Modification method for inorganic carrier and chromium-based polyethylene catalyst

An inorganic carrier and catalyst technology, applied in the field of chromium-based polyethylene catalysts

Inactive Publication Date: 2018-06-26
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The present invention is a method for preparing a composite inorganic carrier for supporting chromium-based catalysts. T

Method used

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Examples

Experimental program
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Effect test

preparation example Construction

[0033] Preparation of chromium-based catalysts: First, weigh 10 g of inorganic carrier, place it in a fluidized bed with temperature control and electric heating device, and roast it at a certain rate of 600 mL / min under high-purity nitrogen. The gas speed was programmed to increase the temperature to 600 ° C for 4 h. Then it was cooled to room temperature under the protection of high-purity nitrogen and transferred to a glove box for storage. Then, under the protection of dehydrated oxygen nitrogen, transfer about 8g of the baked silica gel carrier to the Schlenk bottle, and then add 150mL of dehydrated oxygen refined n-hexane as a solvent and a certain amount of bistriphenylsilane chromium to the bottle in a nitrogen atmosphere. Ester (BC) was used as a chromium source, and BC was fully loaded on the calcined colloidal silica by continuous stirring at 45°C for 4 hours. Afterwards, the temperature was raised to 80° C. and the solvent was evaporated to dryness under a nitroge...

Embodiment 1

[0036] Inorganic carrier silica with an average particle size of 47 microns and a pore volume of 6.3 cm 3 / g, the surface area is 180m 2 / g, the porous inorganic support obtained by aluminum modification.

[0037] The porous inorganic support was immersed in a hexane solution containing dialkylmolybdenum dithiophosphate for 6 hours, and the temperature was 65°C, and then dried in a nitrogen atmosphere at 200°C for 17 hours. The dried inorganic carrier was placed in a sulfuric acid solution (45% by mass), soaked for 8 hours, and then dried in a nitrogen atmosphere at 100°C for 18 hours; the Mo metal content was determined to be 3.5wt% of the total mass of the carrier. The carrier is used to prepare chromium-based catalysts according to the aforementioned method, and the catalyst is analyzed by the catalyst evaluation method. Wherein, the co-catalyst is triethylaluminum, and the polymerized monomer 1-butene, and the performance of the prepared polyethylene product is as follows...

Embodiment 2

[0039] The inorganic support (a mixture of silica, montmorillonite and zirconia) has an average particle size of 82 microns and a pore volume of 8.2 cm 3 / g, the surface area is 290m 2 / g, the porous inorganic support obtained by titanium modification.

[0040] The porous inorganic carrier was immersed in a xylene solution containing molybdenum alkyl salicylate for 3 hours at a temperature of 55°C, and then dried at 160°C for 19 hours in a nitrogen atmosphere. The dried inorganic carrier was placed in hydrochloric acid solution (mass fraction 18%), soaked for 2 hours, and then dried in nitrogen atmosphere at 300°C for 18 hours; the Mo metal content was determined to be 2.8wt% of the total mass of the carrier. The carrier is used to prepare chromium-based catalysts according to the aforementioned method, and the catalyst is analyzed by the catalyst evaluation method, wherein the cocatalyst is triethylaluminum, and the polymerized monomer 1-butene, and the performance of the pr...

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Abstract

The invention relates to a modification method for an inorganic carrier. The inorganic carrier is modified by using organic molybdenum. The modification method comprises the following steps: immersingthe inorganic carrier into an organic solution containing the organic molybdenum at the temperature of 25-100 DEG C for 1-12h, and then, drying the inorganic carrier in a 100-300 DEG C nitrogen environment for 5-20h; and placing the dried inorganic carrier into a strong acid solution, immersing the inorganic carrier for 2-10h, and then, drying the inorganic carrier in the 100-300 DEG C nitrogen environment for 5-20h, wherein the content of Mo metal accounts for 0.01wt%-5wt% of the total weight of the inorganic carrier. The invention further relates to a chromium-based polyethylene catalyst. Negative charges on molybdenum atoms are capable of increasing the electron cloud density of chromium atoms to increase the reduction speed of Cr (VI), so that the induction time of a chromium-based catalyst is shortened, and meanwhile, the copolymerization property of Cr (VI) is improved.

Description

technical field [0001] The invention relates to a method for modifying a catalyst carrier, in particular to a method for modifying an inorganic carrier for a chromium-based polyethylene catalyst, and the chromium-based polyethylene catalyst. Background technique [0002] As an important species of ethylene polymerization catalysts, chromium-based catalysts were first used in the production of polyethylene. From the original silica gel (SiO 2 ) or silica-alumina (SiO 2 -Al 2 o 3 ) on the loaded chromium oxide catalyst has been successfully studied so far, and it has been found that the preparation method of silica gel and the activation method after loading the chromium-based catalyst can change the relative molecular mass of the product (hereinafter referred to as molecular weight). Supported chromium-based catalysts have been widely used in solution, slurry, and gas phase PE production processes. Hogan and Banks of Phillips discovered CrO for ethylene polymerization in...

Claims

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Application Information

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IPC IPC(8): C08F4/02C08F4/22C08F110/02C08F10/02C08F210/02
CPCC08F10/02C08F110/02C08F210/02C08F4/02C08F4/22
Inventor 张瑞王文燕王立娟杨国兴王华赵兴龙杨琦任鹤和树立孙彬彬李冬霞姜进宪王斯晗高宇新宋磊
Owner PETROCHINA CO LTD
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