摘要:
Olefin polymerization catalysts or catalyst systems comprising a mixture, contact product, reaction product or complex comprising as elements or components: (A) at least one metallocene pre-catalyst compound or polymerization active metallocene compound; (B) at least one titanium containing metallocene compound; and when (A) is a metallocene pre-catalyst compound, (C) at least one activator; provided however: (I) the titanium-containing metallocene compound is inactive or substantially inactive for the polymerization of olefins prior to or concurrently with the use of the catalyst system for olefin polymerization. Also disclosed are processes for producing the catalyst system and polyolefins having desirable combinations of properties, including melt index and molecular weight distribution, which properties are particularly desirable for the manufacture of polyolefin film products, especially LLDPE film A preferred catalyst comprises a zirconium or hafnium metal containing metallocene, an inactivated titanocene and a SiO2 support carrier.
摘要:
Olefin polymerization catalysts or catalyst systems comprising a mixture, contact product, reaction product or complex comprising as elements or components: (A) at least one metallocene pre-catalyst compound or polymerization active metallocene compound; (B) at least one titanium containing metallocene compound; and when (A) is a metallocene pre-catalyst compound, (C) at least one activator; provided however: (I) the titanium-containing metallocene compound is inactive or substantially inactive for the polymerization of olefins prior to or concurrently with the use of the catalyst system for olefin polymerization. Also disclosed are processes for producing the catalyst system and polyolefins having desirable combinations of properties, including melt index and molecular weight distribution, which properties are particularly desirable for the manufacture of polyolefin film products, especially LLDPE film A preferred catalyst comprises a zirconium or hafnium metal containing metallocene, an inactivated titanocene and a SiO2 support carrier.
摘要:
The invention concerns catalysts comprising (i) a clad catalyst support comprising (a) a core which comprises alumina particles and (b) about 1 to about 40 weight percent silica cladding, based on the weight of the clad catalyst support, on the surface of the core; the catalyst support having a BET surface area of greater than 20 m2/g and a porosity of at least about 0.2 cc/g; and (ii) 0.1 to 10 weight percent, based on the weight of the catalyst, of catalytically active transition metal on the surface of the clad catalyst support; wherein the catalyst support has a normalized sulfur uptake (NSU) of up to 25 μg/m2. The invention also concerns the production and use of such catalyst.
摘要:
The invention concerns catalysts comprising (i) a cladded catalyst support comprising (a) a core which comprises alumina particles and (b) about 1 to about 40 weight percent silica cladding, based on the weight of the cladded catalyst support, on the surface of the core; the catalyst support having a BET surface area of greater than 20 m2/g and a porosity of at least about 0.2 cc/g; and (ii) 0.1 to 10 weight percent, based on the weight of the catalyst, of catalytically active transition metal on the surface of the cladded catalyst support; wherein the catalyst support has a normalized sulfur uptake (NSU) of up to 25 ?g/m2. The invention also concerns the production and use of such catalysts.
摘要:
The invention concerns catalysts comprising (i) a cladded catalyst support comprising (a) a core which comprises alumina particles and (b) about 1 to about 40 weight percent silica cladding, based on the weight of the cladded catalyst support, on the surface of the core; the catalyst support having a BET surface area of greater than 20 m2/g and a porosity of at least about 0.2 cc/g; and (ii) 0.1 to 10 weight percent, based on the weight of the catalyst, of catalytically active transition metal on the surface of the cladded catalyst support; wherein the catalyst support has a normalized sulfur uptake (NSU) of up to 25 ?g/m2. The invention also concerns the production and use of such catalysts.
摘要:
The invention concerns catalysts comprising (i) a clad catalyst support comprising (a) a core which comprises alumina particles and (b) about 1 to about 40 weight percent silica cladding, based on the weight of the clad catalyst support, on the surface of the core; the catalyst support having a BET surface area of greater than 20 m2/g and a porosity of at least about 0.2 cc/g; and (ii) 0.1 to 10 weight percent, based on the weight of the catalyst, of catalytically active transition metal on the surface of the clad catalyst support; wherein the catalyst support has a normalized sulfur uptake (NSU) of up to 25 μg/m2. The invention also concerns the production and use of such catalyst.
摘要:
A method and an apparatus for manufacturing corrugated boards are disclosed. The method may include the steps of supplying a first web of medium having a first and second sides, wherein each side of the first web having a plurality of flutes, and wherein each flute having a crest, applying a wetting agent and an adhesive composition in a sequential fashion to the plurality of flutes on the first side of the first web, and securing a second web of medium is to the plurality of crests on the first side of the first web to form a single-faced corrugated board.
摘要:
An improved process for selectively forming noncyclic, aliphatic polyamines from the corresponding aliphatic polynitriles by reacting the polynitrile with hydrogen at low temperature under a pressure of from 50 to 5,000 psi in a fixed bed reactor while continuously contacting the reactants with granular chromium and nickel promoted Raney.RTM. cobalt packed therein.
摘要:
Catalysts which are suitable for auto exhaust use are made with a promoter oxide that is deposited in a concentration gradient. A solution of the promoter oxide precursor, e.g., cerous nitrate solution, is impreganted uniformly into the pore structure of a support which can be in the form of beads or extrudates to a level just below the full incipient wetness. The impregnated support is then treated with a gaseous base such as ammonia, under dynamic conditions such as tumbling (to insure uniformity), which causes the precipitation of the promoter oxide in the form of a radial concentration gradient. The resulting product is then dried and calcined at sufficiently high temperature to effect complete conversion of the promoter precursor to its oxide form, e.g., CeO.sub.2.
摘要:
The process of this invention removes impurities from transesterification products comprising primarily fatty acid alkyl esters (FAAE) that are being processed for final fuel products, such as biodiesel. The inventive process is catalytic, and the resulting ester is suitable for use as biodiesel. Metal oxide and mixed metal oxide catalysts are particularly suitable. The invention is particularly suitable for treating fatty acid alkyl ester compositions comprising impurities such as glycerin, sterol glycosides, and/or triglyceride, diglyceride and/or monoglyceride. The invention is particularly useful in treating FAAE transesterification products made using homogeneous alkali catalysts. The treated ester exhibits improved performance under cold weather conditions, which can be measured by methods such as ASTM 7501 Cold Soak Filtration Test (CSFT).