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..

Diffusing-wave spectroscopy and multiple scattering of light in correlated random media

Abstract: We discuss the diffusing-wave spectroscopy technique for multiple scattering of light as introduced in recent experiments. This technique has proven to be useful in probing the self-diffusion of scattering particles in suspension by measuring the light-intensity autocorrelation function. We show how the autocorrelation function depends upon the dynamic structure factor of the medium in the presence of correlations between the scattering particles. There is a simple generalization of the result obtained for uncorrelated media to include the dynamic structure factor. Previous theoretical work has employed the white-noise model, valid for small uncorrelated scattering centers. The results of this model are valid only so long as the propagation of the light can be regarded as diffusive. On short length scales, however, the propagation becomes increasingly ballistic in nature. We present an exact formal solution of the transport equation capable of describing the crossover from ballistic to diffusive propagation. The resulting transport kernel provides a simple correction to the diffusion approximation for large scattering particles, which substantially improves the agreement with measured autocorrelation functions. We also discuss the polarization dependence of the autocorrelation function for both small as well as large scattering particles.

Method for determining the compositional distribution of a crystalline copolymer

Abstract: A method for fractionating crystalline copolymers to determine solubility distribution as a function of temperature. Fractionation is conducted by passing a solvent through a column containing the crystallized copolymer at an increasing temperature from 6° C. to about 120° C. The polymer solution exiting the column is analyzed by infrared spectroscopy or NMR to determine the composition distribution of the copolymer.

Process for manufacturing improved process oils using extraction of hydrotreated distillates

Abstract: A method for producing a process oil in which a naphthenic rich distillate is processed through a single hydrotreating stage, the hydrotreated distillate is then solvent extracted to yield a process oil which passes IP-346 and AMES screening test.

Biodegradable high performance hydrocarbon base oils

Abstract: Discloses novel biodegradable high performance hydrocarbon base oils useful as lubricants in engine oil and industrial compositions, and process for their manufacture. A waxy, or paraffinic feed, particularly a Fischer-Tropsch wax, is reacted over a dual function catalyst to produce hydroisomerization and hydrocraking reactions, at 700 °F+ conversion levels ranging from about 20 to 50 wt.%, preferably about 25-40 wt.%, sufficient to produce a crude fraction, e.g., a C5-1050 °F+ crude fraction, containing 700 °F+ isoparaffins having from about 6.0 to about 7.5 methyl branches per 100 carbon atoms in the molecule. The methyl paraffins containing crude fraction is topped via atmospheric distillation to produce a bottoms fraction having an initial boiling point between about 650 °F and 750 °F which is then solvent dewaxed, and the dewaxed oil is then fractionated under high vacuum to produce biodegradable high performance hydrocarbon base oils.