-371
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• 2015

The kinetic behavior of tetrahydrotricyclopentadiene (THTCPD) isomerization was studied by using two kinds of chloroaluminate ionic liquid (IL) catalyst with different Lewis acidity. THTCPD isomerization pathway was discussed under the different temperature and time as reaction parameters using IL catalysts consisting of 1-butyl-3-methylimidazolun chloride $(BMIC)/AlCl_3$ with low acidity and pyridine hydrochloride $(PHC)/AlCl_3$ with high acidity. The conversion of THTCPD isomerization increased with increasing Lewis acidity of IL catalyst. The THTCPD isomerization pathway changed as a function of reaction temperature and catalyst acidity. In the case of $BMIC/AlCl_3$ IL catalyst, THTCPD isomerization pathway was similar to that of using conventional $AlCl_3$ catalyst. However, two different types of additional pathways (endo, exo, endo-NB ${\rightarrow}$ exo, exo, endo-NB ${\rightarrow}$ exo, exo, exo-NB and endo, exo, endo-NB ${\rightarrow}$ exo, exo, endo-NB ${\rightarrow}$ exo, exo, exo-CP) were appeared when using $PHC/AlCl_3$ IL catalyst.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1844-1850
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• 2006

Two types of catalyst samples were prepared, one sulfated zirconia and the other silica doped sulfated zirconia. The acidity tests indicate that sulfated zirconia doped with silica has higher concentration and strength of acidic catalyst sites than undoped sulfated zirconia. The acidic surface sites have been characterized using FTIR, NMR, pyridine adsorption, TPD, XRD and nitrogen adsorption. Doping with silica increased the concentration of surface Lewis and Brfnsted acid sites and resulted in generation of proximate acid sites.The activity test indicates that doping sulfated zirconia with silica increases both the acidity and catalytic activity for liquid phase dehydration of methanol at 413-453 K. Methanol is sequentially dehydrated to dimethyl ether and ethylene over both catalysts. Significant amounts of propylene are also formed over the silica-doped catalyst, but not over the undoped catalyst.

• Bulletin of the Korean Chemical Society
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• v.22 no.3
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• pp.263-266
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• 2001

Isopropylation of phenol with 2-propanol has been carried out over Na-exchanged ZSM-5 zeolites to determine the effect of catalyst acidity on phenol conversion and product selectivity. The acid type and strength of the catalyst such as Lewis, weak and strong Bronsted acid sites are measured by pyridine adsorbed XPS and the catalytic properties are interpreted in terms of the acid properties. The active site and mechanism for the reaction are suggested based on evidence of study from the reactant adsorbed FT-IR.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.403-406
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• 1990

Two types of new silica catalysts modified with benzenesulfonic acid derivatives were prepared by esterification or phenylation followed by sulfonation. Both catalysts thus prepared were tested as acid catalysts for 2-propanol dehydration and cumene dealkylation reactions. B catalyst () were more active than A catalyst (). Highter catalytic activity for B catalyst may be accounted for by higher resistance to water, higher acid strength, more acidity, and better thermal stability as compared with A catalyst.

• Bulletin of the Korean Chemical Society
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• v.27 no.6
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• pp.821-829
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• 2006

A series of catalysts, $NiO/La_2O_3-ZrO_2/WO_3$, for acid catalysis was prepared by the precipitation and impregnation methods. For the $NiO/La_2O_3-ZrO_2/WO_3$ samples, no diffraction lines of nickel oxide were observed, indicating good dispersion of nickel oxide on the catalyst surface. The catalyst was amorphous to X-ray diffraction up to 300 ${^{\circ}C}$ of calcination temperature, but the tetragonal phase of $ZrO_2$ and monoclinic phase of $WO_3$ by the calcination temperatures from 400 ${^{\circ}C}$ to 700 ${^{\circ}C}$ were observed. The role of $La_2O_3$ in the catalyst was to form a thermally stable solid solution with zirconia and consequently to give high surface area and acidity. The high acid strength and high acidity were responsible for the W=O bond nature of complex formed by the modification of $ZrO_2$ with $WO_3$. For 2-propanol dehydration the catalyst calcined at 400 ${^{\circ}C}$ exhibited the highest catalytic activity, while for cumene dealkylation the catalyst calcined at 600 ${^{\circ}C}$ showed the highest catalytic activity. 25-$NiO/5-La_2O_3-ZrO_2/15-WO_3$ exhibited maximum catalytic activities for two reactions due to the effects of $WO_3$ modifying and $La_2O_3$ doping.

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1623-1632
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• 2006

NiO supported on zirconia modified with $MoO_3$ for acid catalysis was prepared by drying powdered $Ni(OH)_2-Zr(OH)_4$ with ammonium heptamolybdate aqueous solution, followed by calcining in air at high temperature. The characterization of prepared catalysts was performed using FTIR, Raman, XRD, and DSC. $MoO_3$ equal to or less than 15 wt% was dispersed on the surface of catalyst as two-dimensional polymolybdate or monomolybdate, while for $MoO_3$ above 15 wt%, crystalline orthorhombic phase of $MoO_3$ was formed, showing that the critical dispersion capacity of $MoO_3$ on the surface of catalyst is 0.18 g/g NiO-$ZrO_2$ on the basis of XRD analysis. Acidity and catalytic activities for acid catalysis increased with the amount of dispersed $MoO_3$. The high acid strength and acidity was responsible for the Mo=O bond nature of the complex formed by the interaction between $MoO_3$ and $ZrO_2$. The catalytic activity for acid catalysis was correlated with the acidity of the catalysts measured by the ammonia chemisorption method.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.123-128
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• 2011

It has been stand high in estimation to converse from Carbon dioxide to Dimethyl Ether in new alternative fuel energy division in 21C, especially Using of DME in point of view of transportation fuel has been discussed of a new clean energy which is very lower of exhaust gas than gasoline and diesel energy. In this paper it is used ZSM-5 and I developed new catalyst by addition of cerium to control acidity. The new catalyst was proved high conversion rate, when it was conversed from methanol to DME, there wasn't any additional material except DME and water, and I overlooked reaction temperature, reaction time, amount of catalyst, amount of added cerium, effect of water content in methanol, reaction temperature by making change of reaction time. I have conclude that conversion rate to DME was increased as increased of catalyst amounts. The best catalyst condition of without additional product was treated poisoning from ZSM-5 to 5% cerium and new catalyst was not effected in purity of fuel methanol.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.125-131
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• 2022

Effect of sulfation processes on the physicochemical properties of ZrO₂ and TiO₂ nanoparticles were thoroughly investigated. SO₄/ZrO₂ and SO₄/TiO₂ catalysts were synthesized to identify the acidity character of each. The wet impregnation method of ZrO₂ and TiO₂ nanoparticles was employed using H2SO₄ with various concentrations of 0.5, 0.75, and 1 M, followed by calcination at 400, 500, and 600 ℃ to obtain optimum conditions of the catalyst synthesis process. The highest total acidity was found when using 1 M SO₄/ZrO₂-500 and 1 M SO₄/TiO₂-500 catalysts, with total acidity values of 2.642 and 6.920 mmol/g, respectively. Sulfation increases titania particles via agglomeration. In contrast, sulfation did not practically change the size of zirconia particles. The sulfation process causes color of both catalyst particles to brighten due to the presence of sulfate. There was a decrease in surface area and pore volume of catalysts after sulfation; the materials' mesoporous structural properties were confirmed. The 1 M SO₄/ZrO₂ and 1 M SO₄/TiO₂ catalysts calcined at 500 ℃ are the best candidate heterogeneous acid catalysts synthesized in thus work.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.391-396
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• 2015

To investigate the effect of the catalyst synthesis method on the oxidative dehydrogenation (ODH) of nbutenes, $BiFe_{0.65}MoP_{0.1}$ oxide catalysts were prepared with various synthesis methods such as co-precipitation, citric acid method, hydrothermal method, and surfactant templated method. The catalysts were characterized by X-ray Diffraction (XRD), $N_2$ sorption, and $NH_3/1$-butene-temperature programmed desorption ($NH_3/1$-butene-TPD) to correlate with catalytic activity in ODH reaction. Among the catalysts studied here, $BiFe_{0.65}MoP_{0.1}$ oxide catalyst prepared with co-precipitation method marked the highest activity showing 1-butene conversion, 79.5%, butadiene selectivity, 85.1% and yield, 67.7% after reaction for 14 h. From the result of $NH_3$-TPD, the catalytic activity is closely related to the acidity of the $BiFe_{0.65}MoP_{0.1}$-x oxide catalyst and acidity of the $BiFe_{0.65}MoP_{0.1}$ oxde catalyst prepared with co-precipitation method was higher than that of other catalysts. In addition, combined with the 1-butene TPD, the higher catalytic activity is closely related to the amount of weakly adsorbed intermediate (< $200^{\circ}C$) and the desorbing temperature of strongly adsorbed intermediates (> $200^{\circ}C$).