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  • Author: T. Yoshimura x
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Abstract

Trivalent actinides Am(III), Cm(III), and Cf(III) were successfully separated for the first time using capillary electrophoresis in 2-hydroxyisobutyric acid/acetic acid. It was found that the ionic radius was primarily important for separation of trivalent actinides as well as lanthanides in this condition. The stability constants of the Am(III) complexes with 2-hydroxyisobutyrate were estimated using the correlations between the molar fraction ratio of lanthanides and their ionic radii.

Summary

This paper deals with the results of choice feeding tests of two termite species, Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe), with steam-treated and dry-heated samples of Japanese commercial woods. Some steam-treated species were heavily attacked by C. formosanus and R. speratus while all dry-heated samples were attacked not more than unheated controls except for the combination Japanese larch-R. speratus. The steam treatment in some wood species produced feeding attractants which were removed by hot water extraction. Termite species showed some differences in the susceptibility to these substances. Attraction of the termites to steam-treated Japanese beech was different from that to the steam-treated softwoods. These phenomena were discussed with references to heat treatment of wood as well as to termite attractive factors.

Abstract

A new phenolic sesquiterpene, dysoxyphenol (1), and the known sesquiterpene, 7R,10S-2-hydroxycalamenene (2), were isolated from the acetone extract of Dysoxylum densiflorum seeds. The structures of these compounds were determined based on physical, Nuclear Magnetic Resonance, and mass spectral data. Both compounds were evaluated for their antibacterial and antifungal properties against seven pathogenic bacteria and two wood-rotting fungi, respectively. The results showed that both compounds have significant antibacterial properties only against Bacillus subtilis (Minimum Inhibitory Concentration 28 μM), while in the antifungal evaluation compound 1 was found to be more active than compound 2. Therefore, compound 1 has promising antifungal properties that can be developed further for finding new antifungal agents.

Summary

For the solvent extraction experiment on element 104 (Rf), solvent extraction of Zr and Hf as its homologues was performed in tributylphosphate (TBP)/hydrochloric acid (HCl) system using the carrier-free radiotracers 88Zr and 175Hf. Time dependences of the distribution ratios of Zr and Hf were investigated using 6.1 and 10.0M HCl and 0.5 and 2.0M TBP benzene solutions. The distribution ratios in equilibrium were determined for these elements as a function of HCl concentrations in the range of 4.1-10.2M. We found that the neutral chloride complexes of Zr and Hf were formed and extracted into the organic phase within 20 min in HCl with a concentration higher than 6 M. From the results, we propose that solvent extraction of Rf from 4-8M HCl into 2.0M TBP benzene is suitable for investigating the chloride complexation properties of Rf. In addition, for the development of the rapid liquid-liquid extraction apparatus, three types of microchannel devices, namely, a micro reactor, capillary tube and micro-chemical chip, were tested as a mixing-solution part in the apparatus. The chemical reactions of Zr and Hf in the extraction were found to be fast only when using the microchemical chip, which is important for investigations with the 68-s 261Rf.

Abstract

We carried out solvent extraction on the trivalent actinides of Am, Cm, Cf, and Fm and the lanthanides (except Pm) using di(2-ethylhexyl)phosphoric acid (HDEHP) in benzene by a batch method. The extraction constants of the HDEHP complexes for these elements were determined systematically under identical conditions. The tetrad effect was clearly observed in the variation of the extraction constants of the lanthanide series. We found that the extraction constant for Fm(III) is much smaller than that for Dy(III), which have similar ionic radii. The extraction constants for Am(III), Cm(III), and Cf(III) are similar to those for corresponding Ln(III) having similar ionic radii. Two possibilities that account for the lower extraction constant of Fm(III) is suggested.

Abstract

Solvent extraction behavior of carrier-free Mo and W from 0.1–11 M HCl into 0.05 M Aliquat 336-chloroform solution was investigated and compared with that of macro amounts of Mo and W. The distribution ratios of carrier-free Mo and W were in good agreement with those of macro amounts of Mo and W in 6–11 M HCl, while the extraction efficiencies of carrier-free Mo and W were different from those of macro amounts of Mo and W in <6 M HCl. Therefore, it appears that the carrier-free as well as macro amounts of Mo and W form mononuclear species in 6–11 M HCl. The disagreement in <6 M HCl is probably due to the formation of polynuclear species of the macro amounts of Mo and W.