• Journal of Environmental Science International
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• v.20 no.7
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• pp.873-879
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• 2011

Adsorption experiment of carbon dioxide was performed on MCM41 silica impregnated with two kinds of EDA(ethylenediamine) and MEA(monoethanolamine). The prepared adsorbents were characterized by BET surface area, X-ray diffraction and FT-IR. The $CO_2$ capture study was investigated in a U type packed column with GC/TCD. The results of XRD for MCM-41 and amine-impregnated MCM41 showed typical the hexagonal pore system. BET results showed the MCM 41 impregnated amine to have a surface area of 141 $m^2/g$ to 595 $m^2/g$ and FT-IR revealed a N-H functional group at about 1400$cm^{-1}$ to 1600$cm^{-1}$. The $CO_2$ adsorption capacity on EDA and MEA was as follow: MCM41-EDA30 > MCM41 -EDA40 >MCM41-EDA20 >MCM-EDA10 and MCM41-MEA40 >MCM41-MEA30 > MCM41-MEA20> MCM41-MEA10. The MCM41-EDA30 showed the highest adsorption capacity due to physical adsorption and chemical adsorption by amino-group content. The results suggest that mesoporous media with EDA is effective adsorbent for $CO_2$ capture from flue gases.

• Polymer(Korea)
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• v.29 no.2
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• pp.122-126
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• 2005

The effect of Al-MCM-41 preparation methods on the catalytic degradation of linear low density polyethylene (LLDPE) was investigated. Al-MCM-41 catalysts were synthesized by direct method (Al-MCM-41-D) and post treatment method (Al-MCM-41-P) and their characteristics were elucidated by XRD, BET, $NH_3\;TPD,\;^{27}Al$ MAS NMR. TGA kinetic analysis showed that the catalytic activation energies of Al-MCM-41-D and Al-MCM-41-P were 191.54 and 114.26 kJ/mol, respectively. The higher catalytic activity of Al-MCM-41-P would be attributed to its smaller pore size as well as higher number of acid sites that are accessible.

• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.340-344
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• 2007

Catalytic upgrading of pyrolytic bio-oil produced from Japanes Larch was carried out over MCM-41 catalyst. Oil with enhanced stability was produced by the MCM-41 catalyst due to transform oxygen known as a main cause for the instability of bio-oil into $H_2O$, CO and $CO_2$. In addition, the MCM-41 catalyst produced the larger amount of phenolic compounds in the pyrolytic bio-oil product compared with that in the bio-oil produced without catalyst. Especially, the catalytic activity of Al-MCM-41 for the bio-oil upgrading was higher than that of Si-MCM-41 because Al-MCM-41 has the larger amount of acid sites. Also, the better reforming result was obtained when pyrolytic bio-oil vapor passed through catalytic layer rather than Japanese Larch was mixed with catalyst directly.

• Bulletin of the Korean Chemical Society
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• v.20 no.6
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• pp.715-719
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• 1999

The incorporation of cobalt into mesoporous molecular sieves MCM-41 and MCM-48 was carried out. Co-PO/MCM41 and Co-PO/MCM48 were prepared using Co(II) acetate solution adjusted to pH = 3.0 with phosphoric acid by the incipient wetness method. Photoacoustic spectroscopy (PAS) was used to study the local environments of Co(II) incorporated into mesopores. The band around 500 nm in PAS of as-prepared Co-PO/MCM41 and Co-PO/MCM48 with Co(II) acetate solution was changed to triplet bands around 600 nm. This could be assigned to the 4 A2(F)-> 4T1(P) transition of Co(II) surrounded tetrahedrally by oxygen ions after calcination. It may be attributable to that the octahedral cobalt species containing phosphate ligands in coordination sphere reacting with framework's silanol groups to be dispersed atomically onto the surface of mesoporous molecular sieves as a tetrahedral species. This is unlike that the Co in Co-Cl/MCM41 and direct-synthesized Co-MCM41 transforms to Co oxide phase upon calcination. Co-PO/MCM41 and Co-PO/MCM48 were stable while treated with water.

• Analytical Science and Technology
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• v.19 no.3
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• pp.211-217
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• 2006

Diphenyl amine (DPA) was polymerized inside the channels of the mesoporous silica (MCM-41). MCM-41 (C) and MCM-41 (D) were prepared with cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB), respectively and used as hosts. Initially, the self assembly of DPA inside the pores of MCM-41 was made in ${\beta}$-naphthalene sulfonic acid (NSA) medium and subsequently poly (diphenylamine), PDPA was formed by oxidative polymerization. $N_2$ adsorption-desorption measurements of PDPA loaded MCM-41 (C) and MCM-41 (D) show variations in pore volume and surface area between them. A tubular form of poly (diphenylamine), PDPA was envisaged to form in the pores of MCM-41 and supported by high resolution transmission microscopy. The presence of PDPA inside the channel of MCM-41 was further confirmed by FTIR spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.443-454
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• 2013

Various metal ions (transition and base metals) incorporated MCM-41 catalysts can be synthesized using colloidal and soluble silica with non-sodium involved process. Transition metal ion-typically $V^{5+}$, $Co^{2+}$, and $Ni^{2+}$-incorporated MCM-41 catalysts were synthesized by isomorphous substitution of Si ions in the framework. Each incorporated metal ion created a single species in the silica framework, single-site solid catalyst, showing a substantial stability in reduction and catalytic activity. Radius of pore curvature effect was investigated with Co-MCM-41 by temperature programmed reduction (TPR). The size of metallic Co clusters, sub-nanometer, could be controlled by a proper reduction treatment of Co-MCM-41 having different pore size and the initial pH adjustment of the Co-MCM-41 synthesis solution. These small metallic clusters showed a high stability under a harsh reaction condition without serious migration, resulting from a direct anchoring of small metallic clusters to the partially or unreduced metal ions on the surface. After a complete reduction, partial occlusion of the metallic cluster surface by amorphous silica stabilized the particles against aggregations. As a probe reaction of particle size sensitivity, carbon single wall nanotubes (SWNT) were synthesized using Co-MCM-41. A metallic cluster stability test was performed by CO methanation using Co- and Ni-MCM-41. Methanol and methane partial oxidations were carried out with V-MCM-41, and the radius of pore curvature effect on the catalytic activity was investigated.

• Polymer(Korea)
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• v.29 no.4
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• pp.403-407
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• 2005

In this work, the solid polymer electrolyte (SPE) composites, which are composed of poly(ethylene oxide) (PEO), mesoporous mobil crystalline material-41 (MCM-41), and lithium salt, are prepared in order to investigate the influence of MCM-41 contents on the ionic conductivity of the composites. The crystallinity of the SPE composites was evaluated using differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The ionic conductivity of the SPE composites was measured by the frequency response analyzer (FRA). As a result, the addition of MCM-41 into the polymeric mixture prohibited the growth of PEO crystalline domain due to the mesoporous structures of the MCM-41. The $P(EO)_{16}LiClO_4$/MCM-41 electrolytes show an increased ion conductivity as a function of MCM-41 content up to 8 $wt\%$ and a slightly decreased conductivity over 8 $wt\%$. These ion conductivity characteristics are dependent on a change of polymer crystallinity in the presence of MCM-41 system.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1020-1027
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• 1999

Heteropoly acid(HPW) catalysts supported on three different carriers, an amorphous silica, MCM-41 and MCM-48, with different loadings and calcination temperatures have been prepared and characterized by X-ray diffraction, nitrogen physorption, infrared spectroscopy, and $^{31}P$ magic angle spinning NMR. From the result of IR and NMR, it was shown that HPW retains the Keggin structure on the supported catalysts. No HPW crystal phase was developed even at HPW loadings as high as 35 wt % on the MCM-41 and 65 wt % MCM-48. Thus, HPW appeared to form finely dispersed species. In the hydrolysis reaction of di, bis, tri-pentaerythritol, HPW/MCM-41, 48 exhibited higher catalytic activity than $HPW/SiO_2$ or HPW.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.417-423
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• 2006

A series of amine functionalized MCM-41 catalysts were prepared by aminopropyltrimethoxysilane grafting and their catalytic performance in Knoevenagel reaction of selected substrates was investigated. Water resistant and catalytically active amine grafted MCM-41 was prepared by post-synthetic silylation using methyltrimethoxysilane ; hydrogen bonding of the water molecules formed during the condensation reaction to the active N group was suppressed, which led to high TON of the reaction. Amine functionalized MCM-41 prepared by coating method produced high conversion, but the TON of the catalyst was much lower than that of the amine grafted MCM-41; pore volume of the functionalized MCM-41 decreased substantially and large portion of the immobilized amine is believed to be hydrogen bonded to each other, which can result in decrease in the basicity of the N group. A secondary amine group was prepared by room temperature condensation between aminopropylsilane and chloropropylsilane, and the MCM-41 grafted with the secondary amine group demonstrated the highest catalytic activity among the catalysts prepared.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.691-696
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• 2011

CTAB or CTAB-Nafion catalyst were successfully supported on siliceous hollow tubular MCM-41 which synthesized by hydrothermal method using CTAB as a single template or CTAB and Nafion-Na as mixed templates. The properties of two kinds of catalysts were characterized with XRD, SEM and adsorption and desorption isotherms of nitrogen and pore diameter distribution, respectively. Then they were applied to catalyze brominating reaction of 1,7-heptanediol, moreover the rate of brominating reaction with different catalysts was compared. The results showed that catalytic activities of CTAB/MCM-41 and CTAB-Nafion/MCM-41 are better than CTAB, and that of CTAB-Nafion/MCM-41 is the best because of its phase-transfer and strong acidity function. The two kinds of catalysts can be separated from the reactive products and recycled.