| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Substitution of 5-10 atomic% of Ga, Y,or Ca ions for Ni ions in Ni_2P_2O_7 improved the oxydative dehydrogenation of iso-butane at the low temperatures. Ni_2P_2O_7 in which 10% of Ni ions were substituded by Ca ions increased the activity of C_4H_8 formation at 450ﾟC.Ni_2P_2O_7 substituted by 10% Y ions or Ga ions showed the same activity as to that of the Ni-Ca-PO catalyst. As for the oxygen conversion, the effects are not uniform, oxygen was completely consumed over Ni-Ga(10)-PO at 430ﾟC.On the other hand, 50% of oxygen was consumed over Ni-Y(10)-PO at 450ﾟC.The optimun oxygen concentration in the feed was 5-10 atomic%. Substitution by transition metals made the crystallinity weakened. The diffraction intersity decreased by the substitution of 5 atomic% of Ni by Ca. The most intense peak of Ni-Ga(5%)-PO catalyst is shifted to higher angle by 0.45 of 2 rheta. This results are accounted for the following manner. Ionic radius of Ga^<3+> ions, 6.2nm, is smaller than taht of Ni^<2+>,6.9nm. Substituting Ni^<2+> by Ga^<3+>, two thirds of removed Ni^<2+> sites are occupied by Ga^<3+>, and one thirds is vacant. This lead to the reduction of lattice porameter. It is concluded from the XRD and XPS data that a part of transition metal ions are located in the crystal lattice. The catalytic activety of these catalysts such as 450ﾟC is independent to the acid amounts of the catalyst measured by NH_3 TPD.At low temperatures such as 450ﾟC,activation of oxygen on the catalyst surface is a key factor in the catalysis.
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