Mobil

About: Mobil is a based out in . It is known for research contribution in the topics: Catalysis & Zeolite. The organization has 7085 authors who have published 10642 publications receiving 237497 citations. The organization is also known as: Socony-Vacuum Oil Company & Standard Oil Company of New York.

MCM-36: The first pillared molecular sieve with zeoliteproperties

Abstract: Publisher Summary This chapter describes the physical characterization of MCM-36, which unequivocally establishes its existence as a novel large pore pillared material with zeolite properties. MCM-36 is a pillared material obtained from MCM-22 layers. The preparation of MCM-36 involves a lamellar intermediate, designated MCM-22 precursor, produced in a hydrothermal process. The structural information concerning pore system of MCM-36 is revealed by adsorption methods. The layers in MCM-22 posses two kinds of pore systems. One consists of 10-ring interconnected channels within the layers. The second are isolated 12-ring cages on the surface, which result in pockets on the outside of MCM-22 crystal and internal supercages, accessible through 10-ring apertures, inside the crystal. Accordingly, the pore size distribution plot obtained for MCM-22 by Ar physisorption shows two distinct peak in the 6–7 A region. The complex pore structure of MCM-22 is also reflected in the unique three step uptake profile of bulky 2,2-dimethylbutane (DMB) observed in the dynamic sorption experiment.

Process for controlling the mwd of a broad/bimodal resin produced in a single reactor

Abstract: A bimetallic catalyst produces broad or bimodal molecular weight distribution polyolefin resin whose composition depends on the ratio of the concentration of the two metals of the catalyst producing the HMW and LMW components. The bimetallic catalyst produces a broad/bimodal MWD resin whose HMW and LMW components depend on the relative productivity of each of the transition metal sites of the catalyst. Water and/or carbon dioxide are cofed to the polymerization reactor at levels necessary to modify the weight fractions of the HMW and LMW components, thus achieving a target molecular weight distribution, MWD. The invention allows the resin MWD to be adjusted in the reactor. The weight fraction of the high molecular weight component decreases with the addition of the water and/or the carbon dioxide and the FI of the overall product increases with a decrease in the HMW component weight fraction in th e product.

Chemostratigraphic reconstruction of biofacies: Molecular evidence linking cyst-forming dinoflagellates with pre-Triassic ancestors

Abstract: New data from numerous detailed mass-spectrometric studies have detected triaromatic dinosteroids in Precambrian to Cenozoic rock samples. Triaromatic dinosteroids are organic geochemicals derived from dinosterols, compounds known in modern organisms to be the nearly exclusive widely occurring products of dinoflagellates. We observed the ubiquitous occurrence of these dinosteroids in 49 Late Triassic through Cretaceous marine source rocks and the absence of them in 13 Permian-Carboniferous source rocks synergistic with the dinoflagellate cyst record. However, finding dinosteroids in lower Paleozoic and Precambrian strata presents challenging results for molecular paleontologists, evolutionary biologists, palynologists, and especially for those concerned with the food web at various times of biological crisis. Other than the few species known as parasites and symbionts, many other dinoflagellate species are important as primary producers. The presence of Precambrian to Devonian triaromatic dinosteroids gives chemostratigraphic evidence of dinoflagellates (or other organisms with similar chemosynthetic capabilities) in rocks significantly older than the oldest undisputed dinoflagellate fossils (dinoflagellate cysts from the Middle Triassic, ∼ 240 Ma), and older than the putative Silurian ∼ 420 Ma) dinocyst, Arpylorus antiquus (Calandra) Sargent, from Tunisia. This systematic chemostratigraphic approach can shed light not only on lineages of dinoflagellates and their precursors, but potentially on many other lineages, especially bacteria, algae, plants, and possibly some metazoans.

Catalyst composition and process for preparing polymers having multimodal molecular weight distribution

Abstract: There is disclosed a supported olefin polymerization catalyst composition comprising a precursor and a catalyst activator. The precursor comprises a magnesium compound, e.g., dibutylmagnesium, a cyclopentadienyl group - containing zirconium compound, and a titanium and/or a vanadium compound, e.g., TiCl₄, and an organic compound, e.g., an alcohol. The catalyst activator is a mixture of a conventional Ziegler/Natta co-catalyst and a zirconium sites activator, e.g., methylaluminumoxane. The catalyst is used in the presence of small amounts of hydrogen to produce polymers having multimodal molecular weight distribution in a single reactor.