Biomass is an important feedstock for the renewable production of fuels, chemicals, and energy. As of 2005, over 3% of the total energy consumption in the United States was supplied by biomass, and it recently surpassed hydroelectric energy as the largest domestic source of renewable energy. Similarly, the European Union received 66.1% of its renewable energy from biomass, which thus surpassed the total combined contribution from hydropower, wind power, geothermal energy, and solar power. In addition to energy, the production of chemicals from biomass is also essential; indeed, the only renewable source of liquid transportation fuels is currently obtained from biomass.

The Catalytic Valorization of Lignin for the Production of Renewable Chemicals

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

A wide array of forms of palladium has been utilized as precatalysts for Heck and Suzuki coupling reactions over the last 15 years. Historically, nearly every form of palladium used has been described as the active catalytic species. However, recent research has begun to shed light on the in situ transformations that many palladium precatalysts undergo during and before the catalytic reaction, and there are now many suggestions in the literature that narrow the scope of types of palladium that may be considered true “catalysts” in these coupling reactions. In this work, for each type of precatalyst, the recent literature is summarized and the type(s) of palladium that are proposed to be truly active are enumerated. All forms of palladium, including discrete soluble palladium complexes, solid-supported metal ligand complexes, supported palladium nano- and macroparticles, soluble palladium nanoparticles, soluble ligand-free palladium, and palladium-exchanged oxides are considered and reviewed here. A considerable focus is placed on solid precatalysts and on evidence for and against catalysis by solid surfaces vs. soluble species when starting with various precatalysts. The review closes with a critical overview of various control experiments or tests that have been used by authors to assess the homogeneity or heterogeneity of catalyst systems.

On the Nature of the Active Species in Palladium Catalyzed Mizoroki–Heck and Suzuki–Miyaura Couplings – Homogeneous or Heterogeneous Catalysis, A Critical Review

Green solvents for sustainable organic synthesis: state of the art

Short protocols in molecular biology

Mechanism of thermal decomposition of dineopentylbis(triethylphosphine)platinum(II): formation of bis(triethylphosphine)-3,3-dimethylplatinacyclobutane

Sir: Direct electrochemical methods for reduction of NAD(P) to NAD(P)H have not proved sufficiently selective for reduction at the 4-position to give high turnover numbers (TN) for these cofactors.l-3 A combined electrochemicallenzymatic method based on cathodic reduction of lipoamide and lipoamide dehydrogenase (LipDH, EC 1.6.4.3) catalyzed reduction of NAD gave TN 900,4 and hydrogenase-catalyzed reduction of MV2+ by Hz combined with lipoamide dehydrogenase or ferredoxin reductase (FDR, EC 1.6.99.4) catalyzed reduction of NAD(P) gave similar values.5 Nthough the use of electrochemically generated MVl+ to produce NADPH from NADP via reaction with FDR has been reported previously,6'7 application of this redox cycle to regeneration of NAD(P)H for practical organic synthesis has not been described; here we report such a procedure. Reactions were performed under argon in a 1-L threenecked flask containing a magnetic stirring bar and a working electrode of 10 m of coiled tungsten wire8 (0.020-in. diameter, -160-cm2 surface area). The counter electrode was a 2 x 5-in. section of 80-mesh platinum gauze and was separated from the working solution in a glass tube sealed to a fine-porosity sintered glass frit inserted through the center neck of the flask. The reference electrode (SCE) was isolated from the working solution in the same manner. The total charge passed during electrolyses was determined by graphical integration of the recorded current-time curve. Current efficiency was calculated by subtraction of the integrated background currente from the total in-

Enzyme-catalyzed organic synthesis: electrochemical regeneration of NAD(P)H from NAD(P) using methyl viologen and flavoenzymes

Oxidation of lignin model compounds using single-electron-transfer catalysts

Synthesis of 3-Deoxy-D-manno-2-octulosonate-8-phosphate (KDO-8-P) fromD-Arabinose: Generation of D-Arabinose-5-Phosphate using Hexokinase

L'oxydation electrochimique du propanol-2 est realisee sur une electrode de platine dans une solution d'acide sulfurique

Robert Dicosimo

Papers

Mechanism of thermal decomposition of dineopentylbis(triethylphosphine)platinum(II): formation of bis(triethylphosphine)-3,3-dimethylplatinacyclobutane

Enzyme-catalyzed organic synthesis: electrochemical regeneration of NAD(P)H from NAD(P) using methyl viologen and flavoenzymes

Oxidation of lignin model compounds using single-electron-transfer catalysts

Synthesis of 3-Deoxy-D-manno-2-octulosonate-8-phosphate (KDO-8-P) fromD-Arabinose: Generation of D-Arabinose-5-Phosphate using Hexokinase

Oxidation of 2-propanol to acetone by dioxygen on a platinized electrode under open-circuit conditions