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.

Formation of Hollow Helicoids in Mesoporous Silica: Supramolecular Origami

Abstract: In the past, helical shapes in nature have inspired inventions such as the water screw for agriculture, the retaining screw for wine presses, and architectural designs for spiral staircases. Similarly, these days helix-shaped DNA, proteins and carbon nanotubes evoke great interest in biotechnology and nanotechnology. Also biomimetic synthesis of helical morphologies of calcium carbonate, barium sulfate, and silica provides insight into morphogenesis of mineralized spiral forms in biology and ideas for new opportunities in materials science. Herein we describe the synthesis of hollow helicoids made of hexagonal mesoporous silica, a remarkable topology in the materials world. They have a hierarchical architecture comprised of 5 nm diameter channels that coil in the form of a micrometerscale tubular spiral. A population analysis of helicoid shapes defines a surprisingly narrow distribution of pitch and flute widths, pitch angles, inside and outside diameters, and significantly an equal number of leftand right-handed forms. Evidence is presented that morphogenesis involves polymerization-induced differential contraction of a patch of hexagonal silicate liquid-crystal film formed at the air± water interface, which can fold into a hollow helicoid. A supramolecular Origami theoretical model explains the creation and observed narrow distribution of mesoporous silica, hollow helicoid shapes. Mesoporous silica hollow helicoids were prepared by using cetyltrimethylammonium chloride (CTACl) as the surfactant micellar template and tetraethylorthosilicate (TEOS) as the silica precursor. An aqueous solution of CTACl, hydrochloric acid and formamide was aged for 48 h before adding TEOS, and the material was formed after 3 days in a quiescent state. The use of formamide in the synthesis is intentional because upon acid hydrolysis it yields ammonium chloride and formic acid to give an ultimate solution ca. pH 1.9 and an ionic strength that favors hollow helicoid formation. This solution pH is notably higher than the one used in the synthesis of mesoporous silica curved shapes. Control experiments demonstrate that a high concentration of ammonium and formate ions is essential for the formation of mesoporous silica at a pH close to two, which borders on the isoelectric point of aqueous silica. We believe that a low acidity and high ionic strength medium favor a slow rate of silicification, and hence polymerization-induced differential contraction of silicate micelle rods in a patch of silicate liquid-crystal film formed at the air±water interface becomes influential in hollow helicoid formation. Powder X-ray diffraction (PXRD) patterns in Figure 1 clearly define as-synthesized and calcined

Catalytic conversion of olefins to higher hydrocarbons

Abstract: CATALYTIC CONVERSION OF OLEFINS TO HIGHER HYDROCARBONS Abstract An improved continuous process for converting lower olefinic hydrocarbon feedstock to C5+ liquid hydrocarbons by contacting vapor phase olefinic feedstream with acid zeolite catalyst in the presence of recycled diluent stream rich in C3-C4 hydrocarbons in an enclosed reactor at elevated temperature and pressure. The improved technique comprises a system for cooling reactor effluent to recover a heavier hydrocarbon stream containing a mixture of C3-C4 hydrocarbons and C5+ hydrocarbons and debutanizing the heavier hydrocarbons below reactor pressure to obtain a C5+ product stream and a condensed C3-C4 hydrocarbon stream. Operating efficiencies are realized in the heat exchange system by reboiling the debutanized C5+ hydrocarbon product stream by heat exchange with hot reactor effluent, and by recycling and combining at least a portion of the condensed C3-C4 hydrocarbon stream to dilute the liquid olefin hydrocarbon feedstock. By increasing pressure on the liquid olefinic hydrocarbon feedstock and liquid recycle stream to at least the elevated reactor pressure in the liquid state prior to vaporization, energy is conserved. An apparatus arrangement for conducting such a process is also disclosed.

Process and apparatus for the manufacture of embossed film laminations

Abstract: A method for the production of embossed laminar thermoplastic film structures comprising supplying a first length of a thermoplastic film onto the surface of a patterned roller, portions of which pattern are capable of absorbing infrared radiation, subsequently heating the patterned surface to raise the temperature of the film in those areas which are in contact with the infrared absorbent pattern, and finally superimposing a preheated film onto the film on the surface of the patterned roller to produce a laminar structure bonded together along a plurality of intersecting heat seal lines.

Offscraping and underthrusting of sediment at the deformation front of the Barbados Ridge: Deep Sea Drilling Project Leg 78A

Abstract: On Leg 78A we drilled Sites 541 and 542 into the seaward edge of the Barbados Ridge complex, and Site 543 into the adjacent oceanic crust. The calcareous ooze, marls, and muds at Sites 541 and 542 are lithologically and paleontologically similar to the upper strata at Site 543 and are apparently offscraped from the down-going plate. A repetition of Miocene over Pliocene sediments at Site 541 documents major thrust or reverse faulting during offscraping. The hemipelagic to pelagic deposits offscraped in the Leg 78A area include no terrigenous sand beds, but they contain numerous Neogene ash layers derived from the Lesser Antilles Arc. Hence, this sequence is quite unlike the siliciclastic-dominated terranes on land that are inferred to be accretionary complexes. The structural fabric of the offscraped deposits at Sites 541 and 542 is disharmonic, probably along a decollement, with an underlying acoustically layered sequence, suggesting selective underthrusting of the latter. The acoustically layered sequence correlates seismically with pelagic strata cored at Site 543 on the incoming oceanic plate. Cores recovered from the possible decollement surface at both Sites 541 and 542 show scaly foliation and stratal disruption. Approximately lithostatic fluid pressure measured in the possible decollement zone probably facilitates the underthrusting of the pelagic sediments beneath the offscraped deposits. In the incoming section, a transition from smectitic to radiolarian mud with associated increases in density and strength probably controls the structural break between offscraped and underthrust strata. In the Leg 78A area, the underthrust pelagic section can be traced seismically at least 30 km arcward of the deformation front beneath the Barbados Ridge complex.