Direct and selective production of propene from bio-ethanol on Sc-loaded IN2O3 catalysts.

Propene, one of key building blocks for manufacturing plastics and chemicals, could be directly and stably produced from ethanol in good yields. The conversion degree of ethanol to propene reached approximately 60 mol% by using a 3 atom% scandium-loaded indium oxide catalyst at 823 K in the presence of water and hydrogen. The introduction of Sc prevented the reduction of In2O3 to In metal during the reaction, and that of water decreased the coke formation. Both additions resulted in longer lifetimes of the catalysts. The hydrogen addition increased the conversion of acetone to propene. The reaction pathways are also suggested on the basis of the product distributions and the pulse experiments, ethanol→acetaldehyde→acetone→propene, which is quite different from the shape-selective catalysis on zeolites and the dimerization-metathesis of ethene on nickel ion-loaded silica catalysts.

Role of entropy in supramolecular photochirogenesis: enantiodifferentiating photoisomerization of cyclooctenes in chiral sensitizer-immobilized MCM-41 cavities.

To examine the effects of confinement, or low-entropy environments, we employed the mesoporous silicate MCM-41 modified with optically active benzenetetracarboxylates as chiral reaction media to effect the enantiodifferentiating photoisomerization of (Z)-cyclooctene and (Z,Z)-1,5-cyclooctadiene. The ee of the (E)-isomer produced and its temperature dependence behavior in MCM-41 were completely different from those observed in homogeneous solutions. Immobilizing the sensitizer in MCM-41 reduced the contribution of the entropy factor.

One step formation of propene from ethene or ethanol through metathesis on nickel ion-loaded silica.

Increased propene production is presently one of the most significant objectives in petroleum chemistry. Especially the one-step conversion of ethene to propene (ETP reaction, 3C2H4 →2C3H6) is the most desired process. In our efforts, nickel ion-loaded mesoporous silica could turn a new type of ETP reaction into reality. The one-step conversion of ethene was 68% and the propene selectivity was 48% in a continuous gas-flow system at 673 K and atmospheric pressure. The reactivity of lower olefins and the dependences of the ETP reaction on the contact time and the partial pressure of ethene were consistent with a reaction mechanism involving dimerization of ethene to 1-butene, isomerization of 1-butene to 2-butene, and metathesis of 2-butene and ethene to yield propene. The reaction was then expanded to an ethanol-to-propene reaction on the same catalyst, in which two possible reaction routes are suggested to form ethene from ethanol. The catalysts were characterized mainly by EXAFS and TPR techniques. The local structures of the nickel species active for the ETP reaction were very similar to that of layered nickel silicate, while those on the inert catalysts were the same as that of NiO particles.

Synthesis of Biginelli dihydropyrimidinone derivatives with various substituents on aluminium-planted mesoporous silica catalyst.

Biginelli reactions were well catalyzed on mesoporous silica MCM-41 (M41) whose activity was much greater than that of amorphous silica. Octane was the most suitable among 6 kinds of solvents examined. The addition of metal ions on M41 enhanced the catalytic activity in the order Al > Ti > Fe = In. Al-planted M41s with Si/Al ratios of 45-35 showed the highest catalytic activity and could be used repeatedly though a small loss of the activity was observed. The catalysis could widely be applied to obtain various substituted dihydropyrimidinones (DHPMs) with high yields, some of which were very difficult to prepare until now. In addition, Biginelli reactions were combined with formyl C-H insertion reactions of diazoester on mesoporous silica; that is, a tandem one-pot four-component DHPM synthesis was attempted. Acetaldehyde, ethyl diazoacetate, p-tolualdehyde, and urea could be condensed and the corresponding DHPM derivative was obtained with 50% yield on Al-planted M41.

Highly ordered aluminium-planted mesoporous silica as active catalyst for Biginelli reaction and formyl C-H insertion reaction with diazoester.

Al-planted MCM-41s (Al-M41s) with regular mesoporous structure and Si/Al ratio of 23-32 were successfully prepared by the template-ion exchange method in which the template/Si molar ratio and Si/Al ratio were adjusted at 1.44 and 5-15, and showed much higher catalytic activity for the titled reactions than the other types of Al-M41s prepared by post-synthesis or sol-gel methods.

Widespread Inhibition, Antagonism, and Synergy in Mouse Olfactory Sensory Neurons In Vivo.

Sensory information is selectively or non-selectively enhanced and inhibited in the brain, but it remains unclear whether and how this occurs at the most peripheral level. Using in vivo calcium imaging of mouse olfactory bulb and olfactory epithelium in wild-type and mutant animals, we show that odors produce not only excitatory but also inhibitory responses in olfactory sensory neurons (OSNs). Heterologous assays indicate that odorants can act as agonists to some but inverse agonists to other odorant receptors. We also demonstrate that responses to odor mixtures are extensively suppressed or enhanced in OSNs. When high concentrations of odors are mixed, widespread antagonism suppresses the overall response amplitudes and density. In contrast, a mixture of low concentrations of odors often produces synergistic effects and boosts the faint odor inputs. Thus, odor responses are extensively tuned by inhibition, antagonism, and synergy at the most peripheral level, contributing to robust sensory representations.

Remarkable catalysis of a wool-like copper electrode for NH3 synthesis from N2 and H2 in non-thermal atmospheric plasma.

A wool-like copper electrode used to produce non-thermal plasma functioned as an efficient catalyst for ammonia production from N2 and H2 under atmospheric pressure without heating. The catalytic activity increased as the experiments were repeated. The yield of ammonia at H2/N2 = 3 was 3.5%. The intensity of the emission spectra of N2*(C-B) bands was correlated with the ammonia synthesis rate.

Assignment of Nonclassical [Cu(CO)(n)](+) (n = 1, 2) Complex Ions in Zeolite Cages.

A time-resolved FT-IR technique combined with an isotopic tracer method has been applied to study CO adsorbates on Cu(+) ions in copper ion-exchanged zeolites. Three kinds of monocarbonyl species were found to adsorb strongly on Cu-zeolite samples after admission and subsequent evacuation of gas phase CO at room temperature. Their absorption bands were observed at 2146-2160, 2128-2150, and 2097-2129 cm(-1), respectively, dependent on the zeolite structures. In the presence of gaseous CO, the monocarbonyl species at 2146-2160 cm(-1) (so called nonclassical [Cu(CO)](+) complexes) could react with a CO molecule to form a dicarbonyl species [Cu(CO)(2)](+) with nu(sym) bands at 2169-2180 cm(-1). The reactivity of the nonclassical [Cu(CO)](+) complexes was dependent on the zeolite structures, ferrierite > mordenite > ZSM-5 > X-type left harpoon ovet right harpoon offretite/erionite left harpoon ovet right harpoon Y-type > L-type. The remaining two types of monocarbonyl species have little been affected by gas phase CO.

Photochange in pore diameters of azobenzene-planted mesoporous silica materials.

Azobenzene (Az) groups were planted on the pore wall of mesoporous silica MCM-41 (M41) by silylation of triethoxy[4-phenylazo(phenyl)]silane. The optimal surface density of Az groups was 0.9 group nm-2, and too much loading of Az induced the lowering of the efficiency of the trans-cis isomerization due to the congestion of the groups. The reversible change in the pore diameters upon UV-vis irradiation could not be confirmed by N2 adsorption at 77 K but was revealed to be ca. 1.0 nm by the shift of the UV-vis absorption band of p-N,N-dimethylaminobenzylidenemalononitrile introduced into the Az-modified pores.

Remarkable effect of pore size on the catalytic activity of mesoporous silica for the acetalization of cyclohexanone with methanol.

The catalytic activity of mesoporous silica (MCM-41) for the acetalization of cyclohexanone shows a volcano-shaped dependence on the pore diameter. The diameter of the cyclohexanone molecule is ca. 0.75 nm, while its acetalization with methanol was well accelerated on MCM-41 with a pore diameter of approximately 1.9 nm, and smaller or larger pores were not suitable for the catalysis. The catalytic activity was independent of the Al concentration.