Ken‐ichi Shimizu

Heteropolyacids (H3PW12O40, H4SiW12O40) and salts of metal cations (Mn+) and PW12O403− (M3/nPW12O40) act as effective homogeneous catalysts for selective hydrolysis of cellobiose and cellulose to glucose and total reducing sugars (TRS), respectively, in an aqueous phase. For Brønsted acid catalysts, including mineral acid and heteropolyacids, the activity for both reactions increases with a decrease in the deprotonation enthalpies (DPE), indicating that stronger Brønsted acidity is more favorabl

This review summarizes the recent examples of hydrogen transfer-type reactions using supported transition metal catalysts with special emphasis on the one-pot synthesis of chemicals by borrowing hydrogen methodology.

A gamma-alumina-supported silver cluster catalyst--Ag/Al(2)O(3)--has been shown to act as an efficient heterogeneous catalyst for oxidant-free alcohol dehydrogenation to carbonyl compounds at 373 K. The catalyst shows higher activity than conventional heterogeneous catalysts based on platinum group metals (PGMs) and can be recycled. A systematic study on the influence of the particle size and oxidation state of silver species, combined with characterization by Ag K-edge XAFS (X-ray absorption fi

Supported Au nanoparticles (NPs) prepared by colloid deposition method were well characterized, and their catalytic performance was tested for chemoselective reduction of a nitro group of substituted nitroaromatics by H2. Systematic studies on the effects of NPs size and support show small size of Au NPs, and acid-base sites of supports are required for high activity. The Au/Al2O3 catalyst with Au particle size of 2.5 nm selectively hydrogenates a nitro group in the presence of various other red

This paper reports the synthesis of primary amines from alcohols and NH3 by an Al2O3-supported Ni nanoparticle catalyst as the first example of heterogeneous and noble-metal-free catalytic system for this reaction without additional hydrogen sources under relatively mild conditions. Various aliphatic alcohols are tolerated, and turnover numbers were higher than those of Ru-based homogeneous catalysts. The catalyst was recoverable and was reused. The effects of the Ni oxidation states and the aci

Nickel nanoparticles loaded onto various supports (Ni/MOx) have been prepared and studied for the N-alkylation of amines with alcohols. Among the catalysts, Ni/θ-Al2O3 prepared by in situ H2-reduction of NiO/θ-Al2O3 shows the highest activity, and it acts as reusable heterogeneous catalyst for the alkylation of anilines and aliphatic amines with various alcohols (benzyl and aliphatic alcohols) under additive free conditions. Primary amines are converted into secondary amines and secondary amines

Silver clusters immobilized on γ-Al2O3 catalyze direct amide synthesis from alcohols and amines in the presence of catalytic amount of weak base (Cs2CO3). The reaction proceeds by cooperation of the coordinatively unsaturated silver site, as well as acid and base sites of the oxide support (see scheme). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitte

Let's drink to that! Two alcohols (one primary and one secondary) can be coupled in an atom-efficient process by a hydrogen-autotransfer catalytic system in the form of silver subnanoclusters supported on gamma-Al(2)O(3). The recyclable heterogeneous catalyst promoted the one-pot C-C cross-coupling in the presence of a catalytic amount of the weak base Cs(2)CO(3) (see reaction mechanism).

Ni–MoO_x/C showed more than 300 times higher TON than previously reported noble metal-free catalysts for the title reaction.

Recent examples for the acceptorless dehydrogenative coupling reactions of alcohols over heterogeneous catalysts for the one-pot synthesis of value-enhanced chemicals are reviewed.