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Barium (Ba) has been widely and successfully added to three‐way catalysts to effectively control gasoline vehicle emissions. While the introduction of Ba is well‐known to have a very significant impact on three‐way catalysis (TWC) performance, the role of Ba under practical TWC conditions remains insufficiently understood. In this study, we investigated the role of Ba in a Pd‐based catalyst in a standard TWC process using a gasoline vehicle and in situ/operando infrared (IR) spectroscopy. The addition of Ba was found to reduce all of the emissions considered (NOx, CO, and non‐methane hydrocarbons) in the vehicle exhaust gas; it also suppressed supported‐metal aggregation, which is a requirement of a high‐performance catalyst. In addition, IR studies using model powder catalysts revealed that the efficient formation of intermediate surface nitrate species and their subsequent reactions with reductant gases, such as CO, H2, and C3H6 (as a hydrocarbon), play key roles in reducing emissions. This process is akin to the NOx storage and reduction (NSR) mechanism commonly used to control diesel emissions. [ABSTRACT FROM AUTHOR]

A combined catalyst comprising TiO2‐supported Re (Re(1)/TiO2; Re=1 wt%) and H‐MOR (SiO2/Al2O3=90) was found to promote the methylation of benzene using CO2 and H2. This catalytic system exhibited high performance with regard to the synthesis of methylated benzenes and gave high yields of total methylated products (up to 52 % benzene‐based yield and 42 % CO2‐based yield) under the reaction conditions employed in this study (pCO2=1 MPa; pH2=5 MPa; T=250 °C; t=20 h) in a batch reactor. Catalyst screening demonstrated that a combination of Re(1)/TiO2 and H‐MOR (SiO2/Al2O3=90) exhibited superior performance compared to other combinations of supported metal catalysts and zeolites in terms of both yield and selectivity for methylated benzenes. [ABSTRACT FROM AUTHOR]

CeO2 has been found to promote ester forming alcoholysis reactions of tertiary amides. The present catalytic system is operationally simple, recyclable, and it does not require additives. The esterification process displays a wide substrate scope (>45 examples; up to 93 % isolated yield). Results of a density functional theory (DFT) study combined with in situ FT‐IR observations indicate that the process proceeds through rate limiting addition of a CeO2 lattice oxygen to the carbonyl group of the adsorbed acetamide species with energy barrier of 17.0 kcal/mol. This value matches well with experimental value (17.9 kcal/mol) obtained from analysis of the Arrhenius plot. Further studies by in situ FT‐IR and temperature programmed desorption using probe molecules demonstrate that both acidic and basic properties are important, and consequently, CeO2 showed the best performance for the C−N bond cleavage reaction. C−N bond breaking! Alcoholysis of tertiary amide, a C−N bond cleavage reaction, was achieved by a heterogeneous CeO2 catalyst. The present catalytic system has the advantage of being facile and not requiring any additives. The catalyst is moreover recyclable and shows wide substrate scope toward the ester forming process. A possible catalytic mechanism is proposed on the basis of results from density functional theory (DFT) and in situ FT‐IR studies. [ABSTRACT FROM AUTHOR]

Supported metal nanoparticle catalysts were studied for the hydrodeoxygenation of sulfoxides to sulfides under solvent-free and mild conditions (50–155 °C, 1 or 7 atm H2). The catalytic activity for the model reaction of diphenyl sulfoxide depended on the type of metals, support materials and co-loaded oxides of transition metals (V, Nb, Mo, W, Re). Pt and MoOx co-loaded TiO2 (Pt–MoOx/TiO2) showed the highest activity. Pt–MoOx/TiO2 was reusable after the reaction and was effective for the reduction of various sulfoxides and showed a higher turnover number (TON) than previously reported catalysts. Using Pt–MoOx/TiO2, benzylphenylsulfone was reduced by H2 to give phenylbenzyl sulfide via benzylphenyl sulfoxides, which represented the first example of catalytic conversion of a sulfone to a sulfide by H2. Characterization studies of Pt–MoOx/TiO2 show that the surface of TiO2 is covered by small (or thin layer) Mo oxide species with exposed Mo cations as Lewis acid sites, and 4–5 nm sized Pt metal nanoparticles are supported on the Mo oxide-covered TiO2. [ABSTRACT FROM AUTHOR]

Pt-loaded HBEA (H+-exchanged BEA zeolite) is found to be an effective and reusable heterogeneous catalyst for regioselective N-alkylation of indoles with primary aliphatic and benzylic alcohols under additive-free conditions driven by the borrowinghydrogen methodology. Structural and mechanistic studies suggest a cooperative mechanism of the Pt0 site on Pt metal clusters and the Bronsted acid site of the zeolite, in which the Pt0 site is responsible for dehydrogenation/hydrogenation steps and the Brønsted acid site is responsible for the regioselective condensation of indoles with aldehydes to the enamine intermediate. [ABSTRACT FROM AUTHOR]

CeO2 acted as an efficient and reusable heterogeneous catalyst for transesterification of esters with alcohols under the solvent-free conditions at 160 °C. Among the 11 kinds of metal oxides, CeO2 is the most suitable catalyst in terms of catalytic activity, leaching-resistance and reusability. This catalytic system tolerates various esters and alcohols, and valuable esters such as heteroaromatic esters and benzyl benzoates are produced, demonstrating a practical utility of the system. On the basis of kinetic analysis and in situ IR studies of adsorbed species, a reaction mechanism is proposed, in which proton abstraction of alcohol by a Lewis base site of CeO2 to yield alkoxide species is the rate-limiting step. [ABSTRACT FROM AUTHOR]

The front cover artwork for our 10th Anniversary Issue is provided by the research groups of Ken‐ichi Shimizu at Hokkaido University and Kazunari Yoshizawa at Kyushu University (Japan). The image shows a C−N bond cleavage reaction catalyzed by CeO2. See the Full Paper itself at https://doi.org/10.1002/cctc.201801098. "Experimental and computational investigations indicate that cooperative effects of acid‐base functions of CeO2 are key for the efficient promotion of alcoholysis reactions of tertiary amides through C−N bond cleavage to form esters." This and more about the story behind the research featured on the front cover can be found in this issue's Cover Profile. Read the full text of the corresponding research at https://doi.org/10.1002/cctc.201801098. [ABSTRACT FROM AUTHOR]

The Front Cover shows a C−N bond cleavage reaction catalyzed by CeO2. In their Full Paper, T. Toyao et al. demonstrate that CeO2 promotes catalytic alcoholysis reactions of tertiary amides through C−N bond cleavage to form esters. Unlike typical reactions that use homogeneous catalytic systems and require NHC complexes, the new process is operationally convenient and does not require additives. In addition, the catalyst is recyclable and the process has a wide substrate scope. Both experimental and computational investigations indicate that cooperative effects of acid‐base functions of CeO2 are key for the efficient promotion of the reaction. More information can be found in the Full Paper by T. Toyao et al on page 449 in Issue 1, 2019 (DOI: 10.1002/cctc.201801098). [ABSTRACT FROM AUTHOR]

An abstract of the article "Fe3+exchanged Clay Catalyzed Transamidation of Amides with Amines under Solvent-Free Condition" by S. M. A. Hakim Siddiki, K. Kon and colleagues is presented.

CeO2 has been found to promote ester forming alcoholysis reactions of tertiary amides. The present catalytic system is operationally simple, recyclable, and it does not require additives. The esterification process displays a wide substrate scope (>45 examples; up to 93 % isolated yield). Results of a density functional theory (DFT) study combined with in situ FT‐IR observations indicate that the process proceeds through rate limiting addition of a CeO2 lattice oxygen to the carbonyl group of the adsorbed acetamide species with energy barrier of 17.0 kcal/mol. This value matches well with experimental value (17.9 kcal/mol) obtained from analysis of the Arrhenius plot. Further studies by in situ FT‐IR and temperature programmed desorption using probe molecules demonstrate that both acidic and basic properties are important, and consequently, CeO2 showed the best performance for the C−N bond cleavage reaction. C−N bond breaking! Alcoholysis of tertiary amide, a C−N bond cleavage reaction, was achieved by a heterogeneous CeO2 catalyst. The present catalytic system has the advantage of being facile and not requiring any additives. The catalyst is moreover recyclable and shows wide substrate scope toward the ester forming process. A possible catalytic mechanism is proposed on the basis of results from density functional theory (DFT) and in situ FT‐IR studies. [ABSTRACT FROM AUTHOR]

Nickel-nanoparticle-loaded θ-Al2O3 (Ni/θ-Al2O3), prepared by H2-reduction of NiO/θ-Al2O3, acts as an effective and reusable heterogeneous catalyst for acceptor-free dehydrogenation of alcohols in a liquid phase. Among various supports, amphoteric supports (such as θ-Al2O3), having both acidic and basic sites, gave higher activity than acidic or basic supports. Among Ni/θ-Al2O3 catalysts with different Ni particle sizes, turnover frequency (TOF) per surface Ni increases with decreasing Ni particle size. These results suggest that low-coordinated Ni0 sites and metal/support interfaces play important roles in the catalytic cycle. The reaction mechanism is investigated by in situ IR study combined with kinetic analysis (kinetic isotope effect), and the following mechanism is proposed: (1) reaction of an alcohol with Lewis acid (Alδ+)–base (Al—Oδ−) pair site of alumina yields an alkoxide on the Alδ+ site and a proton on the Al—Oδ− site, (2) C—H dissociation of the alkoxide by Ni0 site to form Ni—H and a ketone, and (3) protolysis of Ni—H by a neighboring proton to release H2 gas. The proposed mechanism provides fundamental reasons for the higher activity of Ni on the acid–base bifunctional support (Al2O3) than on basic and acidic ones. [ABSTRACT FROM AUTHOR]

The front cover artwork for our 10th Anniversary Issue is provided by the research groups of Ken‐ichi Shimizu at Hokkaido University and Kazunari Yoshizawa at Kyushu University (Japan). The image shows a C−N bond cleavage reaction catalyzed by CeO2. See the Full Paper itself at https://doi.org/10.1002/cctc.201801098. "Experimental and computational investigations indicate that cooperative effects of acid‐base functions of CeO2 are key for the efficient promotion of alcoholysis reactions of tertiary amides through C−N bond cleavage to form esters." This and more about the story behind the research featured on the front cover can be found in this issue's Cover Profile. Read the full text of the corresponding research at https://doi.org/10.1002/cctc.201801098. [ABSTRACT FROM AUTHOR]

The development of heterogeneous catalysts for green chemical synthesis is currently a growing area in catalysis and sustainable chemistry. Especially the use of renewable carbon resources such as carbon dioxide (CO 2 ) and biomass-derived compounds (e. g. carboxylic acids, esters, and amides) represent highly attractive research targets. As these substances reside in a high oxidation state, efficient reduction processes are required in order to convert these substrates into useful and value-added chemicals. Moreover, in the interest of mass production, these substrates should be reduced by molecular H 2 and a heterogeneous catalyst. In this context, our group has developed advanced catalysts and established design guidelines for catalysts that promote the reductive transformations of carboxylic acid derivatives and CO 2 . Our studies show that cooperative catalysis between Lewis-acidic sites on the catalyst support and supported metal nanoparticles are crucial for the success of these challenging hydrogenations. In this review, we summarize the results of our recent studies on the direct synthesis of value-added chemicals from CO 2 and carboxylic acid derivatives using supported transition-metal catalysts, and we propose a design concept for heterogeneous catalysts that promote these processes., (© 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)