The present disclosure discloses a catalyst composition for olefin polymerization, comprising the following components: a): a solid catalyst component containing magnesium, titanium, halogens, and at least one internal electron donor having a lone pair of electrons; b): an aluminum alkyl compound; and c): an external electron donor containing a first external electron donor C1, which is a malonate compound. In the present disclosure, a catalyst composition having an external electron donor that contains a malonate compound is used in olefin polymerization, in particular propene polymerization, and can significantly improve catalytic activity and hydrogen response of the catalyst and expand molecular weight distribution of polymers, which facilitates development of different polymers.

The present disclosure discloses a catalyst composition for olefin polymerization, comprising the following components: a): a solid catalyst component containing magnesium, titanium, halogens, and at least one internal electron donor having a lone pair of electrons; b): an aluminum alkyl compound; and c): an external electron donor containing a first external electron donor C1, which is a malonate compound. In the present disclosure, a catalyst composition having an external electron donor that contains a malonate compound is used in olefin polymerization, in particular propene polymerization, and can significantly improve catalytic activity and hydrogen response of the catalyst and expand molecular weight distribution of polymers, which facilitates development of different polymers.

The present disclosure provides a gas-phase polymerization process for preparing polyethylene, wherein halogenated alcohols in combination with a Ti based catalyst component and aluminum alkyls as co-catalyst suppress ethane formation or increase polymerization activity.

The present disclosure provides a gas-phase polymerization process for preparing polyethylene, wherein halogenated alcohols in combination with a Ti based catalyst component and aluminum alkyls as co-catalyst suppress ethane formation or increase polymerization activity.

Provided is a solid catalyst component for olefin polymerization, which comprises Mg, Ti, a halogen and an electron donor. The electron donor is selected from at least one of ring-substituted ether-acid ester compounds of the general formula (I). Also provided are a catalyst containing the solid catalyst component and the application of the catalyst in reactions of olefin polymerization, particularly in the reaction of propylene polymerization.

The invention relates to a continuous process for the production of ultra-high molecular weight polyethylene with an Elongational Stress of at least 0.43 N/mm.sup.2. The polymerisation of ethylene takes place in the presence of a catalyst and hydrogen. It is an advantage of the process according to the invention that the use of small amounts of hydrogen during the production of UHM-WPE reduces reactor fouling. Furthermore, the process according to the invention results in longer run times in polymerization reactors, less cleaning cycles to remove reactor fouling and in less need for other anti-fouling agents or anti-static agents.

The invention relates to a continuous process for the production of ultra-high molecular weight polyethylene with an Elongational Stress of at least 0.43 N/mm.sup.2. The polymerisation of ethylene takes place in the presence of a catalyst and hydrogen. It is an advantage of the process according to the invention that the use of small amounts of hydrogen during the production of UHM-WPE reduces reactor fouling. Furthermore, the process according to the invention results in longer run times in polymerization reactors, less cleaning cycles to remove reactor fouling and in less need for other anti-fouling agents or anti-static agents.

A method for producing a propylene-based block copolymer produces a propylene-based copolymer that exhibits excellent stereoregularity, rigidity, and impact resistance in a convenient and efficient manner while achieving high polymerization activity. The method for producing a propylene-based block copolymer includes bringing a catalyst into contact with propylene, or propylene and an α-olefin, and bringing an electron donor compound into contact with the resulting product to produce a propylene-based block copolymer, the catalyst including a solid catalyst component that includes titanium, magnesium, a halogen, and an internal electron donor compound, a specific organoaluminum compound, and a specific external electron donor compound.

A method for producing a propylene-based block copolymer produces a propylene-based copolymer that exhibits excellent stereoregularity, rigidity, and impact resistance in a convenient and efficient manner while achieving high polymerization activity. The method for producing a propylene-based block copolymer includes bringing a catalyst into contact with propylene, or propylene and an α-olefin, and bringing an electron donor compound into contact with the resulting product to produce a propylene-based block copolymer, the catalyst including a solid catalyst component that includes titanium, magnesium, a halogen, and an internal electron donor compound, a specific organoaluminum compound, and a specific external electron donor compound.

The present disclosure provides a catalyst system made from or containing: (A) a solid catalyst component made from or containing (i) a titanium compound supported on a magnesium dichloride; (B) an aluminum alkyl compound; and (C) a halogenated organic ester of formula A-COOR, wherein R is a C.sub.1-C.sub.10 hydrocarbon group and A is a C.sub.1-C.sub.15 saturated or unsaturated hydrocarbon group in which at least one of the hydrogen atoms is replaced by a chlorine atom. The present disclosure also provides a process for preparing an olefinic polymer, including a polymerization step of polymerizing an olefin in the presence of the catalyst system. The present disclosure also provides an olefinic polymer made therefrom.