1991 Fiscal Year Final Research Report Summary
Oxidation of Hydrocarbons Catalyzed by mu-Oxopolynuclear Mixed Metal Complexes
| Project/Area Number |
02650586
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
工業物理化学・複合材料
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| Research Institution | Kyoto Prefectural University |
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Principal Investigator |
KANAI Hiroyoshi Kyoto Prefectural University, Faculty of Living Science, Professor, 生活科学部, 教授 (40026050)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Polynuclear metal complexes / oxidation / mixed valence / mixed metal complexes / mu-oxo / oxidative dehydrogenation / carbon monooxide oxidation |
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| Research Abstract |
(1) The oxidation of styrene has been carried out in O_2 atmosphere with mu-oxotrinuclear ironcarboxylates, [Fe_3O(O_2CR)_6(H_2O)_3]^+. Small differences were found for oxidation rates among complexes which were dissolved in styrene. Relatively high epoxide selectivity was obtained for complexes with carboxylates, their acid strength(pKa) of nearly 4. Benzoate ligands whose Hammett values are from small negative figures to zero gave maximum epoxide selectivity(28%). (2) In the oxidation with mu-oxotrinuclear mixed valence metal carboxylates Fe_2^<III>Fe^<II> and Co_2^<III>Co^<II> are superior in the oxidation rates and epoxide selectivity to their homovalence complexes. Its homologue, V_2^<IV>V^<III> is also effective. However, Mn_2^<III>Mn^<II> has none of effectiveness. Among mixed metal (Fe_2^<III>M^<II>, M = Mn, Co, Ni, Zn, Mg) acetate complexes zinc exerted highest epoxide selectivity(35% at 85ﾟC). No activity was observed for Fe_2^<III>Mn^<II> complex. Almost the same epoxide sel
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ectivity with that for Fe_2III^<Zn>II^< was found for Cr_2>IIIFe^<II> complex. (3) The oxidation was slow at room temperature and requires higher than 70ﾟC. The oxidation rate increases with the increase of temperature and reaches maximum at 95ﾟC. Differences of activity and epoxide selectivity are observed among complexes at low temperatures but were leveled off above 95ﾟC. Highest epoxide selectivity was found at 85-95ﾟC. The decrease of oxygen pressure decreased oxidation rate, but increased epoxide selectivity. Higher than 50% of epoxide was obtained at less than 13 kPa of O_2 pressure. (4) Clustered metal oxide catalysts(Fe loading 7.8 wt%) with 3 metals were prepared by impregnating Fe_2^<III>M^<II>O(OAc)_6(H_2O)_3 (M = Fe, Mg, Zn, Mn, Co, Ni) on SiO_2 followed by calcination. Dehydrogenation of 1-butane to butadiene at 573K were carried out with those catalysts; higher activities than that for M = Fe were obtained for M = Mn and Zn, almost the same for M = Co and Ni, and no activity was observed for M = Mg. Selectivities to butadiene are 71%(Zn), 68%(Fe), 67%(Co) and 53%(Ni). Less
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