Hydrolysis of Diazonium Salts Using a Two‐Phase System (CPME and Water)

A new method for the hydrolysis of diazonium salts, without the formation of tar, was developed. A two‐phase system consisting of cyclopentyl methyl ether (CPME) and water is very effective for the hydrolysis of diazonium salts. Using this solvent system, the diazonium salt prepared from 3‐(4‐nitrophenoxy)aniline gave 3‐(4‐nitrophenoxy)phenol in high yield (96%) within 20 min. The synthesized phenol is an industrially important raw material in polymer syntheses. Furthermore, the use of the present two‐phase system of CPME and water successfully brought about the efficient conversions of several m‐substituted anilines into the corresponding m‐substituted phenols. This is the first example of hydrolysis of diazonium salts using the two‐phase system (CPME and water).     

Delocalization of positive charge in π-stacked multi-benzene rings in multilayered cyclophanes

In the present study, delocalization of a positive charge in π-stacked multi-benzene rings in multilayered para- and meta-cyclophanes, in which benzene rings are connected by propyl chains to form a chromophore array with the face-to-face structure, was investigated by means of transient absorption spectroscopy during the pulse radiolysis using dichloroethane as a solvent. The local excitation and charge resonance (CR) bands were successfully observed. It was revealed that the CR band shifted to the longer wavelength side with the number of the benzene rings. The stabilization energy estimated from the peak position of the CR band showed the efficient charge delocalization over the cyclophanes. Furthermore, the CR bands showed the slight spectral change attributable to the change in distribution of the conformers. The substantially long lifetime of the CR band can be explained on the basis of the smaller charge distribution on the outer layers of the multilayered cyclophanes.     

A compact TOF-SANS using focusing lens and very cold neutrons

We are developing a high-resolution small angle neutron scattering instrument for very cold neutrons (VCN). Our concept includes a magnetic lens for focusing of the beam at the detector plane. The lens consists of one permanent-magnet sextupole array rotating outside another stationary sextupole array, to focus a pulsed white beam of neutrons. Thus the instrument operates in time of flight mode. The prototype magnetic lens has a bore of 15 mm diameter and length of 66 mm, producing a magnetic field gradient oscillating from 1.5×10⁴ to 5.9×10⁴ T/m², with frequency ≤25 Hz. A torque-canceling magnet around the lens suppresses the torque of rotation from the outer array to 1/3.We have demonstrated the performance of the lens, over wavelength range from 30 to 48 Å, on the PF2-VCN beam line at the Institut Laue-Langevin, France. The focused beam image was the same size as the source, without chromatic aberration, with focal length of 1.14 m. We also studied the performance of this configuration for high-resolution SANS, in a compact geometry (just 5 m long). The measurable q range of this system was 0.009 Å⁻¹≤q≤0.3 Å⁻¹ or 0.004 Å⁻¹≤q≤0.08 Å⁻¹ for sample to detector distances of 100 and 465 mm, respectively. Here, we present the results of our lens characterization study along with the SANS results on a tri-block copolymer (F127 Pluronic) and on a stretched polymer blend (with the Shish-Kebab structure).     

Chiral phase transition in lattice QCD with Wilson quarks

The nature of the chiral phase transition in lattice QCD is studied for the cases of 2, 3 and 6 flavors with degenerate Wilson quarks, mainly on a lattice with the temporal direction extensionN _t=4. We find that the chiral phase transition is continuous for the case of 2 flavors, while it is of first order for 3 and 6 flavors.     

Metabolic profiling using Fourier-transform ion-cyclotron-resonance mass spectrometry

With the aid of the extreme resolving power of Fourier-transform ion-cyclotron-resonance mass spectrometry (FT-ICR/MS), we have developed a metabolomics platform for high-throughput metabolic profiling and metabolite candidate identification integrating a data-processing system, the Dr.DMASS program (), and a metabolite-species database, KNApSAcK (). We discuss the potential of this FT-ICR/MS-based metabolic profiling scheme as a general metabolomics tool by clarification of plant metabolic disorders and specific metabolite accumulation patterns caused by herbicidal enzyme inhibitors.     

Biodegradable Polymeric Materials—Not the Origin but the Chemical Structure Determines Biodegradability

It is completely plausible that unmodified materials of natural origin, such as the native macromolecules cellulose or starch, are biodegradable. If these materials are modified then degradation may, depending on the degree of modification, be more difficult or even impossible. In the same manner synthesized macromolecules, whether from renewable or petrochemical sources, could be inert or completey biodegradable, depending on their chemical structure.     

Automated odor-sensing system based on plural semiconductor gas sensors and computerized pattern recognition techniques

Although odor is an inherent characteristic of chemical substances, no methods to measure or identify odor objectively have been available. A computerized method for classification and identification of odor is reported. Odors are detected by using eight semiconductor gas-sensor elements which have different sensing properties for gases; the output from the odor-detecting apparatus for a gas sample is represented by an 8-dimensional vector. The vectors for 30 substances were examined by clustering analysis and four obvious clusters were observed. These clusters corresponded to ethereal, etherealminty, ethereal-pungent and pungent substances.