The one-step conversion of ethanol to 1,3-butadiene was performed using talc containing Zn (talc/Zn) as a catalyst. The influence of the MgO and Zn in the talc on the formation rate and selectivity for 1,3-butadiene were investigated. MgO as a catalyst afforded 1,3-butadiene with a selectivity that was nearly the same as talc/Zn at ∼40% ethanol conversion at 673 K, although the rate of 1,3-butadiene formation over MgO was about 40 times lower than that over the talc/Zn. The introduced Zn cations were located in octahedral sites in place of Mg cations in the talc lattice. The Zn cations accelerated the rate of CHCHO formation from ethanol, resulting in an increase in the rate of 1,3-butadiene formation. However, the rate of CHCHO consumption to form crotonaldehyde was not influenced by Zn, although the distribution of crotonaldehyde was decreased with increasing Zn concentrations. X-ray photoelectron spectra of talc/Zn showed that the O binding energy was increased by increasing the concentration of Zn, while those of both Mg and Si were hardly influenced. DFT calculations were used to estimate the atomic charges on the O, Mg, Si, and Zn atoms when an atom of Zn per unit cell of talc was introduced into an octahedral site. On the basis of the results for the conversion of ethanol into 1,3-butadiene and the corresponding DFT calculations, the roles of the O, Zn, Mg, and Si atoms in the talc catalyst for the formation of 1,3-butadiene from ethanol were discussed.

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A new concept, "radical-controlled" oxidative polymerization of phenols catalyzed by a tyrosinase model complex, has been proposed. A µ-η 2 :η 2 -peroxo dicopper(II) species formed by the reaction between the catalyst complex and dioxygen, reacted with phenol to give "controlled" phenoxy radicalcopper(I) intermediate instead of "free" phenoxy radical. The polymerization of 4-phenoxyphenol was performed by the use of the tyrosinase model complexes, (hydrotris(3,5-diphenyl-1-pyrazolyl)borate)copper (Cu(Tpzb)) chloride complex and (1,4,7-R 3-1,4,7-triazacyclononane)copper (Cu(L R ): R ) isopropyl (iPr), cyclohexyl (cHex), n-butyl (nBu)) dichloride complexes. The structures of these complexes were determined by X-ray crystallography, indicating that the order of steric repulsion of the substituents (R) in the Cu(L R ) complexes is cHex > iPr > nBu. Very little of C-C coupling dimers were afforded with the Cu(Tpzb) catalyst in toluene or THF, and with the Cu(L iPr ), Cu(L cHex ), or Cu(L nBu ) catalyst in toluene. The selectivity of para C-O coupling increased with an increase in the steric hindrance of R for the Cu(L R ) catalysts. On the other hand, the formation of C-C dimers was clearly observed in the polymerization catalyzed by a copper/diamine complex or horseradish peroxidase. The selective polymerization almost without the C-C dimer formation produced crystalline poly(1,4-phenylene oxide) having a melting point, although the polymer contained small amounts of 1,2,4-trioxybenzene units (ca. 1-5 unit %). However, the polymers obtained in the cases involving the C-C dimer formation showed no clear melting points. The reaction mechanism of catalytic cycle and oxidative polymerization is also discussed.

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The role of the zeolite cavity in the production of C 3 H 6 from butene was investigated using various zeolites with pore structures of 8-, 10-, and 12-membered rings (MRs). The reaction mechanism is discussed on the basis of which octyl carbocations produced C 3 H 6 at low conversions of butene. The selectivity for C 3 H 6 was highly dependent on the volume of the zeolite cavity but not on the entrance pore diameter. The optimum cavity volumes of zeolites with 8-, 10-, and 12-MR entrance pore structures were similar, while the highest C 3 H 6 selectivity among the zeolites was different. The most selective production of C 3 H 6 can be accomplished by matching the volume of the specific octyl carbocation to that of the zeolite cavity. This concept can be employed to explain the selective production of C 3 H 6 according to a proposed reaction model. Furthermore, the reaction mechanism for the production of C 3 H 6 from C 2 H 4 was also investigated at low conversion of C 2 H 4 . C 3 H 6 was produced by the β-scission of the same specific octyl carbocations in the conversions of both butene and C 2 H 4 .