Catalytic compositions and processes for depolymerizing polyolefin-based feed into useful petrochemical products are described. The compositions are a composite of a zeolite catalyst component and a co-catalyst comprising an activated clay component and/or a solid base component. These catalyst systems, along with heat, are used to both increase the depolymerization reaction rate of the feed streams and suppress poisoning effects of impurities that may be present in the polyolefin-based feed. This results in a shorter residence time in the depolymerization unit and more efficient process.

Silica-coated alumina activator-supports, and catalyst compositions containing these activator-supports, are disclosed. Methods also are provided for preparing silica-coated alumina activator-supports, for preparing catalyst compositions, and for using the catalyst compositions to polymerize olefins.

Silica-coated alumina activator-supports, and catalyst compositions containing these activator-supports, are disclosed. Methods also are provided for preparing silica-coated alumina activator-supports, for preparing catalyst compositions, and for using the catalyst compositions to polymerize olefins.

A method includes providing a substrate including a tube with a first opening a second opening, depositing a metal film onto a portion of the tube near the first opening, and growing a carbon nanotube by passing a carbon-based gas through the tube and metal film. The gas enters the tube through the second opening and exits the tube through the first opening.

A method includes providing a substrate including a tube with a first opening a second opening, depositing a metal film onto a portion of the tube near the first opening, and growing a carbon nanotube by passing a carbon-based gas through the tube and metal film. The gas enters the tube through the second opening and exits the tube through the first opening.

The present invention relates to: a catalyst for glycerin dehydration; a preparation method therefor; and an acrolein preparation method using the catalyst. According to one embodiment of the present invention, the catalyst is used in glycerin dehydration so as to exhibit high catalytic activity, a high yield and high acrolein selectivity, and has a characteristic in which carbon is not readily deposited, thereby having a long lifetime compared with that of a conventional catalyst.

A method for preparing nanosized sulfide catalysts includes providing an aqueous solution having an organometallic complex, mixing the organometallic complex with a sulfiding agent, an emulsifier, and a hydrocarbon oil to prepare a water-in-oil nanoemulsion; subjecting the water-in-oil nanoemulsion to thermal decomposition and isolating a solid product from the liquid.

Disclosed herein is a mixed phosphate catalyst for converting lactic acid to acrylic acid, which is characterized by a high conversion of lactic acid, a high selectivity for acrylic acid, a high yield of acrylic acid, and correspondingly low selectivity and molar yields for undesired by-products. This is achieved with a particular class of catalysts defined by a mixture of metal-containing phosphate salts. Further, the catalyst is believed to be stable and active for lengthy periods heretofore unseen in the art for such dehydration processes.

A novel method for catalytic dehydration of glycerol to acrolein is provided. A fixed bed reactor is used, which is placed in a microwave unit. The feedstock is introduced into the fixed bed reactor after being preheated and gasified. Continuous glycerol dehydration occurs in the presence of a microwave-absorbing catalyst in the fixed bed reactor to form acrolein. The microwave-absorbing catalyst is composed of an active component loaded on a core-shell structure which consists of microwave absorbent coated by an oxide. The uniformity of microwave heating can reduce the formation of hot spot during the reaction and hence improve the catalyst stability. The process and operation is simple, and the unit can steadily run for a long time.

The method for preparing fluorine-doped lamellar black TiO.sub.2 nanomaterials includes mixing a solution of tetra-n-butyl titanate, n-propanol and hydrofluoric acid together, and then stir the solutions for a period of time. The solution is transferred into an autoclave and reacts at a certain temperature for a period of time. The sample obtained by the reaction is washed and dried. Then, the sample is heated in a protective atmosphere for a period of time so as to produce the fluorine-doped lamellar black TiO.sub.2 nanomaterials. This fluorine-doped lamellar black TiO.sub.2 owns superior optical absorption and electron transport performances.