摘要:
A catalyst support based on aluminum polyphosphate or polyphosphoric acid-impregnated alumina is provided by two alternative techniques. In the first embodiment, an aluminum polyphosphate composition is heated in a dry atmosphere and thereafter impregnated with a zerovalent chromium component under anhydrous conditions. The resulting catalyst is active for olefin polymerization. In the second embodiment, alumina is impregnated with a polyphosphoric acid composition. This resulting polyphosphoric acid impregnated alumina can be used as a support for zerovalent chromium or can be impregnated with a chromium component and oxidized to give an active hexavalent chromium species. The resulting catalysts are advantageous because of their unusual sensitivity to hydrogen thus allowing great leeway in molecular weight control.
摘要:
Ethylene polymer is particularly suitable for the production of tough film is produced under slurry conditions using a fluorided aluminophosphate support and a reaction temperature within the range of 93.degree. to 107.degree. C. in the presence of hydrogen and a small amount of trialkyl boron cocatalyst wherein said aluminophosphate has a phosphorous to aluminum ratio within the very narrow range of 0.15 to 0.4 and wherein said aluminophosphate carrying chromium catalyst is being activated at a temperature within the range of 482.degree. to 704.degree. C. The resulting film is not only substantially superior to film made from the best of the readily available commercial resins but is also better than film made from polymers using a similar catalyst system without the specific combination of parameters of this invention.
摘要:
A catalyst is produced by contacting an already activated silica-titania supported chromium composition with a tertiary alcohol and thereafter reactivating under relatively mild conditions. Such contacting is conveniently carried out by forming a slurry of the catalyst in an inert diluent containing a small amount of the alcohol. The resulting catalyst is useful in olefin polymerization. In such polymerization operations, the catalyst offers the advantage of allowing polymerization at a lower reactor temperature to achieve a given melt flow.
摘要:
In accordance with one embodiment of this invention, a chromium catalyst supported on an aluminum phosphate-containing base is used in conjunction with a boron component either as a part of the base or as a cocatalyst. The resulting catalyst is unique both in its favorable sensitivity to molecular weight control agents such as hydrogen and in its ability to produce a fundamentally different olefin polymer. In accordance with another embodiment of this invention, the chromium is supported on a phosphate base produced using a melt of the aluminum salt.
摘要:
A silica composition is calcined at a temperature high enough to remove some but not all of the hydroxyl content. Generally temperatures of at least 400.degree. C. are required and temperatures above 1000.degree. C. are undesirable, the most preferred temperature being about 600.degree.-800.degree. C. The thus calcined silica is then treated with chromyl chloride at an elevated temperature and finally given a treatment in a carbon monoxide ambient. While the final composition contains chlorine which is normally considered a catalyst poison, the material is surprisingly active as an olefin polymerization catalyst.
摘要:
A catalyst is produced by contacting an already activated silica-titania supported chromium composition with a tertiary alcohol and thereafter reactivating under relatively mild conditions. Such contacting is conveniently carried out by forming a slurry of the catalyst in an inert diluent containing a small amount of the alcohol.
摘要:
In accordance with one embodiment of this invention, a chromium catalyst supported on an aluminum phosphate-containing base is used in conjunction with a boron component either as a part of the base or as a cocatalyst. The resulting catalyst is unique both in its favorable sensitivity to molecular weight control agents such as hydrogen and in its ability to produce a fundamentally different olefin polymer. In accordance with another embodiment of this invention, the chromium is supported on a phosphate base produced using a melt of the aluminum salt.
摘要:
A silica base for a chromium olefin polymerization catalyst is subjected to a high temperature treatment as for instance by passing the silica through a flame in order to alter the surface characteristics. The chromium can be present during the flame treatment or added later. The result is a catalyst capable of giving a broader molecular weight distribution polymer which is of particular value with the silica-titania coprecipitated catalyst used in slurry olefin polymerization.
摘要:
A catalyst suitable for olefin polymerization is produced by combining an inorganic support with a titanium polymer to produce a support for chromium-containing catalyst. The resulting chromium-containing catalyst is activated in a conventional manner. This process allows incorporation of relatively high concentrations of titanium which is beneficial in achieving high melt index values in slurry polymerization systems.
摘要:
A supported vanadium catalyst comprising a vanadium compound on a phosphate-containing base. This catalyst in conjunction with an organoaluminum cocatalyst is capable of giving good activity and producing a polymer having broad molecular weight distribution. The catalyst system is sufficiently sensitive to hydrogen to allow broad leeway in controlling the molecular weight of the resulting polymers.