Masazumi Tamura

Ir-ReOx/SiO2 acted as a highly active and selective heterogeneous catalyst for the hydrogenation of unsaturated aldehydes to unsaturated alcohols in water at low H2 pressure (0.8 MPa) and low temperature (303 K). The catalysis is derived from the synergy between Ir metal and ReOx.

We disclosed the redox properties of CeO2 in organic reactions at low temperature of 303 K. CeO2 works as the most effective heterogeneous catalyst for imine formation from benzyl alcohol and aniline at 303 K among various metal oxides and showed more than 38-fold higher activity than other simple metal oxides. CeO2 is applicable to the reaction of various alcohols and amines and gives high yields (80-98%) and high selectivities (89->99%). Kinetic measurements, MS, and FTIR analyses demonstrated

Abstract CO 2 has a large effect on global warming by greenhouse gases, and development of an effective technique for the reduction of CO 2 is a crucial and urgent issue. From the chemical viewpoint, CO 2 is regarded as a stable, safe and abundant C1 resource, and the transformation of CO 2 to valuable chemicals is promising not only for reduction of CO 2 but also for production of useful chemicals. This mini‐review focuses on the direct conversion of CO 2 with diols, aminoalcohols and diamines

Among various metal oxides, cerium oxide (CeO2) shows the highest catalytic activity for transamidation of picolinamide with n-octylamine. CeO2 acts as a reusable and effective heterogeneous catalyst for transamidation under solvent-free conditions. Transamidation of a variety of amides and amines produced the corresponding N-alkyl amides in high yields. This method provides the first example of a heterogeneous catalyst for transamidation using aliphatic amines as substrates. Characterization of

The scope of metal oxide modified noble metal (M+M′Ox) catalysts was scrutinized in the hydrogenation of crotonaldehyde to crotyl alcohol as a model reaction under mild reaction conditions (303 K, 0.8 MPa, water solvent), demonstrating that MoOx, WOx, NbOx, FeOx and ReOx are effective metal oxides for Ir/SiO2 to enhance both the activity and selectivity, although the optimized (metal oxide)/(Ir metal) molar ratio depends on the metal oxide. MoOx modified Ir/SiO2 catalyst (Ir-MoOx/SiO2 (Mo/Ir = 1

CeO2 acted as a reusable and effective catalyst for the hydration of various nitriles to amides in water under neutral conditions at low temperature (30–100 °C). CeO2 showed notable substrate specificity for nitriles that have a heteroatom adjacent to the α-carbon atom of the CN group (see scheme).

Pure cerium oxide (CeO2) acts as an effective and reusable heterogeneous catalyst for direct synthesis of cyclic ureas from CO2 and diamines even at a low CO2 pressure of 0.3 MPa. 2-Propanol is the most preferable solvent to provide good selectivity. The system composed of a CeO2 catalyst and a 2-propanol solvent is applied to various diamines to provide the corresponding cyclic ureas in high yields (78–98%), including six-membered-ring ureas that are difficult to be synthesized from CO2. Based

Direct polymerization of CO2 and diols is promising as a simple and environmental-benign method in place of conventional processes using high-cost and/or hazardous reagents such as phosgene, carbon monoxide and epoxides, however, there are no reports on the direct method due to the inertness of CO2 and severe equilibrium limitation of the reaction. Herein, we firstly substantiate the direct copolymerization of CO2 and diols using CeO2 catalyst and 2-cyanopyridine promotor, providing the alternat

The control technique of polymer molecular weight is required for the synthesis of versatile polymers with various properties. In our previous work, we found that CeO2 + 2-cyanopyridine catalyst system was effective for the direct synthesis of alternating polycarbonates from CO2 and diols, however, the maximum average molecular weight was ∼1000 g mol–1 (degree of polymerization = 7–8). In this study, we succeeded in the synthesis of alternating polycarbonates with higher molecular weight from CO