Browsing by Author "Saito, Shuji"

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    Homogeneous Catalysis by Pt(Il)-Sn(II) Chloride Complex: Part 2.—Mechanism of the Isomerization of n-Butenes
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (5), 1972) Hirabayashi, Kazuo; Saito, Shuji; Yasumori, Iwao
    The mechanism of the isomerization of n-butencs catalyzed by a methanolic solution of Pt(II)- Sn(II) chloride complex has been studied by kinetic, mass-spcctromctric and microwave-spectro scopic measurements. This isomerization proceeds in the presence of hydrogen. The initial rate of isomerization of 1-butcnc is of half-order with respect to hydrogen and of first-order with respect to 1-butene in the temperature range 0-20’C and total pressures up to 100 Torr. The deuterium distributions in reactants and products have been measured at 20°C in C4H84-D^-f-CH3OD systems. It was found that cis-CH2DCH=CHCH3 and cis-CH3CD=CHCH3 arc formed from 1-C4H8 and trans-2-C4H8, respectively, and CH2=CHCHDCH3 is produced from both cis- and trans-2-C4H8, and that “ simple exchange reaction ” of 1-C4H8 proceeds faster than the isomcrizations, while those of 2-butcnes scarcely occur. Double-bond migration and “ simple exchange reaction ” of propylene in the C3H64-D24-CH3OD system have been studied for comparison with those of n-butene isomerization. Hydrogen atoms in propylene exchanged with different rates depending on their positions. On the basis of these results, a detailed mechanism is proposed, which involves coordination of olefins to platinum hydride complex, formation of alkyl-platinum, and regeneration of olefins.
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    Microwave Spectroscopic Studies of Hydrogen Exchange, Isomerization and Hydrogenation of Unsaturated Hydrocarbons on the Stoichiometric Electron Donor-Acceptor Complexes of Phthalocyanine with Alkali Metals
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (4), 1973) Naito, Shuichi; Ichikawa, Masaru; Saito, Shuji
    Hydrogen exchange, isomerization and hydrogenation of olefins, such as C2H4, C3H6 and C4H8, was studied over the stoichiometric electron donor–acceptor (EDA) complexes of various phthalocyanines with alkali metals (Li, Na, K). The mass and microwave spectroscopic techniques have been shown to be effective for determining not only the deuterium content but also its distribution in the [2H1] and [2H2]-species of the reactant and product molecules. It was accordingly concluded that these three reactions proceed through the same reaction intermediate; the half-hydrogenated state of the olefins, and that the rate-determining step is the process where the π-coordinated olefin becomes the σ-coordinated half-hydrogenated state. The chemisorbed state of the olefins and the mechanisms of these reactions were correlated with the electron configuration of the EDA complexes.