摘要:
Provided is a method of preparation of dialkoxy magnesium that is used as a support for an olefin polymerization catalyst for polyolefin preparation. Specifically, provided is a method of preparation of a support for an olefin polymerization catalyst, which comprises preparation of dialkoxy magnesium by reacting magnesium metal with alcohol in the presence of a reaction initiator, wherein bromine is used as the reaction initiator so as to obtain spherical dialkoxy magnesium.
摘要:
2-pyridyl substituted imidazoles of the formula (I) as shown in claim 1, are provided, which are useful in the treatment of diseases mediated by ALK5 or ALK4 inhibitors or both.
摘要:
Provided is a method for preparing a support for olefin polymerization catalysts used in polyolefin preparation processes. Particularly, provided is a novel method for preparing a support for olefin polymerization catalysts comprising the reaction of metal magnesium with an alcohol in the presence of an additive for initiating the reaction, characterized in that halogenated nitrogen compound is used as the additive for initiating the reaction, resulting in a spherical dialkoxy magnesium support.The spherical support for olefin polymerization catalysts obtained from the method of the present invention has a spherical particle shape with a smooth surface, uniform particle size distribution and 0.25 g/cc or more of bulk density, which makes it suitable for preparing a catalyst that is enough to meet the particle properties required by commercial olefin polymerization processes including, for example slurry polymerization, bulk polymerization, gas phase polymerization and the like.