Search

CN-122011241-A - High-performance polyethylene catalyst and preparation method and application thereof

CN122011241ACN 122011241 ACN122011241 ACN 122011241ACN-122011241-A

Abstract

S1, dispersing a silicon-based dispersing agent in an inert alkane solvent after fluidization treatment, and adding aluminum alkyl to obtain a post-treatment dispersing agent; and S2, dropwise adding the mother liquor obtained in the step S1 into a post-treatment dispersing agent for reaction, adding a titanium-containing compound for continuous reaction, and adding alkoxy silane for continuous reaction to obtain the polyethylene catalyst. Compared with the prior art, the polyethylene catalyst prepared by the method has stable dynamic behavior, and the polymerization product obtained by catalysis has high bulk density and the feasibility of the preparation method is higher.

Inventors

  • BAO NING
  • SUN QIAOQIAO
  • BAI LINLIN
  • Bai Jiatong
  • HAN JIANGYAN

Assignees

  • 上海立得催化剂有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (10)

  1. 1. A method for preparing a polyethylene catalyst, which is characterized by comprising the following steps: S1, dispersing a silicon-based dispersing agent in an inert alkane solvent after fluidization treatment, and adding aluminum alkyl to obtain a post-treatment dispersing agent; Mixing inert alkane solvent, alkyl magnesium, alkyl aluminum and monohydric alcohol to obtain mother liquor; S2, dropwise adding the mother liquor obtained in the step S1 into a post-treatment dispersing agent for reaction, adding a titanium-containing compound for continuous reaction, and adding alkoxy silane for continuous reaction to obtain the polyethylene catalyst.
  2. 2. The method for preparing a polyethylene catalyst according to claim 1, wherein in the step S1, the silicon-based dispersant is selected from any one or more of silica gel, silica gel-alumina, silica gel-titania, The inert alkane solvent is selected from any one or more of n-hexane, cyclohexane, hexane and n-heptane; The aluminum alkyl is a compound of a chemical formula R 3-n AlX n , wherein R is alkyl, X is halogen, and n is 0 or an integer less than 3; the inert alkane solvent is selected from any one or more of n-hexane, cyclohexane, hexane and n-heptane in the components of the mother liquor; The alkyl magnesium is selected from any one or more of n-butyl magnesium, isobutyl magnesium, n-butyl isobutyl magnesium, dioctyl magnesium, butyl octyl magnesium, ethyl magnesium chloride and butyl magnesium chloride; the aluminum alkyl is a compound with a chemical formula of R 3-n Al, wherein R is alkyl, and n is 0 or an integer less than 3; the monohydric alcohol is selected from any one or more of n-octanol and isooctyl alcohol.
  3. 3. The method for producing a polyethylene catalyst according to claim 2, wherein in the components of the post-treatment dispersant, the alkylaluminum is selected from any one or more of triethylaluminum, trihexylaluminum, triisobutylaluminum, ethylaluminum dichloride, diethylaluminum chloride; In the components of the mother liquor, the alkyl aluminum is selected from any one or more of triethyl aluminum, trihexyl aluminum and triisobutyl aluminum.
  4. 4. The method for preparing a polyethylene catalyst according to claim 1, wherein in step S1, the amount of the aluminum alkyl in the components of the post-treatment dispersant is 5-100:1 in terms of the silicon content in the silicon-based dispersant; In the components of the mother liquor, the mass ratio of the inert alkane solvent to the silicon-based dispersing agent is 4-10:1, the mass ratio of the alkyl magnesium to the silicon-based dispersing agent is 0.01-1.0:1, the dosage of the alkyl aluminum is 0.00001-0.001mol/g of the silicon-based dispersing agent, and the mol ratio of the monohydric alcohol to the alkyl magnesium is 0.1-5.0:1.
  5. 5. The preparation method of the polyethylene catalyst according to claim 1, wherein in the step S1, the technological conditions of the fluidization treatment of the silicon-based dispersing agent are that the silicon-based dispersing agent is subjected to fluidization treatment for 0.5-25 hours under the condition of purging inert gas or high-purity air at 20-1500 ℃; The mother solution is prepared by reacting an inert alkane solvent, alkyl magnesium, alkyl aluminum and monohydric alcohol in an inert atmosphere at 15-45 ℃ for 0.5-25 h.
  6. 6. The method for preparing a polyethylene catalyst according to claim 1, wherein in step S2, the titanium-containing compound is selected from any one or more of titanium tetrachloride, tetraethyl titanate, n-propyl titanate, isopropyl titanate, and n-butyl titanate; the chemical formula of the alkoxy silane is R n Si(OR 6 ) 4-n , wherein R is alkyl, and n is an integer less than 4.
  7. 7. The method for preparing a polyethylene catalyst according to claim 6, wherein the alkoxysilane is selected from any one or more of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetra-isobutoxysilane, tetra-n-pentyloxysilane, and tetraisopentyloxy silane.
  8. 8. The method for preparing a polyethylene catalyst according to claim 1, wherein in step S2, the ratio of the mother liquor to the post-treatment dispersant is 0.01-1.0:1 by mass of the alkyl magnesium to the silicon-based dispersant; the dosage of the titanium-containing compound is 0.0001-0.001mol/g silicon-based dispersing agent, and the alkoxy silane is 1-6:1 according to the mol ratio of the alkoxy silane to the titanium-silicon containing compound. The reaction condition of the mother solution and the post-treatment dispersing agent is that the mother solution is fully stirred and reacted for 0.5 to 25 hours at the temperature of 5 to 50 ℃; The titanium-containing compound is added for reaction under the condition of fully stirring at 5-50 ℃ for 0.5-25h; the condition of adding alkoxy silane for reaction is that stirring is fully carried out for 0.5-3h at 5-50 ℃.
  9. 9. A polyethylene catalyst, characterized in that it is prepared by a process according to any one of claims 1-8.
  10. 10. Use of the polyethylene catalyst according to claim 9 for the polymerization of ethylene in a long residence reaction in an ethylene gas phase polymerization plant.

Description

High-performance polyethylene catalyst and preparation method and application thereof Technical Field The invention relates to the field of polyolefin catalyst preparation, in particular to a high-performance polyethylene catalyst and a preparation method and application thereof. Background Polyolefin materials are one of the most important synthetic materials and play an extremely important role in national economy. The rapid development of the polyolefin industry benefits from the high quality and low cost of polyolefin products on the one hand and from the development and development of high efficiency polyethylene catalysts on the other hand. The first time the organic chemist in the german state Ziegler in 1956 found that the TiCl4/Et3Al system could effectively catalyze ethylene polymerization at lower pressures, and subsequently the italian chemist nating developed this catalytic system for the isotactic polymerization of propylene, butadiene, isoamylene, etc., which catalysts were later referred to as Ziegler-Natta (Ziegler-Natta) catalysts. The catalyst is continuously developed, and a large number of polyolefin products in the market are produced by the catalyst of the system. The Ziegler-Natta catalyst is composed of magnesium compound, titanium compound, different electron donors, organic aluminum compound, etc. Many prior art techniques require the addition of an excess of titanium compound for precipitation treatment in order to precipitate the catalyst or to increase the loading of the titanium compound. The catalyst prepared by the preparation method of the catalyst has unstable performance, and the recycling difficulty and environmental protection problem caused by the large amount of titanium compounds are caused. In addition, in the prior art, titanium trichloride/magnesium chloride and the like are used as effective components to be loaded on silica gel to prepare a supported polyethylene catalyst, but the supported polyethylene catalyst is limited by a production process of titanium trichloride, the titanium trichloride is generally obtained by adopting aluminum/aluminum compounds to reduce titanium tetrachloride in the catalyst preparation process or a commercial product AA titanium trichloride (TiCl 3·1/3AlCl3), and the aluminum trichloride not only affects the loading of the effective components to affect the activity of the catalyst, but also can generate undesirable adhesive resin in the polymerization process. Disclosure of Invention The invention aims to provide a polyethylene catalyst, a preparation method and application thereof, and aims to overcome the problems in the prior art. The aim of the invention can be achieved by the following technical scheme: one of the technical schemes of the invention is to provide a preparation method of a polyethylene catalyst, which comprises the following steps: S1, dispersing a silicon-based dispersing agent in an inert alkane solvent after fluidization treatment, and adding aluminum alkyl to obtain a post-treatment dispersing agent; Mixing inert alkane solvent, alkyl magnesium, alkyl aluminum and monohydric alcohol to obtain mother liquor; S2, dropwise adding the mother liquor obtained in the step S1 into a post-treatment dispersing agent for reaction, adding a titanium-containing compound for continuous reaction, and adding alkoxy silane for continuous reaction to obtain the polyethylene catalyst. In some embodiments, in step S1, the components of the post-treatment dispersant are selected from any one or more of silica gel, silica gel-alumina, silica gel-titania, The inert alkane solvent is selected from any one or more of n-hexane, cyclohexane, hexane and n-heptane; The aluminum alkyl is a compound of the formula R 3-nAlXn, wherein R is alkyl, X is halogen, and n is 0 or an integer less than 3. In some embodiments, the SiO 2 in the silicon-based dispersant is present in an amount of 80 to 100wt% of the silicon-based dispersant. Preferably, the content of SiO 2 in the silicon-based dispersing agent is 94.9-99.9wt%. In some embodiments, the silicon-based dispersing agent can be selected from porous particle-shaped substances, and has proper granularity, specific surface area, pore volume and pore diameter, so that the effective substances are conveniently dispersed and loaded on the silicon-based dispersing agent. Preferably, the silicon-based dispersant is spherical particles having a particle size of 20 to 60 μm (more preferably 35 to 45 μm), a specific surface area of 200 to 600m 2/g (more preferably 280 to 450m 2/g), a pore volume of 0.5 to 3.5mL/g (more preferably 1.0 to 2.5 mL/g), and a pore diameter of 30 to 100 μm (more preferably 20 to 50 μm). In some embodiments, the alkyl aluminum is selected from any one or more of triethyl aluminum, trihexyl aluminum, triisobutyl aluminum, dichloro ethyl aluminum, mono chloro diethyl aluminum. The alkyl aluminum can be the pure product or an inert alkane solution thereof, wherein the inert al