Transformations of ethylene in presence of Pd-zeolite catalyst

Electron spin resonance study of peroxy labels in a copolymer of tetrafluoroethylene-hexafluoropropylene

“…23 In urea adducts with n-alkanes of various chain lengths, chain axis rotation with 120°j umps was deduced. 4 This result is in agreement with the known hexagonal symmetry of urea channels, in which the long axis of the guest chain molecules is parallel to the hexagonal axis. All these results indicate the sensitivity of ESR spectra from peroxy radical labels to the environment and to the specific motional mechanism.…”

“…Palladium compounds are well-known for their homogeneous catalytic activity for a variety of reactions with olefins.1-3 In a few papers the results of ethylene dimerization over palladium loaded zeolites have been discussed. [4][5][6] In general the selectivity to form «-butenes has been found to be rather poor even at relatively low ethylene conversion.…”

Determination of the chemical state of palladium in PdNa-X zeolite by electron spin resonance and x-ray photoelectron spectroscopy

“…Introduction Diffusion-controlled reactions play an important role in many areas of chemistry.1•2 Quite recently, Northrup et al introduced a new theoretical approach for determining the rate constants and mechanistic features of such reactions. 3 In this approach, one simulates the relative motion of interacting reactant molecules by computing representative diffusional trajectories, and then obtains the rate constant from the observed frequency of collisions that satisfy the geometric requirements for reactions. Because such realistic features as molecular shape, orientational dependence of reactivity, long-and short-range intermolecular forces, hydrodynamic interactions, and intramolecular structural fluctuations can all be included, the trajectory approach should in principle be quite valuable in the analysis of the complicated types of reactions that are often encountered in organic, polymer, and biological chemistry.…”