We have carried out a mechanistic investigation of aerobic dehydrogenation of cyclohexanones and cyclohexenones to phenols with a Pd(TFA)2/2-dimethylaminopyridine catalyst system. Numerous experimental methods, including kinetic studies, filtration tests, Hg poisoning experiments, transmission electron microscopy, and dynamic light scattering, provide compelling evidence that the initial Pd(II)...

We have studied the dehydrogenation properties of pure and Ti-doped Na3AlH6 surfaces using density functional theory. For the clean surface dehydrogenation is a multistep process, and involves the desorption of AlH4 complexes which disrupt the structure of the surface. By doping the system with Ti, we found that the segregation energy of Ti is negative, therefore favoring localization of the im...

The dehydrogenation of piperidine has been studied and found to have an order of -1.5 with respect to the hydrogen partial pressure. By combining these results with those obtained for pyridine hydrogenation on the same catalyst a complete rate equation for piperidine dehydrogenation together with the stoichiometric number of the rate-determining step of these reactions could be derived. This nu...

H-ZSM5, Zn/H-ZSM5, and Co/H-ZSM5 catalyze thiophene desulfurization with high H2S selectivity using propane as the exclusive hydrogen source. Desulfurization rates and selectivities were much higher than at the H2 concentrations present during propane reactions. Zn+2 and Co+2 cations at exchange sites increased desulfurization rates. On H-ZSM5, desulfurization rates and selectivities with propa...

A novel route to enamines is reported, the dehydrogenation of tertiary amines catalyzed by a "pincer-ligated" iridium catalyst.

Formic acid (FA) is an attractive compound for H2 storage. Currently, the most active catalysts for FA dehydrogenation use precious metals. Here, we report a homogeneous iron catalyst that, when used with a Lewis acid (LA) co-catalyst, gives approximately 1,000,000 turnovers for FA dehydrogenation. To date, this is the highest turnover number reported for a first-row transition metal catalyst. ...

Methanol decomposition and oxidation on Pd(111) at millibar pressure were studied by in situ polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS), on-line gas chromatography and pre- and postreaction X-ray photoelectron spectroscopy (XPS). Various dehydrogenation products such as methoxy CH3O, formaldehyde CH2O, formyl CHO, and CO could be spectroscopically identified. ...

Lactate racemase is the first enzyme known to possess a metal pincer active site. The enzyme interconverts d- and l-lactic acid, which is important for the assembly of cell walls in many microorganisms. Here, we report a synthetic model of the active site of lactate racemase, which features a pyridinium-based SCS pincer ligand framework bound to nickel. The model complex mediates the dehydrogen...