Takahiko Moteki

Biomass-derived light alcohols (e.g., ethanol) may be upgraded via C–C bond formation to form larger alcohols and chemicals. The mechanism for coupling reactions among alcohols (i.e., Guerbet chemistry) is still debated, and the factors that determine the rates of subsequent, and inevitable, reactions among coupling products, and thus the product distributions, are not well understood. Here, the interpretation of the formation rates of products, in situ spectroscopy of surface intermediates, and

Novel pure silica sodalite with hollow sodalite-cages has been synthesized for the first time by topotactic conversion of layered silicate (RUB-15) precursor. This success has been achieved by stepwise syntheses from silicate monomers, through clusters and layers, to microporous crystals. The pretreatment of layered silicate with small carboxylic acids before conversion is a crucial step. The obtained sodalite possesses accessible micropores, as confirmed by physical adsorption of hydrogen molec

Topotactic conversion of crystalline layered silicates into zeolite provides an opportunity to create new chemical compositions, framework types, and macroscopic morphologies that are difficult to achieve by conventional hydrothermal synthesis. We have recently reported the successful synthesis of pure silica sodalite with a unique sheet-like morphology from layered silicate RUB-15 occluding interlayer TMA+ cations. Pretreatment of RUB-15 with acetic acid was found to be crucial for topotactic d

Abstract Conversion of methane towards chemical feedstocks such as oxygenates and hydrocarbons has been studied along with the development of natural gas technology. In this study, CO‐assisted direct conversion of methane into C 1 and C 2 oxygenates was demonstrated over ZSM‐5 supported transition and platinum group metal catalysts. Besides previously investigated Rh, other platinum group metals (e. g., Ru and Ir) were found to be a potential element as the catalyst. Presence of CO was critical

2- and 4-Methylbenzaldehyde, which are useful precursors for phthalic anhydride and terephthalic acid, form by sequential aldol condensations between acetaldehyde and enals and subsequent dehydrocyclization during ethanol upgrading reactions on hydroxyapatite catalysts. The selectivities for methylbenzaldehydes exceed 30%, as a result of rapid cyclization reactions and steric protection that hinders further growth. Such pathways compete with a set of alternating condensation and hydrogenation st

The fluoride method of zeolite synthesis yields materials with unique characteristics such as high Si/Al ratio, large crystal size, and hydrophobic properties, and it has been advantageous for the synthesis of new pure-silica or high-silica zeolites. It is often difficult, however, to incorporate aluminum—and thus bring about useful catalytic properties—in materials prepared through the fluorite method. In this report, we show that FAU-type zeolites are an effective source of aluminum to the gro

Abstract Condensation reactions of biomass derived C 2 and C 4 aldehydes form both ortho ‐ and para ‐tolualdehydes (2‐MB and 4‐MB, respectively). The complete reaction network and the detailed mechanisms, however, have not been fully described. Here, analysis of the products formed by sequential condensation reactions of acetaldehyde and 2‐butenal suggests that 2‐ and 4‐MB products form via aromatization of 2,4,6‐octatrienal and of highly reactive acyclic intermediate(s) formed via self‐addition

Silicalite-1 and siliceous *MRE zeolite were synthesized with a series of highly amphiphilic ammonium cations as organic SDAs. The relationship between the framework type and the chain length of the amphiphilic cation is explained in terms of the intermolecular N-N distance of the elongated SDA.

Catalytic CO-assisted partial oxidation of methane to methanol was demonstrated over Cu-CHA zeolites that were prepared by a one-pot synthesis approach feasible to prepare isolated metal sites.

Preparation of single-walled carbon nanotubes (SWNTs) has been advanced by controlling several parameters including the catalyst and the catalyst support material. Although zeolite has been frequently used as a catalyst support material for the synthesis of SWNTs, detailed surface properties of previously employed zeolites and thus their role as a catalyst support material have not been sufficiently clarified yet. In this study, a clean b-plane surface of silicalite-1, which is a siliceous MFI-t

The charge density mismatch (CDM) approach has been a strategy to apply multiple templates in the zeolite synthesis. In the synthesis of the UZM-4 zeolite, tetraethylammonium (TEA) aluminosilicate solution is used as CDM solution although the TEA cation is not incorporated in the final product. We focused on the aging process to prepare the CDM solution, and a more simplified pathway for the synthesis of UZM-4 is explored. The preparation of homogeneous aluminosilicate solution prior to the addi

We synthesized pure-silica ZSM-48 zeolite with cheap and conventional amphiphilic organic cation, dodecyltrimethyl ammonium cation, as structure-directing agent. Although severe hydrothermal conditions are usually required to utilize organics possessing anisotropic charge distribution, by controlling the water content of the reactant gel, the crystallization was completed within 5 days at 160°C. This approach enabled the ZSM-48 zeolite synthesis with lower synthesis temperature, shorter synthesi

In this manuscript, we have demonstrated CO-assisted methane conversion into small oxygenates using a Rh catalyst supported on zeolites with AEI-, CHA-, and AFX-type structures (specifically, SSZ-39, SSZ-13, and SSZ-16 zeolites, respectively). Methanol, formic acid, and acetic acid were obtained as the oxygenate products and their selectivities were unique to each of the zeolite framework structures. Smaller cage structures were preferable to produce smaller oxygenates and vice versa. Among them