39820results about "Catalyst activation/preparation" patented technology

This invention provides catalyst compositions that are useful for polymerizing at least one monomer to produce a polymer. This invention also provides catalyst compositions that are useful for polymerizing at least one monomer to produce a polymer, wherein said catalyst composition comprises contacting a organometal compound / organoaluminum mixture, a treated solid oxide compound, and, optionally, a second organoaluminum compound. The solid oxide has been treated with an electron-withdrawing compound, in particular a chlorine, preferably zinc chloride and carbon tetrachloride.

A bulk-doped semiconductor that is at least one of the following: a single crystal, an elongated and bulk-doped semiconductor that, at any point along its longitudinal axis, has a largest cross-sectional dimension less than 500 nanometers, and a free-standing and bulk-doped semiconductor with at least one portion having a smallest width of less than 500 nanometers. Such a semiconductor may comprise an interior core comprising a first semiconductor; and an exterior shell comprising a different material than the first semiconductor. Such a semiconductor may be elongated and my have, at any point along a longitudinal section of such a semiconductor, a ratio of the length of the section to a longest width is greater than 4:1, or greater than 10:1, or greater than 100:1, or even greater than 1000:1. At least one portion of such a semiconductor may a smallest width of less than 200 nanometers, or less than 150 nanometers, or less than 100 nanometers, or less than 80 nanometers, or less than 70 nanometers, or less than 60 nanometers, or less than 40 nanometers, or less than 20 nanometers, or less than 10 nanometers, or even less than 5 nanometers. Such a semiconductor may be a single crystal and may be free-standing. Such a semiconductor may be either lightly n-doped, heavily n-doped, lightly p-doped or heavily p-doped. Such a semiconductor may be doped during growth. Such a semiconductor may be part of a device, which may include any of a variety of devices and combinations thereof, and, and a variety of assembling techniques may be used to fabricate devices from such a semiconductor. Two or more of such a semiconductors, including an array of such semiconductors, may be combined to form devices, for example, to form a crossed p-n junction of a device. Such devices at certain sizes may exhibit quantum confinement and other quantum phenomena, and the wavelength of light emitted from one or more of such semiconductors may be controlled by selecting a width of such semiconductors. Such semiconductors and device made therefrom may be used for a variety of applications.

Catalyst compositions comprising a first metallocene compound, a second metallocene compound, an activator-support, and an organoaluminum compound are provided. An improved method for preparing cyclopentadienyl complexes used to produce polyolefins is also provided.

This invention relates to catalyst compositions, methods, and polymers encompassing at least one first Group 4 metallocene compound comprising bridging η5-cyclopentadienyl-type ligands, in combination with at least one second Group 4 metallocene with non-bridging η5-cyclopentadienyl-type ligands, typically in combination with at least one cocatalyst, and at least one activator. The compositions and methods disclosed herein provide ethylene polymers with a bimodal molecular weight distribution.

This invention relates to the field of olefin polymerization catalyst compositions, and methods for the polymerization and copolymerization of olefins, typically using a supported catalyst composition. In one aspect, this invention encompasses precontacting a metallocene with an olefin or alkyne monomer and an organoaluminum compound, prior to contacting this mixture with the acidic activator-support.

A process for the selective production of ethanol by vapor phase reaction of acetic acid over a hydrogenating catalyst composition to form ethanol is disclosed and claimed. In an embodiment of this invention reaction of acetic acid and hydrogen over a platinum and tin supported on silica, graphite, calcium silicate or silica-alumina selectively produces ethanol in a vapor phase at a temperature of about 250° C.

A method of fabricating a long carbon nanotube yarn includes the following steps: (1) providing a flat and smooth substrate; (2) depositing a catalyst on the substrate; (3) positioning the substrate with the catalyst in a furnace; (4) heating the furnace to a predetermined temperature; (5) supplying a mixture of carbon containing gas and protecting gas into the furnace; (6) controlling a difference between the local temperature of the catalyst and the furnace temperature to be at least 50° C.; (7) controlling the partial pressure of the carbon containing gas to be less than 0.2; (8) growing a number of carbon nanotubes on the substrate such that a carbon nanotube array is formed on the substrate; and (9) drawing out a bundle of carbon nanotubes from the carbon nanotube array such that a carbon nanotube yarn is formed.

A method of fabricating a long carbon nanotube yarn includes the following steps: (1) providing a flat and smooth substrate; (2) depositing a catalyst on the substrate; (3) positioning the substrate with the catalyst in a furnace; (4) heating the furnace to a predetermined temperature; (5) supplying a mixture of carbon containing gas and protecting gas into the furnace; (6) controlling a difference between the local temperature of the catalyst and the furnace temperature to be at least 50° C.; (7) controlling the partial pressure of the carbon containing gas to be less than 0.2; (8) growing a number of carbon nanotubes on the substrate such that a carbon nanotube array is formed on the substrate; and (9) drawing out a bundle of carbon nanotubes from the carbon nanotube array such that a carbon nanotube yarn is formed.

This invention provides a compositions that are useful for polymerizing at least one monomer into at least one polymer.

Various catalyst compositions including the contact product of at least one ansa-metallocene compound, at least one organoaluminum compound, and at least one activator-support are disclosed. Processes for forming such compositions and for forming polyolefins with such compositions are also disclosed. Metallocene compounds are also presented.

The present invention relates to a method of producing particles having a particle size of less than 100 nm and surface areas of at least 20 m2 / g where the particles are free from agglomeration. The method involves synthesizing the particles within an emulsion having a 1-40% water content to form reverse micelles. In particular, the particles formed are metal oxide particles. The particles can be used to oxidize hydrocarbons, particularly methane.

The present invention provides metal-containing sulfated activator-supports, and polymerization catalyst compositions employing these activator-supports. Methods for making these metal-containing sulfated activator-supports and for using such components in catalyst compositions for the polymerization of olefins are also provided.

A class of biological sensing devices that include a substrate comprising an array of carbon nanotubes (CNTs) to which are chemically attached biological molecules is disclosed. The attached biological molecules are capable of electrical conductivity that is responsive to chemical changes occurring as a result of their interaction with target species. A means for means for using DNA as a material of potential in molecular electronic sensor devices, being primarily based on molecular electron-transfer reaction processes between DNA-binding donors and acceptors is also disclosed, including composition, method of manufacture and their use are described.

A coated susceptor of electromagnetic energy for chemical processing made of a matrix material that surrounds a non-matrix material that is made from a material that is different from the matrix material, in which the matrix material is constructed of material having lower dielectric losses compared to the non-matrix material, the non-matrix material initially absorbs electromagnetic energy applied to the electromagnetic susceptor to a greater extent than the matrix material, the non-matrix material produces subsequent heat in the matrix material, and the surface of the susceptor is coated with a material that interacts with applied electromagnetic energy of at least one frequency and initially absorbs electromagnetic energy and produces heat.

The present invention relates to a composition and method for storage and controlled release of hydrogen. In particular, the present invention relates to the use of borohydride based solutions as a hydrogen storage source and a catalyst system to release hydrogen therefrom.

A process for the selective production of ethanol by vapor phase reaction of acetic acid over a hydrogenating catalyst composition to form ethanol is disclosed and claimed. In an embodiment of this invention reaction of acetic acid and hydrogen over a platinum and tin supported on silica, graphite, calcium silicate or silica-alumina selectively produces ethanol in a vapor phase at a temperature of about 250° C.

The present invention is directed to a diesel oxidation catalyst for the treatment of exhaust gas emissions, such as the oxidation of unburned hydrocarbons (HC), and carbon monoxide (CO) and the reduction of nitrogen oxides (NOx). More particularly, the present invention is directed to a novel washcoat composition comprising two distinct washcoat layers containing two distinctly different ratios of Pt:Pd.

Provided is an emission treatment system and method for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The emission treatment system has an oxidation catalyst upstream of a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia. Also provided is a method for disposing an SCR catalyst composition on a wall flow monolith that provides adequate catalyst loading, but does not result in unsuitable back pressures in the exhaust.

Catalyst compositions comprising a first metallocene compound, a second metallocene compound, a third metallocene compound, a chemically-treated solid oxide, and an organoaluminum compound are provided. Methods for preparing and using the catalyst and polyolefins are also provided. The compositions and methods disclosed herein provide ethylene polymers having decreased haze while minimizing impact on other properties, such as dart impact.

A process for selective formation of ethanol from acetic acid includes contacting a feed stream containing acetic acid and hydrogen at an elevated temperature with catalyst comprising platinum and tin on a high surface area silica promoted with calcium metasilicate. Selectivities to ethanol of over 85% are achieved at 280° C. with catalyst life in the hundreds of hours.

The present invention provides methods and compositions for the chemical conversion of syngas to alcohols. The invention includes catalyst compositions, methods of making the catalyst compositions, and methods of using the catalyst compositions. Certain embodiments teach compositions for catalyzing the conversion of syngas into products comprising at least one C1-C4 alcohol, such as ethanol. These compositions generally include cobalt, molybdenum, and sulfur. Preferred catalyst compositions for converting syngas into alcohols include cobalt associated with sulfide in certain preferred stoichiometries as described and taught herein.

Nanoparticles of silicon oxide alloys (i.e., oxides of SiMo, SiPt, and SiAl) are produced by laser vaporization of a silicon target and a target of a metal (i.e., Mo, Pt, or Al), in an oxygen containing atmosphere in a diffusion cloud chamber, where the target metal vapors aggregate into novel three-dimensional porous web structures. The structures have a homogeneous composition with a uniform ratio of silicon to the metal.

Catalyst compositions and methods, useful in polymerization processes, utilizing at least two metal compounds are disclosed. At least one of the metal compounds is a Group 15 containing metal compound and the other metal compound is preferably a bulky ligand metallocene-type catalyst. The invention also discloses a new polyolefin, generally polyethylene, particularly a multimodal polymer and more specifically, a bimodal polymer, and its use in various end-use applications such as film, molding and pipe.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

A multi-stage catalytic hydrogenation and hydroconversion process for heavy hydrocarbon feed materials such as coal, heavy petroleum fractions, and plastic waste materials. In the process, the feedstock is reacted in a first-stage, back-mixed catalytic reactor with a highly dispersed iron-based catalyst having a powder, gel or liquid form. The reactor effluent is pressure-reduced, vapors and light distillate fractions are removed overhead, and the heavier liquid fraction is fed to a second stage back-mixed catalytic reactor. The first and second stage catalytic reactors are operated at 700-850.degree. F. temperature, 1000-3500 psig hydrogen partial pressure and 20-80 lb. / hr per ft.sup.3 reactor space velocity. The vapor and light distillates liquid fractions removed from both the first and second stage reactor effluent streams are combined and passed to an in-line, fixed-bed catalytic hydrotreater for heteroatom removal and for producing high quality naphtha and mid-distillate or a full-range distillate product. The remaining separator bottoms liquid fractions are distilled at successive atmospheric and vacuum pressures, low and intermediate-boiling hydrocarbon liquid products are withdrawn, and heavier distillate fractions are recycled and further upgraded to provide additional low-boiling hydrocarbon liquid products. This catalytic multistage hydrogenation process provides improved flexibility for hydroprocessing the various carbonaceous feedstocks and adjusting to desired product structures and for improved economy of operations.

The invention provides a catalyzed soot filter formed on a wall flow substrate having internal walls coated with catalyst compositions. The soot filter maintains a homogeneous flow of the exhaust gases through the internal walls of the substrate along the length of the filter due to the coating design. Both the efficiency and the durability of the catalytic function are increased over conventionally designed catalyzed soot filters. The catalyzed soot filter provides an integrated function for simultaneously treating the gaseous components of the exhaust (e.g., CO and HC) and the particulate matter deposited in the filter.

A class of biological sensing devices that include a substrate comprising an array of carbon nanotubes (CNTs) to which are chemically attached biological molecules is disclosed. The attached biological molecules are capable of electrical conductivity that is responsive to chemical changes occurring as a result of their interaction with target species. A means for means for using DNA as a material of potential in molecular electronic sensor devices, being primarily based on molecular electron-transfer reaction processes between DNA-binding donors and acceptors is also disclosed, including composition, method of manufacture and their use are described.

The present invention relates to an olefin metathesis reaction catalyst where rhenium (Re) oxide or molybdenum (Mo) oxide is supported, as a catalyst main component, on a surface-modified mesoporous silica or mesoporous alumina support, and a preparation method therefor. The olefin metathesis reaction catalyst of the present invention allows highly efficient metathesis of long-chain unsaturated hydrocarbons having at least eight carbons at a low temperature of 150° C. or lower. The catalyst can be separated readily from reaction solution, regenerated at a low temperature of 400° C. or lower by removing toxins accumulated on it during the metathesis reaction, and used repeatedly in metathesis reaction many times, thereby being made good use in commercial olefin metathesis processes.