イソニトリルの重合と金属錯体との反応に関する研究

Trace amounts of Pt- and Ru-doped Ni/Mg(Al)O catalysts were prepared by a citrate method and tested in the oxidative reforming of C3H8 under daily start-up and shut-down (DSS) operation. The activity and the sustainability of the catalysts were compared with those of the Pt- and Ru-doped Ni/Mg(Al)O catalysts derived from hydrotalcite (HT) precursor. The DSS operation of C3H8 reforming was carried Out with O-2 gas or O-2/H2O mixed gas between 200 degrees C and 600 degrees C or 700 degrees C under air purging conditions. The catalysts underwent steaming treatment with H-2/H2O mixed gas at 900 degrees C for 10 h. This allowed us to test the effect of Ni sintering on the catalyst deactivation. Coking was significantly suppressed on both HT- and citrate-derived Ni catalysts. Although both preparations produced highly dispersed Ni particles on the catalysts, the HT-derived catalysts exhibited more finely dispersed Ni particles, resulting in higher activity values than those of the citrate-derived catalysts, The regenerative activity due to redispersion of sintered Ni particles was enhanced over the HT-derived catalysts compared with the activity over citrate-derived catalysts. Although a clear redispersion of Ni particles was not observed in the oxidative reforming, i.e., in the absence of steam, the size decrease in Ni particles was more significant over the HT-derived catalysts than over the citrate-derived catalysts. The Mg(Al)O periclase structure derived from Mg-Al HT likely plays an important role in the regenerative activity of Pt- and Ru-Ni/Mg(Al)O catalysts. Pt-doping was more effective than Ru for the catalyst sustainability in the oxidative reforming of C3H8

Conversion of ethanol to propylene over HZSM-5(Ga) co-modified with lanthanum and phosphorous

Conversion of ethanol to propylene was carried out over HZSM-5(Ga) co-modified with lanthanum and phosphorous (La/P/HZSM-5(Ga)). The propylene yield was strongly dependent on both the La/Ga and P/Ga ratios, and the highest value of ca.29 C-% was obtained at a P/Ga ratio of 1 and a La/Ga ratio of 0.4. FT-IR, P-31 MAS NMR, and Ga-71 MAS NMR measurements demonstrate that the introduced lanthanum reacts with the pre-introduced phosphorous to regenerate some of Bronsted acid sites (Si(OH)Ga), and accordingly, the Bronsted acid sites are homogeneously distributed within the zeolite framework. In addition, the catalytic stability as well as the catalytic activity of HZSM-5(Ga) was effectively enhanced by co-modification with lanthanum and phosphorous because of the suppression of carbonaceous deposition and elimination of gallium from the zeolite framework

Synthesis of lamellar mesostructured calcium phosphates using n-alkylamines as structure-directing agents in alcohol/water mixed solvent systems

Lamellar mesostructured calcium phosphates constructed by ionic bonds were prepared by using n-alkylamines (n-C n H2n+1NH2, n = 8–18) at room temperature in the mixed solvent systems of aliphatic alcohol (C n H2n+1OH, n = 1–4) and water, and the synthetic conditions were investigated in detail. The mixed solvent systems suppressed the formation of crystalline calcium phosphates like brushite (CaHPO4·2H2O) and monetite (CaHPO4) at low temperatures, successfully affording pure lamellar mesostructured calcium phosphates. Other crystalline phases such as hydroxyapatite (Ca10(PO4)6(OH)2) were not formed under the conditions with the Ca/P molar ratios in the range of 0.7–1.0 in the starting mixtures. The Ca/P molar ratio of the lamellar mesostructured calcium phosphates was ca. 1.0, calculated by ICP and 31P MAS NMR data. Interestingly, the kind of alcohols strongly influenced the solubilities of calcium phosphate species and n-alkylamines, and then lamellar mesostructured phases were obtained with some morphological variation

Transformation of LEV-type zeolite into less dense CHA-type zeolite

Hydrothermal conversion of LEV-type zeolite into CHA-type zeolite occurred in the absence of both an organic structure-directing agent and a seed crystal. The LEV-CHA transformation proceeds from a more dense zeolite (LEV) to a less dense one (CHA). When amorphous aluminosilicate hydrogels were used as starting materials, the CHA-type zeolite was not obtained under the present hydrothermal synthesis conditions. From the fact that the LEV-CHA transformation proceeded at lower alkalinity conditions, it was suggested that locally ordered aluminosilicate species (nanoparts) produced by decomposition/dissolution of the starting LEV-type zeolite contribute to the transformation process. On the other hand, at higher alkalinity than that used for the CHA-type zeolite synthesis, LEV-LTA transformation occurred effectively and selectively. These results suggest that there is a large difference in the structures of nanoparts generated by decomposition/dissolution of the starting zeolite in the LEV-CHA and LEV-LTA transformations

Synthesis of high-silica CHA type zeolite by interzeolite conversion of FAU type zeolite in the presence of seed crystals

The influence of seed crystals on the interzeolite conversion of FAU type zeolite into CHA type zeolite was investigated in the presence of benzyltrimethylammonium hydroxide as a structure-directing agent under various hydrothermal synthesis conditions. Pure and highly crystalline CHA type zeolites with a wide range of Si/Al ratios were obtained in a shorter crystallization time as compared with those obtained without seed crystals. Furthermore, we achieved the first successful synthesis of high-silica CHA type zeolite in the absence of Na(+) cations by increasing the seed content. The protonated CHA type zeolite with a Si/Al ratio of ca. 15 yielded the highest propylene yield of ca. 48 C-% in ethanol conversion into light olefins

Fractional Reserve in Banking System

This thesis is aimed to provide understanding of the role of the fractional reserve in the mod-ern banking system worldwide and particularly in Finland. The fractional reserve banking is used worldwide, but the benefits of this system are very disputable. On the one hand, experts say that the fractional reserve is a necessary instrument for the normal business and profit making. On the other hand, sceptics openly criticize the fractional reserve system and blame it for fiat money (money not backed by any physical commodities) creation. According to a third point of view, which is expressed by conspiracy theory followers, a the fractional reserve system primary targets to control the money supply in favor of famous rich families, such as the Rothschild family. Although the fractional reserve system is criticized for many reasons, such as causing a moral hazard, cheating and being not transparent, it still functions successfully all over the world. At least the banking system still exists and seems to exist further. How crucial are the defi-ciencies in the fractional reserve system for which it is criticized? Can they be improved? Or maybe the fractional reserve system is not that up to date anymore and should be replaced by something totally different? To find answers to these questions, I studied history books, up-to-date materials and legisla-tion, especially acts published by the European Central Bank. In addition, I sent questionnaires to several banks in Finland and got examples from real bank practice, which in total helped me to form the final understanding of the role of the fractional reserve system in today’s economy

Preparation of tetrabutylammonium salt of a mono-Ru(III)-substituted α-Keggin-type silicotungstate with a 4,4′-bipyridine ligand and its electrochemical behaviour in organic solvents

The tetrabutylammonium (TBA) salt of a mono-ruthenium(III)-substituted α-Keggin-type silicotungstate with a 4,4′-bipyridine (bipy) ligand, TBA5[α-SiW11O39RuIII(bipy)] (1), which is soluble in various organic solvents, was prepared by a cation exchange reaction of Cs5[α-SiW11O39RuIII(bipy)] with tetrabutylammonium bromide. Compound 1 was characterised using IR, 1H-NMR, elemental analysis, single crystal X-ray analysis, X-ray absorption near-edge structure (XANES) analysis (Ru L3-edge), electron spin resonance (ESR), cyclic voltammetry (CV) and UV-Vis. Single crystal X-ray analysis of 1 revealed that the RuIII unit was incorporated into the α-Keggin-type silicotungstate framework and coordinated by a bipy molecule through a Ru–N bond. CV indicated that the incorporated RuIII-bipy was reversibly oxidised to the RuIV-bipy derivative and reduced to the RuII-bipy derivative in organic solvents. The redox potential of RuIV/III-bipy was found to be affected by organic solvents. Moreover, the RuV-bipy derivative was observed in acetonitrile.This file includes Electronic Supplementary Information.This research was supported by the JST, PRESTO program

Preparation of Preyssler-type Phosphotungstate with One Central Potassium Cation and Potassium Cation Migration into the Preyssler Molecule to form Di-Potassium-Encapsulated Derivative

A mono-potassium cation-encapsulated Preyssler-type phosphotungstate, [P5W30O110K]14− (1), was prepared as a potassium salt, K14[P5W30O110K] (1a), by heating mono-bismuth- or mono-calcium-encapsulat ed Prey ssler-type p hosphot ungstates (K12[P5W30O110Bi(H2O)] or K13[P5W30O110Ca(H2O)]) in acetate buffer. Characterization of the potassium salt 1a by single-crystal X-ray structure analysis, 31P and 183W nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy, high-resolution electrospray ionization mass spectroscopy, and elemental analysis revealed that one potassium cation is encapsulated in the central cavity of the Preyssler-type phosphotungstate molecule with a formal D5h symmetry. Density functional theory calculations have confirmed that the potassium cation prefers the central position of the cavity over a side position, in which no water molecules are coordinated to the encapsulated potassium cation. 31P NMR and cyclic voltammetry analyses revealed the rapid protonation−deprotonation of the oxygens in the cavity compared to that of other Preyssler-type compounds. Heating of 1a in the solid state afforded a di-K+-encapsulated compound, K13[P5W30O110K2](2a), indicating that a potassium counter-cation is introduced in one of the side cavities, concomitantly displacing the internal potassium ion from the center to a second side cavity, thus providing a new method to encapsulate an additional cation in Preyssler compounds.M.S. is grateful for the A-STEP program of the Japanese Science and Technology Agency (JST), and Furukawa Foundation for the Promotion of Technology. X.L. thanks the Spanish Ministry of Science and Innovation (MICINN) (project CTQ2011-29054-C02-01/BQU), the DGR of the Generalitat de Catalunya (grant no. 2014SGR199), and the XRQTC. This work was also supported by the Center for Functional Nano Oxide at Hiroshima University. M.N.K.W. thanks the Indonesian Endowment Fund for Education (LPDP), Ministry of Finance, Republik Indonesia, for a Ph.D. scholarship

ZSM-5ゼオライトの水素化能

プロトン交換したZSM-5 (HZSM-5) およびアルカリ土類金属含有ZSM-5型ゼオライト (M-HZSM-5, M:アルカリ土類金属) 上でエチレンおよびプロピレンの水素化を行った。重合, 異性化, クラッキング, 水素化等の反応が併発するため, 生成物は低分子量のものから高分子量のものまで生成した。HZSM-5上で生成する低分子量のものは主にパラフィンであった。低級オレフィンの収率は用いるゼオライトの種類に依存し, 次の順に増加した。HZSM-5≈Mg-HZSM-5<Ca-HZSM-5<Sr-HZSM-5<Ba-HZSM-5。ベンゼンの水素化分解もこれらのゼオライト上で行った。M-HZSM-5の触媒活性はHZSM-5よりも低かった。M-HZSM-5では, 反応温度約300°Cで反応生成物中に水素化生成物であるシクロヘキサンとその骨格異性体であるメチルシクロペンタンが検出された。水素化の活性点を明確にするため, ゼオライト中に含まれる不純物, 特に鉄の水素化触媒としての効果を詳細に検討した。その結果, 鉄を全く含まないHZSM-5ゼオライトが相当な水素化活性を示すことが明らかとなった。以上の結果から, 炭素-炭素二重結合の水素化の活性点はHZSM-5ゼオライトの強酸点であり, その水素化活性はアルカリ土類金属修飾により抑制されると結論した。Hydrogenation of ethylene and propylene was carried out over the protonated ZSM-5 (HZSM-5) and the alkaline earth metal-containing ZSM-5 type zeolites (M-HZSM-5, M: alkaline earth metal). Products, both of low and high molecular weights, were formed through a variety of reactions such as polymerization, isomerization, cracking, and hydrogenation. The lower molecular weight hydrocarbons produced over the HZSM-5 were mainly paraffins. The yields of light olefins were dependent on the kinds of zeolite used and increased in the following order: HZSM-5≈Mg-HZSM-5<Ca-HZSM-5<Sr-HZSM-5<Ba-HZSM-5. Hydroconversion of benzene was also carried out over these zeolites. The catalytic activity of M-HZSM-5 was lower than that of HZSM-5. In the case of M-HZSM-5, the hydrogenated product, cyclohexane, and its skeleton isomer, methylcyclopentane, were detected in the reaction products at about 300°C. In order to clarify the essential sites for the hydrogenation, effects of impurities, especially iron, contained in the zeolites as hydrogenation catalysts, were studied in detail. It was found that the HZSM-5 zeolite, which does not contain iron at all, showed a significant hydrogenation activity. From these results, we have concluded that the active sites for the hydrogenation of ethylenic double bonds are the strong acid sites of the HZSM-5 zeolite, and that the hydrogenation activity decreases upon the modification of the zeolite with alkaline earth metals

Synthesis of Light Olefins from Synthesis Gas Utilizing Zeolite

ゼオライトを用いて種々の複合触媒を調製し, 合成ガスからのエチレン, プロピレンなどの低級オレフィン合成を検討した。鉄とゼオライトを組み合わせたFe-Ti-V-およびFe-Ti-Mn-ゼオライト触媒では比較的高い(C2=+C3=)選択率が得られた。また, メタン生成の抑制という点から, メタノール合成触媒とゼオライトを組み合わせた複合触媒を用いて反応を行った。アルカリ土類金属で修飾したH-ZSM-5型触媒を用いた複合触媒では, (C2=+C3=)選択率が増加することがわかった。さらにゼオライト触媒の水素化能をも明らかにした。Selective synthesis of light olefins (ethylene, propylene) from synthesis gas was studied utilizing various zeolitebased catalysts. (1) New metal/zeolite catalyst: The catalyst was synthesized hydrothermally from zeolite and Fe(II or III) compounds such as Fe3O4, Fe2O3, FeOOH. Figure 1 shows scanning electron micrographs of Fe3O4 and the Fe3O4/ZSM-5 catalyst. No Fe3O4 particle was observed in the latter. Figure 2(b) shows an X-ray diffraction diagram of this catalyst. The reflections of ZSM-5 and Fe2O3 were observed. Appearance of the diffraction peaks in Fe2O3 are attributed to oxidation of Fe3O4 in this catalyst by calcination in air. Figure 3 illustrates X-ray photoelectron spectra of the catalyst before and after grinding. The catalyst before grinding had very weak peaks of iron. By grinding the catalyst, these peaks became very strong, while the silicon peaks did not substantially change. From these results, it is concluded that the Fe3O4/ZSM-5 catalyst thus obtained has a unique texture in which Fe3O4 particles are enveloped with ZSM-5 zeolite. The results of conversion of synthesis gas over various metal/zeolite catalysts are given in Table 1. (2) Zeolite-based iron catalyst: The catalyst was prepared using FeSO4 and Fe(NO3)3 as a source of iron in the same method described above. The synthetic zeolite-based iron catalyst had a well defined crystalline ZSM-5 structure (Fig. 4). Figure 5 shows the results of conversion of synthesis gas over the catalysts. The catalysts prepared from an Fe(II) compound were more active than those prepared from an Fe(III) compound. The (C2H4+C3H6) selectivity of the former was lower than that of the latter. In order to elucidate these differences involving the activity and the selectivity, X-ray diffraction patterns of various catalysts were measured (Fig. 6). In the case of the catalysts prepared from the Fe(III) compound, the d(084)-spacing sharply increased with the Fe/Si atomic ratio. On the other hand, in the case of the catalysts prepared from the Fe(II) compound, the spacing remained unchanged. This suggests that only Fe(III) can replace a portion of the silicon atoms in the crystal lattice and that Fe(II) is present in enveloped form with the zeolite. The differences of both the catalytic activity and the product selectivity may be attributed to the amount of iron which does not replace a portion of silicon atoms. (3) Zeolitebased iron catalyst promoted with various transition metals: Figure 8 shows the results of conversion of synthesis gas over variously promoted zeolite-based iron catalysts (Fe-M-zeolite catalyst, M: promoter). The (C2H4+C3H6) selectivity increased over the catalyst promoted with Ti, Mn and Zr, with Ti being the most effective. Figure 9 illustrates the influence of the second promoter on CO conversion and the selectivity. Addition of V, Mn and Zr to the Fe-Ti-zeolite catalyst increased the (C2H4+C3H6) selectivity. The high (C2H4+C3H6) selectivity was obtained on the catalyst of Fe:Ti:V(Mn)=1:1:1 (Tables 3 and 4). (4) Composite catalyst composed of methanol synthesis catalyst and zeolite catalyst: Conversion of synthesis gas to light olefins was carried out in a two-stage system (Fig. 12). The C2 and C3 hydrocarbons produced over H-ZSM-5 catalyst were mainly paraffins