摘要:
A high-temperature solution process for making an ethylene polymer blend having a controlled degree of long-chain branching is disclosed. Ethylene is polymerized in the presence of a first Ziegler-Natta catalyst comprising titanium, magnesium, and aluminum in the absence of hydrogen to produce a first ethylene polymer component having substantial long-chain branching. A second ethylene polymer component having little or no long-chain branching is also prepared. Both polymerizations are performed at a temperature from 140° C. to 250° C. The first and second ethylene polymer components are combined to give a polymer blend. The degree of long-chain branching in the blend is controlled by adjusting the relative amounts of the first and second ethylene polymer components. The invention enables the preparation of valuable products having a pre-determined degree of long-chain branching using readily available Zeigler-Natta catalysts, commercially practiced techniques, and conventional equipment.
摘要:
A process to prepare a multimodal polyethylene with controlled LCB distribution is disclosed. In the first stage, ethylene is polymerized in the presence of a Ziegler catalyst that results in a homopolyethylene component having a higher LCB concentration. In the second stage, ethylene is copolymerized with a 1-olefin in the presence of the Ziegler catalyst and a lower concentration of hydrogen resulting in a copolymer component with a lower LCB concentration. The homopolyethylene component and the copolymer component are combined to form a novel multimodal polyethylene.
摘要:
This invention is a method of purifying fuels containing organosulfur impurities. The fuel is oxidized with an organic hydroperoxide in the presence of an oxidation catalyst to form a sulfone product, followed by extraction of the sulfone product by solid-liquid or liquid-liquid extraction. The fuel is then contacted with a decomposition catalyst to remove the residual organic hydroperoxide from the fuel.
摘要:
Single-site catalyst systems useful for polymerizing olefins are disclosed. The catalyst systems comprise an organometallic complex and an activator. The complex includes a Group 3-10 transition metal, M, and at least one indenoindolyl ligand that is pi-bonded to M. The activator is a reaction product of an alkylaluminum compound and an organoboronic acid. Catalyst systems of the invention significantly outperform known catalyst systems that employ a metallocene complex and similar aluminoboronate activators.
摘要:
Prealkylation of a supported catalyst system comprising a transition metal or inner transition metal complex precatalyst and a bulky, non-coordinating anion on an inorganic support by treatment with a solution of metal alkyl in a ratio of metal of metal alkyl to transition metal or inner transition metal of precatalyst less than 20:1, and in an amount of solution insufficient to form a paste or dispersion provides supported catalysts of high olefin polymerization activity which promote production of polyolefins of low polydispersity and improved morphology.
摘要:
A supported olefin polymerization catalyst system and a method of making it are disclosed. The catalyst system comprises: (a) a support chemically treated with an organoaluminum, organosilicon, organomagnesium, or organoboron compound; (b) a single-site catalyst that contains a polymerization-stable, heteroatomic ligand; and (c) an activator. Chemical treatment is a key to making supported heterometallocenes that have high activity and long shelf-lives, and can effectively incorporate comonomers.
摘要:
A vanadium-containing catalyst system particularly suited to the polymerization of blow moldable olefin polymers. The catalyst system includes a supported, first catalyst component prepared by contacting preheated silica, with (1) a compound or complex which includes at least one carbon to magnesium covalent bond and (2) a compound which includes at least one carbon to Group III metal covalent bond. The sequence of contact of the silica with compound or complex (1) and compound (2) is optional. However, unless the compound or complex (1) and the compound (2) contact the silica simultaneously, the product of this contact is next contacted with whichever of compound (1) or (2) does not initially contact the silica. The product of the step of contacting with compounds (1) and (2) is contacted with a vanadium compound which includes at least one halogen atom. Finally, the product of the vanadium compound contacting step is contacted with an alcohol. A second component of the catalyst system is an organoaluminum compound cocatalyst. The catalyst system also includes a halocarbon compound promoter as a third catalyst component.
摘要:
Catalysts useful in olefin polymerization are a mixture of (a) (i) one or more compounds Zn(X.sup.1).sub.2 and one or more compounds Al(R.sup.1).sub.3, or (ii) Zn(X.sup.1).sub.2.2Al(R.sup.1).sub.3, wherein X.sup.1 is halide and R.sup.1 is C.sub.1-12 hydrocarbyl; and (b) one or more of V(X.sup.2).sub.c (OR.sup.2).sub.b-c, VO(X.sup.3).sub.d (OR.sup.3).sub.3-d, or VO(X.sup.4).sub.2, wherein X.sup.2, X.sup.3 and X.sup.4 are halogen, R.sup.2 and R.sup.3 are C.sub.1-18 hydrocarbyl, b is 3-4, c is 0-b, and d is 0-3; and can contain (c) one or more of M(R.sup.5).sub.e (X.sup.5).sub.3-e, Al.sub.2 (R.sup.5).sub.3 (X.sup.5).sub.3 or Mg(R.sup.6).sub.f Y.sub.2-f, wherein X.sup.1 and X.sup.2 are halide, R.sup.1, R.sup.5, R.sup.6 and R.sup.9 are C.sub.1- 12 hydrocarbyl, M is Al or B, e is 0-3, Y is halide, O--(C.sub.1-12 hydrocarbyl) or N(SiR.sup.9.sub.3).sub.2, and f is 0-2.
摘要:
Mixed catalyst compositions comprised of a first supported chromium-containing catalyst component and a second supported chromium-containing catalyst component and which additionally have one or more metallic or non-metallic catalytic agents associated therewith are provided. The additional metallic or non-metallic elements associated with the catalyst components can be aluminum, titanium, zirconium, boron, phosphorous or combinations thereof. The pore volume of the silica supports used for the first and second catalyst components differs by at least 0.3 cc/g. The mixed catalyst compositions of the invention are useful for the preparation of polyolefins. They are particularly useful of polymerization of ethylene in particle form polymerizations to produce high density polyethylene blow molding resins having good processability and physical properties. The improved particle form polymerization process and products obtained thereby using the above-described mixed catalyst compositions are also described.
摘要:
A multiple site solid catalyst component capable of producing polyolefins having a broad or multimodal molecular weight distribution, such as a bimodal molecular weight distribution, is prepared by contacting a particulate solid support with a zirconium compound or complex to bind the zirconium compound or complex to the support, optionally followed by contacting the supported zirconium compound or complex with a Lewis acid to produce an intermediate product, optionally isolating and washing the supported zirconium compound or complex or resulting intermediate product to remove soluble by-products therefrom, and reacting the washed or unwashed supported zirconium compound or complex or intermediate product with a titanium or vanadium compound to produce a solid catalyst component.