Electrochemical oxidation of benzene to phenol

Gas-phase electrochemistry: The direct hydroxylation of benzene to phenol was investigated using an electrochemical cell. The production of phenol over a VO(x) anode was found to be significant at 50?°C. The resultant current efficiency for phenol production and selectivity toward phenol reached 76.5 and 94.7?%, respectively.     

Asymmetric induction in the preparation of helical receptor-anion complexes: ion-pair formation with chiral cations

Asymmetry through ion pairing: Upon addition of chloride and bromide ions, as chiral ammonium salts, to solutions of pyrrole-based π-conjugated linear oligomers, helical structures form with asymmetric induction, which is guided by the formation of diastereomeric ion pairs with chiral counter cations. These ions pairs exhibit circular dichroism (CD) and strong circularly polarized luminescence (CPL) with g(lum) values of greater than 0.1.     

Global existence results for Oldroyd-B fluids in exterior domains

In this paper we consider the set of equations describing Oldroyd-B fluids in exterior domains. It is shown that these equations admit a unique, global solution defined in a certain function space provided the initial data and the coupling constant are small enough.     

Switching in molecular shapes: main chain length driven rod-circle transition of isolated helical polysilanes

Unique conformations such as rod, semicircle, and circle structures of isolated semi-flexible helical polysilanes were observed by atomic force microscopy (AFM); the chain topology was significantly related to the chain length (molecular weight) on the surfaces.     

Study on the intermolecular interaction of C60 and simulations on the orientational properties of C60 in crystals

We developed the new intermolecular interaction model of C(60) with the quantitative accuracy for the molecular orientational properties in crystals. The energy difference (DeltaE) and the activation barrier (E(barrier)) between the two stable orientations (P and H orientations) in crystals are in the values of +14.7 and +260 meV in our model, respectively; these values are in fairly good agreement with the experimental values (DeltaE approximately +11 meV, E(barrier)=+235-+290 meV in experiments). The relaxation calculation for C(60) crystals using our model revealed that there is the reversal of the stable orientations between the P and H orientations under the high H-orientation occupancy (p(H)) in crystals, when p(H)>0.83, DeltaE<0. From the molecular dynamics calculations for C(60) crystals using our model, it is found that the phase transition is induced at T(C)=200-260 K, which is consistent with the experimental value of 260 K. Immediately below T(C), we found a great variety of molecular rotational jumps involving that between the P and H orientations every about 10(-9) s due to the thermal activation. In the high temperature phase (>T(C)), all molecules rotate irregularly like in Brownian motion involving the rotational "slumber" for approximately 10(-12)-10(-11) s.     

Thermodynamic interactions in rubbery polymer/gas systems

The Flory–Huggins interaction parameters χ for 23 gases (He, Ne, Ar, Kr, Xe, H₂, N₂, O₂, N₂O, CO₂, CH₄, C₂H₄, C₂H₆, C₃H₆, C₃H₈, 1,3-C₄H₆, four C₄H₈'s, n-C₄H₁₀, iso-C₄H₁₀, and n-C₅H₁₂) in five rubbery polymers (1,2-polybutadiene (PB), poly(ethylene-co-vinyl acetate)) (EVAc), polyethylene (PE), polypropylene (PP), and poly(dimethyl siloxane) (PDMS) were determined from either literature data on Henry's law coefficient and partial molar volume or those on sorptive dilation for each polymer/gas system. Values of χ for the gases increased in the order of PDMS < PP ≡ PB < EVAc ≡ PE. Among the gases except He and H₂ whose χ values are not reliable, Ne and Xe have respectively the highest and the lowest values of χ for the polyolefins. The χ values of the hydrocarbons were compared together with previously reported χ values of n-alkanes C₃-C₁₀. The dependencies of χ upon concentration and temperature were discussed on the basis of the literature data. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 1049–1053, 1997