64 results about "Methylaluminoxane" patented technology

The invention discloses a method for preparing methylaluminoxane by directly hydrolyzing trimethyl aluminum and a reaction device, and belongs to the technical field of chemical products. Comprising the following steps: introducing low-temperature methane gas containing gas-phase water into a trimethylaluminum organic solution, carrying out hydrolysis reaction under the dual effects of ultrasonic vibration and mechanical stirring and mixing, and filtering to remove solid substances after the reaction is completed, so as to obtain a methylaluminoxane solution. According to the method for preparing methylaluminoxane through direct hydrolysis of trimethyl aluminum, the hydrolysis quality of methylaluminoxane can be guaranteed, generation of gels such as aluminum hydroxide is effectively controlled, and the product yield is greatly increased; and the byproduct methane is high in purity, can be recycled and is free of environmental pollution and energy waste, so that the production cost is remarkably reduced.

The invention relates to the technical field of catalytic synthesis, in particular to a preparation method and polymerization application of a carbon nanotube-based double-cyclopentadienyl bridged metallocene catalyst, and the preparation method comprises the following steps: 1, acidizing a carbon nanotube; 2, dispersing the acidified carbon nanotubes in a methylaluminoxane solution in a nitrogen or inert gas atmosphere to obtain an acidified carbon nanotube dispersion liquid; and 3, mixing the double-cyclopentadienyl bridged metal compound solution with the acidified carbon nanotube dispersion liquid for reaction. According to the invention, the carbon nanotubes are added into an olefin polymerization reaction system in the form of a double-metallocene bridged metallocene catalyst carrier, so that the tensile strength and toughness of polyolefin are improved while olefin polymerization reaction is catalyzed with high catalytic activity.

The invention provides a preparation method of an antistatic metallocene catalyst. The method comprises the following steps: carrying out thermal activation treatment on a silica gel carrier; loading alkyl tin chloride on the silica gel carrier to obtain an alkyl tin chloride modified silica gel carrier; adding methylaluminoxane into the alkyl tin chloride modified silica gel carrier to obtain a methylaluminoxane / alkyl tin chloride modified silica gel carrier; adding a metallocene compound into the methylaluminoxane / alkyl tin chloride modified silica gel carrier for heating reaction, and then adding an antistatic agent to obtain the antistatic metallocene catalyst. Alkyl tin chloride is used for modifying a silica gel carrier and reacts with hydroxyl to greatly eliminate the hydroxyl; the loading capacity can be improved by combining with MAO, and metallocene combination sites can be increased; after the antistatic agent is added, static electricity generated in the reaction process is reduced, the flaking phenomenon is reduced, and the static electricity range can be controlled to be + / -0.02 KV.

The invention provides a supported metallocene catalyst, a preparation method of the supported metallocene catalyst, an ethylene homopolymerization reaction method and an ethylene and alpha-olefin copolymerization reaction method. The supported metallocene catalyst comprises a carrier, and a metallocene compound and a cocatalyst which are supported on the carrier, the carrier is selected from silicon dioxide and / or aluminum oxide; the metallocene compound has a structure as shown in a formula I. Formula I. The polymer particles are regular, and the phenomenon that the reactor adheres to the kettle is relieved; in addition, when the supported metallocene catalyst is used for copolymerization of ethylene and alpha-olefin by adopting a slurry polymerization process, the polymerization activity can be improved, the cost is reduced, and the dosage of methylaluminoxane is reduced.

The invention discloses a supported metallocene catalyst and a preparation method and application thereof, the supported metallocene catalyst comprises a mixture and / or a reaction product of the following components: (A) a reaction mixture of modified alkylaluminoxane and a modified compound, the modified compound being selected from at least one of benzoic acid and substituted benzoic acid; (B) a carrier; (C) a metallocene compound; and (D) an alkane. The supported metallocene catalyst disclosed by the invention is completely prepared by using an alkane solvent, so that the problems caused by using an aromatic hydrocarbon solvent are avoided, the production process of the catalyst is simplified, and industrial implementation is facilitated. The content of Al in the prepared catalyst is larger than 6% by weight, the content of transition metal elements is 0.05-1% by weight, the loading efficiency of the modified methylaluminoxane is improved, the catalyst is used for ethylene polymerization reaction, the performance is good, and the polymerization activity is obviously improved.

The application discloses a preparation method of a single-center catalyst system and application thereof, and the preparation method comprises the following steps: (1) performing vacuum distillation on a modified methylaluminoxane solution, separating out a solvent and aluminum alkyl to obtain a solid product; (2) dissolving the solid product obtained in step (1) with a pentane solution to obtain a homogeneous solution with different aluminum contents; and (3) combining the homogeneous solution obtained in step (2) with a single-active-center catalyst to form a catalyst system. When the single-active-center catalyst system is used for preparing polyethylene wax, different solvents can be avoided from being introduced into a polymerization system, a process flow of the polyethylene wax is simplified, and energy consumption for solvent separation is reduced; reduction of active aluminum helps to improve polymerization activity, the obtained polyethylene wax has lower metal content and narrower molecular weight distribution, the devolatilization efficiency of the polyethylene wax is improved, and the obtained polymer has a VOCs content lower than 20 ppm.

The present invention relates to an efficient process for the preparation of highly active polymerization co-catalysts by reacting methylaluminoxane residues with C6-C18-alkyl aluminum compounds in the presence of a hydrocarbon solvent.

The invention provides an antistatic metallocene catalyst and application thereof. The antistatic metallocene catalyst comprises an antistatic agent / methylaluminoxane / alkyl tin chloride / silica gel carrier and a metallocene compound loaded on the carrier; the antistatic agent / methylaluminoxane / alkyl tin chloride / silica gel carrier is a silica gel carrier modified by an antistatic agent, methylaluminoxane and alkyl tin chloride. Alkyl tin chloride is used for modifying a silica gel carrier and reacts with hydroxyl to greatly eliminate the hydroxyl; the loading capacity can be improved by combining with MAO, and metallocene combination sites can be increased; after the antistatic agent is added, static electricity generated in the reaction process is reduced, the flaking phenomenon is reduced, and the static electricity range can be controlled to be + / -0.02 KV.

The invention provides a method and a system for treating methylaluminoxane gel. The method comprises the following steps: mixing cyclohexane of which the water content is not less than 100ppm and methylaluminoxane gel, and cleaning; the temperature of the cleaning treatment is not higher than 50 DEG C, and the cleaning treatment is carried out at the stirring rotating speed of 50-500rpm. According to the method, gel gathered on the olefin oligomerization cocatalyst storage tank can be removed, and the activity of the catalyst is not influenced.

The present invention relates to a catalytic composition for the selective oligomerisation of ethylene, in particular for the the tetramerisation of ethylene into 1-octene, wherein the catalytic composition comprises: - a chromium-based metal precursor; - a heteroatomic ligand; - methylaluminoxane supported on an inorganic support; - an additive in the form of an aluminium-based compound; wherein the composition has a molar ratio of the aluminium of the methylaluminoxane supported on an inorganic support to the chromium of the metal precursor of greater than 250, and a molar ratio of the aluminium of the additive to the chromium of the metal precursor of greater than 200.

The invention provides a metallocene polyethylene catalyst, a preparation method, application and related products, and belongs to the technical field of catalytic chemistry. The metallocene polyethylene catalyst provided by the invention is prepared from a metallocene compound, methylaluminoxane and modified silica gel, the surface of the modified silica gel is modified by a silicate ester compound containing crown ether groups. Through surface modification of the crown ether functional group, on one hand, the loading effect of the silica gel carrier on the metallocene compound is improved, on the other hand, polar groups provided by the crown ether functional group can control static electricity generated in the stirring and mixing process of a reaction material mixture, and then product coalescence and shutdown inspection are reduced.

The present invention relates to a method for the oligomerisation, preferably tetramerisation, of ethylene to octene-1, the method comprising a step of injecting into an oligomerisation reactor at least the following four compounds: - a chromium-based metal precursor; - a heteroatomic ligand; - methylaluminoxane supported on an inorganic support; - an additive in the form of an aluminium-based compound; wherein the chromium-based metal precursor and the heteroatomic ligand are never brought into contact with the methylaluminoxane supported on an inorganic support in the absence of the additive in the form of an aluminium-based compound.

This invention relates to catalyst compositions for the selective oligomerization of ethylene, particularly for the tetramerization of ethylene into 1-octene, comprising: - a chromium-based metal precursor; - a heteroatom ligand; - a supported methylaluminoxane on an inorganic support; - an additive in the form of an aluminum-based compound; wherein the composition has a molar ratio of aluminum in the supported methylaluminoxane on the inorganic support to chromium in the metal precursor greater than 250, and a molar ratio of aluminum in the additive to chromium in the metal precursor greater than 200.

The invention discloses a synthesis method of oligomerized methylaluminoxane. According to the method, alkyl aluminum of C2 or above is used as a starting raw material, n value distribution of generated MAO can be effectively controlled, high-oligomerization-degree MAO small in molecular weight distribution range and narrow in n value distribution is obtained, the MAO product catalytic activity is relatively concentrated, the method is especially suitable for a process for preparing high-carbon alpha-olefin through ethylene oligomerization, and the selectivity of target alpha-olefin can be remarkably improved.

This invention discloses a method for preparing low-entanglement ultra-high molecular weight polyethylene using an ONN-type Group IV metal catalyst at high temperature. Using methylaluminoxane (MAO) as a co-catalyst, homopolymerization of ethylene is carried out at a polymerization temperature of 50-110 °C and an ethylene pressure of 10-40 atm to obtain a weight-average molecular weight polyethylene (MAH). M w (Greater than 2.5 × 10) 6 g·mol ‑1 Ultra-high molecular weight polyethylene (UHMWPE) was obtained. The resulting virgin particles exhibited a low-entanglement structure, specifically characterized by: a ≥90% decrease or disappearance of the high-temperature melting peak area after DSC annealing; a storage modulus that increased to more than twice its initial value over time during rheological testing at 160 °C; a lamellar or petal-like crystal morphology as shown by scanning electron microscopy; and the ability to be directly pressed into transparent self-supporting films at room temperature. The Ti1 / MAO system, at 110 °C and 40 atm, still yielded a molecular weight of approximately 2.0 × 10⁻⁶. 6 g·mol ‑1 The polyethylene produced exhibits a tensile strength of 40 MPa and an elongation at break of 576% after hot pressing. This invention enables the direct preparation of low-entanglement UHMWPE under industrial-grade high-temperature and high-pressure conditions, resulting in significantly superior processing performance compared to traditional highly entangled products.

A method for polymerizing olefin monomers. The method comprises reacting ethylene and optionally one or more olefin monomers in the presence of a catalytic system, wherein the catalytic system comprises: AlR having a content of less than 50 mol% based on the total molar amount of aluminum. A1 R B1 R C1 Modified hydrocarbon methylaluminoxane, wherein R A1 R B1 and R C1 Independently for straight chains (C1-C) 40 Alkyl groups, branched (C1-C) 40 )alkyl or (C6-C 40 ) aryl; and one or more metal-ligand complexes according to formula (I).

The invention discloses a method for synthesizing alkylaluminoxane from paraformaldehyde and a preparation method of modified alkylaluminoxane. The method for synthesizing alkylaluminoxane comprises the following steps: step 1, reacting paraformaldehyde with trialkyl aluminum to prepare an alkylaluminoxane precursor solution; and 2, pyrolyzing the obtained alkyl aluminoxane precursor to prepare the alkyl aluminoxane. The invention also provides a method for preparing modified alkylaluminoxane by using the alkylaluminoxane. The method provided by the invention can effectively avoid the defects that the existing reaction needs high pressure, is difficult to quantify and cannot realize large-scale production, is more beneficial to the realization of industrial large-scale production requirements, and improves the production speed and safety of methylaluminoxane at the same time.

The application discloses an isocyanate polymerization catalyst and a preparation method thereof, and an isocyanate tar purification method. The polymerization catalyst comprises a main catalyst quaternary ammonium base, a first additive methylaluminoxane and / or trimethyl gallium, and a second additive sodium fatty acid. A mixed solution containing isocyanate polymers, urea, and isocyanate monomers in the system is removed of the monomers by catalytic polymerization in a reactor and by adding the catalyst to obtain isocyanate polymers, which are applied to downstream fields such as boards and adhesives. The application can convert waste tar liquid into by-products for sale, has significant economic benefits, and reduces the waste liquid treatment capacity of the running device and the operation cost of the device.

The application provides a preparation method of alkylaluminoxane and application thereof. The preparation method provided by the application uses ketone compounds to react with alkylaluminum to prepare alkylaluminoxane, avoids the introduction of water, is mild and controllable, has high product yield, and is cheap in raw materials. In addition, unlike the crystallization hydration method which produces a large amount of inorganic salt impurities and is complicated in post-treatment, the preparation method provided by the application has few by-products and is easy to separate and purify. Meanwhile, by adding boron trihalide as an initiator, the chain length of the prepared alkylaluminoxane is suitable, and the alkylaluminoxane prepared by the preparation method provided by the application has high yield. In particular, the alkylaluminoxane, especially methylaluminoxane, prepared by the preparation method provided by the application is used as a cocatalyst and is used in combination with a metallocene catalyst to catalyze ethylene polymerization, and it is found that the cocatalytic performance is excellent.

This invention belongs to the field of petrochemical catalysis technology and relates to a controlled hydrolysis method for trimethylaluminum and its application. The technical features of this invention are as follows: First, hydrated aluminum sulfate is recrystallized in an aqueous solution containing the antisolvent ethanol to prepare small-crystal, plate-like recrystallized hydrated aluminum sulfate. Second, the recrystallized hydrated aluminum sulfate is subjected to low-temperature drying to adjust its water of crystallization content, obtaining a small-crystal, plate-like aluminum sulfate hydrolysant with a specific water of crystallization content. Third, trimethylaluminum is hydrolyzed using the aluminum sulfate hydrolysant with a specific water of crystallization content, controlling the rate and extent of hydrolysis to obtain a methylaluminoxane co-catalyst solution containing aluminum sulfate. The methylaluminoxane co-catalyst solution containing aluminum sulfate prepared by the method of this invention does not require desalting treatment and can be directly used to construct a PNP-Cr ethylene selective tetramerization catalytic system, providing an option for reducing the manufacturing cost of methylaluminoxane and enabling on-site production and use of methylaluminoxane.

The present disclosure provides a catalyst system. In an embodiment, the catalyst system includes a bimodal catalyst (BMC) spray-dried to a support and a trim catalyst. The trim catalyst includes a phenoxy imine catalyst selected from (i) bis(2,4-di-tert-butyl-6 isopropylamino phenoxy imine) zirconium dibenzyl and (ii) bis(2,4-di-tert-butyl-6 isopropylamino phenoxy imine) zirconium dichloride. The catalyst system also includes at least one spray-dried methylaluminoxane activator.

This invention belongs to the field of catalytic materials technology, specifically relating to a pyridinediimide cobalt complex and its preparation method, as well as a method for preparing 1-hexene. A pyridinediimide cobalt complex has the structural formula: ; wherein, R... 1 Selected from fluorine, chlorine, bromine, ester, cyano, benzyl, and hydrogen; R 2 Selected from methyl, ethyl, isopropyl, fluorine, hydrogen, trifluoromethyl, methoxy, R 2 The positions are ortho, para, and meta of aniline; R 3 Selected from cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and hydrogen. This cobalt pyridine diimine complex, under the co-catalysis of methylaluminoxane (MAO), can catalyze the selective oligomerization of propylene to prepare 1-hexene. The oligomerization reaction conditions are mild, and the resulting polyethylene significantly reduces the symmetry and regularity of the polymer chain segments, thereby weakening its crystallinity. While maintaining mechanical strength, it also exhibits excellent flexibility, resistance to environmental stress cracking, and low-temperature impact resistance.

The utility model discloses an intermittent methylaluminoxane / modified methylaluminoxane production and separation combined system which comprises a reaction kettle for reaction, a filtering, washing and drying machine for post-processing solid-liquid products obtained by reaction, a waste liquid tank for collecting washing liquid of the filtering, washing and drying machine, and a product solution tank for collecting products, the vacuum rectifying tower is used for collecting gas products obtained by reaction; and the return tank is used for collecting gas in the vacuum rectifying tower. According to the utility model, a reduced-pressure rectification mode is adopted, the temperature of the bottom of the rectification tower is reduced, the temperature of the whole system is ensured to be within the allowable range of physical properties of reaction materials, and meanwhile, the evaporated aluminum alkyl is recovered through rectification, so that the risk caused by leakage of the aluminum alkyl is reduced to the greatest extent. The device disclosed by the utility model is simple in process flow, relatively high in reaction yield, relatively low in reaction danger level and relatively high in production safety coefficient.

The present invention relates to a catalytic composition for the selective oligomerization of ethylene, more particularly for the trimerization and / or tetramerization of ethylene to 1-hexene and / or 1-octene, respectively, comprising:-at least one chromium-based or titanium-based metal precursor; -at least one support in the form of solid methylaluminoxane (MAO); -at least one additive in the form of an aluminum-based compound. Another subject of the invention relates to an oligomerization process, preferably for the selective trimerization and / or tetramerization of ethylene to 1-hexene and / or 1-octene, respectively, using a catalytic composition according to the invention.

The present invention relates to a chromium catalyst precursor, an ethylene oligomerization catalyst comprising the same, and a method for preparing an ethylene oligomer using the same, and more particularly, to a chromium catalyst precursor which can oligomerize ethylene with high activity and high selectivity even without using methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), an oligomerization catalyst comprising the same, and a method for preparing an ethylene oligomer using the same.

The application belongs to the technical field of conjugated diene polymerization, and particularly relates to a phosphine quinoline ligand, a phosphine quinoline iron complex, a preparation method thereof and application thereof in catalyzing conjugated diene polymerization. The phosphine quinoline ligand and the iron complex are respectively shown as formula I and formula II. The iron complex is a bidentate N, P-coordination catalyst, has a single catalytic active center, and can realize high-activity and high-selectivity polymerization of conjugated dienes by regulating ligand electronic effects, space effects and polymerization conditions. The iron complex only needs 5 equivalents of dry methylaluminoxane to be activated, and still maintains high activity at high temperature (100 DEG C). The obtained polyconjugated diene has narrow molecular weight distribution, and microstructure (cis-1, 4, trans-1, 4, 3, 4 or 1, 2) can be accurately regulated. The reaction system is green, environmentally friendly, low in cost and excellent in thermal stability, and is suitable for industrialized production of high-performance elastomer materials.

The application provides a supported metallocene catalyst and a preparation method, an ethylene homopolymerization method and an ethylene and alpha-olefin copolymerization method. The supported metallocene catalyst comprises a carrier and a metallocene compound and a cocatalyst supported on the carrier; the carrier is selected from silica and / or alumina; the metallocene compound has a structure as shown in formula I. Formula I. The polymer particles of the application are regular, and the reactor sticking phenomenon is reduced; in addition, when the supported metallocene catalyst is used for ethylene and alpha-olefin copolymerization by using a slurry polymerization process, the polymerization activity can be improved, the cost is reduced, and the amount of methylaluminoxane is reduced.

The disclosure provides a catalyst composition for the oligomerization of ethylene to produce one or more linear alpha olefins, the catalyst composition including a chromium compound, a heteroatomic multidentate ligand having an NPNPN backbone, wherein each P is an optionally substituted phosphino group and each N is an optionally substituted amino group, a methylaluminoxane, and triethyl-aluminum.

To provide a polymerization catalyst having excellent copolymerizability capable of efficiently producing a low density and high molecular weight polymer, particularly an ethylene-based polymer and to provide a method for producing an ethylene-based polymer using the same.SOLUTION: There are provided: a polymerization catalyst which comprises a transition metal compound having an electron-donating substituent at a specific site, an organic aliphatic group-modified clay, one or more activation co-catalysts selected from the group consisting of a specific boron compound, a specific aluminum compound, methylaluminoxane and (methyl-isobutyl)aluminoxane and an organic aluminum compound; and a method for producing an ethylene-based polymer using the same.SELECTED DRAWING: None