CHEMISTRY: Clean Coupling

Reduced Chemistry-Diffusion Coupling

In reacting flow problems involving large numbers of chemical species and reactions, reduced chemistry modeling is used to approximately describe, with fewer unknowns, the slow chemical evolutions after the rapid but brief initial transients have decayed. Diffusion transport terms, if present, are modified by the reduced chemistry approximations. This article reiterates that the use of unmodifi...

French Industry and Sustainable Chemistry : The Benefits of Clean Development

New regiospecific isothiazole C-C coupling chemistry.

Regioselective palladium catalysed coupling reactions are achieved in good to high yields, starting from either 3,5-dichloro- or 3,5-dibromoisothiazole-4-carbonitriles 1 and 2, providing 3-halo-5-(hetero/aryl, alkenyl and alkynyl)isothiazoles 3, 4, 6-9 from Stille couplings, 3-halo-5-(hetero/arylethynyl)isothiazoles 14-19 from Sonogashira and 5,5'-bi(3-chloroisothiazole-4-carbonitrile) (13) fro...

3,4,5-triarylisothiazoles via C-C coupling chemistry.

The regiocontrolled preparation of triarylisothiazoles is presented. 3-Halo-5-phenylisothiazole-4-carbonitriles, 1 (hal=Cl) and 18 (hal=I), are converted into the corresponding 4-bromo derivatives 5 (3-hal=Cl) and 24 (3-hal=I) via a Hunsdiecker strategy while the 4-iodo analogues 7 (3-hal=Cl) and 22 (3-hal=I) are prepared via a Hoffmann and Sandmeyer strategy. Regioselective Suzuki, Stille and ...

The surface chemistry of methylene iodide adsorbed on clean and oxygen-covered Mo(100): formation and chemistry of carbenes

Carbene species are grafted onto Mo(100) by the thermal decomposition of methylene iodide, where the decomposition is followed using ultraviolet photoelectron spectroscopy. Carbenes hydrogenate to methane by reaction with surface hydrogen via a secondorder reaction with an activation energy of 21 ___ 2 kJ mol1. Experiments with deuterium show that there appears to be no hydrogendeuterium exchan...