3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

Chemical Routes for the Transformation of Biomass into Chemicals

Ordered mesoporous materials in catalysis

ion from a primary OH group of glyc-erol. 223,231 A similar mechanism was proposed manyyears ago for alcohol oxidation on Pt/C, involving asecond step, the transfer of a hydride ion to the Ptsurface (Scheme 11). 8,87,237 We consider it more feasible that the rate-deter-mining step is the cleavage of the C-H bond at theR-carbon atom. A similar mechanism is now generallyaccepted for Au electrodes (Scheme 12). 238 Despite thestructural differences between Au nanoparticles andan extended Au electrode surface, there are alsosimilarities, such as the critical role of aqueousalkaline medium and the absence of deactivation dueto decomposition products (CO and C x H y frag-ments). 239,240 An important question is the nature of active siteson Au nanoparticles. Electrooxidation of ethanol onAu nanoparticles supported on glassy carbon re-quired the partial coverage of Au surface by oxides. 241 Another analogy might be the model proposed for COoxidation. 219,242,243 According to this suggestion, theactive site consists of an ensemble of metallic Auatoms and a cationic Au

Oxidation of Alcohols with Molecular Oxygen on Solid Catalysts

Recent advances in transition metal catalyzed oxidation of organic substrates with molecular oxygen.

C–H activation has surfaced as an increasingly powerful tool for molecular sciences, with notable applications to material sciences, crop protection, drug discovery, and pharmaceutical industries, among others. Despite major advances, the vast majority of these C–H functionalizations required precious 4d or 5d transition metal catalysts. Given the cost-effective and sustainable nature of earth-abundant first row transition metals, the development of less toxic, inexpensive 3d metal catalysts for C–H activation has gained considerable recent momentum as a significantly more environmentally-benign and economically-attractive alternative. Herein, we provide a comprehensive overview on first row transition metal catalysts for C–H activation until summer 2018.

3d Transition Metals for C-H Activation.

Hyper-coal process to produce the ash-free coal

The liquid-phase catalytic oxidation of benzene to directly produce phenol was attempted under mild reaction conditions using supported Cu catalysts in aqueous acetic acid solvent. Gaseous oxygen and ascorbic acid were used as an oxidant and a reductant, respectively. Among the supported Cu catalysts studied, the Cu catalysts prepared by the impregnation method, irrespective of the oxide supports, the Cu species were considerably leached during the benzene oxidation. A supported Cu catalyst (CuO–Al 2 O 3 ) prepared by co-precipitation of Cu(NO 3 ) 2 ·3H 2 O and Al(NO 3 ) 3 ·9H 2 O inhibited the leaching of Cu species in comparison with the Cu catalysts supported by the impregnation method on Al 2 O 3 , SiO 2 , MCM-41, etc. The influences of the amount of supported Cu, the partial pressure of O 2 , the amount of ascorbic acid, the concentration of acetic acid in the solvent, and the reaction temperature on the phenol yield were investigated using the CuO–Al 2 O 3 catalyst. The aqueous solvent including high concentration of acetic acid (around 80 vol.%) dramatically inhibited the leaching of Cu species in the CuO–Al 2 O 3 catalyst. H 2 O 2 , which is considered to play an important role in phenol formation, was detected during the benzene oxidation catalyzed by CuO–Al 2 O 3 .

Liquid-phase oxidation of benzene to phenol by CuO–Al2O3 catalysts prepared by co-precipitation method

Promoted partial oxidation activity of supported Ag catalysts in the gas-phase catalytic oxidation of benzyl alcohol

Mesoporous silicates (MCM-41 and Al-containing MCM-41) were applied to catalyst supports for liquid-phase benzene oxidation paying attention to their remarkable features, such as large surface area, ordered mesopores and high thermal stability. The MCM-41-supported Cu catalysts were prepared by the method of impregnation (Cu/MCM-41) and ion-exchange treatment (Cu–Na·MCM-41, Cu–H·MCM-41). The liquid-phase oxygenation of benzene to phenol over the MCM-41-supported Cu catalysts was studied using molecular oxygen as an oxidant and ascorbic acid as a reducing reagent for the Cu species. The MCM-41-supported Cu catalysts, particularly the Cu ion-exchanged H·MCM-41 (Cu–H·MCM-41), were more active than the corresponding Cu catalysts supported on SiO2, TiO2, MgO, NaZSM-5, NaY, or KL zeolites. The accumulation of hydrogen peroxide (H2O2) was confirmed during the liquid-phase oxidation of benzene catalyzed by the Cu-supported MCM-41.

Formation of Cu-supported mesoporous silicates and aluminosilicates and liquid-phase oxidation of benzene catalyzed by the Cu-mesoporous silicates and aluminosilicates

The redox behavior and mobility of the Cu ions in Cu ion-exchanged NaZSM-5 zeolites (Cu-NaZ) during oxidation of benzyl alcohol were examined by CO adsorption, IR absorption measurement of CO adsorbed on the Cu-NaZ, and diffuse reflectance spectra measurement. The properties and oxidation state of the Cu ions in Cu ion-exchanged SiO 2 (Cu-SiO 2 ) were also investigated by similar methods, focusing on the comparison with those in the Cu-NaZ zeolites. The Cu-NaZ zeolites with higher degrees of Cu ion exchange were found to have at least two different kinds of Cu ions, in contrast to the Cu-SiO 2 which showed the presence of only one kind of Cu ion

Shigeru Tsuruya

Papers

Hyper-coal process to produce the ash-free coal

Liquid-phase oxidation of benzene to phenol by CuO–Al2O3 catalysts prepared by co-precipitation method

Promoted partial oxidation activity of supported Ag catalysts in the gas-phase catalytic oxidation of benzyl alcohol

Formation of Cu-supported mesoporous silicates and aluminosilicates and liquid-phase oxidation of benzene catalyzed by the Cu-mesoporous silicates and aluminosilicates

Redox behavior and mobility of copper ions in NaZSM-5 zeolite during oxidation