ExxonMobil

About: ExxonMobil is a company organization based out in Irving, Texas, United States. It is known for research contribution in the topics: Catalysis & Polymerization. The organization has 16969 authors who have published 23758 publications receiving 535713 citations. The organization is also known as: Exxon Mobil Corporation & Exxon Mobil Corp..

Detection of an alkyl ethylene complex during ethylene polymerization by a cobalt(III) catalyst. Energetics of the .beta.-migratory insertion reaction

Abstract: The mechanism of carbon-carbon bond formation in transition-metal-catalyzed olefin polymerization reactions is though to be a {beta}-migratory insertion reaction occurring via an intermediate alkyl olefin complex, 1 {yields} 2 {yields} 1{prime} (the Cossee-Arlman mechanism). Although the stepwise polymerization of ethylene (and other alkenes) in homogeneous systems has been studied spectroscopically, intermediate alkyl ethylene complexes have not been detected. Thus, activation energies for the {beta}-migratory insertion reactions of alkyl olefin complexes in polymerizing systems are unknown. They report here spectroscopic detection of an intermediate cobalt alkyl ethylene complex during ethylene polymerization by a Co(III) catalyst together with a kinetic study which allows estimation of {Delta}G{double dagger} for the {beta}-migratory insertion reaction.

Automatic vehicle recognition and customer automobile diagnostic system

Abstract: The present invention is a system and method for identifying a vehicle for the purpose of displaying diagnostic information to the driver. Each vehicle includes a transponder that transmits an encoded character sequence that is unique to that vehicle. In this way vehicle diagnostic measurements made at the establishment entrance can be associated with the vehicle, and displayed to the customer when the vehicle is recognized again at a service area.

Fractal behavior in trapping and reaction: A random walk study

Abstract: We investigate the trapping of a random walker in fractal structures (Sierpinski gaskets) with randomly distributed traps. The survival probability is determined from the number of distinct sites visited in the trap-free fractals. We show that the short-time behavior and the long-time tails of the survival probability are governed by the spectral dimension∼d. We interpolate between these two limits by introducing a scaling law. An extension of the theory, which includes a continuous-time random walk on fractals, is discussed as well as the case of direct trapping. The latter case is shown to be governed by the fractal dimension∼d.