Method for preparing catalyst for slurry-process ethylene polymerization process

Abstract

The invention relates to a method for preparing a catalyst for a slurry-process ethylene polymerization process. According to the method, an electron donor is added during the preparation of the catalyst, so that a catalyst support is restored, and the active center is optimized. Thus, the prepared catalyst is high in activity, sensitive in hydrogen regulation, good in copolymerization performance and uniform in particle size distribution and can be applied to the production of products with high melt index and double-peak polyethylene products. The products with high melt index and the double-peak polyethylene products produced by using the catalyst are high in bulk density, good in grain morphology and low in wax content.

Description

technical field

[0001] The invention relates to a preparation method of a catalyst used in a slurry method ethylene polymerization process, in particular to a preparation method of a supported titanium-based polyethylene catalyst. Background technique

[0002] The catalysts used in the production of high-density polyethylene by the slurry process in my country are mostly prepared by imported foreign technology, generally THB, THE, etc., which are usually used for the production of conventional grades of polyethylene such as injection molding, extrusion molding, and blow molding. The activity of the catalyst is low, and the hydrogen adjustment is not sensitive enough. There are certain problems in the production of high-quality polyethylene products. When producing high-end products, it is necessary to purchase a special catalyst from abroad. Jilin Petrochemical's polyethylene unit uses Basell's Z-501 catalyst. No transfer, high price, forming a technical monopoly and restri...

Examples

Embodiment 1

[0054] Under the protection of nitrogen, the raw material Mg(OC 2 h 5 ) 2 10g, 200ml of n-heptane, stir and heat up. At 55°C, add 6ml of diisobutyl phthalate and 3.3ml of tetramethoxysilane, and keep the temperature for 30 minutes. When the temperature reaches 75°C, drop TiCl 4 9.6ml. After the dropwise addition was completed, the reaction was continued for 1 hour. Stop heating and cool down to 50°C naturally. After settling for 15 minutes, draw off the supernatant. Add 100ml of hexane, stir and heat up to 60°C, stop stirring after 30 minutes, stop heating, settle for 1 hour, and take out the supernatant. Repeat the above washing step 5 times. The catalyst suspension is dried to obtain a solid catalyst.

[0055] After the stainless steel reaction kettle with a volume of 2L is fully replaced with nitrogen, add 1L of hexane, 3ml of triethylaluminum, 5mg of the catalyst obtained above and 0.2MPa of hydrogen, heat up to 50°C, feed ethylene, and keep the reaction temperatu...

Embodiment 2

[0057] Under the protection of nitrogen, the raw material Mg(OC 2 h 5 ) 2 10g, 200ml of n-heptane, stir and heat up. At 60°C, add 8.5ml of di-n-butyl phthalate and 1.6ml of methoxytrimethylsilane, and keep the temperature for half an hour. When the temperature reaches 95°C, drop TiCl 4 24.1ml. After the dropwise addition was completed, the reaction was continued for 1 hour. Stop heating and cool down to 50°C naturally. After settling for 15 minutes, draw off the supernatant. Add 100ml of hexane, stir and heat up to 65°C, stop stirring after 30 minutes, stop heating, settle for 1 hour, and take out the supernatant. Repeat the above steps 6 times. The catalyst suspension is dried to obtain a solid catalyst.

[0058] After the stainless steel reaction kettle with a volume of 2L is fully replaced with nitrogen, add 1L of hexane, 3ml of triethylaluminum, 5mg of the catalyst obtained above and 0.2MPa of hydrogen, heat up to 50°C, feed ethylene, and keep the reaction tempera...

Embodiment 3

[0060] Under the protection of nitrogen, the raw material Mg(OC 2 h 5 ) 2 10g, 200ml of n-heptane, stir and heat up. At 55°C, add 8.5ml of di-n-butyl phthalate and 1.6ml of methoxytrimethylsilane, and keep the temperature for half an hour. When the temperature reached 83°C, 178.8 ml of ethyl titanate was added dropwise. After the dropwise addition was completed, the reaction was continued for 1 hour. Stop heating and cool down to 50°C naturally. After settling for 15 minutes, draw off the supernatant. Add 100ml of hexane, stir and heat up to 60°C, stop stirring after 30 minutes, stop heating, settle for 1 hour, and take out the supernatant. Repeat the above steps 6 times. The catalyst suspension is dried to obtain a solid catalyst.

[0061] After the stainless steel reaction kettle with a volume of 2L is fully replaced with nitrogen, add 1L of hexane, 3ml of triethylaluminum, 5mg of the catalyst obtained above and 0.2MPa of hydrogen, heat up to 50°C, feed ethylene, and...

technical field

[0001] The invention relates to a preparation method of a catalyst used in a slurry method ethylene polymerization process, in particular to a preparation method of a supported titanium-based polyethylene catalyst. Background technique

[0002] The catalysts used in the production of high-density polyethylene by the slurry process in my country are mostly prepared by imported foreign technology, generally THB, THE, etc., which are usually used for the production of conventional grades of polyethylene such as injection molding, extrusion molding, and blow molding. The activity of the catalyst is low, and the hydrogen adjustment is not sensitive enough. There are certain problems in the production of high-quality polyethylene products. When producing high-end products, it is necessary to purchase a special catalyst from abroad. Jilin Petrochemical's polyethylene unit uses Basell's Z-501 catalyst. No transfer, high price, forming a technical monopoly and restri...

Examples

Embodiment 1

[0054] Under the protection of nitrogen, the raw material Mg(OC 2 h 5 ) 2 10g, 200ml of n-heptane, stir and heat up. At 55°C, add 6ml of diisobutyl phthalate and 3.3ml of tetramethoxysilane, and keep the temperature for 30 minutes. When the temperature reaches 75°C, drop TiCl 4 9.6ml. After the dropwise addition was completed, the reaction was continued for 1 hour. Stop heating and cool down to 50°C naturally. After settling for 15 minutes, draw off the supernatant. Add 100ml of hexane, stir and heat up to 60°C, stop stirring after 30 minutes, stop heating, settle for 1 hour, and take out the supernatant. Repeat the above washing step 5 times. The catalyst suspension is dried to obtain a solid catalyst.

[0055] After the stainless steel reaction kettle with a volume of 2L is fully replaced with nitrogen, add 1L of hexane, 3ml of triethylaluminum, 5mg of the catalyst obtained above and 0.2MPa of hydrogen, heat up to 50°C, feed ethylene, and keep the reaction temperatu...

Embodiment 2

[0057] Under the protection of nitrogen, the raw material Mg(OC 2 h 5 ) 2 10g, 200ml of n-heptane, stir and heat up. At 60°C, add 8.5ml of di-n-butyl phthalate and 1.6ml of methoxytrimethylsilane, and keep the temperature for half an hour. When the temperature reaches 95°C, drop TiCl 4 24.1ml. After the dropwise addition was completed, the reaction was continued for 1 hour. Stop heating and cool down to 50°C naturally. After settling for 15 minutes, draw off the supernatant. Add 100ml of hexane, stir and heat up to 65°C, stop stirring after 30 minutes, stop heating, settle for 1 hour, and take out the supernatant. Repeat the above steps 6 times. The catalyst suspension is dried to obtain a solid catalyst.

[0058] After the stainless steel reaction kettle with a volume of 2L is fully replaced with nitrogen, add 1L of hexane, 3ml of triethylaluminum, 5mg of the catalyst obtained above and 0.2MPa of hydrogen, heat up to 50°C, feed ethylene, and keep the reaction tempera...

Embodiment 3

[0060] Under the protection of nitrogen, the raw material Mg(OC 2 h 5 ) 2 10g, 200ml of n-heptane, stir and heat up. At 55°C, add 8.5ml of di-n-butyl phthalate and 1.6ml of methoxytrimethylsilane, and keep the temperature for half an hour. When the temperature reached 83°C, 178.8 ml of ethyl titanate was added dropwise. After the dropwise addition was completed, the reaction was continued for 1 hour. Stop heating and cool down to 50°C naturally. After settling for 15 minutes, draw off the supernatant. Add 100ml of hexane, stir and heat up to 60°C, stop stirring after 30 minutes, stop heating, settle for 1 hour, and take out the supernatant. Repeat the above steps 6 times. The catalyst suspension is dried to obtain a solid catalyst.

[0061] After the stainless steel reaction kettle with a volume of 2L is fully replaced with nitrogen, add 1L of hexane, 3ml of triethylaluminum, 5mg of the catalyst obtained above and 0.2MPa of hydrogen, heat up to 50°C, feed ethylene, and...