Browsing by Author "Tamaru, Kenzi"

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Catalytic Activities of Polynaphthoquinone, Containing various Metal Halides: Dehydrogenation of Formic Acid, Cyclohexene, Ammonia and Alcohols, and Isomerization of Butene
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (9), 1972) Iwasawa, Yasuhiro; Soma, Mitsuyuki; Onishi, Takaharu; Tamaru, Kenzi
The catalytic activities of polynaphthoquinone, containing various metal halides, such as FeCl3, VCl3, MoCl5 and TiCl4, were studied. The polynaphthoquinone was obtained by the oxidation of naphthalene-1,7-diol and successive heat-treatment. The dehydrogenation of formic acid and alcohols occurred in the temperature region 20 to 100°C over both polynaphthoquinone containing FeCl3 and metal free polynaphthoquinone. The selectivity of the dehydrogenation of isopropyl alcohol was characteristically related to the FeCl3 content of the catalyst. The dehydrogenation of cyclohexene at 200°C and the decomposition of ammonia at 300°C were also studied. The catalytic isomerization of cis-but-2-ene to trans-but-2-ene and to but-1-ene in the region 100 to 200°C was markedly affected by the nature and the quantity of the metal halides in the polynaphthoquinone.
Dehydrogenation and Dehydration of Ethyl Alcohol over a Polynaphthoquinone containing various amounts of FeCl3: Selectivity of Formation of Acetaldehyde, Ethylene and Diethyl Ether
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Iwasawa, Yasuhiro; Ogasawara, Sadao; Onishi, Takaharu; Tamaru, Kenzi
The decomposition of ethyl alcohol over polynaphthoquinones with various amounts of FeClj in the temperature range from 150 to 230°C is reported. Adsorption of ethyl alcohol on poly naphthoquinones containing FcC13 is of a Langmuir type, ethyl alcohol being adsorbed selectively on the FeCIj. The mechanism and the selectivity of the formation of acetaldehyde, ethylene and diethyl ether are discussed in detail. The relative ratio of the formation of diethyl ether to ethylene in the dehydration is markedly affected by the FeCl3 content of the catalysts.
Reduction of Methylene Blue by Dihydro-compounds, Catalyzed by Aliphatic Amines, and the Reaction of Methylene Blue with Aliphatic Amines
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (9), 1972) Iwasawa, Yasuhiro; SoxMa, Mitsuyuki; Onishi, Takaharu; Tamaru, Kenzi
Methylene Blue may be regarded as a model compound of flavin co-enzymes, and its reactions in solution are interesting from a biochemical viewpoint. The reduction of Methylene Blue by dihydro-compounds, catalyzed by aliphatic amines, has been studied, and the reaction of Methylene Blue with the aliphatic amines was also investigated to give some information about the semiquinone radicals from Methylene Blue related to flavin co-enzymes. The reactions were carried out in the absence of air at 20 ± 1°C in 1,2-dichloroethane. It was consequently found that the reduction of Methylene Blue by dihydro-compounds was accelerated by the addition of aliphatic amines, and the semiquinone radical of Methylene Blue was formed as an intermediate in the reaction between Methylene Blue and the aliphatic amines.
Spectral distributions of photo-electrochemical reactions over metal phthalocyanine electrodes
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (05), 1977) Meshitsuka, Shunsuke; Tamaru, Kenzi
The spectral distributions of photo-electrochemical currents over cobalt, nickel and copper phthalocynanines were measured in the region 340 to 800 nm. Two distinctive spectra were obtained for each metal phthalocyanine, depending upon the type of the reaction; as an electron was donated from or accepted by the phthalocyanines. In the former case the peak maximum was observed at the shoulder of the Q band in the absorption spectra and in the latter case it was observed at the peak of the Q band. The difference in the photoaction was assumed to be due to the difference in the efficiency of conversion from the excited states to the charge carriers. This assumption was also supported by the fact that the photo-action spectrum for the oxidation was altered by the phase transition from α to β-phase in which the structure of the Q band changed.
Study of the Oxidation of Molybdenum Surfaces by Energy Loss Spectroscopy Combined with Auger Electron Spectroscopy
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Kawai, Tomoji; Kunimori, Kimio; Kondow, Tamotsu; Onishi, Takaharu; Tamaru, Kenzi
The oxidation of molybdenum as an evaporated film and of its annealed surface was investigated by Energy Loss Spectroscopy (ELS) combined with Auger Electron Spectroscopy (AES). The 10 eV and the lower energy loss peaks towards 5 eV were identified as the clean surface and the oxidized layer surface plasma loss peaks, respectively. The behaviours of these surface plasma loss spectra revealed that the oxidation of the evaporated film surface proceeded uniformly, rapidly and without any induction period under vacuum of 10"7 Torr, whereas that of the annealed sample proceeded more slowly through “ oxidized patches ”, exhibiting a considerable induction period under the same vacuum conditions. These phenomena were interpreted with reference to the surface conditions and structures studied by the AES and ELS; the fresh evaporated surface is clean and rough, whereas the annealed surface is smoothed by the heat-treatment and contaminated by sulphur and carbon which partially cover the active surfaces and give rise to the patchy surface oxidation.
Various Reactions Catalyzed by the Electron Donor-Acceptor Complex of Polynaphthoquinone with Potassium
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Iwasawa, Yasuhiro; Fujitsu, Hiroshi; Onishi, Takaharu; Tamaru, Kenzi
The H2-D2 exchange reaction, the synthesis of ammonia, hydrogen exchange reaction of propene with deuterium and the isomerization of butene over the electron donor-acceptor (EDA) complexes of potassium with metal-free polynaphthoquinone and with polynaphthoquinones containing FeCl3 are discussed. H2-D2 exchange over the EDA complexes is catalyzed even at — 789C. The inter mediate in propene-deuterium exchange is the half-hydrogenated isopropyl species. The difference in the poisoning effect of oxygen for the formation of ammonia and to the H2-D2 exchange is also noted.