Catalytic dehydrogenation of chloroethylbenzene

Summary In the dehydrogenation of chloroethylbenzene over a mixed oxide catalyst in presence of water vapor at 600° at space velocities of 0.2–0.35 h^–1 up to 36% of chlorostyrene is formed (yield based on the amount of chloroethylbenzene passed). In the treatment of chlorobenzene in presence of water under the same conditions the chlorine is retained in the nucleus, but when hydrogen is the diluent there is considerable breakdown of the chlorobenzene (50%) with formation of benzene and hydrogen chloride.     

Thermal destruction of two-dimensional graphite islands on refractory metals (Ir, Re, Ni, and Pt)

Thermal destruction of two-dimensional graphite films on Ni(111), Re(10-10), Ir(111), and Pt(111) substrates is studied. It is shown that the detachment of an edge carbon atom from an island is a limiting process stage for all the cases. The activation energy of this process varies from 2.5 eV for nickel to 4.5 eV for iridium. The variation of the activation energy is associated with the ability of the metal surface to form strong chemisorptive bonds with valence-active edges of graphite islands, which loosen C-C bonds in graphite.     

Sodium Intercalation of Graphene Films on Re( $$10\bar 10$$ 10 1 ¯ 0 )

It is shown that during low-temperature (300–500 K) intercalation of sodium atoms into thin multilayer graphene and graphite films on rhenium the first graphene layer plays the role of a trap to which atoms coming on the surface diffuse through a graphite film. The intercalation phase of the interlayer space in the graphite bulk is actively filled at a sodium atoms concentration under the first graphene layer close to the maximum possible (2 ± 0.5) × 10¹⁴ cm^–2. This phase capacity is proportional to the graphite film thickness that can be varied in this work from one graphene layer to ~50 atomic layers. The diffusion energy E _d of Na atoms through the graphite film was estimated to be E _d ≈ 1.4 eV.